Lincoln University Digital Thesis Copyright Statement The digital copy of this thesis is protected by the Copyright Act 1994 (New Zealand). This thesis may be consulted by you, provided you comply with the provisions of the Act and the following conditions of use: 
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you will use the copy only for the purposes of research or private study you will recognise the author's right to be identified as the author of the thesis and due acknowledgement will be made to the author where appropriate you will obtain the author's permission before publishing any material from the thesis. THE EFFECT OF IRRIGATION AND TIME OF HARVEST
ON MATURITY, YIELD, AND GROSS RETURN
OF FOUR VINING PEA CULTIVARS.
A thesis
submitted in partial fulfilment
of the requirements for the degree
of
Master of Agricultural Science
in the
University of Canterbury
By
R.E Scott
Lincoln College
1982
Abstract of a thesis submitted in partial fulfilment of the
requirements for the Degree of M.Agr.Sc.
THE EFFECT OF IRRIGATION AND TIME OF HARVEST
ON MATURITY, YIELD, AND GROSS RETURN
OF FOUR VINING PEA CULTIVARS.
By
R.E Scott
Four vining pea (Pisum sativum L.)
cultivars
'Tere',
'Piri',
'Pania',
and
'Greenfeast 68'
(Gf.68) were grown
either with irrigation at start of flowering and pod fill, or
without
(natural rainfall).
Harvesting began once peas
reached tenderometer (TR) 90 and continued daily until TR 140
was
exceeded.
Harvested
samples were threshed in a
mini-viner, and green pea yield, TR and average sieve size
were
measured.
Subsamples
were analysed for alcohol
insoluble solids (AIS), total solids (TS) and weight per pea.
Botanical characteristics,
yield components and total vine
yield were a190 measured.
TR was highly correlated with AIS and found to be a fast
and reliable method for measuring maturity of peas, although
the TR-AIS relationship varied between treatments.
AIS and
TS would be useful methods for measuring maturity when a
tenderometer is not available.
Irrigation prolonged flowering,
delayed harvest,
and
reduced the rate of TR advance during the first four days of
harvest.
Irrigation also prolonged the harvest period for
all
cultivars except Pania.
The effect of
irrigation
treatments on green pea yield was confounded by a period of
heavy rain which caused waterlogging and subsequent yield
depression in irrigated treatments of Piri, Pania, and Gf.68.
In contrast, the pea yield of the natural rainfall treatments
was enhanced by the rainfall.
The heavy rain prevented
measurement of
the differences
in the yield response of
cultivars to irrigation treatments. Total vine yield,
stem
length,
and number of peas per pod were also adversely
affected by waterlogging.
Pea yield of Gf.68 was also
reduced by vining difficulties attributed to the pointed pod
of this cultivar.
Tere, the earliest cultivar, was not adversely affected
by the heavy rain.
Irrigation enhanced green pea yield of
Tere by 20% due to increases in the number of peas per pod
and pods per node.
Yield increased with maturation but the
rate of increase became smaller with advancing maturity. The
curvilinear yield-TR relationship became linear when yield
was plotted against log(TR-75).
Differences in yield-TR
relationships were measured by comparing regressions of
relative yield (yield at TR 105=100) against log(TR-75). The
respective relationships for natural rainfall and irrigated
treatments of Tere were:
Y
Y
= 27.5
= -21.7
+ 49.1 X, and
+ 82.4 X,
where Y = relative yield and X = log(TR-75).
The four cultivars did not differ from each other in
their
yield-TR
relationships
within
each
irrigation
treatment. The yield-TR relationships of Piri, Pania, and
Gf.68,
in contrast to Tere, were unaffected by irrigation,
although the
riod of heavy rain probably influenced these
results.
The gross return-TR relationship was similar for all
cultivar x irrigation treatments, indicating that one payment
scale may be equally applicable to newer cultivars as it is
to older,
less determinate cultivars (e.g. Gf.68). Gross
return was negatively correlated with maturity, and was
highest for peas harvested below TR 100. The smallest gross
returns for most treatments were for peas at TR 120 to 130.
Yield calculated from yield components over-estimated
vining pea yield and was found to be unreliable as a method
for yield prediction.
This was attributed to problems
associated with the early growth stage at which the yield
components were measured.
CONTENTS
PAGE
CHAPTER
1.0 INTRODUCTION •••••••••
e ••••• eo. " ••• " ••••• " • • • • • • • • • • • • •
.1
............................... . • 4
INTRODUCTION •••.• ... . . ... ... ... . . . ....... .. . ...... • 4
2.0 REVIEW OF LITERATURE. "
2.1
2.2 EVALUATION OF PEA QUALITY AND ITS RELATION
TO MATURITy •••••••••••••••••••••••••••••••••••••••• 6
2.3 OBJECTIVE METHODS FOR DETERMINING MATURITY
OF PEAS •••••••••••••••••••••••••••••••••••••••••••• 9
2.4 THE RELATIONSHIP BETWEEN YIELD AND MATURITY
OF GREEN PEAS ••••••••••••••••••••••••••••••••••••• 18
2.5 EFFECT OF IRRIGATION ON YIELD AND MATURITY
............................... .30
AND METHODS • . . .. .... . .... . ... .. ... .. . .. .. .. • 32
TRIAL •••••• . ... ..... . ... .. .. ...... ... ...... • 32
OF GREEN PEAS •••••
3.0 MATERIALS
3.1 FIELD
3.1.1 Trial site . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . 32
................................. .32
............................. . • 34
Sowing ••••
3.1.2 Cu1tivars.
3.1.3
3.1.4 Trial layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
.............................. .36
VINING PROCEDURE . . . . . ..... .. .. .. . ... .38
3.1.5 Irrigation •••
3.2 HARVEST AND
3.2.1 Botanical characteristics and yield
camp 0 n en t s. . . . . . . . . . . . . . .. . . . . . . . .. . . . .. . . . . . . .. 3 8
................. .39
Vining procedure ••
·.................... . .40
Tenderometer readings. ·. . . .. . .. .. ... . .... . . .42
Size grading .••••••••• ·................... . .42
3.2.2 Harvest of vining samples.
3.2.3
3.2.4
3.2.5
3.3 ANALYSIS OF FROZEN PEA SAMPLES •••••••••••••••••••• 44
3.3.1 Correction for dehydration of frozen
peas ............................................. 44
3.3.2 Alcohol insoluble solids (AIS)
determination ....................................... 44
3.3.3 Measurement of total solids (TS)
content .......................................... 45
3.3.4 Measurement of weight per pea ••••••••••••••• 45
3.4 STATISTICAL ANALYSIS OF YIELD-TR RELATIONSHIPS •••• 46
4.0 RESULTS ••••••••••••••••••••••••••••••••••••••••••••
til
••
48
4.1 RELATIONSHIP OF TR TO OTHER MATURITY
ASSESSMENT METHODS •••••••••••••••••••••••••••••••• 48
4.2 PLANT POPULATIONS •••.••••••••••••••••••••••••••••• 54
4.3 EFFECT OF IRRIGATION AND CULTIVAR ON
MATURITY AND YIELD OF PEAS •••••••••••••••••••••••• 55
4.4 EFFECT OF MATURITY ON PEA YIELD, VINE YIELD
AND GROSS RETURN FROM GREEN PEA CROPS ••••••••••••• 60
4.5 EFFECT OF MATURITY ON SIEVE SIZE •••••••••••••••••• 79
4.6 EFFECT OF CULTIVAR AND IRRIGATION ON
BOTANICAL CHARACTERISTICS AND
COMPONENTS OF YIELD ••••••••••••••••••••••••••••••• 82
4.7 PREDICTION OF YIELD FROM YIELD COMPONENTS ••••••••• 88
5.0 DISCUSSION •••••••••••••••••••••••••••••••••••••••••••• 90
5.1 MEASUREMENT OF MATURITY ••••••••••••••••••••••••••• 90
5.2 EFFECT OF IRRIGATION AND CULTIVAR ON
MATURITY, YIELD AND YIELD COMPONENTS •••••••••••••• 94
5.3 EFFECT OF MATURITY ON PEA SIZE ••••••••••••••••••• I03
5.4 THE EFFECT OF MATURITY ON YIELD OF VINING PEAS ••• I04
5.5 EFFECT OF MATURITY ON GROSS RETURN
FROM PEA CROPS ••••••••••••••••••••••••••••••••••• 110
5.6 RELATIONSHIP BETWEEN OBSERVED AND PREDICTED
YIELD OF PEAS •••••••••••••••••••••••••••••••••••• 113
6.0 CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
ACKNOWLEDGEMENTS ••••••••••••••••••••••••••••••••••••••••• 120
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
APPEND ICES ....................................................... 133
APPENDIX 1 RAINFALL AND TEMPERATURE DATA OVER
THE TRIAL PERIOD •••••••••••••••••••••••••• 133
APPENDIX 2 DETAILS FOR SOWING WITH STANHAY
PRECISION SEED DRILL •••••••••••••••••••••• 137
APPENDIX 3 SOIL MOISTURE CHANGES OVER THE
FLOWERING AND HARVEST PERIOD •••••••••••••• 138
APPENDIX 4 TR-PAYMENT SCALE FOR 1979/80 SEASON ••••••• 140
APPENDIX 5 FIELD RESULTS ••••••••••••••••••••••••••••• 141
APPENDIX 6 MATURITY RESULTS •••••••••••••••••••••••••• 149
APPENDIX 7 'CORRELATION MATRICES FOR MATURITY TESTS ••• 15?
LIST OF TABLES
PAGE
TABLE
2.3.1
Chemical methods for measuring maturity
of green peas .............................................. 10
2.3.2
Physical methods for measuring maturity
of green peas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3.3
Experimental instruments for measuring
maturity of green peas •••••••••••••••••••••••••••• 13
2.3.4
Commercial instruments for measuring
maturity of green peas •••••••••••••••••••••••••••• 14
3.1.1.1 Agronomic and maturity details of
cu1tivars used in this trial •••••••••••••••••••••• 33
3.2.5.1 Sieve size grades for green peas •••••••••••••••••• 42
4.1.1
Maturity parameters for Tere at each harvest •••••• 48
4.1.2
Maturity parameters for Piri at each harvest •••••• 49
4.1.3
Maturity parameters for Pania at each harvest ••••• 49
4.1.4
Maturity parameters for Gf.68 at each harvest ••••• 50
4 .1.5
Coefficients of correlations of AIS and TR
with other tests for maturity of peas ••••••••••••• 51
4.1.6
Coefficients of correlations between harvest
number and tests for maturity of peas ••••••••••••• 51
4.1.7
Regression equations of TR against AIS •••••••••••• 52
4.1.8
AIS values corresponding to TR 90, 105, and 140 ••• 53
4.2.1
Plant popu1ations ••••••••••••••••••••••••••••••••• 54
4.3.1
Flowering times for each treatment •••••••••••••••• 55
4.3.2
Mean TR at each harvest of all treatments ••••••••• 58
4.3.3
Predicted green pea yield at TR 105 and
response to irrigation •••••••••••••••••••••••••••• 59
4.4.1
TR, yield parameters, and gross return at
each harvest for Tere ••••••••••••••••••••••••••••• 61
4.4.2
TR, yield parameters, and gross return at
each harvest for piri •••••••
4.4.3
0
• • • • • .0
•••••••••••••••
61
TR, yield parameters, and gross return at
each harvest for Pania •••••••••••••••••••••••••••• 62
4.4.4
TR, yield parameters, and gross return at
each harvest for Gf.68 •••••••••••••••••••••••••••• 62
4.4.5
Regression equations for green pea yield
against log(TR-75) •••••••••••••••••••••••••••••••• 65
4.4.6
Regression equations for relative yield
against log(TR-75) •••••••••••••••••••••••••••••••• 70
4.4.7
Coefficients of correlation for gross return
/
with yield, TR, and harvest number •••••••••••••••• 78
4.5.1
Coefficients of correlation for average sieve
size wi'th yield, TR, and harvest number ••••••••••• 79
4.6.1
Botanical characteristics for each cultivar ••••••• 82
4.6.2
Components of yield for each cu1tivar ••••••••••••• 83
4.6.3
Number of pods at each fertile node ••••••••••••••• 84
4.6.4
Number of peas/pod at each fertile node ••••••••••• 85
4.6.5
Number of peas at
4.6.6
Percentage of peas at each fertile node ••••••••••• 87
4.7.1
Green pea yield (peas/m2) at TR 105 ••••••••••••••• 89
4.7.2
Comparison of predicted and observed yield
~ach
fertile node ••••••••••••••• 86
at TR 105 .••.•••••••••••••••••••••••••.•..•••••••• 89
5.4.1
Comparison of relative yields from several
sources, at TR 90, 105, and 140 •••••••••••••••••• 108
Al.1
Monthly rainfall and temperature data for
the months including the trial period •••••••••••• 133
Al.2
Temperature and rainfall data for Nov. 12 to
31, 1979 •••••••••••••••••••••••••••••••.••••••••• 134
AI.3
Temperature and rainfall data for Dec. 1979 •••••• 135
Al.4
Temperature and rainfall data for Jan. 1980
and Feb. 1 to 4, 1980 •••••••••••••••••••••••••••• 136
A2.l
Sowing details for field trial ••••••••••••••••••• 137
A4.l
Watties TR-payment scale for the South Island,
1979/80 season ••••••••••••••••••••••••••••••••••• 140
AS.l
Field results for Tere (natural rainfall) •••••••• 141
AS.2
Field results for Tere (irrigated) ••••••••••••••• 142
AS.3
Field results for Piri (natural rainfall) •••••••• 143
AS.4
Field results for Piri (irrigated) ••••••••••••••• 144
AS.5
Field results for Pania (natural rainfall) ••••••• 145
AS.6
Field results for Pania (irrigated) •••••••••••••• 146
AS.?
Field results for Gf.68 (natural rainfall) ••••••• 14?
AS.8
Field results for Gf.68 (irrigated) •••••••••••••• 148
A6.l
Results of maturity measurements on Tere
( natural rainfall) •••••••••••••••••••••••••••• ~ •• 149
A6.2
Results of maturity measurements on Tere
( i rriga ted) •••••••••••••••••••••••••••••••••••••• 150
A6.3
Results of maturity measurements on Piri
(natural rainfall) ••••••••••••••••••••••••••••••• 151
A6.4
Results of maturity measurements on Piri
(irrigated) •••••••••••••••••••••••••••••••••••••• 152
A6.S
Results of maturity measurements on Pania
(natural rainfall) ••••••••••••••••••••••••••••••• 153
A6.6
Results of maturity measurements on Pania
(irrigated) . . • . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . 154
A6.?
Results of maturity measurements on Gf.68
{natural rainfall) •••.•••.•••••••••••••..•••••••• l55
A6.8
Results of maturity measurements on Gf.68
(irrigated) •••••••••••••••••••••••••••••••••••••• l56
A7.l
Matrices of coefficients of correlation
between maturity tests and harvest number
for both irrigation treatments of Tere ••••••••••• l57
A7.2
Matrices of coefficients of correlation
between maturity tests and harvest number
for both irrigation treatments of Piri ••••••••••• l57
A7.3
Matrices of coefficients of correlation
between maturity tests and harvest number
for both irrigation treatments of Pania •••••••••• l58
A7.4
Matrices of coefficients of correlation
between maturity tests and harvest number
for both irrigation treatments of Gf.68 •••••••••• 158
LIST OF FIGURES
FIGURE
PAGE
3.1.1.1 Visual differences between cultivars ••••••• facing 33
3.1.4.1 Aerial photograph of trial site showing
trial layout ••••••••••••••••••••••••••••••• facing 36
3.2.2.1 Sampling frame used to mark out sampling
area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . facing 39
3.2.2.2 Section of trial site from where plot
samples have been harvested •••••••••••••••• facing 39
3.2.3.1 The DSIR mini-viner ••••••••••••••••••••••••••••••• 41
4.3.1
Relationship between TR and harvest number •••••••• 56
4.3.2
Relationship between log(TR-75) and harvest
n umbe r .....••...•..••....•.••.••.•......•.•..•.•.. 57
4.4.1
Relationship between green pea yield and TR
for natural rainfall treatments ••••••••••••••••••• 63
4.4.2
Relationship between green pea yield and TR
for irrigated treatments •••••••••••••••••••••••••• 64
4.4.3
Relationship between green pea yield and
log(TR-75) for natural rainfall treatments •••••••• 66
4.4.4
Relationship between green pea yield and
log(TR-75) for irrigated treatments ••••••••••••••• 67
4.4.5
Relationship between yield and TR for
natural rainfall treatments with fitted
line from yield-log(TR-75) regression ••••••••••••• 68
4.4.6
Relationship between yield and TR for
irrigated treatments with fitted line
from yield-log(TR-75) regression •••••••••••••••••• 69
4.4.7
Relationship between relative yield and
log(TR-75) for natural rainfall treatments •••••••• 7l
4 .4.8
Relationship between relative yield and
log(TR-75) for irrigated treatments ••••••••••••••• 72
4.4.9
Relative yield-log(TR-75) relationship
for all treatments (comparison of the
fitted lines) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
4.4.10
Relative yield-TR relationship for all
treatments (comparison of the fitted lines) ••••••• 75
4.4.11
Gross return-TR relationships ••••••••••••••••••••• 77
4.5.1
Changes in the proportion of peas in each
size grade of natural rainfall treatments
during maturity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
4.5.1
Changes in the proportion of peas in each
size grade of irrigated treatments during
maturity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Al.l
Daily rainfall and mean daily temperature
over the flowering and harvest period •••••••••••• 133
A3.l
Soil moisture changes for Tere and Piri
over the flowering and harvest period •••••••••••• 138
A3.2
Soil moisture changes for Pania and Gf.68
over the flowering and harvest period •••••••••••• 139
CHAPTER
1
INTRODUCTION
PAGE 1
CHAPTER 1
INTRODUCTION
Vining peas are those harvested at the green
by
mechanical
viners
preserved, mainly
dehydration.
by
Peas
and
are
one
appearence,
crop,
but
also
by
canning,
occupying
or
of the vegetable products most
freezing,
as
they
retain
their
flavour and nutritive value well (Martin,
In New Zealand they are the most important
1977)~
stage
pickers, then processed and
freezing,
successfully preserved by
fresh
pod
pea
approximately
10,000
vegetable
hectares each season
(MAP, 1980).
All vining peas are classified as Pisum sativum L.,
in
N.Z.
only
the
grown for processing.
wrinkled
but
seeded (garden pea) types are
Elsewhere
both
wrinkled
and
round
seeded types of this species are grown for vining, the latter
type mainly for canning (Gane,
N.Z.,
King
and
Gent,
1971).
In
because only a very small proportion of the vining pea
crop is canned (MAP, 1980) special canning cultivars are
not
grown for this purpose, and freezing cultivars (usually ,at an
advanced maturity) are canned
comm~).
To
obtain
instead
maximum
season, the use of a range
pea
of
(M.J.Crampton,
production
cultivars,
pers.
throughout
which
differ
a
in
maturity and other agronomic attributes, is often recommended
(Wraight, 1976).
being
bred
and
current use (eg.
quality etc.).
Improved
introduced
cultivars
with
higher yield,
are
also
advantages
disease
constantly
over those in
resistance,
better
PAGE 2
The
yield
maturity
of
green
peas
generally
growers
is
based
1974a).
Payment
quality.
Theoretically
and
gross
return
should
regardless of the stage at
country
the
and
poorer
the increase in yield of a crop
should compensate for the lower price ,paid
peas,
to
on a graduated scale where price per
unit weight decreases as peas become more mature
in
with
over the harvest period, but at the same time their
quality decreases (Anderson and White,
pea
increases
which
for
more
mature
remain relatively constant
it
is
harvested. In this
maturity of peas, on which payment is based, is
measured by a tenderometer, with
tenderometer
reading
(TR)
increasing with maturity (Martin, 1937).
Fulfilment of the concept of equal gross return
on
a
close
relationship
between the payment scale and the
changes in yield with maturity.
become
concerned
experience
with
app~icab1e
to
that
the
obselete
modern
1977).
Furthermore,
differ
in
payment
pea
growers
scale
and
is
is
have
based
no
on
longer
determinate) cultivars (Anon.,
is
belief
that
cultivars
may
rate
of maturity, and their rate of yield
increase with maturity.
If this is so, one payment scale may
not
be
their
Recently
cultivars,
(more
there
depends
suitable
for
application to the range of cultivars
which may be grown over a season (Wraight, 1976).
One previous study in Canterbury examined the effect
maturity
on green pea yield, and found that irrigation had a
significant effect on the relationship (Anderson
1974a).
of
The
and
White,
cultivar used however, is now obselete in this
district, and the relationships found may not be relevant
to
PAGE 3
more
modern
cu1tivars.
This
project
was
undertaken
to
increase the understanding of yield-maturity relationships of
vining peas by studying several modern cu1tivars.
To achieve
this four main objectives were set:
1. to examine the reliability of TR as a method for measuring
maturity
of
green
insoluble
solids
peas,
(AlB)
by
and
comparison
several
with
other
alcohol
maturity
parameters;
2. to study the effect of harvest time on maturity and
of
different
pea
yield
cu1tivars, and to compare the yie1d-TR
relationships of different cu1t.ivars;
3. to
examine
relationships;
4. to
compare
different
the
effect
the
of
irrigation
on
these
and
the
gross
returns
for
each
treatment
at
stages of maturity, to test the assumption that
payment
scale
ensures
similar
irrespective of the stage of harvest.
gross
returns,
CHAPTER
2
REWIEW OF LITERATURE
PAGE 4
CHAPTER 2
REVIEW OF LITERATURE
2.1 INTRODUCTION
The relationship between yield and maturity
different
garden
this study.
processing
This
relationship
is
important
know
what
the
associated
with
It
is
quality
essential
of
difficult
quality,
their
to
which
maturity, are therefore measured instead.
between
to
the
pea
industry, because yield tends to increase as peas
although quality per se is
Factors
several
pea cultivars is the principal interest of
mature, but quality decreases.
processors
of
quality
that
pea
product
is,
measure
also
The
directly.
change with
relationship
and maturity will be reviewed here briefly,
because it is on the basis of this
relationship
that
tests
for maturity are used to estimate pea quality_
Considerable effort has subsequently been applied to the
development
of
simple
and
reliable
measuring the maturity of green peas.
objective methods for
Many studies have also
been undertaken to test the reliability and practicability of
these methods, both for measuring maturity and for estimating
pea
quality.
Many of the published methods for testing the
maturity of peas,
and
evaluation
of
them,
will
also
be
briefly reviewed.
Because quality and maturity are negatively
the
stage
of
maturity
coinciding with optimum pea quality
usually differs from the stage
Some
compromise
must
correlated,
when
maximum
yield
occurs.
therefore be made between quality and
PAGE 5
yield when deciding at which stage a crop wi.ll be
Numerous
studies
into
the yield-maturity relationship have
consequently been carried out, essentially
optimum
stage
at
which
aspect will be reviewed in
relationshi.p
harvested.
a
to
identify
crop should be harvested.
some
depth,
since
it
is
the
This
this
which is central to the practical applicability
of this study.
Finally, it has been found that soil moisture conditions
may
alter
crops,
soil
irrigation,
the
yield-maturity relationship.
moisture
is
often
under
some
In process pea
control
by
so the affect of irrigation on this relationship
will also be reviewed briefly.
PAGE 6
2.2. THE EVALUATION OF PEA QUALITY AND ITS RELATION TO
MATURITY.
Quality
in
peas
is
influenced
by
several
factors
including varietal differences, size, maturity (especially as
it affects tenderness), colour, and flavour
Guyer
and
Ide, 1950).
(Kramer,
Scott,
Measurement of pea quality, however,
is highly subjective, and is usually assessed by organoleptic
(sensory) methods, often involving an experienced taste panel
(Ottosson, 1958).
influenced
by
The results of such an evaluation
how
Bureau
of
Agricultural
consisted, of 100 points divided thus:
maturity, 35;
the
or
weighted.
(1935) reported that the standard scoring method for
canned peas used by the
USDA,
be
it was conducted, who took part, and how
the various components of "quality" are scored
Kertesz
may
can),
flavour, 25;
15;
absence
of defects, 15;
Blanchard and
used
system:
following
tenderness and
clearness of liquor (ie syrup in
size and colour, 10.
the
Economics,
and uniformity of
Maxwell
flavour,
colour and appearence (together), 15;
(1941)
40;
size,
however
texture,
10;
and
30;
form
(roundness and uniformity of shape), 5.
The
different
difference
quality
in
consumer
surveys
(1950) referred to
principal
could
clearly
produce
scores for the same material tested under
the different systems.
on
weighting
Attempts to base
may
one
determinant
which found that flavour
also
survey
of
pea
was
quality
be confusing.
which
found
quality,
most
Kramer et al.
size
was
the
and another survey
important,
texture, colour, and size, in that order.
assessment
followed
by
PAGE 7
The
relationship
examined
by
between
Kertesz
maturity
(1935),
and
quality
was
who found that the scores for
tenderness and maturity from standard USDA organoleptic
were
linearly
total score.
measuring
related
He
test
to the score for flavour, and to the
concluded
that
an
objective
method
for
tenderness and maturity therefore should also give
an objective assesment of quality.
Makower
maturity
(1950)
and
found
quality
meaning
the
relationship
between
in peas was confused because the term
"maturity" had two dif
traditional
that
rent meanings.
(a
stage
of
In
addition
to
physiological ripeness),
maturity in peas may also be a component of quality.
latter
sense,
maturity
affected not only
genetic
by
is
In
the
primarily a textural component,
stage
of
development,
but
also
by
and cultural factors, and changes during processing.
Makower also
physical
showed
quality
that
taste
ripening
of
peas.
panels
Makower,
easiest
and
were
maturity
primary
appraisals.
changes
measures
to
detect
for
skin
texture
in
maturity
during
are
so
closely
scores
organoleptic
This may also explain why organoleptic
physiological
in
Boggs, Burr and Olcott (1953)
confirmed this, finding cotyledon
the
found
components (eg starchiness, skin toughness
anq firmness of cotyledons) were
and
its
quality,
linked,
and
reliable
and
sometimes confused.
Many studies have been undertaken to find
simply
applied objective methods of assessing pea quality by
measuring the physiological maturity of peas {Makower et
1953;
Lee,
Whitcombe
and
Hening,
1954;
and
al.
Torfason,
PAGE 8
Nonnecke
and
Strachan,
1956).
Organoleptic
appraisal
remained the ultimate accepted reference method, however, for
determining quality in peas,
(Makower,
Lynch, Mitchell and Casimir, 1959).
1950~
Ottosson, 1958;
PAGE 9
2.3. OBJECTIVE METHODS FOR DETERMINING MATURITY OF PEAS
The
importance
of
method
for
objective
finding
a
determining
reflected in the number and range
To
be
useful,
an
reliable
objective
of
test
maturity
must
with
be
peas
is
developed.
either
or
be
well
highly
an objective test which is recognised to be
well correlated with
1950;
simple
in
techniques
correlated with organoleptic quality itself;
correlated
and
Makower
et
organoleptic
al.
1953;
quality
(Kramer
Lee et al. 1954;
et
al.
Voisey and
Nonnecke, 1973a).
The various methods have been
how
the
peas
are
treated,
as
mechanical or morphological.
however,
and
classified
according
to
either chemical, physical,
The classification is arbitrary
some methods may fall into more than one group
depending on the classifier's viewpoint.
The chemical methods,
principle
that
in
maturing
general,
peas
are
undergo
based
on
the
biochemical
and
histological changes during development (Boswell, 1924, 1929;
Bisson
and
Jones,
1932;
McKee, Robertson and Lee, 1955).
The amount of a particular component
should
therefore
indicate
that
in
pea's
a
relative
maturity.
Most chemical tests for maturity
or
and
slow,
2.3.1).
some
require
laboratory
pea
are
at
harvest
stage
of
complicated
facilities
(Table
Table 2.3.1 Chemical methods used for measuring maturity of green peas.
Method
Principle
Source
Comments
Source
Total solids
(T.S.)
(Dry matter)
Less water in
more mature
peas.
Kertesz
(1934,1935).
Simple, well
correlated with
other tests, less
reliable than AlS.
Neilson et ale (1947),
Makower et ale (1953),
Lee et ale (1954),
Torfasonet
ale
-(1956).
Water insoluble
solids
More water
soluble solids
in immature peas.
Bonny and
Palmore
(1934).
Slow, but more
accurate than TS,
not widely used.
Bonney and
Palmore (1935),
Kertesz (1935) •
Alcohol
insoluble
solids (AlS)
AlS higher in
more mature
peas.
Kertesz
(1934,1935).
Slow, but very
highly correllated
with organoleptic
tests.
Bonney and Rowe
(1936),
Kramer et ale (1950),
Makoweretal. (1953),
Torfasonetal. (1956),
Adam and Brown
(1948).
Sugar content
More sugar in
younger, less
mature peas.
Blanchard
and
Maxwell (1943) •
Slow and
unreliable.
Makower (1950),
Danielson (1959).
Starch content
higher starch
content in more
mature peas.
Neilsen (1953),
Neilsen and
Gleason (1945).
Slow, impractical
for general use,
varies with cv.
Lee et al.(1954),
Torfasonet al.(1956),
Ottosson (l958) •
Refractive
index of
pea juice
soluble solids
in pea juice
(mainly sugars)
decrease with
maturity.
Lynch and
Mitchell
(1950) •
Simple but
unreliable.
Lynch et al.(1959).
I
'tI
:.:G)
tr:I
~
o
PAGE 11
Physical methods (Table 2.3.2) are usually simple
which
measure
tests
physical characteristics of a sample of peas,
from which its stage of maturity can be determined.
Because
they are non-destructive some physical methods have also been
used to
separate
peas
into
quality grades
(e.g. specific
gravity, and pea size).
The mechanical methods involve the use
of
a
specially
designed
instrument
to measure some physical characteristic
of peas.
Tests
normally
destructive.
are
rapid,
simply
applied,
and
Most of the mechanical tests have not developed
beyond the laboratory or experimental stage (Table 2.3.3).
few,
however,
have
A
proven sufficiently reliable to achieve
commercial adoption (Table 2.3.4).
Morphological methods for estimating maturity
an
aid
for
field
~thod,
Schippers (1965b, 1969) developed
The
method
tenderness
was
of
the
methods
with
themselves.
they
when
more
for measuring maturity were not available.
Schoonens (1971) recommended
method,
peas
highly correlated with alcohol
insoluble solids (AlS) content, and could be used
standard
a
by which all pods on a plant were scored on
their appearance, and on the
contained.
more
assessment of maturity, than a method of
estimating pea quality.
"visual"
are
more
a
"tactile"
modification
inspection
to
of
Schipper's
the
peas
Table 2.3.2 Physical methods for measuring the maturity of green peas.
,
Method
Principle
Comments
Source
Brine flotation
specific gravity
relative density
Peas become less
dense with maturity
and float in known
concentration of
brine.
Shook (1931),
Walls and
Hunter (1937),
Lee (1941),
Martin (1944).
Reliable and may
be used for
quality grading
Boggs et ale
(1942),
Adam and
Dickinson
(1945) ,Adam
(1947),Adam
and Brown
(1948) •
Size grading
sieve grading
Peas become larger
with maturity and
can be screened
into size grades
Bosswell,
(1924,1929),
Boggs et ale
(1942)-. -
Unreliable because
pea size varies with
cultivar and growing
conditions of plant.
Makower
(1950),
Lynch et ale
(1959) •
Viscosity
Viscosity of pureed
peas increases with
maturity.
Elehwany and
Kramer (1956),
Adam (1957).
Simple, generally
Well correlated
with chemical
maturity tests.
Elehwany
and Kramer
(1956),
Adam (1957).
Weight per pea
(or per 100 or
1000 peas)
individual peas
become heavier
with maturity.
Lynch and
Mitchell
(1953).
Unreliable,similar
problems to size
grading.
Makower
et ale (1953),
Ottosson
(1958),
Lynch et ale
(1959) •
------
~--
-
-
----
-
--
-----
-
-
Source
-
-
I
- - -
"'C
:P
G:
tr
I-
'"
PAGE 13
Table 2.3.3 Experimental instruments for measuring maturity
of peas
Ins trument
Method and principle
Source
Pea Crusher
Measures resistance of
peas to crushing. More
mature peas are firmer.
Sayre et al(1931),
H0 r s fa 11 eta 1.( 19 3 2 ) ,
Boggs et al.(I943),
Adam and DIckinson
(1945), Adam (1947),
Adam and Brown
(1948).
Penetrometer
A metal probe measures
the force required to
penetrate pea skins.
Sayre et al(1931),
Boggs et al ..
(1942,1943).
Succulometer
Measures amount of
juice expressed from
a measured sample
of peas.
Lynch and
Mitchell (1950).
Shearometer
sample of peas raised
into a set of blades.
Similar to shearpress
and tenderometer
(Table 2.3.4) but
hand operated and
transportable.
Lynch and
Mitchell (1950).
Miniature
tend e rome t e r
Same principle as
tenderometer, but
compact and hand
opera ted, and
less reliable.
Kramer et ale
-(1950) •
Single pea
maturometer
Same principle as
maturometer but only
tests one pea each
run.
Casimir and
Moye r (19 68 ) •
Ottawa pea
tenderometer
Electronically
measures the force
needed to drive a
sample of peas
through a wire
grid.
Voisey and
Nonnecke (1973b),
Atherton and
Gaze (1980).
Table 2.3.4 Commercial instruments.used for measuring the maturity of green peas.
Comments
Source
Instrument
Principle
Source
Tenderometer
(Martin or FMC
tenderometer)
Measures shear force
needed to drive a set
of moving blades
through a sample of
peas (in p.s.i.).
Martin (1937).
Highly correlated
with organoleptic
and AIS evaluation,
simple and fast.
Walls and Hunter
(1937),
Martin et al.
(1938), a n d
many others
(see text) •
Textu reme ter
(Texturometer)
Measures the
resistance offered
by a sample of peas
to the passage of
25 (5mm) steel pins.
Cristel(1938),
cited by
Kramer et ale
(1950) •- -
Hand operated,
compact and fast,
difficult to
maintain
accuracy.
Torfason et al.
-(1956),
Voisey and
Nonnecke
(1973a).
Maturometer
Measures resistance
of 143 peas to the
passage of one 3mm
steel pin through
each.
Lynch and
Mitchell
(1950) •
Well correlated to
other tests, slower
than tenderometer,
hand operated.
Adam and Holt
(1953),
Sayre (1954) •
Shear press
(Kramer
shear press,
Qualitometer)
Similar to the
tenderometer, tests
res is tance to a set
of blades forced
into a sample of
peas.
Kramer et al.
-(195l),cited
by Torfason
et
ale (1956).
--
Reliable, more
compact than
tenderometer.
Torfason et ale
-(1956),
Ottosson
(1968).
Hardness
meter
Measures the force
needed to drive a
sample of peas
through a brass grid.
Doesburg and
Grevers(1952),
cited by
Lynch et ale
(1959).
Hand operated and
transportable,
but not very
reliable.
Voisey and
Nonnecke
(1973a).
>t:
:t:
C;
t<
I
...
,j:
PAGE 15
Many experimental studies were undertaken to compare the
reliability,
practicability
and
efficiency
of the various
methods for estimating pea maturity and quality, often
an
organoleptic
analysis
as
a
reference
point.
using
The AlS
method has been commended repeatedly as the objective
method
closest to organoleptic tests, with high correlations between
AlS and taste panel data reported by Lee (194la),
ale
(1950)
and Makower et al.(1953).
Kramer
et
AlS thus became firmly
established as an objective method with which other objective
methods may be compared to test their r~liability.
These workers also showed that the
reliable
machine
for
measuring
tenderometer reading (TR) closely
organoleptic
tests.
Several
tenderometer
maturity
of
correlated
studies
peas,
with
also
was
a
with
AlS
and
examined
the
relationship between AlS and TR by regression analysis.
The
relationship:
y = -6.15 + 0.24 X -0.00045 X2
was found for cv.'Alaska' peas, where Y= AlS and X= TR (Walls
and
Kemp
14.1%.
1939).
At
TR 105 for example, AlS was therefore
Lee et ale (1954) pooled data from six
cultivars
and
derived an average relationship:
AlS = -0.49 + (0.1252 x TR).
TR 105 was thus equal to 12.7% AlS.
was
analysed
by
Weckel
and
Three years
Kuesel
following relationships for Alaska and
trial
data
(1955), who found the
cv.'Perfection'
peas
respectively:
where
Y=
AlS,
y
= -3.07 + 0.144 X, and
y
=
and
-1.58 + 0.120 X,
X=
TR.
The
respective
AlS
values
PAGE 10
equivalent
to
TR
105
for
approximately 11 and 12%.
those
of
Adam
Perfection and Alaska peas were
These
(1957).
results
were
similar
to
From data collected from two years
trials, Adam found that AIS = 11.7% at TR 105,
according
to
the relationship:
x
= -1.1 + 0.122 Y,
where X = AIS, and Y = TR.
The
texturemeter
estimates,
and
has
has
also
given
It
maturity
been highly correlated with AIS, TR and
organoleptic results (Kramer et ale
1956).
reliable
1950;
Torfason
et
ale
also had the advantage of compactness, lightness
and portability, but did not become widely used, possibly due
to
difficulty
maintaining
the
system on which it depended
integrity
(Voisey
and
of
the hydralic
Nonnecke,
1973a).
Close correlation between the maturometer index (M.I.) and TR
has also been demonstrated, in England (Adam and
Adam,
1955)
and
in
maturometer has only
where
it
was
by
TR and M.I.
replicate
been
developed
Nonnecke, 1973a).
studied
the
U.S.A.
used
(Lynch
also
(Sayre,
1954),
extensively
in
Australia,
1959;
Voisey and
et
ale
The relationship between M.I.
was
reading
very
high
(r=0.995)
but
and TR
variations
the
was
in
from the maturometer for any given sample
TR
for
the
same
material.
showed that the correlation between AIS and M.I.
was high (r=O.91) but that for AIS v TR was higher
The
but
Sayre (1954), who found that correlation between
were higher than variations in
Sayre
Holt, 1953;
maturometer
(r=O.96).
was also prone to more cultivar variability
than the tenderometer or the texturemeter (Sayre, 1954).
PAGE 17
Apart from AIS, no other chemical methods became
Total
adopted.
solids
analysis, which was simply applied,
gave results which were well correlated with those
(Makower,
methods
Torfason,
1950;
et
of
other
ale 1956).
AIS,
however, was generally considered to be a much more
estimate
of
maturity,
although
it
was
difficult to measure (Makower et ale 1953;
The
widely
reliable
technically
more
Lee et ale 1954).
starch method was cumbersome and subject to error due to
changes in starch composition during maturity,
with cultivar (Kramer et al.1950;
1954).
was
Makower, 1950;
varied
Lee et ale
ottosson (1958) found that the starch content of peas
also
affected
by
environmental conditions.
method (Blanchard and Maxwell,
because
sugars
are
very
1941)
labile
was
also
very slow (Ottosson,1958).
The sugar
unreliable,
before blanching, and are
highly diffusable thereafter (Makower, 1950).
also
which
The method was
Other chemical methods have
been tried and rejected, including carotene and ascorbic acid
content
Peterson
(Pollard,
and
amylose/amylopectin ratio (Adam and Brown,
Guggolz,
Silviera
et al.1953), and
Lynch et al.1959;
1948;
be
a
maturity.
standards,
others
(Makower,
1950;
Ottosson,
1958;
Voisey and Nonnecke, 1973a).
has
proved
relatively reliable physical method for estimating
It has been the basis of the USDA offical
and
was
highly
correlated
organoleptic tests (Lee, 1941a,
Brine
McCready,
and Owens, 1950) amylose content (Makower
Specific gravity testing by brine flotation
to
1944),
Wilcox,
flotation
has
also
been
1941b;
with
Lee
TR,
et
grading
AIS, and
ale 1954).
used to separate peas into
different maturity grades (Martin, 1944).
PAGE 18
2.4.
THE RELATIONSHIP BETWEEN YIELD AND MATURITY
OF GREEN PEAS
The effect of
studied
maturity
on
yield
of
peas
was
by Boswell (1924), who investigated chemical changes
during ripening of pea
increased
seeds.
Although
dry
matter
yield
throughout maturation, sugar yield rose to a peak,
then fell sharply.
Boswell' recommended
immediately
they
the
green
after
sugar
content
peas
be
harvested
reached marketable size, and before
decreased.
Bisson
and
Jones
(1932)
undertook a similar investigation, mainly into changes in the
carbohydrate components of pea seeds,
important
for
determination
believing
of pea quality.
these
most
Like Boswell,
they concluded that green peas should be harvested once their
sugar
content
(per
pea)
had reached a maximum, and before
total sugar yield (per unit area) fell.
by
McKee
Turner
et
and
ale
Lee
physiological
was
confirmed
(1955), Turner and Turner (1957), Turner,
(1957)
and
Danielson
(1959),
whose
studies showed that the changes in pea flavour
during maturity were related not only to
content,
This
decrease
in
sugar
but also to a marked increase in the starch content
of the developing peas.
The influence of stage of
quality
ale
on
the
yield
and
of Perfection peas was studied In Utah by Pollard et
(1944).
including
maturity
Quality
was
measured
by
several
indices,
the tenderness (TR), and starch, ascorbic acid and
carotene content.
Plots were harvested over nine
successive
days, starting at a very immature stage (TR 83) and finishing
at TR 165.5.
from
Over that period, average pea
yield
increased
3.6 T/ha to 7.26 T/ha and starch content increased from
PAGE 19
2.6 to 6.3%, while moisture content decreased
from
81.9
to
75.7% •
The
study
cv.'Early
continued
Perfection'
Peterson, 1947).
the
two
was
for
two
further
included
seasons
(Pollard,
and
wilcox
and
The yield and the yield-TR relationship
were
cultivars
very
similar,
although
Early
Perfection had a slightly higher rate of yield increase
Perfection.
The
rate
of
than
of change in TR, starch content, and
total solids for each cultivar, and in each season, were also
quite
similar.
The yield-TR relationship of both cultivars
changed as maturity progressed, with proportionately
increases
in
yield at higher TR.
smaller
The rate of TR change per
day increased during maturation.
Peas from each harvest
small,
grades:
were
into
high quality peas (grade l);
average quality peas (grade 2);
(grade 3).
divided
three
size
medium sized,
and large, poor quality peas
In both cultivars, the proportion of grade 1 peas
decreased rapidly during maturity, and grade 3 peas increased
rapidly, while grade 2 peas steadily decreased, although more
slowly in Perfection than in Early Perfection (Pollard et ale
1947).
The
peas
within each size grade became less tender
and more starchy during maturation, although the amount of TR
change
varied
with
grade.
The mean TR for grade 1 peas of
both cultivars (pooled) increased only 7 TR points
harvest
the
period, but those in grades 2 and 3 increased 39 and
57 TR points respectively.
both
over
cultivars
The starch
content
of
peas
of
in each grade approximately doubled over the
duration of the experiment.
PAGE 20
Gross returns from crops harvested at different maturity
stages
that
were
a
also
crop
produced
a
harvested
crops
early
in
maturity
Conversely, high gross returns were obtained
were harvested at an advanced maturity, although
most of the
workers
comparatively
They showed
large proportion of high quality peas, but gross
return was low.
when
examined by Pollard's group.
peas
produced
were
of
poor
quality.
These
recommended that prices paid to growers be adjusted,
so that the gross return for high quality peas was similar to
that for lower grades.
Another investigation into the relationship of
maturity
to yield and quality of green peas was conducted in
Maryland
by Kramer (1946).
cv.'Pride'
a
Two cultivars
were
used
in
the
study:
maturing sweet (wrinkle-seeded) pea, and
~ate
Alaska, a small round-seeded early maturing cultivar.
was
harvested
at
Alaska
five stages from TR 96 to TR 147 (9 days)
and 4 harvests were taken for Pride, from TR 83 to TR 165 (10
days).
The
peas
in
this trial were also size graded, and
green pea yield, TR, and AIS were measured for
each
grade at each harvest.
the
peas
Kramer found the same trends as
Pollard et al.(1947), with respect to the decreasing rate
yield
change
for
each
increasing rate of TR
distribution
progressed:
size
peas
cultivar
change
in
with
each
during
time
size
of
maturity;
the
harvest;
the
of
grades
as
maturity
and the rate of TR change for peas in the larger
grades being greater than that for peas in smaller size
grades.
also
of
in
The mean AIS of peas in each grade of both cultivars
increased with maturity but the rate of AIS increase in
each grade remained relatively similar.
PAGE 21
Kramer (1947, 1948) showed that the relationship between
yield, maturity, and quality was relatively constant for each
cultivar.
He
established
proposed
that
once
this
relationship
was
for a cultivar, the yield and maturity index
AlS or TR) at one maturity stage could
yield at other stages of maturity.
be
used
to
predict
Kramer (1948) also stated
that AlS measurements on cooked or raw peas could be used
estimate
the
TR.
He
recommended
peas)
should
with respect to
Kramer
found
round
or
wrinkled
be understood if optimum harvest dates
yield
that
to
that the yield-maturity
relationships of different pea types (ie.
seeded
(e~.
and
quality
were
to
be
achieved.
the yield of Alaska peas peaked about TR
145, hence harvest should never be delayed beyond this point,
or
both
quality and yield would decrease.
were harvested at TR 125, the quality was
only 10% of the potential yield was
When Alaska peas
much
peaked
about
TR 110.
and
The same was
sacrificed~
said for sweet peas like Pride and cv.'Thomas
yield
better,
Laxton'
whose
If harvested at TR 100, 90% of
maximum yield would be achieved, with a much
higher
quality
product.
Similar
Perfection
conclusions
and
Thomas
Laxton
seasons in New York State
that
maximum
85, only 65%
were
drawn
peas
from
study
a
conducted
by Sayre (1952).
over
of
three
The study showed
yield was obtained at a TR of 140, while at TR
of
the
maximum
yield
was
produced.
Sayre
concluded that TR 110 was the optimum harvest stage for these
cultivars
little,
because
above
that
yield
increased
but quality deteriorated rapidly.
relatively
Sayre also showed
that returns per hectare for peas peaked at TR
85-95.
More
PAGE 22
was
paid
to
growers
older peas, and
even
for
high quality young peas than for
with
the
increase
in
yield
during
maturity, the financial returns per hectare decreased.
Lynch and Mitchell (1953) conducted a series
in
of
trials
Tasmania, using cv.'Canners' Perfection' to determine the
relationship between maturity and yield, and to identify
optimum
harvest time (OHT) for peas.
Like Kramer (1946) and
Pollard et al.(1947), these workers found that the
poor
quality
remained
Yield of peas
to
however,
of
intermediate
Lynch and Mitchell used
a
measure maturity, so no relationship between
yield and TR was reported.
peas,
of
reasonably constant during early stages of
maturity, then decreased rapidly.
maturometer
yield
peas increased during maturation, and yield of
high quality peas decreased.
quality
the
Maturometer index (M.I.)
of
raw
was found to be very closely correlated with
AIS of canned peas (r=
+.981~
Lynch and Mitchell, 1950).
A
TR range of 80-140 was found by Sayre (1954) to be equivalent
to . M.I.
120-330,
with
TR
100
approximately
equal
to
M.I. 192.
The influence of maturity on yield-quality relationships
of
peas
in Wisconsin was investigated by Hagedorn, Holm and
Torrie (1955), using two canning
and
'Wisconsin Perfection'
cultivars,
(late).
Alaska
Maturity was measured by
the tenderometer, and quality by size grading.
responses
to
(early)
Actual
yield
maturity varied considerably for each cultivar
over seasons and locations, but
when
compared
in
relative
terms the cultivars had a similar rate of yield increase with
maturity.
Of eight trials using Alaska, one showed a
curved
PAGE 23
response,
as
did
two
of
the
seven
trials, but the average response of
linear.
The
Wisconsin Perfection
yield
to
maturity
was
yield-TR relationship for Alaska and Wisconsin
Perfection peas respectively, were
given
by
the
following
equations:
y=
-1612 + 29.6 X , and
y=
-1432 + 27.9 X ,
where Y= yield of peas in Kg/ha, and X= TR.
Sieve size studies on peas from
proportion
of
both
showed
larger peas increased with maturity.
of peas in each grade also increased
the
cultivars
during
the
Mean TR
maturity,
with
rate of increase greatest in the larger size grades, and
least in the small grades.
These
trends
were
similar
to
those reported by Kramer (1946) and Pollard et al.(1947).
A series of 157 pea trials at Bjuv, Sweden, was
out
by
Ottosson
(1958)
from
1950
to 1957.
involved predominantly wrinkle seeded vining
and
the
These trials
pea
cultivars,
relationship between yield and TR was investigated.
Ottosson found that wide variation in actual
diversity
carried
in
yield,
due
time, location, and cultivar which made direct
comparison between the yield-TR relationships difficult.
proposed
that
yield
responses
unit
at
OHT.
found that the OHT for vining peas in Sweden was at
TR 110, when the yield of sugar in peas was
per
He
to maturity be expressed as
relative yields, calculated as percentages of yield
Ottosson
to
area.
at
its
maximun
He claimed this technique standardised the
position of yield curves from a range of sources,
but
shapes remained relatively unchanged (Ottosson, 1958).
their
The average number of pod bearing nodes on plants
pea
crop
was
found
to
be
a
major
determinant
yield-maturity relationship (Ottosson, 1958).
lowest
fertile
node
several (ie.
the
Pods from
the
matured soonest while those from nodes
In
crop
pool
Crops with only one
nodes
have
plant
less
or
two
"dilution"
pod
effect
bearing
due to the
addition of young peas, and therefore mature sooner and
evenly,
with
a
relatively
lower
yield.
finite, however, because pods from higher
peas
and
of
peas, slightly reducing the rate of maturity and
increasing yield.
per
a
three or more) podding nodes, more tender
peas from younger pods are continually added to the
harvestable
a
of
higher up the plant matured progressively later.
with
in
therefore
contributed
The
nodes
more
effect was
bore
fewer
proportionally less to the
existing population, comprising mainly
larger,
more
mature
peas.
Factors which affect plant growth, such as
soil
or
weather
conditions
and
disease,
unfavourable
also affect the
number of pod bearing nodes, and thereby influence yield
maturation rate.
conditions (eg
and
Ottosson also found that under poor growing
drought,
disease)
skin
toughness
and
dry
matter content increased, without a corresponding increase in
pea growth.
The combination of results from 157 trials
over
seven seasons (1950-4 and 1956-7) gave a curvilinear relative
yield response to maturity, being almost linear from TR 70 to
120, then levelling out to peak near TR 160.
A
Ottosson
further
(1968)
series
of
from
1965
experiments
was
conducted
to 1967, at A1narp, Sweden.
by
He
PAGE 25
confirmed the earlier work with respect to yield
the
distribution
of
maturity (Kramer,
1958).
Plant
peas
various
Pollard
1946~
density,
physical condition,
in
soil
sowing
et
size
and
and
grades during
al. 1947;
moisture,
time,
curves
Ottosson,
soil fertility and
cultivar
used
were
reported to affect the yield-maturity relationship (Ottosson,
1968).
the
He also found a strong positive relationship
number
of
accumulated
heat
units
and
between
the number of
fertile nodes, and that both temperature and
the
fertile
Ottosson (1968)
nodes
affected
maturation
rate.
number
concluded that the OHT was TR 100 for freezing peas,
and
of
TR
110-115 for canning peas.
Salter (1962) and NeIder (1963) showed that the normally
curvilinear
relationship
between
yield
and
maturity
transformed to a linear relationship when the log
plotted
is
a
against log ( TR-TR ) ,
value,
relationship
usually
simplified
between TR 85 and 120.
was
where TR= measured TR, and TRO
O
base
yield
was
75.
The
linearity
interpolation
this
of
corrected yield
for
The model:
y=
was
proposed
by
Berry
(1963)
to
describe
the
tenderometer-yie1d relationship of green peas where
e, TO' A,
and Bare contants, T=TR and W=weight
peas
plant.
of
Berry found approximate values for
shelled
e
and TO
per
of 1.25
and 64 respectively, and when the yield transformation:
y=
e-~~j 1.25
was regressed against TR, a linear relationship was obtained.
PAGE 26
This
model
was
used
successfully
by
Salter
(1963)
to
transform data from irrigation trials.
Berry recommended that the values of TO
adjusted to suit the data to be analysed.
8 at 70
and
1.0
respectively,
Berry
e should be
and
By setting TO
(1966)
and
successfully
fitted the model to data from 12 irrigation or density trials
carried out over five years, with TR ranging from 77 to
The
value
153.
of 1 for 8 was proposed where yield approached an
upper limit with increase in
situations
where
the
TR.
8=<1
yield-maturity
was
suggested
curve
for
showed a yield
decrease at high maturities, as found by Kramer
(1948),
and
Sayre (1952).
Changes in agronomic characters during
studied
for
several
Schippers (1965a).
cultivars
dif
harvest), but no
reference.
A
the appearence
described
pea
maturation
cultivars grown at Otara, N.Z, by
He showed that the yield response of
red
with
were
maturity
recognised
(as
maturity
pea
measured by date of
index
was
used
for
visual method for measuring maturity based on
and
firmness
of
the
by Schippers (1965b, 1969;
pods
and
peas,
was
see section 2.2) which
correlated well with AlS.
The yield-TR relationship for cv.'Victory Freezer' peas,
grown
under
irrigated
and
dry land
conditions,
investigated by Anderson and White (1974a) at
They
found
a
Lincoln,
was
N.Z.
different yield-TR relationship for irrigated
peas than for unirrigated peas (section 3.4).
Equations
for
lines of best fit were derived, using data from TR 85 to 140.
PAGE 27
The respective equations for irrigated and non-irrigated peas
were:
-
2.76X 2 -16.35
(R= 0.91)
y= 45.72X -10.89X 2 -47.30
(R= 0.95)
y= 14.18X
2
where Y= yield of green peas in Kg/m and X= lo910 TR
Like many of the studies
White
above,
to
referred
Anderson
and
found that the rate of TR increase was greater at high
An
harvest
of
stage
peas in Canterbury of 100-110 TR was
for
unirrigated
maturity.
optimum
TR than at early stages
recommended because the increase in yield beyond
this
stage
of maturity was small (or negative).
The yield-maturity relationship, of cv.
Perfection'
peas
was
investigated
by
'Dark
Skinned
Pumphrey, Ramig and
A11maras (1975), in a series of 17 experiments conducted over
11
years
in
U.S.A.
Oregon,
considerable variation in pea
from
individual
Their
yields,
When
trials.
results
and
yield
revealed
yield-TR
was
curves
converted
percentages of the yield at TR 100, however, points from
trials
to
all
could be plotted together, and a curvilinear yield-TR
relationship was derived.
separately,
giving
the
Two irrigated trials were analysed
following equation for line of best
fit:
Y= -1059.1 - 8.405 X + 200.0
where Y= percent
xO. 5
(R= 0.84)
yield, and X= TR.
The equivalent relationship for dryland peas was:
Y= -1640.8 -14.134 X + 3
The different curves for
.1
irrigated
xO. 5
and
(R= 0.81)
dryland
peas
similar to those found by Anderson and White (1974).
were
PAGE 28
Results from cultivar x irrigation trials, conducted over
three
years,
were
used
by
Martin
methods of interpolating pea
maturities
(e.g.
TR
yields
105).
(1981)
to compare six
corrected
Martin
found
to
generally
agreement between methods, especially when yield
were
large,
from
each
and when more than
The
plot.
treatments
matured
at
one
sample
agreement
was
the
time
same
standard
good
differences
was
reduced
harvested
when
many
or rapid maturation
prevented sampling close to the optimum maturity stages.
No
single method was superior in all situations.
There is
optimum
some
harvest
diversity
time
in
(ORT)
for
what
is
in which
they
respectively).
same
stage
cultivars for
1958).
In
was
and
England the
105
canning
in
Sweden
(Salter,
1962,
1963;
(Ottosson,
Berry,
1966;
1970), while the "practical canning stage" is from
(Reynolds,
1970).
Berry, 1966), or
Similar
TR
115
standards apply in New
Zealand (Anderson and White, 1974a), but because
6%
canning.
"practical freezing stage" for peas
TR 115 to 120 (Salter, 1962, 1963;
125
for
found to be optimal for harvest of all
freezing
is from TR 95 to
Reynolds,
100
TR 110 was recommended by Sayre (1952) as the
ORT for both Perfection and Thomas Laxton peas
to
are
Kramer (1946, 1948) suggested different TR stages for
harvest of Alaska and Pride peas for canning (TR 125 and
The
the
vining peas, depending on
cultivar, their end use, and the country
grown.
considered
only
about
of the annual pea harvest in recent years has been canned
(MAF, 1980), most peas over
TR
105
destined
by
freezing, but as lower grade
(catering)
for
preservation
packs
(R.K.
Cawood,
at
pers.
harvest
comm.).
are
still
Caution
should
therefore
exercised
when
interpreting
processing quality" in terms of TR alone,
to the intended method of preservation.
without
"optimum
reference
PAGE 30
5. EFFECT OF IRRIGATION ON YIELD AND MATURITY OF GREEN PEAS
The beneficial
especially
when
effect
of
irrigation
on
yields,
applied at critical growth states, has been
well demonstrated (Salter and Goode, 1967).
experiments
pea
by
In
the
U.S.A.
Monson (1942) and Smittle and Bradley (1966)
showed that irrigation before flowering had little effect
pea
yields,
but
irrigation
increased pea yield.
Maurer,
concluded
that
and
after
flowering
Pumphrey and Schwanke (1974) found that
pod fill was the most ef
Similary
during
on
ctive
Ormrod
and
stage for yield enhancement.
Fletcher
(1968)
in
Canada,
water stress after flowering depressed green
pea yield, whereas stress during
the
vegetative
stage
did
not.
In England, Salter (1962, 1963), and Salter and Williams
(1967)
and
also
pod
fill
confirmed
1971;
1981;
found
that
increased
irrigation
green
of
pea
peas at
yield.
flowering
This
by trials in New Zealand (Stoker, 1973;
Anderson and White 1974a, 1974b;
White,
Sheath
and
Meijer,
Martin
1982).
was
Anderson,
and
Tabley,
Trials
in New
Zealand also show that garden pea seed yield was enhanced
irrigation
at
flowering
Anderson and White, 1974bi
and
pod fill (Stoker, 1975, 1977;
White et al. 1982).
Other agronomic characteristics may also be af
irrigation
in peas.
by
cted
by
Several studies, for example have shown
that irrigation reduces the rate of pea
maturation
and
may
delay the optimum harvest stage up to one, week compared with
unirrigatea peas (Salter 19621
Smittle
and
Bradley,
1966;
PAGE jl
Salter
and
Williams,
Anderson
19671
and
White,
1974a1
Pumphrey and Schwanke, 1974).
Irrigation
may
yield-maturity
also
curve.
alter
Anderson
the
and
shape
White
of
the
(1974a)
and
Pumphrey et ale (1975) found that irrigated peas did not reach
a
yield
plateau,
even
at
TR
140, while unirrigated peas
peaked in yield at TR 120-125, after which
yield
decreased.
This effect, however, was not found by Salter (1962, 1963) or
Smittle and Bradley (1966), who showed that the shape
of the
yield-maturity curves for irrigated and unirrigated peas were
similar, although
general
they
the
found
slope
that
of
the
irrigated
yield-TR curve than non-irrigated peas.
possib1~
explanations,
particularly
lines
peas
differed.
have
These
with
number of podding nodes, were discussed by
a
In
steeper
effects,
and
reference to the
Ottosson
Salter (1963), and Anderson and White (1974a).
(1958),
CHAPTER
3
MATERIALS AND METHODS
,
PAGE 32
CHAPTER 3
MATERIALS AND METHODS
3.1.
FIELD TRIAL
3.1.1. Trial site.
The trial was located in
paddock
R17
of
the
Lincoln
College Research Farm, on an imperfectly drained Wakanui silt
loam (T.
had
Webb, Soil Bureau, DSIR, pers.
comm.).
The
land
been in grazed ryegrass/white clover pasture for over 12
years,
and
an
MAF
soil
analysis:
quick-test
gave
the
6.2
33
10
17
23
pH
P(Olsen)
Ca
K
Mg
Because the fertility (particularly phosphate), and
suitable
for
peas
(Gane
et
following
ale
pH
were
1971, McCleod, 1979) no
fertilizer was applied.
Trifluralin herbicide (Treflan)
incorporated
soil, at recommended rates, six days
with
before sowing.
some
the
Post emergence herbicides were not
hand-weeding
was
subsequently
carried
used
out
was
but
when
necessary.
3.1.2. Cultivars.
Four garden pea cultivars suitable for
processing
were,
in
'Tere',
which
were
Canterbury were selected for the study.
'Piri',
all
not
'Pania', and 'Greenfeast
68'
and
They
(Gf.68),
bred at Lincoln, by Crop Research Division,
DSIR (Figure 3.1.1).
is
cultivation
Tere, which was only released in
yet widely grown.
1980,
Pania and Piri were both released
in 1974 (Crampton and Goulden, 1974).
Pania
has
been
the
PAGE 33
main
cultivar
grown
for
vining
while Piri has been grown on
where
a
in Canturbury since 1979,
smaller
crops could not be irrigated.
area,
particularly
Gf.68, released in 1968
(Crampton, 1968), was the main vining cu1tivar in
until
superseded
by
Pania, which is easier to vine and has
better green pea colour (R.K.
comma ) •
pers.
All
Cawood, J.
cultivars
used
normal foliage, and bear single and
and
agronomic
Canturbury
details
of
the
Wattie
Canneries,
are determinate, with
double
pods.
Maturity
cu1tivars used are given in
Table 3.1.1.1 and in the components of yield results (Chapter
4, section 4.6).
Figure 3.1.1.1 (facing)
Two photographs show visual
differences between cultivars (taken 6.1.80, 55 days
after sowing): GF=Gf.68, PA=Pania, PI=Piri, TE=Tere,
I=irrigated,
N.R.= natural rainfall, X= buffer.
Table 3.1.1.1. Agronomic and Maturity details of Cultivars
used in this trial.
Cultivar
Maturi ty
type
Node to
first
flower
Pod
apex
Cotyledon
colour
Attributes
Tere
early
10-11
blunt
green
High yielding
early cultivar.
Piri
medium
13-14
blunt
green
Tolerant of
dryer soils~
Pania
late
14-16
blunt
green
Very high
yield, widely
adapted
throughout
N.Z.
Gf.68
late
14-16
pointed
yellow
Reliable yield
in a range of
soils.
Difficult to
vine,
pale peas.
PAGE 34
3.1.3 Sowing
Seed of
Lincoln,
all
cultivars
together
with
was
obtained
standard
although those for Piri and Pania
from
the
DSIR,
germination certificates,
were
one
year
old.
An
additional germination test was conducted, using the standard
moist towel method.
showed
The aggregated results
from
all
tests
that Tere, Piri and Pania had germination percentages
of 90-92%, while that for Gf.68 was 86 per cent.
An electro-conductivity test for seed
carried
out (R.C.
which had a "high" score (Gane et al.
there
should
particularly
as
be
the
(Gane et ale
seed)
problem
was
optimum
1971).
Captan ('Orthocide 65',
a.i./Kg
no
trial
planting season, when
occur
was
Close, Lincoln College, pers.
cultivars had a "very high" vigour score
that
vigour
65%
except
1971).
with
also
comm.) All
Greenfeast,
This indicated
seed
emergence
to be sown late in the pea
soil
temperature
conditions
The seed was slurry treated with
a.i.),
at
label
rates
(0.8g
to protect against seed and seedling rot, and
damping-off fungi.
The trial was sown on November 12 and 13, 1979, using
"Stanhay"
a
precision seed drill with 10 sowing units, using a
15cm row
spacing.
cultivar
were
Before
tested
(NZIAE, Lincoln Col
sowing,
seed
samples
of
each
in a special Stanhay calibration rig,
gel to determine which belts, bases
and
drive speeds should be used to achieve populations of 100-110
plants per m2 •
variables
Details of the belts, drive speeds and
are given in Appendix 2.
other
During drilling care was
PAGE 35
taken to prevent
Blockages
did
seeds
jamming
however,
occur,
drilled, seed flow
within
from
each
but
the
sowing
after
unit
was
each
units.
strip was
checked,
and
any
crop's
stage
of
blockage was cleared.
It is sometimes useful to
express. a
development in terms of days from sowing.
In this experiment
November 12, 1979 was considered the date of sowing
even though Piri and Fania were
morning.
would
actually sown
A difference of one day at
probably
make
sowing
(day 0),
the following
time,
however,
negligable difference to the time when
plants began flowering, or reached harvest maturity.
3.1.4. Trial Layout
The trial was of a standard split plot design.
plots
were
out
the
treatments
other
non-irrigated
with
irrigation
treatments,
they
of
each
(natural
one
irrigated
rainfall).
bordered
natural
Where
rainfall
were separated by a buffer strip 2.5m wide
(Figure 3.1.4.1).
one
in a randomised block layout with five
There were two main plot treatments,
blocks.
and
set
The main
Each main plot was split into four
cultivar.
single drill strip 41.0m
Thecultivar
long
and
plots constituted a
1.35m
wide
separated from adjacent plots by a gap 0.65m wide.
were sub-divided for harvest
into
12
plots,
sub-plots
(10
rows),
The plots
3.2m
long
(Figure 3.l.4.1), with a buffer zone 1.3m long at each end of
the plot.
each
This layout was used to facilitate irrigation, but
cultivar
x
irrigation
combination
was
considered a separate treatment within the trial.
effectively
Over
the
PAGE 36
harvest
period
{section
3.2.3},
successive daily harvests
were made from each replicate of each treatment.
Fisure 3.1.4.1 (facing) Negative print from a false colour
infra-red aerial transparency of the trial site with
a trial plan superimposed. Natural rainfall plots of
Tere and the buffer
(marked X, also Tere) stand out
as lighter strips.
3.1.5. Irrigation.
Three l3mm alkathene pipes (laterals) were placed
apart
300mm
along the central area of the irrigated plots when the
pea plants were IOO-lSOmm high.
tank
4m
above
header pipe.
spring
ground
stored
in
a
header
level was fed to laterals via a 5lmm
Water flow into the laterals was controlled
clamps,
so
individual
separately when required.
O.Smm
th~ough
Water
plots
by
could
be
irrigated
Water was delivered
to
the
plot
microtubes 225mm long, located 300mm apart on
alternate sides of the laterals.
Irrigation was
flowering
and
pod
lied
fill,
to
the
the
two
appropriate
growth
reported to be most responsive to irrigation
Salter
and
1974b).
Goode,
1967;
of
began at early flowering, when
and
capacity.
On
continued
this
stages
of peas
(Salter,
a
Wakanui
about 33%.
soil
1963;
irrigated
treatment
15% of plants had fully open
until
site
each
field
the
soil
capacity
reached
was
type,
field
reached
approximately 27-28% soil moisture content, which seemed
for
at
Stoker, 1973, White and Anderson,
The first irrigation
blossoms,
plots
at
low
with a winter field capacity of
It is quite normal, however, for a soil to have a
)AGE 37
lower
field
capacity in summer than in winter (T.Webb, Soil
Bureau, pers.
comm.).
The appearence
within
two
days
of
irrigated
plots
changed
from the start of irrigation.
elongated
rapidly
Irrigated
plots
and
became
remained
bright
green
noticably
Stern apices
in
different in appearence from N.R.
plots of the same cultivar throughout the rest of
period (Figure 3.1.1.1).
the
trial
Changes in soil moisture during the
flowering and harvest period were
gravimetric methods.
colour.
monitored
using
standard
The top 50mm of soil was removed before
a sample was drawn by auger from the next 250mm for
moisture
determination.
A period of very heavy rain (114.6mm) several days after
the
first
irrigation
Al.4, Figure Al.l
of
of Pania and Gf.68 (Appendix 1, Table
Appendix 3, Figure A3.1) led to symptoms
waterlogging
in
the
irrigated plots, where many plants
became yellow and stunted.
therefore
only
given
Irrigated
sufficient
plots
water
of
Pania
during
were
the second
irrigation to raise the soil moisture above the 50% available
level
(Appendix 3, Figure A3.2), and Gf.68 was not irrigated
at all during
pod
(Appendix
Figure
3,
fill,
in
A3.2.).
spite
of
low
soil
Tere and Piri, however, which
were first irrigated earlier than Pania
and
appear
irrigated
badly
waterlogged,
moisture
and
were
Gf.68
did
to
not
field
capacity during the pod fill stage (Appendix 3, Figure A3.l).
The
irrigation at pod fill, where applicable, began when the
pods at the first fertile node were almost fully swollen.
PAGE 38
3.2. HARVEST AND VINING PROCEDURE
3.2.1. Botanical characteristics and yield components.
Immediately before the vining of
ten
plants
were
randomly
each
(Hardwick
and
began
selected from each replicate for
measurement of botanical characteristics
yield
treatment
Milbourn, 1967;
and
components
of
Reynolds, 1970).
The
following parameters were measured for each plant:
(1) number of nodes up to and including the first fertile
node,
from
the
first
node above cotyledonary
attachment;
(2) stem length from soil level to plant apex;
(3) pod length at first two nodes, measuring
each node where double pods occurred;
one
pod
at
(4) number of ovules per pod at each fertile node
(small,
immature ovules were counted but shrivelled ovules
were not);
(5) number of pods per node at all fertile nodes including
flat pods.
From this data it was possible to calculate other
characteristics
viz:
pods
fertile nodes per plant;
proportion
of
yield
also be calculated.
sample
were
treatment.
per
plant;
and peas
per
peas
fertile
per
node.
plant
plant;
The
contributed by each fertile node could
The results from each 10 plant replicate
combined
to
produce
mean
values
for
each
PAGE 39
3.2.2. Harvest of vining samples.
The maturity of each treatment was monitored
visual
methods
using
the
of Schippers (1965b,1969) and tactile method
of Schoonens (1971).
The
harvest
period
for
a
treatment
began when the TR average over all five replicates reached TR
90.
Harvests of a particular treatment continued daily until
the
mean
of
the
pooled
readings exceeded TR 140, as most
commercial crops are harvested within these limits (Reynolds,
1970;
Anderson and White, 1974a).
For each harvest a sub-plot was selected
randomly
each plot of the treatment, and within this a 2.5m 2
area was marked out
(Figure
3.2.2.1).
with
a
tubular
steel
from
sampling
sampling
frame
The sampling area measured 2.78m long and
0.9m wide, and comprised the six innermost rows of the 10 row
drill
strip,
leaving
two
guard
rows on each side (Figure
3.2.2.2).
In plots where a row was absent due to blockage in
the
drill,
seed
mis si ng
row.
an inner guard row was substituted for the
Subsequent
investigation
showed
that
this
departure did not significantly alter the yield from affected
plots.
All plants within the sampling area
were
pulled
by
hand, counted, and placed in a bag, which was then weighed to
measure total vine yield •.
Figure 3.2.2.1 (facing, top) Sampling frame used to mark out
the sampling area in each sub-plot. To ease handling,
the frame was only 1.39m long, and was placed on two
adjacent parts of the sub-plot to mark the correct· area.
Fi
re 3.2.2.2 (facing, lower) A section of the trial site
wi
re areas,
from
which
samples have been
harvested. The guard rows can be seen at the side
of the sampled area.
-"""--
PAGE 40
3.2.3 Vining procedure.
The vines from
continuous
flow
each
sampling
mini-viner,
area
similar
Reynolds (1966) and Wraight (1976).
"Unilever"
design
used
field samples (Figure
modified
to
sample,
very
automatically
The
peas
discarded.
into
a
that described by
The machine was
accumulation
small
to
fed
of
the
many factories for vining small
3.2.3.1).
minimise
and
in
were
Any
mini-viner
of
debris
«7.lmm
remaining
had
in
been
the pea
diameter)
were
debris was easily
removed manually and additional cleaning equipment (Reynolds,
1966;
Wraight, 1976) was not required.
Problems were experienced when vining
the
pods
the
15%
of
pod
Peas contained in the broken end
were discarded with the thrashed vine, and thus
did not contribute to the measured yield.
to
Many
of this cultivar did not open longtitudinally, but
broke transversely instead.
of
Gf.68.
of
the
yield
of
Gf.68
Approximately
was estimated to be lost,
although no accurate assessment was made.
probably
10
The
problem
was
related to the type of pods borne by this cultivar.
Unlike most vining pea cultivars in current use, Gf.68 has
a
pointed pod apex (Table 3.1.1.1), making it less suitable for
mechanical harvest (Reynolds, 1970).
were
The
more
mature
pods
worst affected, so the proportion of peas lost probably
increased with maturity.
After vining, the
rinsed
Three
in
cleaned
sample
of
green
peas
was
fresh water, drained, and weighed for plot yield.
rate 500g sub-samples were
then
taken
from
each
plot
s i e ve
s u mp e ,
Z~
o ne
a n lysis :
t or:."
a nd
anoth e !::" Eo r:-
t nc e co rn
il
for
t h irr]
a na l y s ls la te r-.
P i g l.l r ~ 3 . 2 . 3 . 1 Th e DS IR min i -v in e r u!-"c! d
n the harvest of
t his trial.
Pea vin e wa s fe d into the hopp e r at t he
fa r e nd o f the machi ne , and s pen t vi ne and t r ash wa s
jected from the near end.
Peas were c ollected in a
t ray under the mid d le section of the vine r .
..','.',',',','.'.'.','.'.',','.','
..
I' !',',',',''',',','"
,'t I t ' I I ' ,I I
I
,',,\",,',','.',',',',','.',',1""',1',',.,',',',',',',1., ,
H'" H111,',',',',',11',',"flllltt'"''
.'" . ,1 t 111 1',-,
",,,\1"/"."""""":':':':.:',',11',',',','''.',',',',',:.;,:•
.•:,:,',1
:.-:,;,;':':;:;:::;:::::::::;::::':':':':-;';':;:;::;;:::::::::::~::::;-:,:"
t llll:",1I1I
'....\',',!,'
.... ,II.'.' .. I'll1,
•• ',""'1 11111 11 I l . II
IfJ" ,,1111 I
J
-
PAGE 42
3.2.4. Tenderometer readings.
Maturity
FMC
of the green
tende rometers
Christchurch.
each
peas was
J.
at
measured on the
Wattie
Canneries,
three
Hornby,
A 100g (approx.) sample of peas was placed
tenderometer,
and
a
mean
of
in
the three readings was
calculated for each plot.
Apart from keeping samples in a cool place,
procedure
was
special
followed to ensure that TR was not altered by
the holding time between vining and
studies
no
have
TR
measurement.
Other
shown however that TR is unaffected by holding
up to six hours after vining (Martin, Lueck and Sallee, 1938;
Adam and Holt, 1953).
3.2.5. Size grading.
Peas in the 500g sieve size sub-sample were passed
two
screens
(10.3mm
over
and 8.7mm) and classified according to
the British grading schedule shown in Table 3.2.5.1 (all very
small peas were discarded during vining).
Table 3.2.5.1 Sieve size grades for green peas.
(After Schoonens, 1971).
PEA SIZE
>10.3mm
8.7 to lO.3mm
7.1 to 8.7mm
< 7.lmm
BRITISH GRADE
large
medium
small
very small
EQUIVALENT USDA
STANDARD GRADES.
6 and 7
4 and 5
2 and 3
0 and 1
PAGE 43
The percentage of peas in each grade was calculated
and
used to compute an estimate of the average USDA sieve size as
described by Schoonens (1971), using the formula:
(%smal1 x 2.5)+(%medium x 4.5)+(%large x 6.5)
100
3.3 ANALYSIS OF FROZEN PEA SAMPLES.
3.3.1. Correction for dehydration of frozen peas.
During May
analysed
for
1982,
the
alcohol
insoluble
content, and weight per pea.
were
completely
frozen
500g
pea
samples
solids
and
total
Before
analysis,
thawed, and reweighed.
were
solids
the
samples
It was assumed that
all change in weight after thawing was due to dehydration
of
the peas during freezing, although some loss of water soluble
compounds (eg.
sugars)
factor
was
(C.F.)
may
have
calculated
occurred.
for
each
A
correction
sample
using the
formula:
C.F.= (thawed weight/500g) x 100
This factor was then used to convert the results of
on
thawed
peas
so
analysis
they could be expressed relative to the
original fresh weight.
3.3.2. Alcohol insoluble solids (AIS) determination.
Twenty five grams of thawed peas were macerated for
minutes
in
a
Waring
Blendor
with 150ml 80% ethanol, then
rinsed with a further 100mi 80% ethanol
500ml
kjeldahl
flask.
The
pureed
into
peas
a
at
83 0 C.
The
long-necked
and ethanol were
heated to boiling by placing for 30 minutes in a
held
two
water
bath
water bath was located in a ventilated
fume cupboard to promote refluxing of any ethanol given
off.
The mixture was then filtered under suction through a weighed
filter paper (Whatman no.l) in a buchner funnel.
and
The
paper
residue were rinsed with a further 50ml 80% ethanol, and
oven dried overnight at 80 0 C.
The dry weight of residue
was
PAGE 45
calculated
and
expressed
as
a percentage of the corrected
fresh weight.
The method for measuring AIS used in this experiment was
a
combination of several methods reported elsewhere.
It was
most similar to the methods described by McMahon, Cassidy and
Isaacs
(1981)
and
D.G.
Grant (pers.
amount of peas and ethanol used were
comm.), although the
adjusted
to
suit
the
equipment available.
3.3.3 Measurement of total solids (TS) content.
A 40g sample of thawed peas was crushed
mortar
and
pestle,
in
a
placed in a weighed tin, and dried in a
hot air oven for 20 hours at BOoC.
were
coarsely
The tin and dried
sample
then reweighed and the total solids content of the peas
calculated and expressed as a
percentage
of
the
corrected
fresh weight.
3.3.4 Measurement of weight per
~
The average weight of peas in each sample was calculated
using the following procedure.
a 50g sample of thawed peas was
The corrected fresh weight of
calculated
using
the
C.F.
for each sample thus:
fresh weight=(thawed weight/C.F.) x 100
The number of peas in the sample was then
fresh
weight
divided
by
the
corrected average pea weight.
number
counted,
and
the
of peas, to give the
PAGE 46
3.4 STATISTICAL ANALYSIS OF YIELD-TR RELATIONSHIP
The
data
used
comparison
the
for
of
yield-TR
relationships was restricted to those harvests with a mean TR
between TR 90 and 140.
a
TR
less
than
within this data set, any plots
90 or greater than 140 were also excluded.
The plotted yield-TR relationships of
curvilinear,
and
therefore
(Figures 4.4.1 - 4.4.2).
TR
transformation:
most
difficult
treatments
to
were
compare directly
When yield was plotted against
the
10910(TR-75), a linear, or nearly linear
relationship was produced in most
This
with
transformation
cases
(Figures
4.4.3-4).
was suggested by NeIder (1963).
NeIder
also recommended log transformation of yield, to improve
the
linearity, but this was not found necessary.
Deviations in plant population
significant
were
found
irrigated
treatments
maintain
were
yield
corrected
experimental
was
a
On
significant
treatments of Tere and Fania, however all
for
population
consistancy.
Yield
population deviation was made by regression
pea
have
effect on the yield of irrigated treatments.
close examination, the effect on yields was only
on, for
to
deviation,
to
correction
for
analysis,
where
regressed against 10g(TR-75) with population
deviation from the treatment mean as a covariate.
The adjusted
deviation)
(TR-75).
yields
(i.e.
corrected
for
population
of each treatment were then regressed against log
The data was tested for the presence of outliers by
comparing studentised residuals with significant values given
by Lund (1975), and six points were subsequently omitted from
PAGE 47
further
analysis
(Appendix 5).
The restricted data set for
each treatment was again regressed against log(TR-75).
the
resulting
From
equations the mean yield at TR 105 could then
be calculated
for
use
in
the
subsequent
calculation
of
relative yield.
Differences among the
treatment
were
measured
different stages of
Anderson
(1975).
The relative
105.
by
and
as
White
yield
relationships
comparing
maturity,
(1958),
expressing
yield-TR
in
studies
(1974a)
for
relative
and
each
of
yield
by
was
at
Ottosson
Pumphrey
plot
each
et ale
found
by
the observed yield as a percentage of yield at TR
Relative yield was regressed against log(TR-75) and the
fitted lines were compared by analysis of variance.
The
restricted
calculations
data
set
was
to
pea
yield,
relating
including correlations.
of
.the
figures
used
in
gross
used,
AIS-TR
between
to
For
maturity
TR, AlS etc.) almost a full data set was
points
from
the
last
treatment, with a mean TR of over 140.
the
returns, etc.
relating to yield, given in Chapter 4.
(e.g.
including
other
This data was also used as the basis
most calculations, tables, and figures relating
measurements
any
relationship
however,
harvest
for
each
For the comparison of
including
correlations
them, two outlying points were omitted (Appendix 6).
CHAPTER 4
RESULTS
PAGE 48
CHAPTER 4
RESULTS
4.1 RELATIONSHIP OF TR TO OTHER MATURITY ASSESSMENT METHODS.
Results are given in Tables 4.1.1 to 4.1.4 of
tenderometer
reading
(TR),
pea
irrigation
(P.Wt.),
mean
Alcohol insoluble solids (AIS),
total solids (TS), average sieve size (Ave.S.S.)
per
the
for
each
treatments.
The
harvest,
TR
and
of
and
weight
all cultivar and
Ave.S.S.
were
both
measured on fresh raw peas immediately after vining, but AIS,
TS, and P.Wt.
from
were measured on thawed frozen peas.
Results
analysis 6f thawed peas were subsequently corrected for
waterloss during freezing (Chapter 3, section 3.3.1), and are
expressed on a fresh weight basis.
Table 4.1.1 Maturity parameters for both irrigation
treatments of Tere at each harvest.
Harvest
number
TR
AIS
( %)
1•
2.
3.
4.
5•
6•
7•
90
94
104
115
131
136
150
9.3
10.3
11.7
12.8
14.1
15.3
16.4
1.
2.
3.
4•
5.
6•
7•
8.
96
95
101
113
116
116
132
146
8.6
8.9
9.3
10.4
11.3
11.4
13.4
15.3
Total
solids
Ave.S.S.
( %)
Natural rainfall
15.3
5.05
16.0
5.29
17.3
5.58
19.3
5.90
20.4
5.97
20.4
6.05
21.8
6.24
Irrigated
14.9
15.6
15.7
16.9
18.5
18.1
17.3
20.0
4.64
4.40
4.95
5.33
5.52
5.79
5.97
6.13
Weight
per pea
(g)
0.489
0.524
0.546
0.593
0.645
0.667
0.665
0.437
0.421
0.442
0.498
0.525
0.548
0.594
0.611
PAGE 49
Table 4.1.2 Maturity parameters
treatments of Piri
TR
Harvest
number
AIS
(%)
1.
2.
3.
4.
5.
6.
7.
93
102
106
117
129
135
155
8.9
10.3
10.6
11.9
13.8
14.1
16.0
1.
2.
3.
4.
5.
6.
7•
8.
9•
90
94
97
99
106
7.4
8.4
9.2
9.9
10.6
11.9
12.8
14.7
17.1
III
120
133
148
for both irrigation
at each
harvest.
Total
solids
Ave.S.S.
Weight
per pea
(g)
( %)
Natural rainfall
4.04
14.5
17.6
5.19
5.34
17.4
18.5
5.55
19.4
5.97
17.8
6.01
20.8
6.15
Irrigated
13.6
13.4
15.3
16.7
16.4
18.8
19.1
18.1
22.3
4.25
4.66
5.26
5.23
5.41
5.49
5.62
5.77
6.11
0.426
0.473
0.480
0.513
0.586
0.612
0.630
(
0.378
0.417
0.479
0.478
0.473
0.539
0.544
0.591
0.648
Table 4.1.3 Maturity parameters for both irrigation
treatments of Pania at each harvest.
Harvest
number
TR
AIS
(% )
1.
2.
3.
4.
5.
6.
7•
8•
93
98
106
110
118
131
137
158
8.2
10.1
10.5
11.1
12.8
15.0
16.3
19.4
1.
2.
3.
4.
5.
6.
7.
93
94
102
109
120
130
143
8.9
9.1
10.7
11.5
13.7
14.3
16.5
•
Total
s.ol ids
Ave.S.S.
( %)
Natural rainfall
11.9
4.36
14.1
5.10
14.8
5.38
15.6
5.19
19.0
5.46
20.7
5.63
21.2
5.91
25.2
6.00
Irrigated
16.5
16.7
18.4
18.8
20.4
21.0
22.4
5.02
4.90
5.18
5.50
5.88
6.13
6.08
Weight
per pea
(g)
0.422
0.440
0.479
0.497
0.525
0.527
0.545
0.596
0.446
0.471
0.487
0.546
0.571
0.581
0.603
PAGE 5
Table 4.1.4 Maturity parameters for both irrigation
treatments of Gf.68 at each harvest.
TR
AIS
{%}
93
101
104
113
122
136
149
10.1
12.2
12.8
14.4
16.3
17.6
18.8
92
92
97
102
110
124
136
159
10.2
11.0
11.9
12.6
13.8
16.0
17.6
19.7
Harvest
number
1.
2.
3.
4•
5.
6•
7•
1•
2•
3•
4.
5•
6•
7•
8•
The
relationships
Ave.S.S.
each
found
be
correlation
with
Weight
per pea
{g}
Natural rainfall
15.0
4.79
17.2
5.12
18.9
5.23
20.0
5.66
22.2
5.86
23.6
5.88
24.7
5.94
Irrigated
18.0
18.6
18.6
20.0
20.5
22.4
22.9
24.8
between
AIS,
0.439
0.466
0.461
0.506
0.515
0.551
0.565
4.83
4.86
5.42
5.57
5.84
5.80
5.89
5.96
TR,
0.453
0.434
0.501
0.492
0.529
0.537
0.548
0.545
TS,
P.Wt.
highly
between
TS, P.Wt.
TR,
Correlation matrices
were
computed
although
correlated
with
AIS,
although
in
the
TR and AIS was particularly high {Table
and Ave.S.S.
were also
well
correlated
with the exception of P.wt., correlation
with TR was slightly poorer than with AIS {Table 4.1.5}.
changes
and
treatment {Appendix 7}, and all other methods were
to
4.1.5}.
Ave.S.S.
were measured by correlation analysis, with AIS as
the reference standard.
for
Total
solids
{ %}
The
maturity parameters also displayed high positive
correlations with harvest number {Table 4.l.6}, and therefore
time of harvest.
PAGE 51
Table 4.1.5 Coefficients of correlation between AIS and TR,
total so lids (TS), pea we igh t (P. Wt. ) I
and Average
sieve size (Av~S.S~) i
and between TR and 'rs, p"v-lt.
and Ave.S.S.
Ii
Piri
Tere
Cu1tivar
II
.
.
. rrlga
tlon
N.R.
treatment *
i (no. of pairs) (34)
I
!Cornparison
IRR. NoR"
(40) (35)
Pania
.
Gf.68
IRR. N.R.
(44 ) (40)
IRR. N.R.
(35) (35)
IRR.
(40)
I
I
IAIS V TR
.955
.96S
981
'" 9tL!. ",984
,,981)
,,961
,,969
AIS V TS
" 941
" 792
.HIO
.907 .952
" <)
87
,. 9 ~;5
.96 ;;
AIS V P .. Wt.
.907
.917
.94~
.922 .897
.898 .873
.756
AlS V Av.S.S.
.910
.875 .937
e895 .893
,,9) .1
.97,5
,,840
TR V TS
.921
.781 .788
.745 .940
.966 .918
.944
'rR V P.Wt.
.909
.941 .948
.883 .916
.894 .883
.713
TR V Av.S.S.
.914
.913 .914
.833 .881
.905 .8.62
.772
I
*
N.R. = Natural rainfall,
Table 4.1.6
---
IRRp -
Irri
ted
Coefficients of cOl'.Telation
tween harvest
number (H.N .. )·and tests tor maturity ot peas.
Cultivar
Piri
Tere
~
Irrigation
treatment
N.R.
(No. of pairs) (34)
...,. ..¢ - -
Pania
IRR. N.R.
(40) (35)
IRR. N.R.
(44) (40 )
IRR. N.R.
(35) (35)
IRR.
(40 )
• 968
.882 .962 .
.931 .946
.941 .951
.. 919
Comparison
H.N. V AIS
11
V TR
.978
.890 .972
.913 .944
.943
~922
.921
II
V TS
.920
.710 , 75 'J
,831 .924
,93]
,943
,
II
V P.Wt.
.917
.895 .962
.861 .930
.911 .878
.791
"
V AV.S.S.
.931
.883 .941
.843 .929
.898 .938
.890
oJ4 f
Cf • •
PAGE
The AIS-TR
regression
relationship
analysis,
to
was
investigated
further
for
all
by
determine whether a given stage of
maturity, as measured by AIS, corresponds with a
stage
~L.
treatments.
similar
TR
The regression equations (Table
4.1.7) revealed significant differences, particularly between
Gf.68
and the three other cultivars,and also between the two
irrigation treatments of Tere.
to
TR
The AIS values
corresponding
90, 105, and 140 are given in Table 4.1.8.
Irrigated
Tere increased from 7.7 to 14.6% AIS over the TR range of
to
140,
the
while
same
TR
calculated,
Gf.68 N.R.
range.
90
increased from 10.4 to 18.3 over
The
mean
for
all
treatments
was
and an AIS range of 9.1% to 16.2% was equivalent
to the TR range of 90-140, with an AIS of 11.1% corresponding
with TR 105 (Table 4.1.8).
Table 4.1.7 Regression equations of TR against AIS
for each treatment.
Treatment
Equation
*
R2
( %)
Number
of pairs
S.E.
of b.
Tere
"
N.R.
IRR.
y= 10.6 + 8.29 X
y= 33.2 + 7.34 X
92.3
93.1
34
40
.42
.32
Piri
"
N.R.
IRR.
y= 18.8 + 8.30 X
y= 40.1 + 6.25 X
96.2
96.5
35
44
.28
.18
Pania
"
N.R.
IRR.
y= 42.4 + 5.92 X
y= 33.7 + 6.55 X
96.8
96.8
40
35
.18
.21
Gf.68
N.R.
IRR.
y= 24.8 + 6.30 X
y= 16.9 + 6.85 X
92.3
94.0
35
40
.32
.28
..
*
Y = TR,
X = AIS
Table 4.1.8 AlS values calculated for TR 90,
105, and 140, using the regression
equations given in Table 4.1.3.
Treatment
TR 90
TR 105
TR 140
Tere
N.R.
lRR.
10.7
7.7
11.4
9.8
15.6
14.6
Piri
"
N.R.
lRR.
8.6
8.0
10.4
10.4
14.6
16.0
Pania
"
N.R.
lRR.
8.0
8.6
10 .. 6
10.9
16.5
16.2
Gf.68
"
N.R.
lRR.
10.4
10.7
12.7
12.9
18.3
18.0
9.1
11.1
16.2
"
Mean
4.2 PLANT POPULATIONS
The number
examined
by
of
plants
analysis
of
in
each
variance.
significantly different from each
Pania
and
Gf.68,
but
Tere
different from Pania and Gf.68
within
cultivars
were
harvested
Piri
(Table
and
were
neither
non-significant,
were
significantly
4.2.1).
irrigation treatment or harvest number.
relationship
was
Tere and Piri were not
other,
and
sample
Differences
irrespective
However,
when
of
the
between plant population and yield was examined
by regression analysis, a significant relationship was
found
within the irrigated treatments (Chapter 3, section 3.4).
Table 4.2.1 Plant populations for all treatments,
and the mean for each cultivar with
both irrigation treatments pooled.
Cultivar
Population
(Plants per m2 )
N.R.
IRR.
Mean
Tere
106.6
107.5
106.7
Piri
106.7
105.8
106.0
Pania
92.2
91.8
92.0
Gf.68
93.2
91.0
92.4
S.E of difference between means within
an irrigation treatment, 1. 37; between
means within a cultivar, 1.34; between
pooled means, o .97.
PAGE 55
4.3.
EFFECT OF IRRIGATION AND CULTIVAR ON MATURITY AND YIELD
OF PEAS.
The duration of the flowering period
was
prolonged
by
irrigation
(Table
of
all
4.3.1).
cultivars
The greatest
difference was between natural rainfall (N.R.) and
irrigated
Tere,
where irrigation delayed the end of flowering by seven
days.
Irrigation prolonged flowering of the other
cu1tivars
by two to three days.
Table 4.3.1. Effect of Cu1tivar and Irrigation Treatment on
flowering times (lS/12/S0=36 days from sowing).
Treatment
Flowering
dates
start
end
Duration of
flowering
(days)
N.R.
18.12.79
29.12.79
11
IRR.
1S.12.79
5. 1.S0
IS
N.R.
23.12.79
7. 1.S0
15
"
IRR.
23.12.79
10. 1.80
IS
Pania
N.R.
25.12.79
12. 1.S0
IS
II
IRR.
25.12.79
14. 1.SO
20
Gf.6S
N.R.
27.12.79
IS. 1.S0
22
IRR.
27.12.79
21. 1.S0
25
Tere
n
Piri
The
effect
of
irrigation
treatments
and
cu1tivar
differences on the maturation rate of green peas was measured
by daily change in TR.
The rate of TR increase by
irrigated
treatments at early stages of maturity (3.5 TR points per day
over the first four days of harvest) was usually slower
that of N.R.
day).
than
treatments at the same stage (5.4 TR points per
Over later harvests, however, the rate of TR
of irrigated and N.R.
increase
treatments was similar (9.4 points for
irrigated compared with 9.2 for N.R.
treatments).
The
rate
PAGE 56
of
TR
change
proportionately
with
Both
4.3.1).
curvilinear,
normally
was
increase
irrigation
in
harvest
increasing
number
(Figure
treatments of Tere, however, were
less consistant in their pattern of TR change than the
treatments,
and
a
clear
trend
log(TR-75) was plotted against
section
3.4),
was
less
harvest
other
obvious.
number
When
(Chapter
4,
a more linear relationship was found for most
treatments (Figure 4.3.2).
Figure 4.3.1 The relationship between TR and time of harvest
(harvest number) for both irrigation treatments of each
cultivar:- - - = natural rainfall;
= irrigated.
TERE
160
PIRI
150
140
I
130
cc
w
f- lC0
W
L
a
cc
110
W
0
Z
W
f-
100
~0
0L
/,
.,r
/
/
/
/,
,(
I
I
I
I
.,r
./
I
!
I
I
..-"
/
I
I
I
140
(C
w 1ce
f-
?'
lLJ
a
110
W
0
Z
W
f-
100
./
...-"
/
/
;r
I
/
~-
"
'I
..-"
/
/
, , - - -"
/
/
/'
/
/
/"
I
I
I
!
I
/
I
l'
i...
~e
e
-"
/
IP'"
e
/
I
.r
I
GREENFEAST
130
(C
./
PANIA
./
L
or'
/
".
I
I
~~--1_~L-~
150
z
/
..-"
/
I
./
I
I
~~
./
160
~
.
~~T~T
3
4
5
B
HARVEST NUMBER
7
8
S
e
1
2
3
4
5
B
7
HARVEST NUMBER
8
3
PAGE 57
Figure 4.3.2 The relationship between log(TR-75) and harvest
number for both irrigation treatments of each cultivar:
- - - = natural rainfall;
= irrigated.
1.8
'I'
0:::
Cl
0
-J
/
I
(() 1.6
l-
PI RI
TERE
e.e
1.4
b
·1. f
~
,/
/
f
/
I
/
,... ---"
,/
,/
~
/,
,
/
I
/
/
.,-
/'
?
I
I
/'
,/
/
?'
--
.....
/
/
)'
1.e
GF.S8
PANIA
e.e
-.....
1.8
?'
(() 1.6
I'....
I
l0:::
Cl
0
-J
1.4
/
/
1~
/
I
/
,-
/
I
J'
?'
,-
"
./
e
1.0
(3
1
C
3
4
5
6
7
8
:'l
(3
HARVEST NUMBER
/
/
/
.--
C
-- ...
3
I
/
/
4
,/
,/
?
5
I
/
~
6
/'
/'
.
7
8
~
HARVEST NUMBER
The regression of log(TR-75) against harvest number gave
the
following
equations
for N.R.
and irrigated treatments
respectively:
where Y
=
Y
=
1.15+0.105 X
Y
=
1.13+0.086 X
log(TR-75), and X = harvest number.
PAGE 58
Irrigated
treatments
were
slower
generally
progressing
through the harvest period, and were harvested for one or two
days more than the corresponding N.R.
exception however, with the N.R.
plots.
Pania
was
an
plots being slower maturing
than those with irrigation (Table 4.3.2.).
Although the general trend
increase
in
always occur.
greater,
or
TR
was
towards
a
curvilinear
with time, as described above, this did not
Often the day to
day
TR
smaller, than expected.
changes
were
much
Occasionally there was
no TR increase from one day to the next, and a small decrease
was recorded for harvest 2 of irrigated Tere (Table 4.3.2).
Table 4.3.2 Mean TR for each harvest of all treatments with
date of harvest (13/1/80 = 62nd day from sowing).
Treatment
Date
N.R.
Pania
Piri
Tere
IRR.
N.R.
96
95
101
113
116
116
130
146
93
102
106
117
129
135
155
IRR.
N.R.
IRR.
Gf.68
N.R.
IRR.
( , 80)
13/1
14/1
15/1
16/1
17/1
18/1
19/1
20/1
21/1
22/1
23/1
.24/1
25/1
26/1
27/1
28/1
29/1
30/1
31/1
1/2
2/2
3/2
90
94
104
115
131
136
150
90
94
97
99
106
111
120
133
148
93
98
106
110
119
131
137
158
93
94
102
109
120
130
143
93
101
106
113
122
136
148
92
92
97
103
110
124
136
160
PAGE 59
Irrigation enhanced the green pea yield of Tere by 20
%
but the yield from irrigated plots of all other cultivars was
significantly lower than from N.R.
yield
plots (Table 4.3.3).
response of the irrigated plots in general appeared to
be negatively related to cultivar maturity (as
node
The
to first flower, Table 2.1.1).
lower in yield than
irrigation
all
treatment,
other
due
by
Gf.68 was significantly
cultivars,
partly
indicated
irrespective
of
to the difficulty vining
this cultivar (Chapter 3, section 3.1.5).
Table 4.3.3 Predicted green pea yield at TRI05
and response to irrigation.
Irrigation treatment
IRR.
N.R.
Cultivar
Pea yield (Kg/ha)
Irrigation response
(% of N.R. yield)
Tere
8747
( 74)
10532
(112)
20
Piri
8618
(74)
8176
(143)
-5
Pania
11191
(148)
10290
(133)
-8
Gf. 68
8048
( 77)
7363
(147)
-9
(Figures in parentheses are S.E.'s of the predicted yields)
It is also evident that yield ranking for the
treatments
do
not
irrigated
relate to those from the N.R treatments.
Without irrigation Pania significantly
out yielded
Tere
and
Piri, which were not significantly different from each other.
The yield of irrigated Tere and Pania were not
different,
but
were
significantly
irrigated Piri (Table4.3.3).
higher
significantly
than
that
of
PAGE 60
4.4 EFFECT OF MATURITY ON PEA YIELD, VINE YIELD
AND GROSS RETURN FROM PEAS
The yield of green peas from
over
all
treatments
increased
the harvest period (TR 90 to 140), although the rate of
increase
(Tables
differed
with
4.4.1 to 4.4.4).
TR, as a scatter
relationship
was
of
treatment
and
stage
of
When the yield was plotted against
observed
data
points,
a
curvilinear
generally found (Figures 4.4.1 and 4.4.2).
The curvilinearity was less evident for the N.R.
of
Tere
and
maturity
Piri,
or
for irrigated Gf.68.
treatments
When the mean
yield and TR values were plotted,
they
linear, especially
For regression analysis of
above TR 100.
tended
to
be
the yield-TR relationship, however, only the individual
data
points
were used.
plot
In all cases analysis was conducted
on the restricted data set (TR 90-140)
for population deviation.
more,
with
yield
adjusted
PAGE 61
Table 4.4.1 Tenderometer reading,
yield parameters,
and
gross return at each harvest for both irrigation
treatments of Tere.
Harvest
numbe r
1
2
3
4
5
6
Mean
**
1
2
3
4
5
6
7
Mean
TR
Pea
yield
(Kg/ha)
Relative
yield
(TR 105=100)
93
94
104
115
129
134
7487
7995
8575
9278
9764
10166
Natural rainfall
85.6
91.4
98.0
106.1
111.6
116.2
96
96
102
113
119
116
129
8892
9250
10261
11849
12152
11151
12550
Irrigated
84.4
87.8
97.4
112.5
115.4
105.9
119.2
Vine *
yield
(T/ha)
Gross
return
($/ha)
40.4
36.8
36.4
38.8
38.4
36.8
38.0
1531.7
1594.7
1312.4
1195.3
1025.1
1077.5
53.2
49.6
50.8
52.4
47.6
52.4
1748.8
1781.5
1766.2
1493.5
1434.8
1369.7
1291.5
--
51.2
* Vine was not weighed when rain present on the foliage.
** For Tables 4.4.1-4.4.4, S.E. of the difference between
vine yield means for
cultivar: 1.64.
irrigation
treatments
within a
Table 4.4.2 Tenderometer reading,
yield parameters~
and
gross return at each harvest for both irrigation
treatments of Pirie
Pea
yield
(Kg/ha)
Rela tive
yield
(TR 105=100)
Vine
yield
(T/ha)
Gross
return
($/ha)
6
93
102
106
117
129
135
7595
8040
8797
9268
10059
10528
Natural rainfall
88.1
93.3
102.1
107.5
116.7
122.2
40.4
40.4
42.4
39.2
41.2
1510.8
1296.6
1279.0
1124.4
1058.3
1107.9
1
2
3
4
5
92
95
97
99
106
5459
6235
7593
8305
8511
8784
8999
9826
Harvest
number
1
2
3
4
5
Mean
6
7
8
Mean
TR
III
120
133
Irrigated
66.8
76.3
92.9
101.6
104.1
107.4
110.1
120.2
--
40.8
49.2
46.0
50.4
--
51.2
50.8
46.8
43.6
48.4
1197.4
1188.6
1377.7
1489.6
1265.1
1185.0
1035.6
1066.8
PAGE 62
Table 4.4.3 Tenderometer reading,
yield parameters, and
gross return at each harvest for both irrigation
treatments of Pania.
Harves t
number
TR
Pea
yield
(Kg/ha)
1
2
3
4
5
6
7
Mean
93
98
106
110
118
131
137
9389
10288
11257
11976
12478
12734
13392
1
2
3
4
5
6
Mean
96
95
102
109
120
130
8382
9480
9999
10795
11302
12113
Relative
yield
(TR 105=100)
Natural rainfall
83.9
91.9
100.6
107.0
111.5
113.8
119.7
Irriqated
81.5
92.1
97.2
104.9
109.8
117.7
Vine
yield
(T/ha)
Gross
return
($/ha)
47.6
-
1904.9
1857.8
1654.1
1658.5
1444.3
1335.9
1401.4
50.8
50.8
48.8
46.4
44.8
48.0
. 48.4
1610.8
1912.6
1607.8
1466.0
1264.5
1309.8
50.8
49.6
46.8
43.2
44.4
47.2
Table 4.4.4. Tenderometer reading,
yield parameters,
and
gross return at each harvest for both irrigation
treatments of Gf.68.
Harvest
Number
TR
Pea
yield
(Kg/ha)
1
2
3
4
5
6
Mean
93
101
104
113
122
127
7033
7428
8245
8607
8806
9112
1
2
3
4
5
6
7
Mean
92
93
97
102
110
124
132
6424
7030
7340
7037
8029
7088
8575
Relative
yield
(TR 105=100)
Natural rainfall
87.4
92.3
102.4
106.6
109.4
113.2
Irrigated
87.3
95.5
99.7
95.6
109.1
96.3
116.5
Vine
yield
(T/ha)
Gross
return
($/ha)
44.4
41.6
43.6
42.0
40.0
36.4
41.2
1424.2
1250.7
1270.9 .
1101.5
1014.3
947.0
43.6
45.2
48.8
45.2
44.0
39.2
43.6
44.1
1286.5
1451.8
1347.2
1136.8
1086.3
762.0
914.3
PAGE 63
Figure 4.4.1 Relationship between green pea yield and
TR of the natural rainfall treatments of each
cultivar, showing the scatter of data points
( 0 ) and the trend in harvest means ( A
A).
PAGE 64
Figure 4.4.2 Relationship between green pea yield and
TR for the
irrigated
treatments of each
cultivar,
showing the scatter of data points
( c ) and the trend in harvest means (A
... ) •
PIRI
TERE
15
14
13
t1l
.r::
H~
aDD
p: 11
0
- l 10
W
1-1
>-
a:
w
(L
8
~
•
j
.
~
D
.o~~~:D:
D
8
. .
.. .
__L
___
7
~
D
6
~-L
5
L
.L_
PANIA
15
~
I
GF.68
14
13
t1l
.r::
1E
•
D
p: 11
10
S
8
.
7
.~.
o
0
.
•
6
5
3el
100
110
1~0
130
TENOEROI'1ETER READ! NG
140
100
110
1~
TENOEROf"IETER READING
140
PAGE 65
TR
was
Chapter
3,
section
relationship.
a
linear
transformed
3.4,
relationship
the
log(TR-75),
to
linearise
as
described
the yield-maturity
evolved for most treatments (Figures
The harvest means and and the fitted
regression
equation
observed
the
scatter
data points (Figures 4.4.3 and 4.4.4).
In most
cases the regression line
conformed
well
to
the
distinctly bi-phasic yield response to
the
predicted
yield
values
increasing
the
predicted
maturity.
from the regression were
plotted against corresponding TR values, the curve
by
observed
The notable exception was irrigated Piri, which had a
data.
When
described
data also fitted the observed points well
(Figures 4.4.5 and 4.4.6), and emphasised the
curvilinearity
of the original yield-TR data.
Table 4.4.5. Regression equations for yield (Kg/ha)
against log(TR-75).
Treatment
Equation
*
R2
( %)
No. of
pairs
S.E.
of b
Tere
Tere
N.R.
IRR.
y= 2406+4293 X
y= 2281+8675 X
85.7
86.6
25
31
365.3
634.2
Piri
Piri
N.R.
IRR.
y= 448+5532 X
y= -529+5893 X
88.6
59.8
29
36
382.1
829.3
Pania N.R.
Pania IRR.
y= 1485+6571 X
y= 1197+6156 X
70.5
72.7
33
27
762.9
754.7
Gf. 68 N.R.
Gf. 68 IRR.
y= 1578+4380 X
y= 3659+2506 X
77.3
25.8
27
32
474.8
776.1
*
line
for yield against log(TR-75)
(Table 4.4.5) were also plotted to compare with
of
in
When yield was plotted against the log(TR-75),
4.4.3 and 4.4.4).
from
to
Y =Pea yield (Kg/ha),
X = log(TR-75).
PAGE 66
Figure 4.4.3 Relationship between green pea yield and
log(TR-75) for the natural rainfall treatments
of each cultivar,
showing the scatter of data
points (0 ), harvest means (A) and fitted line
from the regressions given in Table 4.4.5, with
pea yields converted to T/ha.
PIRI
TERE
15
,-----,,.-----.---,-···········T······
14
13
ttl
.s::
C
le
11
.
.'~
10
~
(C
IJ.J
IL
DO
8
7
6
5
GF.68
PANIA
15
14
13
ttl
.s::
11:
j:::: 11
0
..--1
IJ.J
t--1
113
>-
:J
IJ.J
5
a::
(L
u
0
•o
D
.~
~--D
7
"0
~
~_IJ
p
~
~D
b
U
U
6
5
L
1.<:'
1.4
Log
1.6
(TR~75)
loB
1.2
_....L.-_....L.-_--'-,~____..l. ..............._ ____..l.~
1.4
Log
1.8
(TR~75)
1.8
PAGE 67
Figure 4.4.4 Relationship between green pea yield and
log{TR-75) for the irrigated treatments of each
cultivar,
showing the scatter of data points
( 0 ),
harvest means ( .. ) and fitted line from
the regressions given in Table 4.4.5, with pea
yields converted to T/ha.
PIRI
TERE
15
14
13
,-..
t1:I
.r.:::.
C
H~
..
11
10
.......
>-
.
~.
3
....
D-
..
8
7
••
o
•
•
L--...........l._~~ -'.'-----'I'--.__
6
...
5
Po
L.~_~~
L-..-.-L
.....
GF.68
PANIA
15
•
U
u ....
I
14
13
Ie
" o.
.
. . .;-<o~~.u
.
11
>
HI
lI.
3
8
...
~
~/D
•
.. .
7
6
5
~. _--L~-,--_-,-----.-J'--- .....1..-
1.2
1.4
1.6
Log (TR-75)
L--..----'-_-L-.....L.........~ ___'__
1.e.
1.4
Log
1.6
(TR~75)
___.L... _ __'__________'
1.8
PAGE 68
Figure 4.4.5 Relationship between green pea yield and
TR for the natural rainfall treatments of each
cultivar, with data points ( a) and fitted line
from values predicted by regression of pea
yield against log(TR-75).
15
TERE
PIRl.
PANIA
GF.68
14
13
(\l
.s::.
Ie
i===
11
a
10
---1
W
H
>-
9
<C:
w
8
0-
0"
7
6
5
15
14
13
(\l
Ie
I-
11
a
10
.s::.
......
---1
W
H
9
a:::
w
8
>-
0-
7
6
5
50
100
1113
1213
130
TENDEROMETER READING
1413
913
100
1113
120
1313
TENDEROMETER READING
1413
PAGE 69
Figure 4.4.6 Relationship between green pea yield and
TR for irrigated treatments of each cultivar,
with data points
(0)
and fitted line from
values predicted by regression of pea yield
against log(TR-75).
PAGE 70
The observed pea yield for each treatment was
be
influenced
the
to
by factors other than stage of maturity (e.g.
cu1tivar, soil moisture, plant density etc.).
of
found
yield-maturity
relationship,
were expressed as relative yield,
For comparison
therefore, yield data
with
the
yield
of
each
treatment at TR 105 (Table 4.3.2) equal to 100 (Figures 4.4.7
and
4.4.8).
The
relative
yield
was
regressed
against
log(TR-75), and the equations from these relationships (Table
4.4.6) were the basis for comparison between treatments.
R2
The
,statistic from regressions of both pea yield and relative
yield against log(TR-75) show that,
irrigated
Gf.68,
a
high
with
the
exception
proportion of change in yield was
explained by change in maturity (Tables 4.4.5 and 4.4.6).
Table 4.4.6 Regression equations for Relative Yield
against log(TR-75).
Treatment
*
Equation
of
*
R2
( %)
No. of
pairs
S.E.
of b
Tere
Tere
N.R.
IRR.
Y= 27.5+49.1 X
Y=-2l.7+82.4 X
85.7
86.6
25
31
4.18
6.02
Piri
Piri
N.R.
IRR.
Y= 5.20+64.2 X
Y=-6.47+72.l X
88.6
59.8
29
36
4.43
10.14
Pania N.R.
Pania IRR.
Y= 13.3+58.7 X
Y= 11.6+59.8 X
70.5
72.7
33
27
6.82
7.34
Gf.68 N.R.
Gf.68 IRR.
Y= 19.6+54.4 X
Y= 49.7+34.0 X
77.3
25.8
27
32
5.90
10.54
Y=Relative yield (% of yield at TR 105),
X=log(TR-75).
PAGE 71
Figure 4.4.7 Relationship between relative yield and
log (TR-75) for the natural rainfall treatments
of each cultivar, with data points (0) and the
fitted line from regressions in Table 4.4.6.
TERE
130
PIRI
&)
.
(S)
....... lee
II
If)
.
..
(S)
....... 110
a::
I0
.
10a
......J
IJ..J
~
IJ..J
Be
......J
70
lJ..J
a::
a
•
>
.......
Ia::
.
a
!'}0
..
a
....
0
01'
.a
60
GF.68
PANIA
130
..
&)
(S)
....... lea
II
If)
(S)
....... 110
a::
I0
H:la
a.
0
.
..
.•
.
.
......J
IJ..J
H
>lJ..J
>
.......
la::
......J
IJ..J
a::
ao
a
~0
Be
0
•
70
60
1. e
1.4
1.6
Log (TR-7S)
1.8
1. e
1.4
Log (
1.6
1.8
j
j
PAGE 72
Figure 4.4.8 Relationship between relative yield and
log(TR-75) for the irrigated treatments of
each cultivar, with data points (D) and the
fitted line from regressions in Table 4.4.6.
TERE
130
PIRI
.•.
,-,
CS)
(S)
,.....;
II
..
lee
If)
CS)
...-!
a:
f-
0
0
lHl
0
0
100 .
••
0
.0
--.J
l!.J
H
>-
l!.J
II
3el
>
8G
....J
LLJ
70
H
fa::
a:
.
u"
a
~.
•
•
....
"
0
•
0
se
8(S)
..-i
II
If)
CS)
..-i
a:
f0
GF.68
PANIA
130
..
leG
D
0
•
1113
D
D·
100
D
•
•
•
..
l!.J
>-
LLJ
3el
>
Be
....J
LLJ
70
H
fa::
a:
se
....
•
...
... •
--.J
H
"
D
"
•
D
1.e
1.4
1.6
Log (TR-75)
1.8
1. e
1.4
1.6
Log (TR-75)
1.8
PAGE 73
When
the
treatments
slopes
were
for
compared
relative
with
each
difference between them was found.
treatments
did
yield
the
The slopes
of
abnormally,
5.60
to
irrigated
differ however, although Gf.68 was suspected
Because Gf.68 was
the data from the irrigated treatments
were recompared omitting Gf.68, and the F ratio
from
N.R.
other, no significant
to have a major influence on this outcome.
behaving
of
1.69,
was
which was non-significant.
reduced
The common
line for all N.R.
treatments (pooled) was compared with
common
the pooled irrigated treatments (excluding
line
Gf.68).
for
The line for the irrigated treatments was found by
test
to
made
between
be
cultivar.
significantly steeper, so comparisons were then
the
two
irrigation
treatments
within
were
for
each
The lines for the two irrigation treatments for
almost
identical,
and those for Piri were very
similar to each other (Table 4.4.6, Figure 4.4.9).
lines
!
A significant difference, however, was only found
within Tere.
Pania
the
The
two
Gf.68 appeared to be relatively different (Figure
4.4.9), but the difference
was
not
significant.
The
two
lines for Gf.68 could not realistically be compared, however,
due to the poor relationship between yield and maturity found
for
the
irrigated
treatment
Tables 4.4.5 and 4.4.6).
of
this
cultivar (R 2 =25.8%,
PAGE 74
Figure 4.4.9 Relative yield-log(TR-75) relationship for
both irrigation treatments of each cultivar:
- - - - = natural rainfall,
= irrigated.
8(S)
.-i
II
TERE
130
PIRI
lee
If)
(S)
........
cc
110
l-
/'
a 10e
~
lLJ
H
>--
~
./
lLJ
>
H
I-
a:
./
./
./
/'
./
/'
/'
/'
/'
/'
./
/'
/'
/'
r'
./
/'
00
/'
/'
/'
/
/.
Y'
;/
,/
,/
/'
/'
,/
,,-
~
,.,.;
~
lLJ
cc
70
60
(S)
GF.68
PANIA
130
CS)
.-i
II
l()
(S)
lee
.-i
0:: 110
f-
/'
a lee
.-J
UJ
H
}-
UJ
>
H
I-
a:
~
,'/
./
/
,/
,/
,/
,/
/'
/'
./
,/
,/
./
,/
;/
00
~
lLJ
0::
70
60
1.e
1.4
1.6
Log (TR-75)
1.~
1.e
1.4
1.6
Log (TR-75)
1.8
PAGE 75
The relative yield values predicted from
in
the
equations
Table 4.4.6 were also plotted against corresponding TR so
that the relative yield-TR
of
treatments
each
curves
cultivar
for
could
the
be
two
irrigation
compared
(Figure
4.4.10).
Figure 4.4.10 Relative yield-TR relationship for
both irrigation treatments of each cultivar:
irrigated.
- --= natural rainfall,
(S)
(S)
..-i
PIRI
TERE
130
120
II
lJ)
(S)
..-i
a:
I-
1Hl
100
0
--.J
lLJ
f-i
>>
80
a::
--.J
w
70
lLJ
r-;
I
50
,-
,/
/
/
/
A
'"
.-
-'
"
,"'-
-'
-'
.....
-- --
./
;/
~
V'
/.
h
h
./
~
./
---- ----
--
----
/J
/.
I0::::
60
.pANIA
130
(S)
(S)
..-i
II
GF.68
120
,.-
lJ)
(S)
..-i
a:
I-
110
.--:
100
0
--.J
lLJ
>W
>
f-i
r-;
!}0
/
/
/
/
/
/
/'
".-
.-'
.-'
-- ----
.-'
"/
80
I-
a::
--.J
w
0::::
70
60
!}0
100
110
120
130
TENDEROMETER READING
140
~
100
110
120
130
TENDEROMETER READI NG
140
PAGE 76
Vine
treatment
yield
over
did
not
change
significantly
for
any
harvest period (Tables 4.4.1 to 4.4.4),
the
despite the increase in the weight of peas borne on the vine.
Some day to day fluctuation in vine yield was probably caused
by variation in the amount of dew present on the vine at
time
of harvest.
the fluctuations to
the
An unsuccessful attempt'was made to relate
days
when
dew
was
recorded.
It
is
likely, however, the order in which samples were harvested on
a day with heavy dewfall would also have a
on
the
variation
in measured vine yield.
early in the day, for example, would
therefore
be
heavier
retain
strong
influence
A plot harvested
more
dew,
and
than if it were harvested later, when
some (or all) of the dew had evaporated.
PAGE 77
The gross return for each sample was calculated from the
vined
pea yield using Wattie Canneries' payment schedule for
the 1979/80 season (Appendix 4), when
carried
out.
Returns
were
early stages of maturity, and
the
highest
lowest
field
trial
for peas harvested at
about
TR 120
to
(Table 4.4.1 to 4.4.4., Figure 4.4.11).
Figure 4.4.11 Gross return-TR relationship for
both irrigation treatments of each cultivar:
- - -= natural rainfall;
- irrigated.
TERE
ee
~
fIRI
18
16
Cd
.r:
......
fh 14
Z
cc.
:::)
f-
w
cc.
(IJ
(IJ
0
cc
G
Ie:
10
8
6
PANIA
eEl
18
@
(S)
-
.
16
....
"""-
"'-,
Cd
.r: 14
......
"""-
GF.68
.........
fh
...... .....
/'
"- --&."
=>
f-
lLJ
cc. 10
'" "-
'" "'-
a::::
G
8
6
-...
--- ...... "-
V
(IJ
(IJ
0
.""-r-
.......
:z:
a:::: Ie
100
110
lce
130
TENDEROMETER READING
140
30
100
was
110
lC0
..
130
TENDEROMETER READING
140
130
PAGE 78
The relationship between gross return and pea yield, TR,
and
number
harvest
analysis.
yield
and
With the
gross
were
also
exception
return
of
for
examined
the
correlation
comparisons
irrigated
significant negative correlations were
by
Piri
found
in
between
and
Gf.68,
all
cases
(Table 4.4.7).
Table 4.4.7 Coefficients of correlation between gross
return ($/ha) and green pea yield (Yld.),
TR, and Harvest number (H.N.).
Cu1tivar
Irrigation
treatment
(no. of
pa irs)
Tere
Pania
Piri
Gf.68
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
(25)
(31 )
(29)
(36)
(33)
(27)
(27)
(32)
Comparison
$/ha
v Y1d. -.795
-.511 -.715
-.078 -.493
-.506 -.629
-.047
" v TR
-.911
-.733 -.844
-.682 -.824
-.816 -.887
-.796
" v H.N.
-.884
-.769 -.715
-.477 -.769
-.680 -.809
-.782
PAGE 1Y
4.5 EFFECT OF MATURITY ON SIEVE SIZE.
The changes in Ave.S.S.
for
all
treatments
during
(Tables
4.1.1
maturity
were
similar
to 4.1.4), and was well
correlated with TR, yield and harvest number (Table 4.5.1).
Table 4.5.1. Coefficients of correlation between Ave.S.S.
and pea yield, TR, harvest number (H.N.) and P.Wt.
Piri
Tere
Cultivar
Irrigation
treatment
( no. of pairs)
Pania
Gf.68
N.R.
(25)
IRR. N.R.
(31) (29)
IRR. N.R.
(36) (33)
IRR. N.R.
(27 ) (27 )
IRR.
(32)
.844
.878 .917
.761 .840
.799 .885
.525
Comparison
Ave.S.S.
v yield
"
v TR
.896
.926 .938
.813 .873
.909 .931
.830
"
v H.N.
.893
.865 .938
.799 .895
.859 .951
.904
"
v P.Wt.
.841
.929 .922
.872 .842
.796 .826
.860
The pattern of changes in sieve grade proportions during
maturity
were
also similar for all treatments, although the
absolute amounts in each
4.1.4).
When
these
grade
data
differed
(Tables
4.1.1
to
were plotted against TR (Figures
4.5.1 and 4.5.2), the interrelationship between the different
size
grades during maturation could be seen.
The proportion
of small peas (7.1-8.7mm) remained low and decreased over the
harvest period.
The medium sized (8.7-l0.3mm) peas comprised
a substantial proportion of the pea sample during
stages
of
maturity,
but
progressed, while the large
proportion.
decre.ased
peas
(>
rapidly
10.3mm)
the
as
early
maturity
increased
in
The average size of the peas increases steadily
PAGE 80
during maturity, reflecting a
small
peas,
and
a
decrease
in
the
medium
and
steady increase in the dominance of the
large peas.
Figure 4.5.1 .Changes in the proportion of peas in each
size grade during the maturation of peas in the
natural rainfall treatments of each cultivar:
A = small~.
= medium;" = large.
TERE
lee
~
PIRI
80,...-
~
f!:
a
l-
60-
LL
a
:z
a
1-1
I-
413
c:
a
J
-i
(L
~ ,ee
-'
(L
t
13
I~'
PANIA
lee
~
•
+
(;F.68
,"",'80
'*
f!:
a
~
l-
60
LL
a
:z
a
1-1
~
a
(L
a
a::
(L
413
ee
j
!l0
100
11<1
11:.0
1313
1413
TENDEROMETER READING
1513
160
53
100
111<1
11:.0
1310
1413
READING
1510
160
PAGE 81
Figure 4.5.2 Changes in the proportion of peas in each
size grade during the maturation of peas in the
irrigated treatments of each cultivar:
It. == small;.
== medium~ y
= large.
TERE
1013
*
FIRI
··········r
I
I
I
I
I
I
I
80
~
a:
I0
l-
60
LL
0
z
0
,......,
40
I-
a::
0
CL
0
a::
(L
~
e0
- ......
0
FANIA
100
~
-r--'--1
GF.68
1
I
I
I
I
I
80
_~~--T
....J
a:
IC)
l-
I
60:
LL
C)
Z
0
,......,
I-
40
---
0:
C)
CL
0
a::
CL
e0
e
I
!30
100
110
120
130
140
TENDEROMETER READING
150
160
50
100
110
~
I
120
I
I
130
...
,
•
I
I
140
TENOEROMETER READING
t_J::U
150
160
PAGE B2
4.6.
THE EFFECT OF CULTIVAR AND IRRIGATION ON BOTANICAL
CHARACTERISTICS AND COMPONENTS OF YIELD.
The number of nodes to the
differed
for
each
cultivar,
first
but
fertile
was
affected by the
irrigation
treatments
contrast,
length
all
stem
of
(Table
cu1tivars
increase with irrigation, although
varied with cultivar.
not
the
node
significantly
4.6.1).
showed
amount
(F.N.)
of
In
a marked
increase
With the exception of Tere, pod length
of all cultivars was decreased by irrigation.
Table 4.6.1
Botanical characteristics
for each cultivar
(number of nodes to first fertile node
(F.N.),
stem and pod length,
and increase in stem
length with irrigation).
Nodes to
1st. F.N.
Irrigation
treatment N.R.
Stem length
(mm)
Increase*
wi th IRR.
( %)
Pod length
(mm)
IRR.
N.R.
IRR.
IRR./N.R.
N.R.
IRR
Cultivar
Tere
11.1
10.9
303
454
50
6.4
7.7
Piri
13.9
13.1
443
701
5B
7.4
7.1
Pania
14.5
14.1
439
602
37
7.5
7.1
G.f.6B
15.7
15.7
466
594
28
B.6
7.B
-
0.10
0.16
S.E. of
mean
0.29
0.23
14.8
27.6
* Increase in stem length is the difference (IRR. - N.R.)
expressed as a percentage of N.R.
PAGE 83
The effect of irrigation on yield
measured (Table 4.6.2).
per
plant
exception
was
of
was
also
The number of fertile nodes and pods
increased
Tere,
components
by
irrigation,
but,
with
irrigation decreased peas per pod.
Piri, Pania and G.f.68, therefore, the final number
of
the
For
peas
per plant was similar regardless of irrigation treatment, but
Tere gave a positive increase in number
with
irrigation.
of
peas
per
plant
Gf.68 had significantly more fertile nodes
per plant than the other cultivars, but fewer pods per node.
Table 4.6.2. Components of yield for each pea cultivar
(except weight per pea).
Fertile
nodes
per plant
Irrigation
treatment
pods
per node
peas
per pod
peas per
plant *
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
N.R
IRR.
Tere
2.5
3.2
1. 69
1.65
4.0
4.4
17.2
22.8
Piri
2.8
3.3
1. 85
1. 66
4.4
3.8
21.4
20.4
Pania
2.6
3.3
1.86
1.75
5.9
5.2
28.6
29.1
G.f.68
3.2
4.4
1. 52
1. 31
5.1
4.6
24.9
26.7
0.14
0.27
0.125
0.067
0.16
0.17
Cultivar
S.E.
of mean
*
1.01
1.86
This is the observed value, rather than the product from
multiplying the yield components,
which was slightly
different due to rounding errors.
PAGE 84
The number of pods per node and peas per pod produced by
each
plant
were partitioned according to the F.N.
they were borne.
second
F.N.
The number of pods borne at the
was
very
similar
for
pods
first
and
all cultivars, with a
slight depression from irrigation (Table 4.6.3).
of
at which
The
number
fell -sharply at the third and other fertile nodes,
although there was some response to irrigation, especially by
Tere.
Table 4.6.3 Number of pods borne at each fertile node (F.N.).
Node
1st F.N.
Irrigation
treatment N.R.
2nd F.N.
3rd F.N.
Others
IRR.
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
1.6
1.6
1.8
0.7
1.4
0.1
0.4
Cu1tivar
Tere
1.9
Piri
1.9
1.8
1.B
1.7
1.1
1.2
0.1
0.6
Pania
1.9
1.B
1.9
1.B
1.0
1.0
0.1
1.0
Gf.6B
1.7
1.7
1.7
1.6
1.0
1.1
0.4
1.4
S.E. of
mean
0.06
O.OB
0.05
0.05
0.15
0.14
O.OB
0.33
-
PAGE 85
The number of peas per pod at the
without
irrigation
for
nodes,
all
cultivars
irrigation than without.
peas
per
pod
fell
F.N.
was
greater
all cultivars, and except for Tere,
the same was true at the second
fertile
first
Under
only
F~N.
set
more
irrigation
at
other
peas per pod with
irrigation,
slightly
fertile nodes, but without
At the third and
the
number
of
the third and other
the
decline
in
the
number of peas per pod was much steeper (Table 4.6.4).
Table 4.6.4 Number of peas per pod at each fertile node.
Node
Irrigation
treatment
1st F.N.
2nd F.N.
3rd F.N.
Others
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
Tere
4.7
4.2
3.7
4.8
3.0
4.4
0.6
4.2
Piri
5.0
3.5
4.3
3.9
3.2
3.9
2.1
3.4
Pania
6.2
5.2
6.1
5.4
5.2
5.5
2.7
4.2
Gf.68
5.9
4.9
4.9
4.5
4.3
4.7
3.3
4.0
S.E.of
mean
0.19
0.31
0.14
0.22
0.36
0.21
0.73
0.35
Cultivar
PAGE Hb
The peas produced by each plant
were
also
partitioned
according to the node at which they were borne (Table 4.6.5).
With the exception of Tere, unirrigated plants bore more peas
than
irrigated plants at the first and second fertile nodes,
but at
the
occurred.
third
The
and
other
distribution
fertile
of
nodes
the
converse
peas per node was therefore
similar to that described for peas per pod.
Table 4.6.5
Node
Irrigation
treatment
Number of peas borne at each fertile node.
1st F.N.
2nd F.N.
3rd F.N.
Others
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
Tere
9.0
6.7
6.1
8.7
2.0
6.0
0.1
1.4
Piri
9.9
6.4
8.1
6.7
3.2
4.7
0.3
2.5
Pania
11.8
9.4
11.3
9.9
5.0
5.4
0.5
4.4
Gf.68
10.1
8.2
8.6
7.3
4.1
5.3
1.5
5.8
0.79
0.32
0.44
0.58
0.76
1.34
0.44
Cultivar
S.E of
mean
0.39
PAGE 87
The distribution of peas between the fertile
also
was
expressed as of percentages of the total number of peas
per plant (Table 4.6.6).
approximately
82%
Plants in the N.R.
treatments bore
of their potential pea yield at the first
two fertile nodes, while irrigated peas bore only
at
nodes
the
nodes.
same
(especially Tere and
total
yield
at
the
The
plants
Piri)
bore
F.N. ,
first
irrigated plants bore only
about
in
the
N.R.
approximately
about
6S%
treatment
half
their
but at the same node the
30%
of
their
total
pea
yield.
Table 4.6.6 Percentage of total pea number borne
at each fertile node.
Node
1st F.N.
Irrigation
treatment N.R.
2nd F.N.
3rd F.N.
Others
IRR.
N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
Cultivar
Tere
52.5
29.3
35.5
38.1
11.6
26.3
0.6
6.5
Piri
46.1
32.3
37.7
33.4
lS.l
22.8
1.6
11.5
Pania
41.6
33.2
39.6
3S.8
17.1
17.5
1.7
13.S
Gf.68
41.2
31.2
34.7
27.7
16.3
20.0
5.8
19.7
S.E.of
mean
2.28
3.24
1.38
2.88
1.97
2.21
1.20
4.27
PAGE 88
4.7 PREDICTION OF YIELD FROM YIELD COMPONENTS.
The plant samples used for yield component analysis were
taken
at
an early stage of maturity (before vining harvests
began) so the measurements taken from
regarded
as
measurements
of
them
potential yield.
were not measured at that stage, because
counted
were
still
very
made
many
however,
pea was
calculated
against
log(TR-7S),
from
the
because
linear
the
be
the
peas
An effort at
using
on samples of vined peas.
only
Pea weights
of
small and immature.
yield prediction was attempted,
measurements
should
pea
weight
The weight per
regression
of
P.Wt.
P.Wt.-TR relationship was
curvilinear for most treatments.
A predicted
Table
pea 'yield'
(i~. number
of
per
m2 ,
4.7.1) was calculated from the mean number of peas per
plant (Table 4.6.2) and mean plant population
A
peas
(Tabl~
4.2.l).
yield in Kg/ha was then calculated from the number of peas
per m2
yield
and the calculated pea weight.
When
the
predicted
was compared with the observed (vined) yield at TRlOS,
the difference varied considerably
between
treatments,
was particularly high for irrigated Gf.68 (Table 4.7.2).
and
PAGE 89
Table 4.7.1. Green pea yield (peas/m 2 )Ca1culat d from
peas per plant and plants per m2
Peas per
plant
Irrigation
treatment
P2
Green
as
per m
Plant~
per m
*
N.R.
IRR.
106.7
183S.2
2432.8
20.4
106.0
2268.4
2162.4
28.6
29.1
92.0
2631. 2
2677.2
24.9
26.7
92.4
2300.8
2467.1
N.R.
IRR.
Mean
Tere
17.2
22.8
Piri
21.4
Pania
Gf.68
Cultivar
*
Mean population for both irrigation treatments.
Table 4.7.2. Comparison of predicted and observed yield
at TR lOS.
Mean weight
per pea
(g)
Irrigation
treatment N.R.
Yield
Predicted
(Kg/ha)
Observed
Difference
in yield
*
IRR. N.R.
IRR.
N.R.
IRR.
N.R.
IRR.
Cultivar
Tere
.S70
.S16 10457
12591
8747
10S32
16.4
16.4
Piri
.528
.501 11978
10812
8619
8176
28.0
24.4
Pania
.472
.517 12420
13800 11191
10290
9.9
25.4
Gf.68
.480'
.499 11088
12289
7362
27.4
40.1
*
8048
Difference is expressed as percentage of predicted yield.
CHAPTER
5
DISCUSSION
PAGE 90
CHAPTER 5
DISCUSSION
5.1.
MEASUREMENT OF MATURITY
The significant correlations between maturity assessment
methods
used
in this experiment confirm many of the studies
reviewed in Chapter 2 which advocated the use of such
or
compared
their ef
ctiveness for measurement of maturity
and quality.
Even after freezer storage for
years,
total
AIS,
solids
(TS)
and
more
than
measurements
made
harvest (Appendix 7).
on
fresh
two
weight per pea (P.Wt)
measurements were still highly correlated with TR
size
tests,
peas
and
sieve
immediately
after
Thus, although methods like AIS and TS
are relatively slow, they have the advantage that they may be
used to measure maturity of peas a
harvest.
This
may
be
considerable
especially
important
time
if
after
there is
limited or no access to a fast and simple method, such as TR.
Although correlation coefficients between the
methods
for
measuring
maturity
were
high
(Table
Appendix 7), the relationship between any two
differed
between
treatments
(Table
absolute terms, therefore, one method
4.1.1
may
different
4.1.5;
methods
to
not
often
4.1.4).
be
In
directly
comparable with another, although both may vary at a constant
rate during maturity, hence the high correlations obtained.
The
AIS-TR
relationship
was
examined
by
regression
analysis, and differences were found in the intercept (a) and
slope (b) terms of regression equations for several treatment
(Table 4.1.7).
This variation indicates that the two methods
PAGE 91
measure changes in different components of maturing peas, and
that peas from different treatments vary in the rate at which
one component changes in respect to the other (Table 4.1.8),
In this experiment an AIS of aproximately 11%
with
TR
105.
This was similar to the results of Lee et ale
(1954), Wecke1 and Kuesel (1955), Adam
and
Gaze
(1980).
1953:
(1957)
and
Atherton
It is also within the AlS maturity limits
set in Australia for pea
(Sykes
coincided
cultivars
Scheltema,
Sykes
harvested
and
for
freezing
Last, 1961).
The AlS
values found here are lower than those published by Kramer et
al.
(1950) and Adam and Brown (1957), who found the optimum
harvest maturity of peas was about
AlS
13
to
14%.
Their
studies were on peas intended for canning, however, when more
mature peas (than those
preferred
for
freezing)
would
be
considered optimum (Chapter 2, section 2.4).
Other
studies
relationship
here.
A
have
varies
difference
with
was
also
shown
that
the
AIS-TR
different cultivars, as was found
commonly
reported
between
round
seeded Alaska type peas, and the wrinkled seeded garden peas.
The latter type generally had an AlS of
1.5
to
2.5%
lower
than the round seeded peas at the same TR (Weckel and Kuesel,
1955;
however,
Ottosson,
1958;
Lesic,
1975).
In
New
Zealand,
only garden peas are cultivated for vining, so this
source of variation
does
not
exist.
Differences
in
the
AIS-TR relationship have also been reported between different
garden peas however,
so
dif
unusual.
(Adam, 1955;
Atherton and Gaze,
1980),
rences found between cultivars in this trial are not
Seasonal differences also appear
to
significantly
PAGE 92
affect
the
AIS-TR relationship of garden peas (Adam, 1955).
The speed and method of vining has been
the
tenderness
1967).
shown
to
influence
of peas (Casimir, Mitchell, Lynch and Moyer,
Maturity as measured by a chemical
method
like
AIS
would probably be unaffected, hence disparity between the two
methods could be introduced.
In this experiment, AIS determination was
thawed
peas
which
had
results expressed as
weight.
The
been
a
used
and thawed
The
1961).
on
frozen raw (unblanched), with
percentage
of
the
original
fresh
AIS method was originally developed to measure
maturity of canned peas (kertesz, 1934,
been
conducted
1935),
but
it
has
successfully
to measure the maturity of raw peas
frozen
(Kramer,
AIS
peas
Scheltema
1954~
et ale
measurements made on different substrates,
,
however, may not be directly comparable.
Kramer (1948) found that at TR 105, the
Alaska
peas
was
14.2%,
peas of the same line.
Laxton,
AIS
of
canned
while 15% AIS was recorded for raw
The difference was greater for Thomas
which at TR 105 had an AIS content of 12.3 and 14.7%
for canned and raw peas
respectively.
(1950),
(1950) and Adam and Holt (1953) also
Kramer
et ale
Lynch
and
found that the AIS of raw peas was about one or
higher than the same material after canning.
Mitchell
two
percent
Ottosson (1958)
found that at low maturities the AIS of raw and thawed frozen
peas
was
content
very similar, but with increasing maturity the AIS
of
raw
peas
became
comparatively
higher.
Near
TR 200, however, the AIS of raw peas was only about 1% higher
than that of similar peas which had been frozen.
PAGE 93
In New Zealand, most peas for processing
between
harvested
90 and 140, so these were taken as the lower and
TR
upper maturity/quality limits for
Nonnecke
are
(1973)
compared
the
this
trial.
Voisey
and
A1S ranges for the upper and
lower quality limits of peas from 20 different studies.
found
that
at
the upper quality (i.e.
the A1S varied from
while
at
6.0
to
17.1%
s.d. 3.05),
the higher maturity limit, the range was from 13.9
experiment
range of
low maturity) limit
(mean 9.1%,
to 27.2% A1S (mean 22.7%, s.d. 3.98).
this
They
The
A1S
values
from
(Table 4.1.4) are therefore well within the
results
from
a
large
number
of
other
studies
relating to pea maturity.
The purpose of examining the AIS-TR relationship was
confirm
that
measuring
maturity
Coefficients
were the R2
4.1.3),
the
but
significantly
reliability
tenderometer
and
quality
has
of
a
reliable
peas
for
method for
processing.
of correlation between A1S and TR were high, as
statistics from the regression
the
regression
different.
equations
This
cast
analysis
were
some
(Table
in some cases
doubt
on
the
of the tenderometer as a means of estimating pea
quality, compared with A1S.
TR
is
to
In other studies however,
where
been compared directly with quality and maturity, as
measured by organoleptic methods, the tenderometer was
to be almost as good as AIS (Chapter 2, section 2.3.).
found
PAGE 94
5.2.
EFFECT OF IRRIGATION AND CULTIVAR ON MATURITY,
YIELD AND YIELD COMPONENTS
Irrigation and cultivar treatments in many cases
had
a
significant effect on both maturity and yield of garden peas.
These results did not consistently agree with other
reports,
however, especially on the effect of irrigation on pea yield.
Irrigation applied at the beginning of flowering
and
during
pod fill has usually been found to significantly increase the
yi~ld
of green peas
experiment
only
response.
less
(Chapter
one
2,
section
cultivar,
2.5.).
Tere,
displayed
Irrigated Piri yielded slightly but
than
the
relatively
N.R.
large
In
this
such
a
significantly
treatment, while Pania and Gf.68 gave
yield
depressions
from
the
irrigated
irrigated
treatments
treatment (Table 4.2.1).
The
aberrant
(especially
of
behaviour
of
the
Pania and Gf.68) was probably due to changes
in soil moisture conditions caused
(114.6mm)
the
very
Peas are one of the most sensitive crop
anaerobic
soil
conditions
caused
(King, 1979), particularly just before and
(Erickson
and
Van Doren, 1960;
Suhail, 1979;
Dennis,
this
rainfall
he~vy
on January 2 and 3, 1980 (Appendix 1, Figure Al.l,
Table Al.4).
to
by
Jackson, 1979;
1980).
growth
during
flowering
Cannell, Gales, Snaydon and
Belford, Cannell, Thomson
display
changes,
and
distinct
can
and
Jackson,
ale
1980).
and Belford et ale
physiological
and
suffer depression of yield
(Erickson and Van Doren, 1960;
1979;
by waterlogging
Pea plants subjected to waterlogging during
stage
morphological
plants
1979;
Cannell
et
PAGE .95
Excessive soil moisture from flowering to
reported
by
Bartz
cited
by
Salter
Frese,
Czeratzki
irrigation
during
and
Korte
and Goode (1967), found that in a
season when wet conditions prevailed, yield was
by
was
(1959) to reduce pod fill of Alaska peas
more than any other treatment.
(1955),
maturity
flowering.
reduced
15%
The maintainance of high
soil moisture levels throughout the growth of vining peas was
also
shown
by
with
plants
appropriate
Stoker
which
(1973) to depress pea yield compared
received
stages
of
less
growth.
rainfall
observed
is
this
trial
interaction
between
treatments,
and
the
the
but
at
more
The variation in effect of
irrigation treatments and
in
water,
on
different
cultivars
thought to be the result of an
rainfall
and
the
irrigation
growth stage the peas were at when the
rain occurred.
The irrigated treatment of the earliest cultivar,
Tere,
experienced three distinct periods when soil moisture reached
field capacity, separated by intervals when soil moisture was
much lower (Appendix 3, Figure A3.l).
soil moisture periods, due to the
near
the
end
of
The second of the high
heavy
rainfall,
occurred
flowering, close to petal fall, when only
small yield responses would be expected (Salter, 1963).
N.R.
treatment
of Tere was at the flat pod stage of growth
when the heavy rainfall occurred, when
insensitive
1965;
to
Salter
The
irrigation
and
Goode,
(Salter
1967).
peas
1963;
are
relatively
Salter and Drew,
For
this
cultfvar,
therefore, the period of heavy rain apparently had no adverse
affect on the irrigated
yield.
The
N.R.
treatment,
treatment,
and
however,
may
have
enhanced
probably
received
PAGE 96
little benefit from
treatment
rain,
out yielded
and
the
at
N.R.
TR
105,
the
treatment
by
irrigated
20%
(Table
4.3.3).
The heavy rainfall period occurred during
irrigated
Piri (Table 4.3.1;
and
irrigation
may
rain
be
expected
Drew, 1965), although soil moisture at the time
was already high from 'irrigation (Appendix 3,
The N.R.
of
Appendix 1, Table Al.4, Figure
Al.l) when a yield response to
(Salter
flowering
Figure
A3.1).
treatment of Piri was also flowering when the heavy
occurred,
positively
and
to
the
could
also
to
respond
rain (Salter and Goode, 1967).
It seems
unusual, however, that the N.R.
be
expected
treatment, which received
a
single moist period during late flowering should out yield the
irrigated treatment of
irrigation
during
early
(Table 4.3.1, 4.3.3;
appears
the
same
cultivar,
which
received
and mid flowering, and at pod fill
Appendix 3, Figure A3.1).
It therefore
that the irrigated treatment suffered adversely from
excessive water, which reduced its yield to below that of the
N.R.
treatment.
enhanced
by
treatments,
Yield of the latter treatment may have been
the
it
rain,
is
but
impossible
with
to
(waterlogging) reduced yield and how
only
two
irrigation
tell how much one effect
much
another
(natural
rainfall) may have enhanced it.
The
irrigated
significantly
lower
treatments
of
Pania
yielding
than
the
and
In both cases, the rainfall occurred
soon
irrigation,
(Appendix 3, Figure A3.2).
when
soil
were
corresponding N.R.
treatments.
after
Gf.68
relatively
moisture was still high
The natural
rainfall
treatments
PAGE 97
were near the middle of the floweri?g when the rain occurred,
so a positive response to additional soil moisture was likely
(Salter
and
probable
Goode,
that
waterlogging
1967).
the
rain
In this situation it is highly
caused
a
yield
reduction
by
in the irrigated treatments, but enhanced yield
of the N.R.
treatments.
the
of
effect
As discussed above,
waterlogging
research
into
and soil oxygen deficiency has
shown that peas are particularly sensitive to such conditions
immediately
before,
and
1979:
Jackson, 1979:
stage
of
growth
during
flowering
Belford et ale
when
yield
(Cannell et ale
1980).
responses
to
This is also a
irrigation are
greatest.
It is proposed that in this trial the
depressed
yields
from irrigated treatments of Piri, Pania, and Gf.68, were the
combined effect of waterlogging in irrigated treatments,
and
a
The
yield
response
to rainfall in the N.R.
treatments.
nearer the period of heavy rain was to the critical sensitive
growth
stage (i.e.
the start of flowering), the greater its
effect on yield depression or enhancement.
Irrigated
Piri,
being slightly earlier flowering than Pania or Gf.68, did not
exhibit as large a yield depression, even though it sustained
the
most prolonged period of high soil moisture (Appendix 3,
Figure A3.1).
Irr(gated Pania and Gf.68,
being
closer
to
the start of flowering on January 2 and 3 (Table 4.3.1), were
probably more sensitive to waterlogging.
which
the
N.R.
treatment
of
Piri
The later stage
received
at
the rain is
probably also a major reason why this treatment did not yield
even
more
than
it did relative to irrigated Pirie
treatments of Pania
and
Gf.68,
however,
almost
The N.R
certainly
PAGE 98
responded
to
the rain, hence the greater difference between
the two irrigation treatments
with
Pirie
Tere,
waterlogging
and
of
being
did
not
these
cultivars
earlier,
display
the
compared
apparently
escaped
abnormal
effects
exhibited by the other three cultivars.
The results
Pania,
and
of
both
Gf.68,
irrigation
therefore,
are
treatments
not
heavy
rain.
The
magnitude
of
except
for
Tere,
between cultivars.
further
and
the
effects
the abnormal behaviour
invalidates any conclusions on the effect
yield,
Piri,
the outcome of the
imposed treatment alone, but were confounded by
of
of
of
precludes
Problems experienced
irrigation
yield
when
on
comparison
vining
Gf.68
restrict any conclusions which may be drawn from the
yield and maturity of this cultivar.
The soil description (Chap.
the
possibility
of
a
sustained
through impaired drainage.
revealed
3, section 3.1.1)
period
of
Examination of the
waterlogging,
soil
profile
mottling in the subsoil, although under more normal
Canterbury summer conditions, the
not be a problem (T.
imper
ct
Webb, Soil Bureau, pers.
drainage
experiment
also
would
comm.).
Several other parameters measured during the
this
supports
course
of
support the theory of waterlogging in
the irrigated treatments, and a yield response to rain by the
N.R.
Pirie
treatments
of
Pania,
Gf.68
and to a lesser extent,
PAGE 99
The results given here (Table 4.4.1 to 4.4.4) show
that
the vine yield from irrigated Tere and Piri were greater than
from respective N.R.
treatments
of
treatments, but
those
from
irrigated
Pania and Gf.68 were not significantly higher
than from N.R.
treatments.
(Table
was also much smaller from irrigated plots of
4.6.1)
The
increase
Pania and Greenfeast than corresponding
and
Pirie
The
differences
in
in
stem
treatments
length
of
vine yield and stem length
response to irrigation by Tere and Piri, compared with
ofPania
and
Gf.68,
Tere
those
are believed to reflect the effect of
different amounts of waterlogging on plant growth.
Salter
(1963)
respectively,
found
and
(1974b),
and
Anderson
that
irrigation increased haulm growth
and total green (vine) weight of peas.
In
White
this
trial
the
irrigated treatments of Pania and Gf.68 failed to display the
increase in vine yield which would be
from
irrigated
Jackson
(1979)
waterlogging
plants.
and
reduced the rate of
thought
be
expected
Studies by Cannell et ale
Belford
induced
normally
et
ale
(1980)
(1979),
showed
that
premature quiescence of stern apex, and
internode
extension.
This
effect
is
to be the reason why the responses in vine yield and
stem length to irrigation, of Pania and Gf.68, were less than
expected.
vine
yield
treatments
It -is also suggested that the large difference in
and
of
stern
Piri
length
reflects
between
the
the
two
slightly
growth at which it was exposed to the period of
compared with Pania and Gf.68.
irrigation
later stage of
heavy
rain,
PAGE 100
Physical changes in the
irrigated
eight
of
plants
in
the
treatments of Gf.68 and to a lesser extent, Pania,
were also observed.
patches
appearence
Most noticable was
the
development
of
of yellow plants within the irrigated plots, five to
days
after
inspection,
the
many
of
heavy
these
rain
occurred.
On
closer
plants were found to be stunted
near the stem apex, with smaller leaflets than those found on
healthy plants of the same cultivar.
Plants in the irrigated
plots of Piri, Pania, and Gf.68 also tended to become pale in
colour at an earlier stage of
N.R.
ln
treatments.
plant
than the corresponding
mat~rity
These effects are consistent with
growth
described
by
Cannell
et ale
changes
(1979) and
Jackson (1979) for waterlogged peas.
Measurements made on yield components
major
difference
also
indicate
in the behaviour of Tere compared with the
other cultivars.
The pod length and number of peas per
for
increased
Tere,
were
The
of peas per plant were also significantly higher from
the irrigated treatment of Tere, but there was no
between
pod,
by irrigation, but for all other
cultivars the reverse occurred (Tables 4.6.1 and 4.6.2).
number
a
irrigation
treatments
of
difference
the other cultivars, for
this parameter (Table 4.6.2).
Although
attributed
to
these
the
differences
effects
of
in
yield
waterlogging,
entirely consistent with the conclusions of
(1979)
and
waterlogging
Jackson
(1979).
depressed
nodes, and thereby yield.
the
components
These
number
of
Cannell et ale
are
they are not
Cannell
workers
fruiting
et
found
ale
that
(fertile)
(1979) and Belford
PAGE 101
et ale
by
(1980) also found that waterlogging
reducing
depressed
the number of pods per plant.
yield
The results from
this trial show that both number of fertile nodes and
of
pods
per plant were greater from irrigated treatments of
all cultivars (Table 4.6.2, pods per plant by
of
nodes
per
unaffected by
Gf.68,
number
plant
and pods per node), and appeared to be
waterlogging.
the
mUltiplication
older,
It
less
was
also
determinate
noticable
that
cultivar,
had
significantly more fertile nodes per plant, but less pods per
node than the other cultivars.
The other cultivars were very
similar to each other in these parameters (Table 4.6.2).
Disagreement between the results of this experiment, and
(1979), Jackson (1979) and
those described by Cannell et ale
(1980) on the effect of waterlogging on yield
Belford et ale
components,
may
result
from
the
differences
maturity when the waterlogging occurred.
was
waterlogging
not
controlled,
in stage of
In this
and
experiment
coincided
different stages of maturity for each cultivar.
A
with
a
reduction
in pod fill (peas per pod) attributed to excess soil moisture
at
flowering,
as
described
by
Bartz
(1959),
is
more
the
N.R.
consistant with the results of this experiment.
It is interesting
treatments
of
per node at
that
plants
in
first
fertile
node
than
plants
in
the
irrigated treatments (Tables 4.6.3 and 4.6.5).
This suggests that
depresses
note
all cultivars had more peas per pod, and peas
the
corresponding
to
irrigation
at
the
start
of
flowering
yield at the first node, particularly by reduction
in number of peas per pod.
PAGE 102
From the results of Tere alone, it
appears
that
yield
enhancement . by . irrigation is through -increase in the number
of fertile nodes, and increase in the number of peas per
(Table
4.6.2).
The
number of pods per node was relatively
insensitive to changes in soil
moisture
(Table
4.6.2,
and
an increase in peas per pod directly increased the
4.6~3),so
number of peas per
fertile
pod
nodes
node.
An· increase
the
number
ale
(1982)
Anderson and White (1974b) and
also found that irrigation increased
green pea yield by increasing the number of peas per pod
pods
per
of
per plant, therefore, also directly increased
the number of pods per plant.
White· et
in
plant.
and
Anderson and White also found, as in this
study, that irrigation
increased
the
proportion
of
yield
characteristics
were
contributed by nodes higher up the plant.
The
flowering
relatively
and
unaffected
by
maturity
waterlogging.
The
duration
of
flowering and time to harvest were prolonged in the irrigated
treatments
for
of all cultivars (Table 4.3.1 and 4.3.2).
Pania,
the
progressing
irrigated
through
treatments
were
also
treatments
(1974a)
and
(Table
4.3.2).
were also later and slower maturing in
experiments by Salter (1963),
White
slower
the harvest period, with a smaller rate
of TR increase per day, especially at low TR
Irrigated
Except
Stoker
Pumphrey
and
(1973),
Schwanke
Anderson
and
(1974).
The
exponential rate of TR increase with time, as found
in
this
experiment, has also been observed in other studies were this
relationship
Kramer,
was
1946;
examined
(Pollard
Hagedorn
et
Anderson and White, 1974;
al
et
1955;
Pumphrey et ale
al.
1944,
1947;
Ottosson,
1958;
1975).
PAGE 103
5.3.
THE EFFECT OF MATURITY ON PEA SIZE.
The proportion of peas in
dramatically
medium
during
and
maturity,
large
size
with
all
treatments behaving similarly (Figures 4.5.1 and 4.5.2).
The
grades
changed
the
proportion of small peas in any treatment was never great and
decreased to near zero at
changes
found
Pollard et al.
peas.
The
in
high
maturity.
sieve
size
this trial were similar to those found by
(1947) with Perfection and
results
The
Early
Perfection
of Kramer (1946) also show very similar
trends from Alaska and Pride
peas
during
maturity,
as
do
those of Lynch and Mitchell (1953), for Canner's Perfection.
The rapid increase in yield of peas at early
stages
of
maturity is probably due to the growth of peas in each grade,
and the passage of small and medium peas into the medium
large
size grade respectively.
and
As the volume of peas in the
two smaller grades reduced and the large peas
reached
maximum size, the rate of yield increase would decrease.
their
PAGE 104
5.4 THE EFFECT OF MATURITY ON YIELD OF VINING PEAS
Both green pea yield and relative yield
maturity
during
the
harvest
yield, relative yield,
(Tables
and
4.4.1 to 4.4.4).
period.
TR
increased
With few exceptions,
increased
at
each
rate
period (Appendix I).
of
TR
influenced
increase
by
are
not
temperature
without
during
the
Short term fluctuations in the
uncommon,
as
maturity
through
heat
cool
periods
yield
increase
in
patterns,
accummulation (Seaton, 1955).
increase
harvest
The exceptions noted were probably
due to sampling variation and changes in weather
harvest
with
In
corresponding
converse applies during warmer weather (M.J.
is
unit
may
TR, while the
Crampton, pers.
comm.).
The relative decrease in
harvest
of
irrigated
yield
Tere
is
and
TR
actually
at
the
the
sixth
result of an
inarease in the mean yield and TR from the fifth harvest
to
the
3.4;
due
elimination of an outlying value (Chapter 3, section
Appendix 5, Table A5.2).
No
satisfactory
explanation
is tendered for the variability in yield of Gf.68, except for
the difficulty experienced in vining
N.R.,
however,
display
have
observation,
fluctuations.
sustained
increased
its
yield
by
yield
The
Gf.68
severe
effects
of
the irrigated treatment may also
variability.
parameters
As
measured
treatments, including yield components,
than
cultivar.
which was equally difficult to vine, did not
similar
waterlogging
this
4.3.3, 4.4.5, 4.6.1 to 4.6.6).
on
we~e
comparable measurements made on N.R.
a
more
general
irrigated
variable
treatments (Table
PAGE 105
The
relationships
(measured
and
by
4.4.7),
between
pea
yield
and
TR), were generally curvilinear (Figures 4.4.6
with
progressively
the
rate
smaller
of
yield
increase
as TR increased.
a1.
(1944,
1947),
similar
relationships
then decreased at higher TR.
TR was also reported
Kramer
showed
by
~ramer
(1975)
also
peas
peaked
near
TR
Decrease in yield at high
(1948)
and
Sayre
(1952).
that Alaska peas peaked in yield about TR 145
to 150, but the 'sweet peas'
Laxton
Pollard
for irrigated vining peas, but
found that the yield of non-irrigated
120,
by
Ottosson (1958), and Salter (1963).
Anderson and White (1974a) and Pumphrey et al.
found
becoming
These relationships
were similar to yie1d-TR relationships described
et
maturity
peaked
about
TR
(garden peas) Pride
110.
Sayre,
and
Thomas
however, found that
Thomas Laxton peaked at TR 125, while Perfection peaked at TR
130-135.
Hagedorn
relationship
et
al.
in
five
(1955)
out
of
found
a
seven
trials with Wisconsin
linear
yield-TR
Perfection, and in seven of eight trials with Alaska.
three
excepted
cases,
a curvilinear relationship was found
with yield levelling off at high
harvest
means
of
some
In the
TR.
treatments
In
this
trial,
the
tended to have a linear
yield-TR relationship, but the observed data points were more
curvilinear in distribution.
The shapes of yield-TR relationships may
by a number of factors.
be
influenced
Several workers have found variation
in the yield-TR relationships of different cultivars (Pollard
et
al.
1947;
Kramer, 1948;
Sayre, 1952;
Hagedorn et al.
PAGE 106
1955;
Ottosson, 1958).
The relationship was also
be affected by irrigation (Salter, 1963,
1974a;
been
Pumphrey et ale
1975).
Other
found
to
Anderson and White,
factors
'which
have
found to affect the yield-maturity relationship include
location,
time
of
sowing,
disease,
seasonal
variation,
temperature, and soil type (Ottosson, 1958, 1968).
In this experiment the relationships between
maturity
were
yield
and
examined by regression analysis of the linear
relationship between relative yield (relative to yield at
105)
and
log(TR-75).
The
slope
of a common line for the
pooled data from irrigated treatments (excluding
significantly
treatments.
steeper
When
only
however,
was
cultivar- results were
found
to
have
different relationship for each irrigation
4.4.6,
Figure
Gf.68)
was
than the comparable line for all N.R.
~individual
Tere
TR
The
4.4.9).
slopes
a
analysed,
significantly
treatment
for
(Table
both' irrigation
treatments of Piri and Pania were clearly very similar, while
those
for
relative
Gf.68
were
not
yield-Iog(TR-75)
be
comparable
relationship
of
due to the poor
the
irrigated
treatment (R 2 =26%).
The inconsistency of these results indicates that
relationships
these
have also been affected by interaction between
the imposed treatments and the period of heavy rain discussed
above.
The objective of comparing the yield-TR relationships
of several vining pea cultivars in the presence or absence of
irrigation, therefore, could not be achieved.
PAGE 107
Tere was the only cultivar which apparently escaped
adverse
effects
could be
of
examined
the
for
heavy
the
yield-maturity relationship.
rain, so only this cultivar
effect
of
irrigation
is
consistant
with
of
a
decrease
the
the
N.R.
with the results of Salter (1962),
Anderson and White (1974a) and Pumphrey et ale
absence
on
The greater rate of increase in
relative yield from irrigated Tere, compared
treatment
the
in
yield
at
(1975).
high
The
TR by any N.R.
treatment, including Tere, was possibly due to the period
of
rain.
The relative yield of Tere at several stages of maturity
was
compared
with
results
from
several
similar
trials
conducted elsewhere, where curved yield-TR relationships were
found
(Table
5.4.1).
The
results from irrigated Tere are
very like those of. irrigated Victory Freezer and Dark Skinned
Perfection
reported
Pumphrey et ala
by
Anderson
and
(1975), respectively.
White
They
(1974a)
and
also
very
are
similar
to the results for Perfection given by Pollard et ala
(1947).
The
Victory
Freezer
results
and
decrease at high TR,
however,
of
N.R.
DSP,
as
Tere
in
that
discussed
the results of N.R.
number
and
of
location.
similar
yield
above.
from
dryland
of Tere did not
Up
to
TR
120
Tere, Victory Freezer, and DSP
are all very similar, in spite of
time,
differ
differences
in
cultivar,
The agreement among the results from a
trials
is
also
generally
good,
relative yield at TR 140 varying most (Table 5.4.1).
with
PAGE lOB
Table 5.4.1 Comparison of relative yields from several
sources, at TR 90, 120 and 140, (yield at TR 105 = 100.)
Source
Relative yield
Treatment
TR 90
TR 120
TR 140
This Trial
(Lincoln 1979/BO)*
Tere
Tere
N.R.
IRR.
B2.2
75.2
10B.7
114.5
116.5
127.5
Anderson and White
(1974a)*
(Lincoln 1970/71)
Victory
Freezer
N.R.
IRR.
73.8
79.2
110.0
116.0
106.8
132.1
Pumphrey et al.
(1975) 17 trials
over 11 years
in Oregon *
Dark
N.R.
Skinned
Perfection IRR.
73.5
75.9
110.7
114.3
104.7
121. 2
Pollard et a1.
(1947) Several
trials in Utah
(1943-45)**
Perfection
Early
Perfection
78.0
114.5
128.6
63.4
112.4
132.5
Sayre (1952)
Several trials in
N.Y. 1948-51**
Thomas
Laxton
Perfection
---
78.9
81.3
110.5
113.8
111.2
119.4
Ottosson (1958)
157 trials in
Sweden 1951-57 **
Several
cultivars
--
76.0
119.0
134.0
*
**
--
--
,-
calculated from data given
estimated from plotted data
Ottosson
(1958)
relationship
was
(fertile) nodes.
nodes
than
a
postulated
function
that
of
the
the number of pod bearing
Although irrigated Tere
Tere
N.R.,
the
same
yield-rna turi ty
was
had
more
rtile
also
true
for the
irrigated treatments of the other cultivars,
show
significant
relationships
From
this
of
differences
their
respective
which
between
the
irrigation
did
not
yield-TR
treatments.
study it appears that the number of peas per pod,
and particularly the number of peas per pod at higher fertile
nodes,
are
also
yield-maturity
a
major
determinants
relationships.
Irrigated
of
the
Tere
shape
also
of
had
PAGE 109
considerably
more
pods
at
the
third F.N.
than Tere N.R.
(Table 4.6.4) and the proportion of peas per plant
the
second,
borne
at
third and subsequent fertile nodes by irrigated
Tere plants (71%) was much higher than that borne at the same
nodes by N.R.
plants (48%, Table 4.6.6).
that the yield
considerably
of
peas
from
higher
nodes
was
increased
by irrigation, which caused a delay in the rate
of maturity and maintained a higher rate
compared
These results show
with
of
yield
increase
unirrigated plants of the same cultivar.
The
mechanism of yield increase, was by an increase in number
fertile
nodes,
of
peas per pod , and pods per node at elevated
nodes, rather than an increase in the number of fertile nodes
alone, as reported by Ottosson (1958).
Lack of change in vine yield with maturity, as found
this
trial,
has
also
been
reported by Lynch and Mitchell
(1953), Mitchell and Lynch (1954) and Ottosson (1958).
and
Lynch
Mitchell (1953) concluded that the potential increase in
vine yield due to increase in
compensated
by
increase
the
weight
of
peas
may
be
the loss of a similar weight of water during
maturity of the vine.
It is also probable that much
of
the
in pea weight is due to transportation of water and
assimilates from the plant
(Pate
in
and
would occur.
body
into
the
developing
peas
Flinn, 1977), so little net change in vine weight
PAGE 110
5.5 EFFECT OF MATURITY ON GROSS RETURN FROM GREEN PEA
CROPS.
The relationship between gross return
and
TR
for
all
treatments were very similar (Figure 4.4.11), suggesting that
one payment scale might satisfactorily serve for a number
different
vining
pea cultivars.
Gross return, however, was
negatively correlated with pea yield, TR, and harvest
(Table
4.4.6),
TR 100 (Tables
decreased
and
was
4.4.1
4.4.4,
number
for peas harvested under
Figure
4.4.11).
Returns
with maturity to a minimum between TR l19_and 131,
An
depending on treatment.
between
greatest
to
of
gross
return
almost
identical
relationship
and TR was described by Sayre (1952),
for Perfection peas grown in New York.
The relationship
for
Thomas Laxton peas was also similar, except that gross return
continued to decrease above TR 135.
Pollard et ale
yield
relationships
(1947) described
of~
of
peas
gross
produced.
flat
rate,
the
high TR.
should
opposite
applied
adjusted
to
on
give
a
low
TR,
to peas of poor quality with a
These workers suggested that the
be
based
In that situation, poorest gross
returns were obtained for high quality peas with
while
return-pea
Perfection and Early Perfection peas
grown in Utah, where payment was on a
weight
the
producers
payment
of
schedule
low TR peas "a
greater or at least equal" gross return compared with growers
producing
high
TR
high quality product.
to
produce
peas, and thus encourage production of a
Sayre (1952) states that encouragement
high quality peas was the reason why the payment
system which he described, was designed.
In New Zealand this
PAGE III
system
seems
unfair
to the grower, who has no control over
the maturity at which his crop will be harvested.
The pea processing industry in Canterbury depends on
export
market
which
demands
an
inexpensive product, so a
comparatively high proportion of the
high
TR
(R.K.
Cawood,
pers.
crop
comm.).
is
harvested
be
of
the
every-day-catering
(TR 90-115),
and
(TR 115-120).
The probability of a crop being
an
advanced
TR,
the
peas
(E.D.C) grade (TR 120 to
130),'while 38% of the peas packed were in the
the
at
Over the past five
years, the market has required (on average) 48% of
to
an
remaining
14%,
retail
grade
catering
grade
harvested
at
yielding a relatively low gross return, is
therefore comparatively high.
Under the current system a farmer can conceivably obtain
a
higher gross return for a poor low yielding crop harvested
early, than an agronomically
advanced maturity.
better
crop
harvested
at
an
It is the desire of pea growers to ensure
that TR-payment scales are aligned with the concept of
equal
gross return from a crop, regardless of the maturity at which
it is harvested (Anon., 1977;
and
Process
Growers
P.C.
Federation,
Boyes,
pers.
N.Z.
Vegetable
comm.).
An ideal
formula, embracing all situations, is probably impossible
obtain,
climate,
as
many
time
yield-maturity
separate
scales
variables
of
sowing,
relationship
were
(e.g.
soil
probably be impracticable.
soil moisture, cultivar,
type
etc.)
(Ottosson,
developed,
to
their
affect
1968).
the
Even
application
if
would
PAGE 112
It is apparent
relative
yield
of
from
Table
5.4.1,
however,
that
the
most cultivars, especially from TR 90 to
120 remain within reasonably
narrow
limits.
An
"average"
gross return-TR relationship, therefore, more satisfactory to
growers than that currently in use, should be attainable.
general
the
irrigated
and
N.R.
treatments set upper and
lower limits for relative yield at a given TR (Table
This
suggests
that
In
5.4.1).
one scale for irrigated and another for
non-irrigated peas may be
appropriate.
As
found
in
this
trial, however, non-irrigated plants may not always behave as
such.
Although
irrigation
the
relationships
treatments
for
most
cultivar
x
were not significantly different, the
effects of heavy rain precluded valid comparisons being made.
A
satisfactory
general
relationship for several cultivars,
with and without irrigation, therefore, was not found.
PAGE 113
5.6 RELATIONSHIP BETWEEN OBSERVED AND PREDICTED YIELD
OF PEAS.
The
observed
mUltiplication
yield,
of
yield
and
yield
components
treatment, mainly to confirm the
components
used
elsewhere
predicted
from
the
were compared for each
reliability
in this study.
of
the
yield
The relationship
between the two yield parameters for each treatment, however,
varied considerably.
Two main factors are recognised which may partly explain
the
discrepancy.
samples
on
Firstly, for practical reasons, the plant
which
yield
collected
for
commenced.
Weight per pea was not
because
many
each
components
of
the
treatment
ovules
were
immediately
measured
counted
The pea weight factor used in the
predicted
yield,
data.
before
at
were
vining
that
stage
were still small and
immature.
therefore,
measured,
calculation
of
was derived from the vined pea
The average weight/pea for the
vined
peas,
however,
was based on a sample from which very small peas «7.lmm) had
been
discarded.
artificially
This
weight
factor
would
be
high, because the number of peas counted in the
yield component analysis included the very small
yield
therefore
predicted
from
the
yield
components
peas.
The
was therefore
inflated, as there was no way of estimating at the time yield
components
were
measured,
which
peas would be larger than
7.lmm at TR 105.
The second source of error which may explain some of the
discrepancy
in yields, was the failure of predicted yield to
PAGE 114
take into
account
component
ovule
or
measurement),
pod
abortion
although
this
(subsequent
possibly
to
occurred
(Hardwick, Andrews, Hole and Salter, 1979), especially in the
waterlogged plots.
In this trial, therefore a very close agreement
the
observed
and
predicted
yield
because of problems relating to the
which
yield
components
were
however, had similar levels of
could
between
not be expected,
early
growth
measured.
stage
Tere
difference
and
between
at
Piri,
the
two
yield parameters for each irrigation treatment (Table 4.7.2).
In contrast,
between
Pania
and
Gf.68
difference
Gf.68,
much
poorer
agreement
the two yield values for the irrigated (waterlogged)
treatment than for the N.R.
large
had
may
treatment
exhibited
also
reflect
by
the
(Table
4.7.2).
The
Gf.68, especially irrigated
difficulty
of
vining
this
cultivar.
It was obvious from these
predicted
comparisons
(observed)
yield.
The
higher than observed yield
considered
7.lmm at TR 105.
potential
yield
and
method
for
predicted
may
be
estimating
yield was always
more
realistically
an estimate of potential yield, assuming that all
peas counted developed to
obviously
pea
from yield components, taken at a relatively early
stage of rna turity, is not a reliable
vining
that
have
yield
maturity,
and
were
larger
than
Environmental and genetic factors, however,
a
profound
realised.
affect
on
Hardwick
the
proportion
et
encountered similar problems when they failed to
ale
of
(1979)
rela te
the
yield of pea crops to several yield components, including the
PAGE 115
number of pods per plant, and the number of pods at
each
of
the first four fertile nOdes.
Comparison between predicted and observed yield did
confirm
the reliability of the yield components, but did not
prove their unreliability either.
yield
not
components
It did show, however, that
may not be a reliable basis for predicting
vining pea yield, particularly when the
measured at a practical harvest stage.
components
are
not
CHAPTER
6
CONCLUSION
PAGE 116
CHAPTER 6
CONCLUSION
The maturity of
correlated
AIS
with
than
AIS,
were
relationship
peas
measured
by
TR
was
highly
and moderately better correlated with
other
between
as
methods
AIS
tested.
Although
the
and TR differed among treatments,
the variations were similar to those reported elsewhere.
tenderometer
is
a
reliable,
fast
and
measuring the maturity of raw green peas.
is
not
available
analysis.
maturity
can
frozen
raw
peas
weight can be analysed later.
method for
If a
tenderometer
measured
by AIS or TS
When immediate measurement on fresh
inconvenient,
sieve
be
simple
The
raw
peas
is
with a known original fresh
The weight per pea and average
size measurements would be less acurate, as the amount
of change over a large maturity range is comparatively small,
and
they
are
also
more
susceptible
to
cultivar
and
environmental variation.
Only one
irrigation.
cultivar,
Tere,
gave
yield
response
treatments.
The
timing
waterlogging
of
the
in
period
waterlogging confirmed research elsewhere that pea roots
very
to
The effect of irrigation on the other cultivars
was inconclusive, as heavy rain caused
irrigated
a
sensitive
to
the
of
are
anaerobic conditions close to flowering.
Yield of the natural rainfall treatments of Pania
and
Gf.68
was enhanced by the rain.
The yield response of Tere to irrigation, was due to
increase
in the number of fertile
nodes~per
an
plant and number
PAGE 117
of peas per pod, especially at the higher fertile nodes.
number
of
fertile
treatments
decreased
of
nodes was also higher in the waterlogged
Piri,
the
number
Pania,
of
and
peas
Gf.68,
per
but
pod.
waterlogging in this trial emphasises the
control
The
waterlogging
The
need
effects of
for
careful
of soil moisture for peas about the flowering stage.
The adverse effects of anaerobiosis may occur more frequently
than
recognised,
especially
on heavier, moisture retentive
soils, and soils which are compacted.
Irrigation
maturity,
and
prolonged
with
the
flowering,
exception
delayed
of Pania, increased the
duration of the harvest period (TR 90 to l40).
TR
.increase
by
irrigated
harvest
The
rate
of
treatments was slower during the
first four days of harvest, but after that TR increased at
rate
similar to the natural rainfall treatments.
The delays
in maturity of the irrigated treatments may result
increased
proportion
exponential,
from
the
of total yield borne at higher fertile
nodes of irrigated plants.
be
a
TR increase with time
although
day
to
day
tended
changes
to
were
occassionally very small or negative.
In all treatments the proportion of peas in
and
large
medium
grades changed most rapidly, so that about 80% of
the peas were in the large grade at the end
period.
the
Change
in
average
of
the
harvest
sieve size was moderately well
correlated with increase in green pea yield.
Green
pea
yield
of
all
treatments
increased
with
maturity, but the rate of increase was curvilinear, declining
PAGE 118
as the peas matured.
most
cultivars
The
were
yield-maturity
very
similar
and
unaffected by irrigation treatments.
rain
on
these
treatments,
relationships
The
were
apparently
effect
however,
of
heavy
precluded
valid
comparison, and this aspect should be re-examined under
suitable
environmental
conditions.
of
more
In addition, the effect
of controlled waterlogging treatments on a range of
maincrop
vining pea cultivars should be thoroughly investigated.
The irrigated treatment
waterlogging,
had
a
of
Tere,
significantly
in
greater
increase with maturity than the natural
The
steeper
yield-TR
curve
was
absence
rate
rainfall
of
of yield
treatment.
due to an increase in the
proportion of peas borne at higher nodes.
at
the
Prudent irrigation
flowering and podfill is therefore recommended as a means
of delaying the onset of harvest
maturity
while
increasing
the rate of yield accummulation.
However, because Tere is an
early maturing cultivar, general recommendations
be
should
drawn from the results of this cultivar alone.
not
Most peas
grown for processing are later maturing and usually have
potential to set more peas
Gross returns were
maturity,
r plant than early cultivars.
negatively
correlated
with
Peas from TR 119 to 131 attracted
the
gross returns, approximately two thirds of the maximum.
which
yield,
and time of harvest, with maximum returns for peas
under TR 100.
trend
the
~pplied
to all
treatments
including
irrigated
lowest
This
Tere,
had the greatest rate of yield increase with maturity.
The results show that the payment sca
which applied
the
similar gross returns
1979/80
season
did
not
ensure
during
irrespective of
maturity
however,
the
that
at
gross
harvest.
They
return-TR
treatments was similar, and that one
do
indicate,
relationship
payment
of
scale
all
may
be
measured
on
applicable to a range of different cultivars.
Yields
plants
predicted
at
an
from
early
stage
observed (vined) yield.
the
use
of
an
yield
of
components
maturity
were
The differences were
higher than
attributed
to
inappropriate weight/pea factor, and to the
abortion of peas and pods, especially by plants stressed with
waterlogging.
Both
problems
were associated with the fact
that yield components were measured
maturity,
so
the
the
case
of
Gf.68,
and
early
stage
observed
be
accurately
determined.
the
lack
yields.
of
The
agreement
results
between
show
that
analysis of yield components was an aid to understanding
effect
of
different
treatments on yield.
reliable
for
especially
final
green
pea
yield,
method
measurements were taken at a comparatively immature stage
development.
the
It may also have
indicated potential yield, but it was not a
estimating
of
a cultivar with pointed pods, poor
vining also contributed to
predicted
an
status of yield components at the optimum
harvest stage (TR 105) could not
In
at
when
of
ACKNOWLEDGEMENTS
PAGE 120
ACKNOWLEDGEMENTS
I
am indebted
guidance,
to
many
encouragement,
this project.
people
for
their
and criticism during the course of
cannot mention everyone
I
assistance,
some way, but to those not
who
helped
me
in
cifically named, including many
personal friends, I extend my thanks.
Others to
whom
I
am
especially grateful are:
Prof.
advice
in
J.G.H.
the
encouragement;
White, my supervisor,
for
guidance
planning and conduct of the trial;
and
patient
and
helpful
and
positive
criticism
during
preparation of the manuscript.
Dr
W.A.
Jermyn
wise
encouragementi
advice
on
thesis
D.S.Goulden,
and
much
for
and
words;
preparation.
needed
coaxing
understanding,
Also
Mr
and
helpful
T.P.Palmer,
Mr
Dr J.W.Ashby for comments and criticism of
the manuscript.
Mr G.
Meijer and staff at the Field Service Centre
assistance
with
sowing
and
irrigating
the
for
trial,
and
Webster
and
supplying vehicles when necessary during harvest.
Mr R.A.
others
who
Banfield, Mr D.
Lake, Miss B.M.
assisted with planting, field work, and harvest,
sometimes giving up summer weekends to do so.
Mr
A.R.
Wallace
for
advice
statistical analysis of results.
and
assistance
with
PAGE 121
Members of Applied Biochemistry Division, DSIR, Lincoln,
for
sharing space, equipment and ideas which made laboratory
analysis of frozen samples possible.
Miss K.B.
and
Mr
Hatherton, Miss A.
R.
Lamberts
for
Hodgins, Mr
advice
and
W.
Rennie,
assistance
with
preparation of figures.
Dr A.
McKinnon and Dr
P.D.
Jamieson
for
assistance
with final printing of thesis.
J.
Wattie's
available,
and
Canneries
particularly
for
making
Mr R.K.
the
tenderometers
Cawood for advice and
discussion on several aspects of the trial and thesis.
The DSIR for supplying
seed,
miniviner,
and
computer
facilities used for data analysis and thesis preparation.
And
finally
laboratory
thesis.
Mr
A.C.
Russell
who
assisted
with
analysis of frozen samples and typed most of this
with willingness and reliability he assisted most in
the completion of this study.
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PAGE 122
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Objective methods for determining the
maturity of peas, with special reference to the
frozen product. Technical bulletin 256. 17pp.
New
York State Agricultural Experimental-siation.
Lee, F.A. 1941b: Determining the maturity of frozen peas
A rapid objective method. Industrial and engineering
chemistry, analytical edition 13: 38-39.
Lee, F.A.; Whitcombe, J.; Hening, J.C. 1954:
A critical
examination
of
objective
methods for maturity
assessment in frozen peas.
Food technology
8:
126-133.
Lesic, R. 1975: Parameters of yield and of quality by
processing
peas
in
ripening
process.
Acta
horticulturae 52 :223-229.
Lund,
R.E.
1975:
Tables for an approximate test
outliers
in
linear
models.
Technometrics
473-476
for
17:
Lynch, L.J.; Mitchell, R.S:
1950: Physical measurement of
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of Australia.
Lynch, L.J.;
Mitchell, R.S.
1953:
The definition and
prediction of the optimal harvest time of pea canning
crops. Bulletin 273. 44pp. CSIRO of Australia.
PAGE 127
Lynch, L.J.1 Mitchell, R.S.1 and Casimir, D.J. 1959:
The
chemistry and technology of preservation of green
. peas .. ·· A{3vances in food research 9: 61-151.
McCready, R.M.; Guggolz, J.i
Silviera, V.;
Owens, H.S.
1950:
Determination
of starch and amylose in
vegetables
Application
to
peas.
Analytical
chemistry ~7: 1156-1158.
McKee, H.S.; Robertson, R.N.; Lee, J.B. 1955:
Physiology
of pea fruits 1. The developing fruit. Australian
journal of biological
ience 8: 137-163.
McLoed, C.C. 1979: Pea rates of seedingxfertiliser trial
results 1970-78.
In Jermyn, W.A. ed. Proceedings
of pea agronomy workshop, Lincoln college, July 20,
1979. 25pp.
McMahon,
C.R.;
Cassidy, K.S.;
Isaacs, R.
1981:
The
Lockyer processing pea variety testing programme,
1980. Queensland Horticulture technical memorandum
no. 4.
6lpp. Queensland Horticulture Department of
Primary Industries, Brisbane.
MAF, 1980: New Zealand horticulture statistics 1980.
Media
services,
Ministry
of
Agriculture
Fisheries, Wellington.
Makower, R.U. 1950:
maturity of
403-408.
Methods of measuring the tenderness and
processed peas.
Food technology 4:
Makower, R.U.;
Boggs, M.M.;
Burr, H.Kd
1953:
Comparison of methods for
maturity factor in frozen peas. Food
43-8.
Martin,
R.J.
1981:
vining peas.
agriculture 2.:
41pp
and
Olcott, H.S.
measuring the
technology 7 :
Yield-tenderometer relationships in
New Zealand journal of experimental
387-391.
Martin, R. J • i Tab1ey, F. J • 1981:
Effects of irrigation,
time of sowing, and cultivar on yield of vining peas.
New Zealand journal of eXEerimental agriculture 9:
297.
PAGE 128
Martin, S. 1977: Nutrient values of frozen vegetables as
compared to fresh and canned. Quick frozen foods
40.34-36, 38, 41-44, 46-47, 49-50, 52-53, 233-236,
245.
(Food science and technology abstracts (1980)
12: 84-(abstract no. IJ 128).
Martin, T. 1944 Quality grading of peas by brine separation.
Food packer ~(April):
34-36.
Martin, W.M. 1937: An apparatus for evaluating
in peas. Canning trade ~(29): 7-14.
tenderness
Martin, W.M.; Lueck, R.H.; Sallee, E.D.
1938:
Practical
application of the tenderometer for grading peas.
Canning age 19(March): 146-149, 193-196.
Maurer, A.R.; Ormrod, D.P.; Fletcher, H.F. 1968: Responce
of peas to environment 4. Ef ct of five soil water
regimes on growth and development of peas.
Canadian
journal of ~ant science 48: 129-137.
Mitchell, R.S.; Lynch, L.J. 1954: The optimal canning time
of pea canning and freezing crop in New York State.
II. The short term prediction of optimal harvest
time. Food technology 8: 187-88.
Monson, O.W. 1942: Irrigation of seed and canning peas in
the Gallatin Valley, Montana. Bulletin 4P5. 23pp.
Montana Agricultural Experiment
Neilsen, J.P. 1943: rapid
index to maturi
and engineering
38-39.
determination of starch
an
starchy vegetables. Industrial
analytical edition 13:
Nielsen, J.P.; Campbell, H.i
Bohart, C.S.;
Masure,M.P.
1947:
Degree of maturity influences the quality of
frozen peas. Part II. Food Industries 19: 103-106,
204.
Neilsen, J.P.; Gleason, P.C.
starch.
Industrial
analytical
NeIder, J.A.
1945: Rapid determination of
and
engineering chemistry,
131-134.
1963: Yield-maturity relationships in peas.
reeort of the National Vegetable Research
Stat10n, Wellesbourne (1962)13: 64.
Annu~l
PAGE 129
Ottosson, L. 1958: Growth and maturity of peas for canning
and freezing_ Vaxtodling, Plant Husbandry 9. l12pp.
Almqvist and Wikel Is, Uppsala.
Ottosson, L.
1968:
(Experiments with vining peas
4.
Harvest
time,
maturation
and
weed
control. )
Lantbrukshogskolans Meddelanden serie ~ nr.
106.
1-32.
Pate,
Flinn, A.M. 1977: Fruit and seed development.
In.
Sutcliffe,
J.F.:
Pate, J.S.
eds.
The
Physiology of the Garden Pea.
AcademiC-- Press.
London. 500p.
J.S.~
Pollard,
L.H.1
Peterson, H.B.;
Wilcox,
E.B.
1944:
Influence of stage of maturity on yield and quality
of perfection peas. Western Canner and packer May
1944: 19-39.
Pollard,
L.B.:
Wilcox, E.Bd
Peterson,
H.B.
1947:
Maturity studies with canning peas. Bulletin 328
16pp. Utah Agricultural Experimental Station.
Pumphrey, F.V.1
Ramig,
R.Ed
Allmaras,
R.R.
relationships
in 'Dark
Xield-tenderness
Perfection' peas. Journal of the American
for Horticultural Science 100: 507-509.
1975:
Skinned
Society
Pumphrey, F.V.: Schwanke, R.K. 1974: Effects of irrigation
on growth, yield and quality of peas for processing.
Journal of the American Society for Horticultural
Science 99:---104-106.
Reynolds, J.D.
1966:
Methods for assessing vining pea
varieties in field trials. Journal of the National
Institute of Agricultural Botany 10: 571-593.
Reynolds, J.D. 1970: Improvement and evaluation of vining
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Institute of Food Science and Technology,
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different growth stages.
Journal of horticultural
science 37: 141-149.
Salter,
P.J.
1963:
The effects of wet and~ dry soil
conditions
at
different
growth stages on the
components of yield of a pea crop.
Journal of
horticultural science 38
321-334.
PAGE 130
Salter, P.J.; Drew, D.H. 1965:
the response of Pisum
Nature 206:
1063-1064.
Root growth as a factor in
sativum L.
to irrigation.
Salter, P.J.; Goode, J.E. 1967: Crop responses to water at
different
stages
of
growth.
Commonwealth
Agricultural Bureaux, Farnham Royal, Bucks,
England.
245p.
Salter,
P.J.;
Williams, J.B.
1967:
The
effects
of
irrigation on pea crops grown at different plant
densities.
Journal of horticultural science 42:
59-66.
Sayre, C.B. 1952: Tenderometer grades, yields,
and
returns of peas. Canning trade 74(51): 8-9.
Sayre,
gross
C.B.
1954:
Comparison of the tenderometer and
maturometer for measuring the quality of raw peas.
Proceedings of the American Society for Horticultural
Science 63: 371-377.
Sayre, C.B.; Willaman, J.J.;
Kertesz, Z.I. 1931:
Factors
affecting the quality of commercial canning peas.
Technical bulletin 176.
76p.
New
York
State
Agricultural Experimental Station.
Schippers, P.A. 1965a: Evenness of maturity and rate of
ripening in peas. Otara report no.~.
l6pp. Crop
Research Division, DSIR.
Schippers, P.A.
1965b:
Changes in agronomic characters
during ripening of peas. Otara report no. 2. 14pp.
Crop Research Division, DSIR.
Schippers, P.A. 1969:
Maturation of peas 1.
A visual
method of maturity assessment. Netherlands journal
of agricultural science 17:
153-160.
Schoonens, J.G. 1971: Recording and estimating the maturity
and
yield
of pea plants.
Food technology in
Australia 23:
156-164.
Seaton, H.L.
1955:
Scheduling plantings and predicting
harvest maturities for processing vegetables. Food
technology ~202-209.
PAGE 131
Shook, C.F. 1932: Quality grading of peas as an
comply with the McNary-Mapes standards.
trade 54(39): 10-11.
Smittle,
aid to
Canning
D.A.;
Bradley, G.A.
1966:
The
effects
of
irrigation, planting and harvest dates on yield and
quality of peas. Proceedings of the American Society
for Horticultural Science 88:
441-446.
Stoker, R. 1973: Response of viner peas to water during
different phases of growth. New Zealand journal of
experimental agriculture ~ 73-76.
Stoker, R. 1975: Effect of plant population on yield of
garden peas under different moisture regimes. New
Zealand journal of experimental
agriculture ~
333-337.
Stoker, R. 1977:
Irrigation of garden peas on a good
cropping soil.
New Zealand jo~rnal of experimental
agriculture ~ 233-236 •
Strachan, G.
1956:
An
. Torfason, W.E.; Nonnecke, I.L.;
evaluation of objective methods for determining the
maturity of canning peas.
Canadian journal
of
agricultural science 36: 247-254.
Turner, D.H.; Turner, J.F. 1957: Physiology of pea fruits.
III Changes in starch and starch phosphorylase in the
developing seed. Australian journal of biological
science 10: 302-309.
Turner, J.F.; Turner, D.H.; Lee, J.B. 1957: Physiology of
pea fruits.
IV Changes in sugars in the developing
seed. Australian journal of biological science 10:
407-413.
Voisey, P.W.; Nonnecke, I.L.
1973a:
tenderness II.
A review of
texture studies 4: 171-195.
Measurement of pea
methods. Journal of
Voisey, P.W.; Nonnecke, I.L.
1973b:
Measurement of pea
tenderness V.
The Ottawa pea tenderometer and its
performance in relation to the pea tenderometer and
the FTC texture test system.
Journal of texture
studies 4:323-343.
PAGE 132
Walls, EoPo1 Hunter, H.A.
1938:
Grading
The
quality, 1937 investigations.
14-15, 20-22.
Walls,
raw peas for
canner ~(11):
E.P.;
Kemp, W.B.
1939:
Relationship
between
tenderometer readings and alcohol insoluble solids in
Alaska peas. Proceedings of the Americam Society for
Horticultural Science 37: 729-730.
Wecke1, KoG.; Kuese1, D.C.
1955:
Quality and yield of
fresh and processed peas.
Research bulletin 186,
of
Wisconsin
Agricultural
33pp.
University
Experiment Station.
White, JoG.H.; Sheath, G.W.; Meijer, G.
1982:
Yield of
garden pea - field responses to variation in sowing
rate and irrigation.
New
Zealand
journal
of
experimental agriculture 10:
155-160.
Wraight, M.J. 1976: Assessment of new vining pea cu1tivars
in Hawkes Bay. Proceedings of the Agronomy Society
of New Zealand 6:
19-22.
APPENDICES
PAGE 133
APPENDIX 1
RAINFALL AND TEMPERATURE DATA OVER THE
PERIOD OF THE TRIAL.
Source: Lincoln College Meteorological Station
(Lincoln no. 3, Station H32643)
Table Al.l Monthly rainfall and temperature data for
----the months including the trial period (data
given here is for the whole month,
and not
just the days in the trial period).
data (oe)
Temperature
Month
Year
Rain
(mm)
EPT
ft
max.
min.
mean*
AHU**
Nov.
1979
50.9
99.9
19.0
8.7
13.9
236.8
33.3
127.2
21.9
9.9
15.9
307.4
134.9
115.1
22.4
10.6
16.5
325.1
55.3
90.1
21.0
10.7
15.9
287.2
Dec.
Jan.
tl
1980
Feb.
tl
# Evapo-transpiration calculated by the Priestly-Taylor
method.
* mean=arithmetic average of daily means for the month.
The daily mean is: (max. + min.}/2
** Accumulated heat units above a base temp. of 4 o C.
Figure Al.l Daily rainfall and mean daily temperature
over the flowering and harvest period (17/12/79
.
to 4/2/80; rainfall under 0.5mm not shown).
,-...
0
108.9rnrn
0
'-"
l.LJ
0::
E
25 ""'
E
.......
c5
::J
Ia:
0::
20
~0
lLJ
IL
Z
L
l.LJ
I- 15
15
>-
0
II
Z
LLJ
>-
10 «
0
a: 10
L
«
0:
I:::::!
-.J
;-;
a:
-l
-l
«
u..
S
0
5
3S
(17/12179)
41:
4~
56
63
DAYS FROM SOWING
713
77
84
«~
0)
PAGE 134
DAILY WEATHER DATA OVER THE TRIAL PERIOD
Table A1.2 Temperature and rainfall data for November
---- 12 to 31, 1979.
Days from
sowing
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Date
Nov.
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Daily
rain
(mm)
----6.1
0.2
---
--2.0
23.7
1.1
------------0.2
--5.9
---
Daily
Max.
22.5
21.8
15.7
13.8
17.9
23.2
17.4
17.3
'19.2
20.6
22.8
23.2
22.0
19.4
20.5
24.8
22.6
21.0
22.7
temperature (oe)
Min.
2.9
8.9
11.5
7.6
3.9
8.6
10.6
11.0
12.2
9.5
9.5
7.8
7.6
8.5
11.0
14.1
13.5
11.4
10.9
mean
12.70
15.35
13.60
10.70
10.90
15.90
14.00
14.15
15.70
15.05
16.15
15.50
14.80
13.95
15.75
19.45
18.05
16.20
16.80
PAGE 135
Table Al.3 Temperature and rainfall data for December, 1979.
Days from
sowing
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
Date
Dec.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Daily
rain
(mm)
--9.3
--------0.2
----0.9
0.3
----5.4
----------0.4
--------0.4
7.8
8.6
---------
Daily
temperature (oC)
Max.
Min.
mean
21.5
25.5
20.3
19.9
20.4
28.9
15.2
16.0
16.8
21.4
22.6
23.4
19.7
20.5
17.9
23.9
28.6
26.0
23.4
24.5
20.0
26.0
29.4
30.5
28.9
21.4
14.4
15.6
16.3
19.5
19.6
9.2
15.1
11.9
4.7
5.1
9.5
4.3
4.5
8.4
12.5
12.5
13.2
6.1
8.0
12.2
4.0
11.3
16.8
7.3
8.1
9.5
10.7
13.9
18.5
21.6
6.7
8.8
11.2
10.2
6.4
4.7
15.35
20.30
16.10
12.30
12.75
19.20
9.75
10.25
12.60
16.95
17.55
18.30
12.90
14.25
15.05
13.95
19.95
21.40
15.35
16.30
14.75
18.35
21.65
24.50
25.25
14.05
11.60
13.40
13.25
12.95
12.15
PAGE 136
Table Al.4 Temperature and rainfall data for January
and February 1 to 4, 1980.
Days from
sowing
SO
Sl
S2
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
Date
Jan.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Daily
rain
(mm)
---
108.9
5.7
-------
-----
----0.5
2.4
----0.9
2.0
----0.2
---
--8.3
6.0
-----------------
Daily temperature (oC)
max.
min.
mean
22.1
20.1
11.5
15.4
17.5
18.4
19.7
20.9
18.4
21.3
20.5
24.4
26.4
25.0
21.0
27.7
13.4
19.3
25.6
24.8
22.9
20.3
19.5
25.6
25.5
27.2
29.0
24.8
23.2
31.2
31.7
13.9
12.0
8.3
8.2
5.9
9.2
11.9
8.2
9.9
9.4
13.0
13.4
11.5
11.4
15.2
16.2
11.6
4.6
10.2
6.9
11.2
7.7
14.2
7.6
8.8
6.8
16.5
5.1
11.5
14.5
12.6
18.00
16.05
9.90
11.80
11.70
13.80
lS.80
14.55
14.15
15.35
16.75
18.90
18.95
18.20
18.10
21.95
12.50
11.95
17.90
15.85
17.05
14.00
16.85
16.60
17.15
. 17.00
22.75
14.95
17.35
22.85
22.15
24.9
30.5
31.1
18.6
10.3
12.7
14.9
14.5
17.60
21.60
23.00
16.55
Feb.
81
82
83
84
1
2
3
4
----0.1
0.6
APPENDIX 2
DETAILS FOR SOWING WITH STANHAY PRECISION SEED.DRILL.
Table 2.1
Cultivar
Sowing details for field trial.
Holes/belt
Hole size
(mm)
Pulley
*
Seed
spacing
(mm)
Seeds/m
2
Germination
(% )
Expected
populatio~
(plants/m )
Tere
40
11.1
std.
5.71
116
92
106.7
Piri
40
9.5
std.
5.71
116
91
105.6
Pania
40
9.5
std.
5.71
116
90
104.4
Gf. 68
36
11.1
fast
5.08
131
86
112.7
* This setting is for the pulley located at the "knee joint". A small (ie. fast) pulley may
be fitted here to facilitate sowing at heavy rates; std = standard pulley.
The A pulley on the master land wheel was used for all cultivars, and a T base was also
used at all times. Chokes were not used.
REFERENCE
Stanhay S766 Precision seed spacing drill instruction book.
"d
>
G1
ttl
I-'
W
-I
PAGE 138
APPENDIX 3
SOIL MOISTURE CHANGES OVER THE FLOWERING
AND HARVEST PERIOD
Figure A3.1 Soil moisture changes for Tere and Piri
over the flowering and harvest period:
Triangles represent observed points, and
the lines. indicate projected patterns of
soil moisture change: - y - - natural
rainfall;...
.... = irrigated;
I = peak
due to irrigation.
--...=
TERE
30
e8.
,--,.
26
"#. e4
w
a::: ee
~
I-
if)
1-1
C)
L
...-.J
I--i
C)
if)
e0
18
16
14
12
10
35
4e
56
4::1
e6
I'
J
,...."
I
I
24
I
I
w 22
a:::
~
L
...-.J
1-1
C)
if)
'.
\
\.
\
I
I
20
1
18
I
I
16
I
'.
\
\
\
\
.,
....
?
,
'v 'v.
"-
I
14
I
'1t
12
10
84
I
e8
if)
I--i
C)
77
PIRI
313
~
0
70
63
35
(17/12/79)
42
4::1
I
I
56
63
DAYS FROM SOWING
"-
.,:...
"- \ II
v
70
"-
"-
"-
.,
77
,,
84
PAGE 139
Figure A3.l Soil moisture changes for Pania and
Gf.68 over the flowering and harvest period:
Triangles represent observed points,
and
the lines indicate projected patterns of
soil moisture change: ...... - - -"T == natural
rainfall
== irrigated;
I == peak
due to irrigation.
t"
..
PANIA
e8
c6
*
24
~c.c
:J
I
t020
I--t
o
L
18
--.J
~ 16
(f)
14
12
35
4e
56
63
713
77
84
713
77
84
GREI:NFEAST 68
28
c6
14
12
1(3
35
(17/12179)
43
56
63
DAYS FROM SOwING
PAGE 140
APPENDIX 4
TR-PAYMENT SCALE FOR 1979/80 SEASON,
CANTERBURY
Table A4.1 Watties tenderometer reading-payment scale
---- for the South Island, 1979/80 season
Grade
Tenderometer reading
Price (cents/Kg)
0
Not exceeding
90
22.611
1
Over 90 not over 95
20.390
2
"
95
..
3
"
100
4
"
5
6
7
"
100
17.915
"
II
105
15.710
105
II
"
110
13.780
"
.,
110
"
"
115
13.230
"
120
11.835
II
120
115
..
10.525
* From J.Wattie Canneries green pea agreement for
South Island pea growers, 1979/80 season.
PAGE 141
APPENDIX 5
FIELD RESULTS
(FULL DATA SET FOR EACH TREATMENT)
Table A5.1 Field results for Tere (natural rainfall)
Harvest
number
Rep.
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
**
6
7
7
7
7
7
*
**
Plants per
plot
*
265
278
281
274
266
276
267
266
272
262
252
271
254
282
266
271
251
257
261
259
262
259
257
259
273
254
259
274
279
296
258
269
277
275
283
Peas per
plot (g)
1855
1744
1790
1901
1746
1984
1984
1985
1953
2111
2007
2173
2245
2094
2190
2340
2245
2267
2415
2273
2307
2252
2517
2420
2496
2386
2160
2571
2691
2590
2267
2410
2459
2445
2560
TR
92
86
89
93
88
98
95
93
91
93
104
106
102
103
103
120
113
112
114
115
130
140
126
126
135
133
143
129
137
138
160
145
141
151
152
2
Plot size for all treatments = 2.5m
Data omitted from yield analysis (see text,
Chap. 3, section 3.4)
PAGE 142
Table A5.2 Field results for Tere (irrigated).
Harvest
number
Rep.
Plants per
plot
peas per
plot (g)
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
288
245
270
277
290
256
288
256
254
285
267
259
247
281
280
266
255
268
257
265
266
262
262
267
276
256
286
264
276
285
255
265
256
265
276
228
255
263
263
276
2681
2032
1727
2384
2570
1966
2522
2119
1784
2765
2926
2100
1826
3104
2272
3113
2697
2600
3003
3137
3073
2824
2050
3039
3210
2650
2747
2686
3066
3041
2867
3287
2848
3268
3111
3362
3104
3135
3032
3298
**
**
**
TR
99
96
90
100
95
92
95
93
88
105
115
93
96
104
95
120
107
109
112
118
119
III
102
120
128
115
III
III
123
121
132
139
121
126
143
157
139
140
146
150
Data omitted from yield analysis (see text,
Chap. 3, section 3.4)
PAGE 143
-
Table A5.3 Field results for Piri (natural rainfall).
Harvest
number
**
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
**
Rep.
.'
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5·
Plants per
plot
266
259
272
276
260
266
271
262
273
254
264
273
293
260
263
270
265
274
274
274
262
256
254
265
273
261
267
272
258
256
260
262
262
269
273
Peas per
plot (g)
TR
1994
1995
1933
1911
1661
2040
1970
2052
2070
1916
2237
2226
2244
2054
2240
2331
2345
2244
2413
2258
2629
2428
2457
2587
2468
2533
2709
2657
2874
2627
2942
2515
2609
2761
2725
95
93
91
96
92
105
102
101
104
97
109
109
108
101
104
119
120
116
115
117
131
134
122
130
129
139
133
134
134.
135
149
163
153
150
159
Data omitted from yield analysis (see text,
Chap. 3, section 3.4)
PAGE 144
Table A5.4 Field results for Piri (irrigated).
Harvest
number
Rep.
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
8
8
8
8
8
9
9
9
9
9
Plants per
plot
275
276
267
266
268
255
270
259
271
258
297
254
271
267
267
280
253
256
266
270
259
246
240
268
279
260
260
263
257
272
262
268
257
263
256
262
286
250
269
270
259
258
265
283
266
Peas per
plot (g)
1447
1094
1213
1171
1343
1435
1527
1670
1594
1660
2051
1694
1950
1853
2088
2180
1968
2011
2172
2059
2006
2452
1624
2217
2204
2239
2169
2142
2175
2207
2133
2582
2153
2338
1968
2480
2620
2379
2605
2260
2496
2339
2785
2722
2471
TR
94
87
88
89
90
93
98
88
94
96
97
93
97
98
101
101
93
100
100
99
112
101
100
105
113
III
104
III
109
119
125
116
118
120
119
137
116
140
136
135
151
141
151
144
151
PAGE 145
-
Table AS.S Field results for Pania (natural rainfall).
Harvest
number
Rep.
Plants per
plot
Peas per
plot (g)
1
1
1
1
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
207
215
214
236
242
249
241
232
240
229
234
240
247
246
237
231
228
241
247
220
226
226
240
231
236
237
211
223
233
215
262
217
220
214
265
231
226
217
228
238
2392
2170
2111
2518
2487
2722
2598
2510
2342
2733
2838
2817
2783
2796
2900
3366
2795
2707
3050
3065
3078
3000
3117
2965
3440
2999
3164
3000
3365
3338
3689
3384
3127
3475
4003
3240
3259
3287
3823
3813
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
**
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
**
TR
94
92
93
92
92
99
102
98
97
94
106
110
108
107
100
112
114
109
113
104
120
118
121
117
116
140
137
127
128
123
143
134
138
138
134
181
156
154
142
159
Data omitted from yield analysis (see text,
Chap. 3, section 3.4)
PAGE 146
Table A5.6 Fiela results for Pania (irrigatea).
Harvest
number
Rep.
Plants per
plot
Peas per
plot (g)
TR
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
233
212
215
232
238
235
217
239
223
237
230
239
229
228
241
224
230
224
210
228
216
238
213
234
228
225
226
235
231
232
239
216
234
239
226
2268
2088
2180
2038
2156
2413
2225
2577
2196
2487
2430
2691
2496
2310
2807
2467
2831
2634
2549
2624
2715
3011
2686
2776
2710
2959
3210
3056
2908
3023
2785
3280
3009
2919
2969
98
88
89
92
97
99
88
93
94
95
108
97
103
96
107
113
105
112
110
106
126
114
121
119
122
138
120
134
130
127
156
132
137
144
146
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
l:'Alit;
Table A5.7 Field results for Gf.68 (natural rainfall).
Harvest
number
Rep.
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
**
**
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
Plants per
plot
243
219
224
222
225
253
240
244
217
243
248
256
250
233
222
230
223
255
242
236
222
240
207
245
219
238
226
227
221
215
229
221
237
242
208
Peas per
plot (g)
TR
1896
1812
1591
1683
1749
1962
1825
1809
1825
1927
2276
1960
2089
1987
2080
2252
2332
2094
2004
2119
2181
2292
2122
2209
2144
2445
2203
1833
2178
2321
2403
2087
2242
2308
2229
94
94
91
92
93
103
109
97
102
95
108
104
104
101
101
112
123
112
106
III
132
126
120
115
118
145
154
126
124
131
164
155
139
140
146
Data omitted from yield analysis (see text,
Chap. 3, section 3.4)
l.'l{
Table AS.8 Field results for Gf.68 (irrigated).
Harvest
number
Rep.
1
1
1
1
1
2
2
2
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
S
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
Plants per
plot
237
231
232
196
206
230
241
229
234
228
233
231
232
213
219
241
246
230
217
312
228
229
235
232
208
217
220
243
237
219
238
241
239
226
226
238
238
228
251
228
Peas per
plot (g)
TR
1683
1470
1655
1680
1399
1401
1588
1917
1644
1971
1785
1715
1902
1845
1890
1525
1720
1945
1746
1895
1873
2117
2412
1924
1689
1764
1561
1935
1951
1644
1864
1741
2508
1896
2143
2028
1855
2264
1915
1987
93
91
91
93
91
87
93
95
92
93
96
97
92
99
100
98
103
103
103
105
107
113
106
114
109
126
117
123
133
121
125
142
135
142
136
145
166
147
168
171
APPENDIX 6
RESULTS FOR MATURITY MEASUREMENT ON PEAS
(ALL DATA FROM TR, AVERAGE SIEVE SIZE
AND LABORATORY ANALYSES)
Table A6.1 Results of maturity measurements on Tere
- - (natural rainfall).
Harvest
number
Rep.
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
**
6
6
7
7
7
7
7
**
TR
92
86
89
93
88
98
95
93
91
93
104
106
102
103
103
120
113
112
114
115
130
140
126
126
135
133
143
129
137
138
160
145
141
151
152
(%)
Total
solids
(% )
Average
sieve
size
Weight
per pea
(9)
9.38
9.04
9.38
9.59
9.25
10.42
8.50
10.82
9.95
9.84
12.36
11.88
10.67
12.02
11.51
13.89
12.85
11.99
12.49
12.75
14.28
15.55
13.25
13.46
13.91
15.55
16.62
14.54
14.90
14.95
15.89
16.68
17.36
16.70
15.52
16.09
14.74
15.20
15.30
15.09
17.17
13.84
17.43
17.23
14.25
18.76
18.08
16.00
16.41
17.25
19.84
19.42
18.28
19.58
19.18
19.96
20.76
20.54
19.55
21.00
20.64
21.31
20.53
19.84
19.90
23.04
20.95
22.41
21.48
21.04
5.250
4.890
4.970
5.180
4.970
5.496
5.300
5.252
5.152
5.232
5.804
5.768
5.352
5.404
5.576
6.008
5.984
6.008
5.94.4
5.652
5.892
5.964
6.068
5.976
5.968
6.148
5.986
5.928
6.018
6.156
6.220
6.284
6.116
6.304
6.268
0.526
0.481
0.494
0.476
0.470
0.529
0.554
0.536
0.523
0.476
0.566
0.560
0.531
0.510
0.564
0.651
0.589
0.555
0.577
0.593
0.654
0.652
0.628
0.639
0.651
0.706
0.651
0.619
0.715
0.641
0.652
0.693
0.654
0.677
0.648
AIS
Data omitted from AIS-TR analysis (see text Section 3.4).
Table A6.2 Results of maturity measurements on Tere
- - (irrigated).
Harvest
number
Rep.
1
1
1
1
1
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
TR
99
96
90
100
95
92
95
93
88
105
115
93
96
104
95
120
107
109
112
118
119
111
102
120
128
115
111
111
123
121
132
139
121
126
143
157
139
140
146
150
AIS
( %)
Total
solids
(%)
Average
sieve
size
Weight
per pea
(g)
9.40
7.85
7.50
8.94
9.09
8.89
9.12
8.93
8.47
9.26
10.92
8.25
8.60
9.59
8.90
11.76
9.49
9.46
10.33
10.80
13.13
10.77
9.73
11.86
11.03
11.27
10.18
10.79
13.10
11.79
12.66
13.73
13.00
12.66
14.72
17.49
14.04
13.71
15.26
16.09
16.22
13.91
12.62
15.29
16.45
13.29
16.35
17.02
14.75
16.53
18.86
14.47
14.58
15.99
14.70
18.93
15.94
17.19
15.95
16.33
20.79
19.31
15.49
18.41
18.47
18.22
17.38
18.27
17.75
19.07
17.43
17.97
16.81
15.73
18.50
20.90
20.72
19.97
19.91
18.70
4.832
4.616
4.166
4.976
4.764
4.128
4.542
4.320
4.194
4.812
5.488
4.692
4.480
5.496
4.592
5.552
5.196
5.048
5.308
5.528
5.668
5.400
4.956
5.688
5.872
5.672
5.520
5.800
6.000
5.968
6.000
6.120
6.004
5.628
6.108
6.136
6.096
6.112
6.008
6.280
0.481
0.399
0.416
0.443
0.448
0.419
0.435
0.425
0.388
0.437
0.508
0.408
0.382
0.483
0.427
0.545
0.453
0.480
0.498
0.517
0.518
0.534
0.462
0.546
0.567
0.542
0.528
0.514
0.573
0.585
0.569
0.614
0.580
0.583
0.625
0.613
0.602
0.616
0.601
0.624
Table A6.3 Results of maturity measurements on Piri
---- (natural rainfall).
Harvest
number
Rep.
1
1
1
1
1
2
2
2
2
2
3
3
1
2
3
4
5
1
2
3
4
5
1
2
3
3
4
4
4
4
4
5
5
5
5
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
3
5
6
6
6
6
6
7
7
7
7
7
3
TR
95
93
91
96
92
105
102
101
104
97
109
109
108
101
104
119
120
116
115
117
131
134
122
130
129
139
133
134
134
135
149
163
153
150
159
(%)
Total
solids
( %)
Average
sieve
size
Weight
per pea
(g)
8.69
8.95
8.88
9.29
8.84
10.64
9.78
9.74
11.40
9.69
10.68
11.16
11.49
9.30
10.31
12.00
12.32
12.32
10.70
11.92
13.93
14.53
12.94
13.78
13.66
14.64
13.91
14.46
13.81
13.86
15.59
16.61
15.41
16.44
16.01
14.05
13.89
15.64
14.68
14.01
18.59
16.75
15.79
18.30
18.35
17.86
18.13
18.49
15.92
16.74
18.43
19.84
18.87
17.74
17.50
19.47
21.39
20.14
18.09
18.11
17.88
17.90
17.58
17.73
17.84
19.74
22.06
21.32
19.97
20.92
4.608
4.668
4.512
4.756
4.648
4.968
5.324
5.176
5.348
4.920
5.084
5.620
5.632
5.040
5.328
5.544
5.744
5.460
5.516
5.496
6.076
5.940
5.976
5.976
5.884
5.984
5.912
6.124
5.948
6.088
6.016
6.236
6.128
6.172
6.176
0.452
0.432
0.405
0.427
0.411
0.481
0.469
0.499
0.460
0.458
0.489
0.483
0.504
0.454
0.469
0.523
0.528
0.480
0.527
0.508
0.561
0.582
0.587
0.590
0.609
0.597
0.604
0.631
0.611
0.615
0.614
0.644
0.633
0.630
0.628
AIS
Table A6.4 Results of maturity measurements on Piri
---- (irrigated).
Harvest
number
Rep.
TR
AIS
( %)
Total
solids
( %)
Average
sieve
size
Weight
per pea
(g)
1
1
1
1
1
2
2
2
2
2
3
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
94
87
88
89
90
93
98
88
94
96
97
93
97
98
101
101
93
100
100
99
112
101
100
105
113
8.02
7.00
7.04
7.15
7.67
8.29
8.98
7.84
8.15
8.71
9.20
8.97
9.10
9.30
9.60
10.60
8.94
9.99
10.30
9.83
11. 23
10.32
9.42
10.53
11.36
11.95
11. 35
11.65
11.16
13.37
12.99
12.88
12.48
12.57
13.21
13.78
10.41
14.92
14.75
15.21
17.49
16.33
16.81
17.31
17.78
15.74
13.76
14.18
10.10
14.15
12.75
12.24
14.40
14.41
13.04
15.21
14.80
14.98
15.85
15.44
17.62
15.36
17.49
15.81
17.19
17.36
14.97
15.05
17.18
17.67
19.66
19.14
18.46
17.40
19.18
20.17
19.22
19.39
18.10
18.88
16.89
17.32
18.36
18.24
19.90
22.77
20.87
21.40
23.14
23.27
4.376
4.128
4.200
4.100
4.448
4.496
4.904
4.320
4.844
4.732
5.444
4.808
5.092
5.420
5.544
5.280
4.832
5.476
5.276
5.304
5.652
4.988
5.172
5.656
5.592
5.484
5.192
5.378
5.492
5.886
5.624
5.648
5.588
5.644
5.612
5.792
5.224
5.848
6.040
5.956
6.076
5.968
6.088
6.188
6.200
0.397
0.367
0.394
0.376
0.358
0.453
0.434
0.350
0.423
0.426
0.499
0.454
0.460
0.491
0.489
0.499
0.416
0.546
0.465
0.466
0.482
0.401
0.466
0.478
0.536
0.536
0.482
0.521
0.566
0.589
0.547
0.561
0.583
0.508
0.520
0.589
0.537
0.628
0.615
0.586
0.634
0.707
0.624
0.623
0.653
3
3
3
**
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
9
9
9
9
9
**
III
104
III
109
119
125
116
118
120
119
137
116
140
136
135
151
141
151
144
151
Data omitted from AIS-TR analysis (see text Section 3.4).
PAGE 153
Table A6.5 Results of maturity measurements on Pania
---- (natural rainfall).
Harvest
number
Rep.
1
1
1
1
1
2
2
2
2
2
3
3
3
3
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
TR
94
92
93
92
92
99
102
98
97
94
106
110
108
107
100
112
114
109
113
104
120
118
121
117
116
140
137
127
128
123
143
134
138
138
134
181
156
154
142
159
AlS
(% )
Total
solids
( %)
Average
sieve
size
Weight
per pea
(g)
8.83
8.27
8.20
8.80
8.12
10.98
10.48
9.37
9.36
10.18
10.10
10.97
11.02
10.78
9.62
10.79
11.59
10.80
11.83
10.35
13.03
12.97
13.53
12.44
12.25
16.02
15.40
15.03
15.06
13.29
16.63
16.85
17.44
15.41
15.39
21.91
20.41
18.32
17.03
19.38
11.84
11.98
12.15
13.22
11.97
17.00
15.82
10.14
13.78
13.64
13.90
16.21
15.08
15.53
13.14
15.88
15.84
15.35
19.02
12.02
18.23
19.37
19.44
19.41
18.76
21.53
19.89
21.23
21.27
19.66
23.60
22.25
19.21
21.27
19.87
27.32
25.95
23.82
24.16
24.85
4.564
4.460
4.624
4.428
4.692
5.423
5.112
4.872
5.028
5.076
5.384
5.380
5.304
5.437
5.336
5.264
5.156
5.122
5.220
5.188
5.360
5.444
5.504
5.432
5.576
5.592
5.780
5.620
5.552
5.608
5.928
5.872
5.936
5.956
5.856
6.096
5.940
5.856
6.052
6.036
0.399
0.407
0.403
0.398
0.430
0.458
0.422
0.452
0.429
0.437
0.491
0.489
0.454
0.493
0.469
0.472
0.511
0.476
0.519
0.505
0.516
0.557
0.511
0.516
0.523
0.577
0.495
0.525
0.525
0.516
0.549
0.537
0.518
0.564
0.557
0.643
0.587
0.565
0.584
0.602
PAGE 154
Table A6.6 Results of maturity measurements on Pania
---- (irrigated).
Harvest
number
Rep.
1
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
TR
,
98
88
89
92
97
99
88
93
94
95
108
97
103
96
107
113
105
112
110
106
126
114
121
119
122
138
120
134
130
127
156
132
137
144
146
AIS
(%)
Total
solids
(% )
Average
sieve
size
Weight
per pea
(g)
9.52
8.81
8.37
8.64
9.31
9.93
8.48
9.20
8.61
9.48
10.98
9.63
10.44
9.50
12.67
12.13
10.38
11.97
11.69
11.46
14.42
12.55
13.67
13.72
13.93
16.00
13.25
13.86
14.55
14.09
17.79
14.57
16.51
16.91
16.65
16.52
16.39
15.99
16.21
17.26
17.19
15.97
16.78
16.24
17.50
18.80
17.62
17.80
17.44
20.48
18.77
18.14
19.12
19.14
18.86
20.88
18.98
20.20
20.60
21.20
21.56
19.50
21.42
21.22
21.33
23.50
21.08
22.09
22.95
22.37
5.068
4.596
4.724
5.474
5.244
5.112
4.752
5.044
4.794
4.788
5.300
4.968
5.144
4.912
5.576
5.412
5.388
5.640
5.516
5.528
5.932
5.688
5.912
5.936
5.908
6.136
6.256
6.148
6.016
6.088
6.068
5.948
6.064
6.164
6.176
0.493
0.433
0.433
0.460
0.409
0.511
0.435
0.500
0.457
0.451
0.503
0.463
0.499
0.491
0.480
0.548
0.519
0.551
0.564
0.550
0.545
0.569
0.565
0.576
0.598
0.621
0.547
0.582
0.555
0.601
0.604
0.579
0.588
0.640
0.604
.
Table A6.7 Results of maturity measurements on Gf.68
(natural rainfall).
Harvest
number
Rep.
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
TR
94
94
91
92
93
103
109
97
102
95
108
104
104
101
101
112
123
112
106
III
132
126
120
115
118
145
154
126
124
131
164
155
139
140
146
(% )
··Total
solids
( %)
Average
sieve
size
Weight
per pea
(g)
10.59
10.14
9.98
9.53
10.44
12.78
12.97
11.35
12.53
11.25
14.27
13.77
11.82
12.29
11.98
13.59
14.92
14.36
14.26
14.73
16.35
18.21
16.62
15.13
15.21
18.28
19.77
16.92
16.67
16.42
20.31
19.34
17.62
17.94
18.75
16.28
15.87
13.96
14.77
14.28
15.86
18.87
17.94
17.39
15.74
19.87
17.70
19.33
19.62
18.00
19.68
19.69
21.22
19.19
20.26
20.17
23.96
23.40
22.41
20.84
24.50
25.49
22.66
22.91
22.55
25.84
26.16
23.31
23.23
25.06
4.896
4.964
4.648
4.744
4.712
5.060
5.272
5.040
5.216
5.008
5.372
5.196
5.320
5.124
5.160
5.800
5.692
5.564
5.524
5.728
5.848
5.896
5.992
5.792
5.792
5.920
5.932
5.800
5.848
5.920
5.968
5.972
5.936
5.836
5.972
0.452
0.459
0.404
0.437
0.443
0.457
0.511
0.449
0.468
0.444
0.466
0.481
0.435
0.475
0.448
0.511
0.544
0.504
0.479
0.491
0.556
0.518
0.483
0.520
0.496
0.555
0.557
0.515
0.576
0.551
0.566
0.565
0.606
0.531
0.556
AIS·
PAGE 156
Table A6.8 Results of maturity measurements on Gf.68
---- (irrigated).
Harvest
number
Rep.
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
TR
93
91
91
93
91
87
93
95
92
93
96
97
92
99
100
98
103
103
103
105
107
113
106
114
109
126
117
123
133
121
125
142
135
142
136
145
166
147
168
171
AIS
(% )
Total
solids
(% )
Average
sieve
size
Weight
per pea
(g)
10.48
9.67
10.47
10.18
10.43
9.47
10.75
11.33
11.56
11.66
12.76
12.03
11. 52
11.27
12.16
11.85
12.64
12.18
12.71
13.43
14.87
15.97
9.44
14.14
14.51
17.10
15.03
15.37
17.20
15.23
16.53
18.30
16.91
18.54
17.97
17.45
19.64
18.69
22.19
20.60
18.32
18.20
17.31
18.58
17.51
17.80
19.28
18.33
18.69
19.03
18.87
18.27
19.09
17.58
19.41
19.91
19.73
20.29
19.78
20.44
22.11
21.54
19.29
19.38
20.16
23.40
21.31
21.09
23.64
22.74
21.58
23.08
22.93
23.41
23.44
24.05
24.62
23.12
26.93
25.43
4.920
4.688
4.812
4.856
4.840
4.584
5.008
4.932
5.004
4.796
5.392
5.368
5.120
5.560
5.672
5.452
5.564
5.600
5.564
5.692
5.872
5.876
5.684
5.936
5.848
5.984
5.564
5.716
6.100
5.664
5.784
5.756
5.972
6.016
5.944
5.944
5.932
5.872
5.980
6.060
0.477
0.449
0.434
0.451
0.449
0.400
0.440
0.457
0.422
0.450
0.476
0.455
0.484
0.590
0.499
0.502
0.447
0.475
0.510
0.525
0.540
0.546
0.486
0.533
0.540
0.525
0.521
0.530
0.551
0.559
0.531
0.531
0.570
0.555
0.553
0.507
0.542
0.556
0.541
0.578
PAGE 157
APPENDIX 7
CORRELATION MATRICES FOR MATURITY TESTS
Table A7.l Matrices of coefficients of correlation
--oetween maturity tests and harvest number
for both irrigation treatments of Tere.
Natural rainfall
TR
TS
P.Wt.
Ave.S.S
Harv.no.
AlS
TR
TS
0.955
0.941
0.907
0.910
0.968
0.921
0.909
0.914
0.978
0.883
0.915
0.920
P.Wt.
0.900
0.917
Ave.S.S
0.931
Irrigated
AlS
TR
TS
P.Wt.
Ave.S.S
Harv.no.
0.965
0.792
0.917
0.875
0.882 .
TR
0.781
0.941
0.913
0.890
TS
0.788
0.799
0.710
P.Wt.
0.951
0.895
Ave.S.S
0.883
Table A7.2 Matrices of coefficients of correlation
between· maturity tests and harvest number
for both irrigation treatments of Pirie
I
Natural rainfall
AlS
TR
TS
P.Wt.
Ave.S.S
Harv.no.
0.981
0.810
0.945
0.937
0.962
TR
0.788
0.948
0.914
0.972
TS
0.718
0.792
0.757
P.wt.
0.939
0.962
Ave.S.S
0.941
Irrigated
TR
T.S
P.Wt.
Ave.S.S
Harv.no.
AlS
TR
TS
0.982
0.907
0.922
0.895
0.960
0.852
0.908
0.861
0.927
0.845
0.850
0.879
P.Wt.
0.912
0.898
Ave.S.S
0.882
Table A7.3 Matrices of coefficients of correlation
--oetween maturity tests and harvest number
for both irrigation treatments of Pania.
Natural rainfall
AIS
TR
T.S
P.Wt.
Ave.S.S
Harv.no.
0.984
0.952
0.897
0.893
0.946
TS
TR
0.940
0.916
0.881
0.944
0.893
0.882
0.924
P.wt.
0.891
0.930
Ave.S.S
0.929
Irrigated
TR
T.S
P.Wt.
Ave.S.S
Harv.no.
AIS
TR
TS
0.984
0.982
0.898
0.911
0.941
0.966
0.894
0.905
0.943
0.881
0.905
0.931
P.Wt.
0.877
0.911
Ave.S.S
0.898
Table A7.4 Matrices of coefficients of correlation
~tween maturity tests
and harvest number
for both irrigation treatments of Gf.68.
Natural rainfall
AIS
TR
T.S
P.Wt.
Ave.S.S
Harv.no.
0.961
0.955
0.873
0.925
0.951
TS
TR
0.918
0.883
0.862
0.922
0.839
0.931
0.943
P.Wt.
0.862
0.878
Ave.S.S
0.938
Irrigated
AIS
TR
T.S
P.Wt.
Ave. S. S
Harv.no.
0.969
0.962
0.756
0.840
0.947
TR
0.944
0.713
0.772
0.921
TS
0.700
0.795
0.914
P.Wt.
0.855
0.781
Ave.S.S
0.890