Seed and embryo size relationships with seedling and mature plant... by Gregg Raymond Carlson

advertisement
Seed and embryo size relationships with seedling and mature plant performance in barley
by Gregg Raymond Carlson
A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE
in Agronomy
Montana State University
© Copyright by Gregg Raymond Carlson (1982)
Abstract:
The performance of two barley cultivars, as affected by seed size, was evaluated under laboratory and
field conditions. Four seed size classes and an unsized control were evaluated for each of the cultivars
'Ingrid' and 'Klages' at Bozeman and Havre in 1978. Two size classes and an unsized control for each
of the same two cultivars were evaluated in large plots at Havre in 1981. All seed size classes consisted
of dimensional separations prepared with a commercial precision sizer. In laboratory evaluations it was
shown that rates of imbibition, respiration and germination were higher for small seed than for large
seed. Speed of emergence was not affected by seed size. Large seed consistently produced more
seedling dry matter than all smaller sizes and the unsized controls. Seed size was negatively correlated
with percent kernel protein and percent kernel lysine. The percent of lysine protein as affected by seed
size, was dependent upon cultivar. In the 1978 field evaluations, large seed of 'Ingrid' produced plants
with more fertile tillers than plants from small seed. Seed size did not affect 'Klages' tiller production.
Plant height at maturity was not affected by seed size even though differences at early seedling stages
were prominent.
At Havre, small seed produced plants with fewer seeds per head and lower kernel weights than larger
size classes or unsized seed.
Large seed of 'Ingrid' produced plants yielding more than small or unsized seed at Havre, but 'Klages'
yield was not affected by seed size.
In the 1981 field evaluations, seed size did not affect tiller production or yield.
Embryos were excised from samples of sized seed of the barley cultivars 'Ingrid' and 'Klages' to study
the relationships of embryo size with seed size, and to compare performance of seedlings cultured from
isolated embryos with that of seedlings from corresponding whole seed size classes. Embryo weight
was positively- correlated with seed weight in both cultivars. Performance of seedlings arising from
isolated embryos in 'Ingrid' exhibited strong positive correlation to that of the size class of whole seeds
from which they were excised. In contrast, when isolated from their natural endosperm, 'Klages'
embryos were nearly identical in seedling performance regardless of embryo size or size of whole seed
from which they were isolated. STATEMENT OF PERMISSION TO COPY
In presenting this thesis in partial fulfillment of the require­
ments for an advanced degree at Montana State University, I agree that
the Library shall make it freely available for inspection.
I further
agree that permission for extensive copying of this thesis for scholarly
purposes may be granted by my major professor, or, in his absence, by
the Director of Libraries.
It is understood that any copying or publi­
cation of this thesis for financial gain shall not be allowed without my
written permission.
Signature
t / c CSSfr / rC/.
SEED AND EMBRYO SIZE RELATIONSHIPS WITH
SEEDLING AND MATURE PLANT PERFORMANCE
IN BARLEY
by
GREGG RAYMOND CARLSON
A thesis submitted in partial fulfillment
of the requirements for the degree
MASTER OF SCIENCE
in
Agronomy
Approved:
Chltirman,' Graduate Committee
Urzmjz.
Head, Major Department
Graduate Dean
MONTANA STATE UNIVERSITY
Bozeman, Montana .
August, 1982
ill
. ACKNOWLEDGMENTS
I wish to express my sincere appreciation to my major professor.
Dr. Loren E-. Wiesner, for his valuable guidance, encouragement, and
generous support provided during the entire course of my graduate
studies; Dr. Scott Cooper, Mr. Howard Bowman, Mr. Robert Eslick and
Mr. Lee Hart for their help and cooperation in serving as members of
my graduate committee.,
I also wish to express special appreciation to Dr. Scott Cooper
for his generous personal contribution of time in assisting me with the
preparation of this thesis.
My appreciation;is extended to Mr. and Mrs. Mark E. Peterson for
their extensive support and cooperation with field research conducted
in conjunction with my studies.
My family and my wife, Ruth, deserve special gratitude for the
patience, understanding and support provided me in the completion of
this degree.
/
TABLE OF CONTENTS
. Page
VITA...........................
ii
A C K N O W L E D G M E N T S ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
in
LIST OF TABLES .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
v
ABSTRACT .. . . . . . . . . . . . . . . . . .
LITERATURE REVIEW
. . . . . . . . .
vii
....................
I
Seed Size Relationships .. .. . . . . . . . . . . . . . . . . . . . . - . ..
Seed Characters . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Seedling G r o w t h . . . . . . . . . . . .
Mature Plant Growth . .. . . . . . . . . . .. . . . . . . . . . . . .
Elements of External Influence . . . . . . . . . . . . .
CHAPTER I.
EFFECTS OF SEED SIZE ON SEEDLING
PERFORMANCE AND YIELD IN BARLEY . . . . . . . . . . . . . .
15
Introduction................
Materials and M e t h o d s . . . . . . . . . . . . . . . . . . . . . . . . . . .
Results and d i s c u s s i o n . . . . . . . . . . . . .
CHAPTER II.
SEED SIZE AND EMBRYO SIZE RELATIONSHIPS .
WITH SEEDLING PERFORMANCE IN BARLEY . . . . . . . . . . .
Introduction........
Materials and M e t h o d s . . . . . . . .
Results and D i s c u s s i o n . . . . . . . . . . . . . . . . . . . . . . . . .
LITERATURE CITED
I
3.
6
9
11
15
17
26
46
.
.
46
47
52
56
V
LIST:OF TABLES
Table
I.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Page
Mean 100-seed weights for four size classes .
within two, 2 -rowed barley cultivars. as
separated by a commercial precision sizer . . . .
........
27
Mean 1 ,000-seed weights for two size classes
and the unsized controls within two, 2 -row
barley cultivars as separated by a commercial
precision s i z e r . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .
29
Effects of four seed: size classes and unsized
seed of two barley cultivars on laboratory
seed and seedling performance . . . . . . . . . . i . . . . .
30
Effects of four seed size classes, and unsizedseed of two barley cultivars on seed composition
34
. . . . . .
Effects of two seed size classes and unsized seed
of two barley cultivars on number of tillers pro­
duced per plant in single seed size treatments
at Bozeman, 1978 .. . . . . . . . . . . . . ■ . . . . . . . . . . . . .
. .
37
Effects of two seed size classes, sown in alter­
nating rows, on number of tillers produced per
plant by two barley cultivars at Havre, 1978 . . . . . . . .
39
Effect of three seed size classes and unsized seed
on the number of seeds produced per head for two
barley cultivars at Havre, 1978 . . . . . . . . . . . . . . . . . . . . .
40
Effects of three seed size classes and unsized
seed on the.weight of individual kernels produced
^
for two barley cultivars at Havre, 1978 . . . . . . . .
41
Effects of two seed size classes and unsized seed
on grain yield of two barley cultivars sown in
single seed size treatments at Hav r e i 1978 . . . . . . . . . . . .
43
Effects of two seed size classes and unsized seed
on the number of tillers per plant for two barley
cultivars at Havre, 1 9 8 1 . . . . . . . . . . . . . . . . . . . . . . .
.
45
vi
LIST OF TABLES (Continued)
Table
11.
Page
Effects of embryo size on performance of
seedlings from isolated embryos of sized seed
of two barley c u l t u r e s . . . . . . . . . . . . . . . . . . . . . . . . . . . .
53
vii
ABSTRACT
The performance of two barley cultivars, as affected by seed size,
was evaluated under laboratory and field conditions. Four seed size
classes and an unsized control were evaluated for each of the cultivars
1Ingrid1 and lKlages1 at Bozeman and Havre in 1978. Two size classes
and an unsized control for each of the same two cultivars were evaluated
in large plots at Havre in 1981. All seed size classes consisted of
dimensional separations prepared with a commercial precision sizer. In
laboratory evaluations it was shown that rates of imbibition, respira­
tion and germination were higher for small seed than for large seed.
Speed of emergence was not affected by seed size. Large seed consis- 3
tentIy produced more seedling dry matter than all smaller sizes and the
unsized controls. Seed size was negatively correlated with percent ker­
nel protein and percent kernel lysine. The percent of lysine protein
as affected by see0 size, was dependent upon cultivar. In the 1978
field evaluations, large seed of lIngrid1 produced plants with more fer­
tile tillers than plants from small seed. Seed size did not affect
'Klages1 tiller production. Plant height at maturity was not affected y
by seed size even though differences at early seedling stages were pro-3
minent. At Havre, small seed produced plants with fewer seeds per head
and lower kernel weights than larger size classes or unsized seed.
Large seed of 1Ingrid1 produced plants yielding more than small or un­
sized seed at Havre, but 'Klages' yield was not affected by seed size.
In the 1981 field evaluations, seed size did not affect tiller produc­
tion or yield.
;
Embryos were excised from samples of sized seed of the barley I
cultivars 'Ingrid' and 1Klages' to study the relationships of embryo I
size with seed size, and to compare performance of seedlings cultured
from isolated embryos with that of seedlings from corresponding w h o l e f
seed size classes. Embryo weight was positively- correlated with seed J
weight in both cultivars. Performance of seedlings arising from iso­
lated embryos in 'Ingrid' exhibited strong positive correlation to that
of the size class of whole seeds from which they were excised. In con­
trast, when isolated from their natural endosperm, 'Klages' embryos
were nearly identical in seedling performance regardless of embryo size
or size of whole seed from which they were isolated.
LITERATURE REVIEW
Seed Size Relationships
Historical Aspects
Many workers have studied the influence of seed size on crop per­
formance.
As indicated by Derr in 1910(14), Yokoi reported that due.to
an awareness of the influence of seed size, specific gravity separation
of seed had been in use in the Orient for over 250 years.
In other
reference by Derr (14), RumpIer, in 1896 concluded that only the heaviest
third of a barley seed lot should be sown.
Hicks and Dabney (21) dis­
credited the specific gravity approach to seed separation and advocated
centrifugal separation.
They stressed the need to consider individual
plants in selection instead of seed lot separation alone.
They recog­
nized strong seed origin effects, and made reference to early work con­
ducted by H e l lriegel who claimed difference between mature plants from
large and small seed is greater in impoverished soil than when richly
supplied with food material.
Arny (I) cited Georgeson, Burtis and Otis' work with wheat and
oats.
They reported that when using seed size classes separated by
screen, advantages in yield of large over small seed were meaningful,
but advantages of large over the original uni zed lot varied with crop
and lot.
Arny (I) cited work by Williams and Welton in 1913 where it
was concluded that effects of seed size vary with method of separation,
2
hand versus air-screen cleaner.
They further concluded that effects of
seed size vary with the population achieved through the method of
seeding rate determination, equal numbers of seed versus equal weight of
seed per unit area.
Arny (I) questioned the concepts associated with ■
the entire seed size issue.
Factors affecting results could be (I) the
degree of difference in seed size, (:2) the effect of stand density in
allowing a particular size to express its potential, (3) possible mask­
ing effects due to differences in soil fertility and moisture, and
(4) control of experimental error.
Kiesselbach and Helm (29), published,an extensive historical sum­
mary of small grain seed size work in conjunction with a report bf their
own findings.
They summarized conclusions from sixty experiments con­
ducted over a wide span of time and locations,
Kiesselbach (30) having
continued his cereal seed size research work, published a second review
summary in 1924 with no major changes seen in the overall conclusions
drawn.
In this publication, Kiesselbach (30) stressed the importance of
bearing in mind the practical significance of such investigations.
He
stated that practicality depended upon the degree to which the methods
of seed size comparison are applicable to farm conditions; and that a
sound recommendation regarding the principle of mechanical, grading of
seed could hardly be made from a mere comparison of extremes.
He con­
cluded that the vital question centered on how graded seed compared with
3.
the original ungraded lot, and that little previous research had
addressed that concern.
Although indirectly related to practical application of seed size
relationships at the commercial farm level, the influence of seed size
on effective selection in crop breeding programs has been thoroughly
studied (9, 16, 17, 25, 26).
Seed Characters
Mass
Tjhe word "size" alone is not totally descriptive in terms of its
application in seed size research.
Seed "size" may refer to dimensional
length and width, seed.weight, or seed density.
"Test Weight" expresses
weight of a given volume of seed, and depends upon the density of indi­
vidual seeds, average weight per seed, seed shape and dimensional size
(50).
Choice of one method for sizing seed within a given lot may or
may not simultaneously rank other characters of seed mass.
For example,
when using screens or sieves for making dimensional size separations in
seed, separation on the basis of the density character of mass may not
occur.
As a consequence, some workers have endeavored to prepare dis­
tinct research lots of seed differing in the manner in which the sizing
was accomplished.
and density.
Lill (33) separated seed by weight, dimensional size,
He found significant correlations existed between
4
germination and seed density; however, germination was independent of
dimensional size alone.
Seed size-varies within and between plants.
Austenson and Walton
(2) reported 300% variation in individual seed weight within a single
wheat spike.
Seed size variation within a field crop will partly depend
on genetic differences, nutritional effects, disease and the position
of the seed on the inflorescence (51).
Dennis and Jones as reported by
Wood, et al. (51) found 35% of the variation in seed weight in 'Proctor'
barley was attributable to between-plant differences, 13% due to betweenear differences, and 52% as a result of seed location within the ear.
Structure
Recently, increased attention has been given the relative propor­
tions and functions of embryo and endosperm as influenced by size (34,
42, 47).
In a study of 'Arivat1 barley, higher percentages of endosperm
and embryo seed components occurred with large seed as compared with
medium and small (42);
[
In Triticale, embryo length and width were
positively correlated with seed length and width (41).
Tallberg, in
working with a barley cultiyar and its high lysine mutant, found that
the resultant increase in embryo/endosperm wieght ratio with the mutant
did not effectively improve the amino-acid composition of the total seed,
and that differences in amino-acid composition were entirely confined to
the endosperm proteins (47).
Lowe and Ries (34) successfully transferred
5
wheat empryos from low and high protein seed to similar endosperms.
No
significant difference was noted in dry weight of the seedlings subse­
quently grown; however, significant differences in seedling dry weight
were obtained from the original high and low protein source seed.
They
concluded that endosperm was the primary factor affecting seedling
j
growth.
Genetics
Cultivars differ in response to seed size effects on various
plant growth characters (6, 13, 16, 41).
Chemical Composition
Seed chemical components and plant performance are correlated (11,
16, 34, 49).
Barley seedling emergence is positively correlated with
endosperm A-amylase at 3 and 5 days, and ATP and TAP of hydrated embryos
(11).
Seedling vigor was positively correlated with seed protein in
wheat when size was held constant (16, 34).
However, other workers con­
cluded that chemical composition of seed (12, 36) and more specifically,
protein differences, were not reflected in yield (37).
Welch (49)
believes that seed protein content affects yield only under conditions
of poor nutrition; and that increasing seed protein levels with nitrogen
fertilizer could be imposing interaction effects with changes in mineralcomposition.
6
Origin
The importance placed upon the consideration of the effects of
sedd lot origin has varied among crop scientists. In 1896, Hicks and
Dabney (21) suggested that crop performance was strongly related to seed
geographic origin.
Some recent studies have shown barley seedling and
yield performance differences closely related to seed origin (36).
Others have shown no relationship between performance and seed origin
(12, 43).
SeedlingGrovrth
Respiration
James and James (23) reported that Brown and Morris had developed
techniques in 1890 which allowed researchers to perform studies on
mature plants cultured from excised embryos.
Patterns of barley respir­
ation activity within dormant whole seed, imbibed whole seed and excised
embryos have been extensively studied (7, 23), but respiration of excised
embryos as influenced by seed size or embryo size has not.
Germination
till (33) reported that differences in germination capacity of
wheat as influenced by seed size were somewhat dependent on the method
of making the size separations.
Seed sized by density separation
clearly exhibited decreased ability to germinate as density decreased.
7
However, differences in germination capacity between sizes separated by
sieve were inconsistent.
Others have shown little potential for en­
hancing the percentage germination of a given seed lot through grading
for large seed by sieve separation (51).
Some workers have shown that
smaller seed possesses significantly higher germination than larger seei
(39).
Muchena and Grogan (39) showed this effect with corn grown under
simulated water stress and suggested that smaller seeds might require
less water in view of their smaller volume.
They further theorized tha'
under conditions of limited soil moisture, one could obtain more rapid
germination with small seeded strains.
Vegetative Development
Optimum stand establishment is initially influenced by the rate of
germination and seedling emergence.
The percent of total emergence
barley and the rate at which it occurs, as influenced by seed size,
not consistent (11, 13, 19, 20, 28).
Tanakamaru and Inouye (48) showed
positive relationships between seed size and strength of plumule elonga­
tion in barley.
However, soil compaction imposed additional effects on
plurtiule performance within seed size.classes.
Plumule diameter increased
with increasing compaction; however, increases were greater with small
seed than with large (48).
Barley emergence is reduced when coleoptiIe
length is less than sowing depth (19).
Positive relationships between
barley coleoptiIe length and culm height are then of concern when
[
8
selection for reduced culm height is one objective in a breeding program
(10).
Ceccarelli and Pegiati (10) concluded that coleoptile width is
negatively correlated with seed weight, but coleoptile length depends
mainly on genetics.
Rate and percent emergence decreases with increased
sowing depth, but is decreased less with large seed than with small
(19).
Larger seeds, because of embryo and nutrient reserves (51), en-
p *
hance early seedling top growth (3, 10, 16, 20, 25, 26, 28, 34, 44, 51).^
The most common measure of seedling top growth is that of dry matter pro­
duction at a particular chronological age or stage of maturity.
Kaufmann and Guitard (27) reported large seedlings from large seeds had
longer and wider first and second leaves than small seedlings from small
seeds.
Young seedlings with greater leaf areas intercept more radiation
and produce greater quantities of assimilates for growth, and production
and maintenance of tillers (51).
Root dry weight is positively correlated with seed size (25, 34).
Tillering Capacity
Larger seedlings from large seed should have the capacity to pro- ^
Z
duce and maintain greater numbers of tillers and thus increase yield \ yk
potential.
Seed size and number of tillers produced per plant has been
highly correlated by many workers (2, 13,-25, 28, 44).
However, others
have seen no affects of seed size on tiller production (5, 31).
9
Tillering capacity as a selection character is limited because of exter­
nal effects imposed by plant population density (13).
Although influ­
enced by plant density, tiller survival has been shown to be further
associated with seed size.
Hampton (20) did not find significant dif­
ferences in number of wheat tillers produced between plants arising from
large or small seed.
However, tiller losses during subsequent growth
were higher among plants grown from small seed.
Establishment of Inflorescence
Grain yields are related to the number of heads per plant, per
unit area; and to the number of kernels per head (I, 2, 51).
Wood,
et al. (51) concluded that the first-determined component of yield
(number of fertile culms per unit area) was most affected by seed size
since its effects are most pronounced at early growth stages (51).
Workers have shown earlier heading and ripening dates among plants grown
from large seed in barley and other cereal grains (25, 26, 28).
Mature Plant Growth
Vegetative Development
Since the primary unit of economic yield among cereal grains is
the seed itself rather than forage, studies of seed size affects on
straw yields are limited.
Breeders have selected for reduced culm
length, however, shorter culms may reduce coleoptile length and lead to
10
reduction of seedling vigor and emergence (10).
Arny (I) observed that
variation in plant height from second leaf to six weeks growth in
cereals was marked between plants produced from large seed in compari­
son to small, but such variation usually did not remain relative at
maturity.
When positive correlations exist between initial seed size
and final grain y i e l d , seed size and straw yield are also positively
correlated (29, 46).
Grain Yield *3
"Yield is a complex character which is the resultant of many en­
vironmental and inherent factors acting together [5]."
Regardless of.
the timing and degree of expression among the factors involved, grain
yield in. barley remains a function of (I) the average number of heads
or fertile spikes per plant, (2) the average number of kernels per head,
(3) the average kernel weight, and (4) the average number of plants per
unit area.
These four components of yield are affected by seed size.
Each component is subject to a wide host of influences other than seed
size itself; and interactions between the components themselves, and
with other variables, are very complex.
Differences in the average number of fertile tillers produced by
a single plant are not consistently correlated with initial seed size
(2, 5, 13, 25, 28, 31, 44).
11
Hisher yields are correlated with an increased number of seeds per
head (I, 51), but correlation between initial seed size and average
number of kernels produced per head is not consistent (2, 3, 5, 28).
When kernels do develop normally, a decrease in yield is accom­
panied by an increase in average weight of individual kernels produced
(I).
Yield component interactions support the general belief that a
tendency for natural compensation among the components exists.
Grain
kernel weight is considered the yield component least associated with
initial seed size (2, 26),
Population density may condition the responses of the other com­
ponents with, or possibly without, affecting ultimate yield (18).
Elements of External Influence
Competition
Montgomery (38) stated that,
Competition as a factor in modifying the character of plant
populations, by means of destroying of hindering those
which are least fit to survive under the particular environ­
ment has been recognized as one of importance since Darwin
pointed out its effective workings.
Many workers have concluded that competition between plants signifi­
cantly affects individual plant performance (15, 28, 29, 38).
Kiesselbach (29) found that yields of wheat plants grown from large
seed, sown in a mixture with small seed, were 13% greater than yields
from plants grown in plots where only large seed was planted.
12
Competition also affects yields of plants from large and small seed when
each size class is sown alone within rows, but alternated from row to
row (15, 28, 29, 38).' When grown in alternating rows with plants from
small seed, plants from large seed yield more than when adjacent rows
are also seeded to large seed.
These yield increases for plants from
large seed are at the expense of reduced yield among plants from small
seed.
A similar pattern is shown when comparing alternating row plant­
ings of large and medium seed, and medium and small seed (15).
Competition is not limited to that associated with special inter­
action between plants grown from seeds of differing size.
Competition
influences the performance of plants from seed of uniform size when
planted at sufficient density.
As population density is increased with
an increase in seeding rate, a gradual increase in yield is obtained up
to the limits of optimum density.
cultivar (18).
Optimum density varies with crop and
In oats, increase of seeding rate beyond the optimum
density does not increase or decrease yield; but in barley, sharp yield
reductions may occur when optimum density is surpassed (18).
Different methods of determining seeding rate in studies comparing
large and small seed alter the population density achieved; and affect
competition and yield component interaction.
Seeding rate of cereal
grains is normally expressed as weight, volume or number of individual
seeds per unit area.
Considerable controversy occurs in the literature
as to the most appropriate method to use when comparing seed lots
13
differing in seed ^ize (I., 9, 13, .17, 18, 20, 28, 29).
However, the .
most important consideration when determining seeding rate is the pur­
pose of the planting.
If the objective of the planting is to compare
the performance of individual plants, such as in a breeding selection
program, the ramifications of ignoring the influence of seed size and
its relationships with plant desnity could be serious.
In contrast,
farm seeding rates are most often expressed as weight or volume; and
effects of seed size need be considered in an entirely different way.
There is further potential for competition effects in farm plant­
ings because of lack of precision in spacing seed within the row.
As
reported by Bonnet and Woodworth, Engledow in 1926 stated that a drilled
field of grain is "simply a vast aggregate of little patches on which
the plants are spaced or crowded to different degrees [5]."
Investi­
gations comparing uniform within-row spacing and irregular placement
at the ,same total planted population showed that regularity of seeding
could be largely ignored incconducting seeding rate trials (47).
Competition with, or capacity to withstand association with, other
non-crop organisms is an additional factor bearing possible correlation
with the effects of seed size.
Larger, more vigorous seedlings pro­
duced from large seed should compete best with weeds and resist insect
and disease pests.
As reported by Austenson and Walton (2), McFadden
found greater incidence of loose smut infection in plants from small
)
14 .
seed classes.
Other investigations have not shown correlations of
disease infection with seed size (27).
Soil Medium
Tanakamaru and Inouye (48) reported that plumule elongation
strength increased, in plants from both large and small seed, with
increasing levels of soil compaction; but plumule strength was posi­
tively correlated with seed size under all levels of compaction.
Variability in plant growth characters attributable to differences
in seed size decreases with increasing levels of soil fertility (I, 27).
Enhanced response in laboratory seedling growth from large seeds with
high protein content was more pronounced when nitrogen in the growth
medium was limited (34).
Weather
Favorable growing season precipitation and temperature conditions
reduce or totally eliminate variablity in plant growth characters
associated with seed size (I, 29).
CHAPTER I
EFFECTS OF SEED SIZE ON SEEDLING PERFORMANCE
AND YIELD IN BARLEY
Introduction
Barley is one of the oldest cultivated grains.
Barley kernels
were found in excavations of early civilizations believed to date back
some IQyOOO years (32).
Barley is grown in nearly all cultivated areas
of the temperate zones and certain subtropical and high altitude re­
gions (32).
Barley is important worldwide, and used for human and live­
stock food.
Montana grows over 1,000,000 acres of barley annually and ranks
among the top five states in the nation in production (40).
Growers
expend considerable labor and capital supplying cultural and nutritional
needs of their cereal crops, but many do not devote adequate attention
to seed quality.
Seed lots, as harvested, contain seed of widely varying size and
quality (2, 51). Hordeum distichum L. (2-rowed barley), represented by
the cultivars studied in this thesis, normally possesses one fertile
central spikelet and two sterile lateral spikelets borne alternately on
nodes of the rachis of the complete spike (32).
In contrast, 6-rowed
barley (Hordeum vulgare L.-) has lateral spikelets that are normally fer­
tile.
The lateral kernels are smaller due to crowding, but are capable
16
of germination.
Variation in kernel size occurs within a single spike
of the 6-rowed type, but kernel size variation also occurs within
2 -rowed types.
Within a crop,, the range of seed size varies partly due
to plant-to-plant genetic ,differences, inter-plant competition, and
location on the inflorescence.
The latter affects flowering times and
nutrition of the seed as it develops (51).
Many researchers have investigated the potential for separating
out and sowing only the larger seeds.
This normally results in.larger,
more vigorous seedlings capable of maintaining growth advantage through
to grain maturity (16, 25, 26, 28, 51).
However, to be of practical,
significance at the farm level; the degree of separation necessary to
obtain enhanced yields must be accomplished on a commercial scale.
Our objectives were (I) to determine if significant yield dif­
ferences among sized 2wrowed feed and malt barley seed lots could be
obtained when the separation was made with available commercial-scale
equipment, and (2) to determine if laboratory seed size evaluations
could serve as meaningful indicators of expected field performance
within a given cultivar.
Materials and Methods
General Procedures
Commercial seed ,lots of known genetic purity and close geographic
oigin were purchased 1in-dirt1 for each of the two, 2 -rowed barley
cultivars studied.
The cultivars 'Ingrid1 and 1Klages' were selected
because of similar maturity and because they represent feed and malting
types, respectively, based on gibberellic acid activity as determined
by Barr (4),
Representative one-kilogram samples from the seed lots
were air cleaned with an Oregon Continuous Blower and graded over a
series of precision laboratory pan sieves.
These separations were made
to determine percentage composition of each lot by sieve size and to
compare accuracy of separation by hand sieves^ with that achieved with
commercial-scale grading equipment.
Size classifications were repre­
sented by those seeds which remained on top of 8/64, 7/64, 6/64, 5.5/64,
5/64 and 4.5/64 x 3/4-inch sieves respectively; and those seeds which
passed through the 4.5/64 x 3/4-inch sieve.
The remainders of the two
seed lots were then processed with a commercial, 3-screen air screen
cleaner adjusted for minimal separation of chaff and other light foreign
material.
Average cleanout on the two lots was limited to 2.5% in order
to retain the small seed component.
Representative samples of each seed
lot of the two cultivars were retained for future use as unsized
controls.
18
T h e r e m a i n i n g c l e a n e d p o r t i o n of ea ch seed lot of t h e tw o cu lt iv a r s w a s t h e n p r o c e s s e d into f o u r s i e v e si ze s by u t i l i z a t i o n of a
I
single-cylinder Carter
Precision Sizer sequentially fitted with 6/64,
5.75/64 and 5.5/64-inch slot cylinders.
The seeds which did not pass,
through the dimensional sizing cylinders were classified as large,
medium and medium-small, respectively.
Those seeds which did pass
through the final, and smallest, cylinder were classified as small.
The percentage of the original lot represented by each of the four size
classifications was determined for both cultivars.
One-hundred-seed-
weights were determined for the size classes and the unsized controls.
Seed size differences were evaluated by factorial analysis of variance
with four replications in a completely random design.
These seed size
classes were used for all studies except the 1981 North Havre field
study.
For the 1981 study, uncleaned seed lots of aiIngridl and jKIages1
were purchased and cleaned with a 3-screen air screen cleaner.
Cleaned
seed lots were sized into two classes with a commercial single-cylinder
precision sizer fitted with a 6/64-inch slotted cylinder.
The seed
which passed through the slots was classified as small; and the seed
1 Mention of a trademark or proprietory product does not constitute a
guarantee or warranty of the product by the Montana Agricultural Experi­
ment Station and does not imply its approval to the exclusion of other
products that may also be suitable.
19
which remained in the cylinder was classified as large.
One-thousand-
seed-weights were determined for the size classes and the unsized con­
trols.
Seed size differences were evaluated by factorial analysis of
variance with four replications in a completely random design.
Rate of imbibition
'
Samples consisting of ten randomly-selected seeds from each of
the four size classes and the unsized control within each cultivar were
used for imbibition studies.
These seed samples were air dried, weighed,
and placed in 10-ml glass vials.
An equal volume of water was added to
each vial using a systematic pattern within replications whereby a vial
was filled every 60 seconds.
When all vials were filled, the seeds in
the first vial had been soaking for I hour.
These seeds were then
emptied onto a germination blotter; surface dried with a paper towel and
weighed.
Within 60 seconds the seeds had been returned to the vial and
water added.
This procedure was followed continuously from vial to vial
for 8 hours, and resumed again after the 14th and 24th hours of imbibi­
tion.
Rate of imbibition indices (RI) were determined using the fol­
lowing formula.
mg water imbibed
hours to first measurement
+ • • • +
mg additional water imbibed after previous measurement
hours to last measurement
20
Means are the average of six replications totaling 120 seeds per size
treatment and 300 seeds per cultivar.
These data were evaluated using
a factorial analysis of variance within a randomized complete block
design.
Whole Seed Respiration
Samples consisting of 20 randomly-selected seeds were weighed for
each of the four size classes and unsized control within each cultivar.
The seed samples were p re-soaked in distilled water at room temperature
(22.5°C) for 8 hours and then transferred to active flasks and assigned
at random to stations on the 14-station Gilson Differential Respirometer.
The active flasks were prepared in accordance with the manufacturer's
standard procedure, and allowed to equilibrate for 20 minutes in a 25°C
water bath with mild agitation.
Four active flasks were prepared with­
out seed and affixed to the remaining respirometer stations to serve as
system checks.
Following equilibration, micrometer readings were re­
corded every 15 minutes for 2 hours.
The average Og uptake per inter­
val, adjusted to standard temperature and atmospheric pressure, was
calculated.
The average adjusted uptake was then expressed as ul Og
uptake per gram seed weight per minute.'
of five replications.
Treatment means are the average
These data were analyzed using factorial analysis
of variance within a randomized complete block design.
21
Speed of Germination
Four samples consisting of 100 seeds were randomly selected for
each of the four size classes and unsized control within each cultivar
using a seed counter.
Seeds were randomly positioned on moistened
germination towels and placed in a germinator at 16°C.
Germinated ..seeds
were counted every 6 hours until all seeds within a lot had germinated;
or until no further germination occurred.
day basis in. quarter-day increments.
Counts were expressed on a
A seed was considered to have
germinated when shoot growth reached the distal end of the seed and
normal root development had occurred.
Mean total germination was
evaluated using factorial analysis of variance with four replications
in a completely random design.
Speed of germination indices (SG) were
determined using the following formula adapted from methods by Maguire
(35).
SC = (
number of normal seedlings
Il (first,day germination observed)
" * .*
number of additional normal seedlings after previous counts
days from first germination
!
I
Means are the average of four replications totalling 800 observations
per size treatment.
These data were evaluated by factorial analysis of
variance in a completely random design.
22
Speed of Emergence
Four sieve size classes and the unsized control for each of the
two cultivars were evaluated in a growth chamber for speed of emergence.
Single seeds were planted at uniform 2.5-cm depths in separate SuperCell Conetainers containing ground vermiculite.
Treatment r ows, con­
sisting of 14 cells each, were arranged in a randomized complete block
design with six replications.
Between-plant spacing and between-row
spacing was 2.8 cm and 7.6 cm, respectively.
Frames supporting the
individual cells were placed in a large, shallow vat containing a modi­
fied Hoagland's #1 nutrient solution (.22).
Modification consisted of
reducing the amount of IM CafNOgjg from 5 to 3 ml per liter.
Low volume
transfer pumps were installed in the vat to maintain continuous solution
circulation.
Initially, the planting cells were flushed from the top
with nutrient solution to provide uniform wetting; but thereafter, the
solution was allowed to wick from the bottom of the cells.
Nutrient
solution was added as necessary, and the solution was changed every ten
days.
Chamber temperature was maintained at 21°C for 90 hours to allow
for germination and emergence.
The temperature was then reduced to
15°C for the next 24 hours and further reduced to IO0C for the duration
of the experiment.
A 16-hour photoperiod was maintained using a cool
white flourescent source for 8 hours and an additional 8 hours with a
combination of cool white f lourescent and mercury vapor lamps.
23
Seedling emergence counts were made every 6 hours and expressed
on a day basis in quarter-day increments.
Speed of emergence indices
(SEm) were determined using the following formula.
qc
/ number of seedlings emerged
\\ (first day emergence observed)
' * "
number of additional seedlings emerged after previous count
days from first emergence
Means are the average of six replications.
These data were evaluated
using factorial analysis of variance in a randomized complete block
design.
Seedling Topgrowth
>
The experimental materials used for the speed of emergence evalu­
ations were maintained in the growth chamber as previously described.
Seedlings were harvested 42 days after planting by cutting the culms at
the top of the plastic cells in which they were growing.
Treatment
rows consisting of 14 plants were bulked together, oven dried at 79°C
for 72 hours, and weighed.
Dry weight means expressed in mg topgrowth
per plant are the average of six replications totaling 168 observations
for size treatments and 420 observations for cultivar effects, tested by
factorial analysis of variance in a randomized complete block design.
The experiment was retained intact for an additional 42 days •
after which a second harvest was taken.
Dry weight means expressed as
24
mg vegetative regrowth per plant were !.determined and tested in the same
manner previously described for the initial 42-day growth.
Seed Composition
Representative 500-gm samples of all size classes and the unsized
control for each of the two cultivars were submitted to the Montana
State University Cereal Quality Laboratory for determination of percent
kernel protein, percent kernel lysine, percent protein lysine, barley
diastatic power and barley extract.
Means are the average of four
replications statistically evaluated by factorial analysis of variance
in a completely random design.
Field Performance *
Field evaluations were conducted at two locations, Bozeman and
Havre, in 1978.
An additional field planting was made in 1981 at a
North Havre location using large plot sizes.
The 1978 field investigations were conducted using the same seed
size classes as used in previous laboratory evaluations.
A six-
replication-split-plot design was used with a factorial arrangement of
treatments, namely sieve sizes (including unsized controls and derived
composites), seeding rate methods, and cultivars.
llIngrid1 and 'Klages
cultivars were assigned to main plots and remaining factors to sub­
plots.
Size treatments consisted of large, medium, medium-small and
small, plus the unsized control; a composite of large and small derived
25
by mixing equal numbers of each seed size; and alternate row plantings
of (I) large and small seed, (2) large and medium seed, and (3) medium
and small seed.
Seeding rate methods were (I) equal number of seed per
unit area and (2) equal weight of seed per unit area.
The basic seeding
rate for determining all rates within a cultivar was 18 kg per ha for
medium-size seed.
Individual plots consisted of six, 6-meter rows
spaced 30.5 cm apart.
The center 4.9.meters of the second and fourth
rows were designated for data collection in all single seed size treat­
ments while the second through fifth rows were utilized in the
alternating-row treatments.
Since the total compliment of treatments
did not represent all possible combinations at all levels of all factors,
analysis of variance testing procedures were varied accordingly.
Mature plant data were collected at the Havre location and means
were tested by analysis of variance for yield, number of plants per
meter, tillers per plant, seeds per head, weight per seed and plant
height.
Plant height of mature plants was expressed as the mean distance
from the soil surface to the tip of the spike, not including the awns.
The Bozeman crop was lost to hail three days after heading.
The only
mature plant data evaluated was the number of tillers per plant.
The third field investigation was conducted North of Havre in
1981.
A completely random design was employed with a factorial arrange­
ment of six treatments consisting of small and large size classes plus
the unsized control for each of the two cultivars.
Plots were
26
12.9 meters wide and 427 meters long.
five times.
Each treatment was replicated
Plots were seeded with a triple set of 4.3-meter standard
furrow drills with a 35.5 cm row spacing.
N and PgO^ were applied at
1.8 and 10.0 kg per ha through fertilizer attachments on the drills at
planting.
Equal numbers of seed per unit area were sown, based on the
rate of 8.3 kg per ha for the unsized seed within each cultivar.
I
Grow-
ing season precipitation was 16.5 cm supplementing 12.7 cm plant avail­
able soil moisture stored in the upper 122 cm of the profile at planting
The number of plants per meter, number of tillers per plant and grain
yield was measured.
After trimming plot length to a uniform 402 meters,
the center of each plot was harvested with a standard combine equipped
with a 6.7 meter grain header.
Yield and other performance character
means were evaluated by factorial analysis of variance.
Results and Discussion
Seed Sizing
Mean 100-seed weights for the four size classes within the
'Ingrid1 and lKlages1 cultivars used for. laboratory and field investi­
gations in 1978 are shown (Table I).
S m a l l , medium-small, and medium
size classes were 55%, 72% and 80% as heavy as the large seed class,
respectively.
The original unsized lots, consisted of an average of
68.9% large, 9.6% medium, 11.2% medium-small and 10.3% small seed.
27
Table I.
Mean 100-seed weights for four size classes within two,
2 -rowed barley cultivars as separated by a commercial pre­
cision sizer.
Treatment C o m b i n a t i o n s Mean
Sieve Size
Cultivar _ _ _ _ _ _
> 6.00/64-inch - large
Ingrid
Klages
> 5.75/64-inch - mediurn
Ingrid
Klages
> 5.50/64-inch - medium small Ingrid
Klages
< 5.50/64-inch - small
Ingrid
Klages
100-seed weight
(g)_ _ _ _ _ _ _ _
4.34 b
4.51 a
3.28 e
3.80 c
2.95 f
3.45 d
2.25 h
2.55 g
C.V. (%) = 1.76 ( VEM57 x )(100).
Means followed by a common letter are not statistically different
at the IS Significance level.
28
Effectiveness of component separation with the commercial precision
sizer, as expressed in percent of original lot represented by each sieve
size, was remarkably close to that achieved by hand with laboratory pan .
sieves.
Mean 1 ,000-seed weights for the two size classes and unsized con­
trol for the 'Ingrid1 and 'Klages1 cultivar seed lots used in 1981 field
investigations are shown. (Table 2).
Small and unsized classes were 64%
and 95% as heavy as the large seed class, respectively.
There was less
difference between seed weights of large and small sizes in the 1981
seed lots than those used in 1978.
Rate of Imbibition
Rate of imbibition (RI) (Table 3) for large and unsized seed was
slow compared to medium and medium-small seed.
fastest rate of imbibition.
The small seed had the
The cultivar 1Ingrid,' o v e n a l l sizes,
imbibed water faster than did 'Klages.'
The rapid rate of imbibition
for small seed could be due to the smaller amount of seed material being
wetted.
The cultivar x size interaction was highly significant.with the
difference in rate of imbibition between the cultivars decreasing as
seed size increased.
29
Table 2.
Mean 1 ,000-seed weights for two size classes and the unsized
controls, within two, 2-row barley cultivars as separated by
a commercial precision sizer.
T reatment Combinations
Cultivar
Sieve Size
Mean I,OOO-=Seed weight
(g)
> 6.00/64-inch - large
Ingrid
Klages
47.36 a
45.83 b
< 6 . 00/64-inch - small
Ingrid
Klages
29.09 e
30.53 d
Ingrid
Klages
46.05 b
42.68 c
Original lot - unisized
c.v.(%) = 1.34
(x/EMS/ x)(100)
Means followed by a common letter are not statistically different
at the 5% significance level.
Table 3.
Effects of four seed size classes and unsized seed of two barley cultivars
on laboratory seed and seedling performance.
Treatment Combination
Ingrid-Large
Ingrid-Medium
Ingrid-Medium small
Ingrid-Small
Ingrid-Unsizeda
Klages-Large
Klages-Medium
Klages-Medium small
Klages-Small
Klages-Unsizedb
Whole Seed
Iotal
100-seed wt. Germination Respiration
ul Oz/g/min.
%
g
4.34 b
3.28 e
2.95 f
2.25 h
-
4.51
3.80
3.45
2.66
a'
c
d
g
99.25
99.75
98.50
.98.50
98.25
98.00
99.00
99.00
98.25
97.75
ab
a
ab
ab
ab
ab
ab
ab
ab
b
.682
.816
.884
1.229
.715
.384
.436
.474
.567
.420
c
b
b
a
c
b
ef
e
d '
ef
Kate-Speeo indices
Imbibition Germination Emergence
(SEm)
(SG)
(RH
21.01
24.54
25.44
30.00
21.87
17.93
19.04
19.74
21.32
18.74
Cd
b
b
a
c
f
ef
de
c
ef
42.71
51.35
50.75
52.53
42.07
39.66
42.53
48.78
50.85
45.75
9.16 b
d
9.18 b
a
ab ■ 9.54 ab
9.42 ab
a
9.4.1 ab
d
10.16 a
e
10.14 a
d
10.08 a
b
ab 10.10 a
9.99 ab
C
Seedling lop Growcn
Initial 6-wks 6-wks Regrowth
mg/plant
mg/plant
642.84
562.91
527.67
434.02
.577.03
860.44
795.44
700.89
673.45
771.44
c
d
d
e
d
a
b
c'
c
b
1343.0
1222.0
1072.0
832.4
.1093.0
905.8
1033.0
887.9
923.8
1016.0
a
ab
be
d
be
Cd
bed
cd
Cd
bed
Cultivar
3.21 b
3.60 a
98.85 a
98.40 a
.865 a
.456 b
24.57 a
19.35 b
47.88 a
45.51 b
Large
Medium
Medium small
Small
Unsized
4.43
3.54
3.20
2.46
-
98.63
99.38
98.75
98.38
98.00
.533
.626
.679
.898
.567
19.47 C
21.79 b
22.59 b
25.66 a
20.31 C
41.19
46.94
49.77
51.69
43.91
c.v.(%)
1.76
1.17
4.94
3.42
Ingrid
Klages
9,34 b
10.09 a
548.90 b
760.33 a
1113.0 a ■
953.2 b
Size Class
(VEMGy-R)(IOO)
a
b
c
d
ab
a
ab
ab
b
8.32
d
c
b
a
d
e
c
b
a
d
9.66
9.66
9.82
9.76
9.71
6.51
a
a
a
a
a
751.60
679.20
614.30
553.70
674.20
8.26
a
b
c
d
b
1124.0
1128.0
' 980.1
878.1
1054.0
a
a
ab
b
a
16.96
Means followed by a common letter within any single group are not statistically different at the 5% significance level.
t?The unsized Ingrid seed lot contained 75.48% large kernels..
The unsized Klages seed lot contained 62.36% large kernels.
CO
O
31
Whole Seed Respiration
Expressed on a per gram seed weight per minute basis, O2 uptake
by seeds increased with decreasing seed size (Table 3).
Significant
differences existed among the means for small, medium-small arid medium
size seed.
Gas exchange for large and unsized seed was similar and
lower than that for any of the smaller seed sizes.
The O2 uptake by
1Ingrid1 seed was nearly double that of 'Klages1 although the mean
1Ingrid1 seed weight was only 17% less than 'Klages1. The cultivar x
size interaction was highly significant with differences in favor of
1Ingrid1 at smaller seed size narrowing as seed size increased.
Water
imbibition was not completed within the 8 hours the seeds were soaked
prior to initiating measurement of gas exchange.
swell, they become more permeable (23).
As the seed tissues
It is possible that due to
higher rates of imbibition, there is greater tissue permeability earlier
in small seeds,than in large seeds.
The center of.rapid early activity,
after coming in contact with free water, is the embryo (23); and slower
gas diffusion through greater amounts of endosperm material in large
seeds could also explain the greater O2 uptake by small seeds in these
first 10 hours.
Speed of Germination
There was no significant difference among means of the four size
classes or the two cultivars for percent total germination (Table 3) as
32
determined using the tolerances established by Association of Official
Seed Analysts.
'Ingrid' seeds germinated more rapidly than 'Klages' (Table 3).
Germination speed decreased as seed size increased (Table 3) and was
related to RI (Table 3).
significant.
The cultivar x size interaction was highly
Small seed of 'Klages' germinated faster than small seed
of 'Ingrid', but large seed of 'Ingrid' germinated faster than large
seed of 'Klages'.
Speed of Emergence
Speed of emergence (SEm) was not affected by seed size, but
'Klages' seedlings emerged faster than those of 'Ingrid' (Table 3).
The cultivar x size interaction was not significant.
One would have
expected speed of emergence (SEm) to be influenced by seed size since
RI and speed of germination indices indicate that small seeds imbibe
water and germinate faster than do large seeds.
Since seed size is
positively correlated with strength of plumule elongation in barley
(48), it is possible that the differences in plumule elongation
strength mask early differences in rate of imbibition and speed of
germination.
Seedling Topgrowth
Large seeds produced more dry matter at 42 days than did small
seeds (Table 3).
'Klages' produced an average of 38.5% more topgrowth
I
33
than did 1Ingrid.1 These data support other data showing that early
seedling topgrowth increases with seed size (3, 10, 16, 20, 25, 26, 28,
34, 44, 51).
Since the plants were grown in separate cells affording equal
access to nutrients and equal space for root development, competition
was not a factor influencing growth until the plants were large enough
to shade one another.
Results from this study were perhaps influenced
by row-to-row shading to a degree greater than that which would occur
in the field where row spacing is wider.
Seed size affected vegetative regrowth during an additional
42 days following first harvest (Table 3), but to a lesser degree.
1Ingrid1 produced the greatest amount of dry matter regrowth.
The
cultivar x size interaction was significant with cultivar differences
increasing as seed size increased.
Seed Composition
-
% Kernel Protein
Seed size was negatively correlated with percent total protein
(Table 4) due to a larger proportion of the protein-rich embryo to
endosperm as seed size decreases.
Seed size relationships with protein
are quite a different matter when protein is considered on a basis of
absolute quantity per seed (34).
Table 4.
Effects of four seed size classes and unsized seed of two
barley cultivars on seed composition.
%
Kernel
Lysine
%
Protein
Lysine
%
Kernel
Protein
%
Barley Extract
(dry basis)
Diastatic
Power
(DP)
Ingrid-Large
100-seed wt.
■g
4.34 b
.34 e
3.05 gh
13-40 e
72.80 abed
Ingrid-Medium
3.28 e
.40 b
3.25 ef
14.55
71.30 bed
114.10 b
Ingrid-Medium small
2.95 f
.38 c
3.00 h
15.10 b
68.85 de
109.00 b
Ingrid-Smal I
2.25 h
.46 a
3.15 fg
16.50 a
65.65 e
168.80 a
.37 d
3.15 fg
13.70 d
71.25 Cd
Treatment Combination
Ingrid-Unsizeda
-
C
83.03 be
92.69 be
Klages-Large
4.51 a
.29 -f
3.70 a
9.60 j
73.50 abc
67.16 c
Klages-Medium
3.80 c
.29 f
3.60 ab
10.10 i
74.35 abc
82.80 be
Klages-Medium small
3.45 d
.30 f
3.45 Cd
111.80 b
2.66 g
.33 e
3.35 de
11.50 9
13.00 f
75.60 a '
Klages-Smal I
71.85 abed
106.50 b .
.30 f
3.55 be
10.60 h
75.40 ab
105.30 b
Klages-Unsized^
-
CuItivar
Ingrid
3.21 b
.39 a
3.12 b
14.65 a '
69.97 b
113.50 a
Klages
3.60 a
.30 b
3.53 a
10.96 b
74.14 b
94.71 a
Large
4.43 a
.31 d
3.38 a
11.50 e
73-15 a
75.09 c
Medium
3.54 b-
.35 b
3.43 a
12.32
72.82 a
98.44 be
Size Class
C
Medium small
3.20 c
.34 be
3.23 b
13.30 b
72.22 a
110.40 b
Smal I
2.46 d
.40 a
3.25 b . 14.75 a
68.75 b
137.70 a
.33 c
3.35 a
12.15 d
73.32 a
.17
2.33
Unsized
c.v. (%) (VEMS/ x )(100)
1.76
1.93
1.78
99.01 be
14.42
Means followed by a common letter within any single group are not statistically different at
the 5% significance level.
“The unsized Ingrid seed lot contained 75.48% large kernels.
0The unsized Klages seed lot contained 52.36% large kernels.
35
% Kernel Lysine
Means for small, medium, unsized and large differed significantly,
and decreased with increasing seed size.
on a percent-kernel basis (Table 4).
that of percent kernel.protein.
'Ingrid' had the highest lysine
This relationship was similar to
The cultivar'x size interaction was
highly significant with cultivar differences in kernel lysine becoming
narrower with increasing seed size.
% Protein Lysine
Large, medium and unsized seed had protein with higher lysine than
medium-small and small seed (Table 4).
than 1Ingrid1 protein.
significant.
'Klages1 protein had more lysine
The cultivar x size interaction was highly .
'Klages' percent protein lysine increased and 1Ingrid'
percent protein lysine decreased as seed size increased.
Diastatic Power (DP)
Diastatic power (DP) measures the ability of a barley kernel to
convert starch to maltose, an important quality in the malt types.
Diastatic power means for small seed were higher than those for large
seed (Table 4).
Smaller seeds are higher in DP due to the scutellum,
which secretes the diastase, being nearly as large in small seed as it
is in large seed which contains more starch to convert (32).
'Ingrid'
had a higher DP than 'Klages.' The significant cultivar x size
36
interaction showed that lKlages1 DP should exceed that of 'Ingrid' when
seed size increases beyond that of the large seed evaluated here.
Barley Extract
Small seed had a lower percent barley extract than other seed
sizes (Table 4).
lKlages1 had more barley extract than 'Ingrid.1
Field Performance - 1978
Tillering Capacity
Plants from large seed of the cultivar 'Ingrid' produced more
fertile tillers than plants from small seed when sown in single seed
size treatments at Bozeman (Table 5).
Large seed did not produce more
tillers than unsized seed.
Seed size did not affect tiller number in 'Klages' at Bozeman
(Table 5).
At Havre, tiller production was similar among seed sizes in either
cultivar.
Fertile tillers per plant averaged only 1.3 over cultivars
and seed sizes in single seed size treatments.
The base seeding rate
of 18 kg/ha for seed of medium size was established for the Bozeman
location, but was also used at Havre.
These plant densities were too
high for any appreciable tillering to occur, under the conditions at .
Havre.
37
Table 5.
Effects of two seed size classes and unsized seed of two
barley cultivars on number of tillers produced per plant
in single seed size treatments at Bozeman, 19.78.
Tillers/Plant(number)
Size Class . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Ingrid
K Iages'
Large
2.9 a
2.6 a
Small
2.3 b
2.2 a
Unsized
2.8 a
2.3 a
c .v . (VrE M S Z -X)(IOO)
10.0% .
16.0%
M e a n s w i t h i n a c o l u m n f o l l o w e d b y a c o m m o n le tt er are no t s t a t i s t i ­
c a l l y d i f f e r e n t at t h e 1% s i g n i f i c a n c e l e v e l .
38
When adjacent rows were sown alternately with large and small
seed, competition between seed size classes occurred. Plants in rows
sown with large seed produced more tillers than did plants in rows sown
with small seed of the cultivar .'Ingrid1 at Havre, but seed size did
not affect tiller production in the cultivar 'Klages' (Table 6).
Seeds per Head
Seed size was positively correlated with the number of seeds
produced per head at Havre.
Plants from small seed produced an average
of 1.7 fewer seeds per head than plants from large, unsized arid mediumsmall seeds (Table 7).
There was no significant difference among culti-
vars, among population densities, or among any of the factor inter­
actions.^
These results indicate that the number of seeds produced per head,
an important component of yield (I, 51), was positively influenced by
initial seed size.
Seed size influence on number of seeds produced per
head may.be expressed to a greater degree when tiller numbers are low.
Kernel Weight
The weight of individual kernels produced on plants grown from
small seed was 1.8 mg less than that with plants from unsized, large
and medium-small seed at Havre (Table 8).
'Klages1 produced kernels
3.2 mg lighter than 1Ingrid1. Population density did .not affect kernel
weight.
39
Table 6.
Effects of two seed size classes, sown in alternating rows,
on number of tillers produced per plant by two barley
cultivars at Havre, 1978.
'
Size Class_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
TillersZpiiant (number)
Ingrid
Klages
Large
1.5 a
1.3 a
Small
1.2 b
1.2 a
c.v. ( V em?/ lO(ioo)
20.5%
14. 5%
M e a n s w i t h i n a c o l u m n f o l l o w e d b y a c o m m o n le tt er a r e n o t s t a t i s t i ­
c a l l y d i f f e r e n t at t h e 5% s i g n i f i c a n c e level.
40
T a b l e 7.
E f f e c t of t h r e e seed size c l a s s e s and u n s i z e d se ed on the
n u m b e r of se ed s p r o d u c e d p e r h e d d f o r tw o b a r l e y c u l t i v a r s *
at Ha vr e, 1978.
'
Seeds/Head
Size Class_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ._ _ _ _ _ _ (no.)
Large
19.0 a
Medium-Small
18.3 a
Small
17.3 b
Unsized
18.8 a
e.v. (%) = 7.9 (VWx)(IOO)
Means.followed by a common letter are not statistically different
at the 5% significance level.
*Means are the average value for seed size treatment effects over
both cultivars 'Ingrid' and lKlages1.
41
T a b l e 8.
E f f e c t s o f t h r e e se ed si ze c l a s s e s and u n s i z e d se ed on the
w e i g h t of in d i v i d u a l k e r n e l s p r o d u c e d f o r t w o b a r l e y cultiva r s at Ha v r e , 1978.
Weight/Kernel
(mg)
Seed Class
Large
38.8 a
Medium-small
38.8 a
Small
37.1 b
Unsized
39.0 a
Cultivar
Ingrid
40.0 a
Klages
36.8 b
c.v.(%) = 4.2
(x/EMS/ x )(IOO)
Means followed by a common letter within a single effect group are
not statistically different at the 1% significance level.
42
Although kernel weight is considered the yield component least
associated with initial seed weight (2, 3, 5, 28), low plant tiller
numbers in this study.may have accounted for greater expression of seed
size influence on grain kernel weight.
Plant Height
Plant height was not affected by seed size or population density
at Havre.
Visual differences were prominent during early stages of
growth at both locations in 1978, but these were not reflected at plant
maturity.
Grain Yield
Plants from large seed yielded 2.6 and 2.0 Q/ha more than plants
from small and unsized seed, respectively, for the cultivar 'Ingrid'
grown in single seed size treatments at Havre, but 'Klages1 grain yield
was not affected by seed size (Table 9).
Population density did not
affect grain yield of either cultivar.
Yield differences between plants from large seed and plants from
small seed may have been greater under lower population densities.
Lower population densities probably would have allowed more-vexpression
of the greater tillering capacity others have shown (2, 13, 25, 28, 4.4)
for plants from large seed.
43
Table 9.
Effects of two seed size classes and unsized seed on grain
yield of two barley cultivars sown in single seed size
treatments at Havre, 1978.
Grain.Yield
(Q/ha)
Size Class
Ingrid
Klages
Large
22.1 a
18.5.a
Small
19.6 b
19.3 a
Unsized
20.1 b
18.8 a
c .v . (v/EMS/ x)(100)
"11.1%
17.5%-
Means within a column followed by a common letter are not statist!calIy different at the 5% significance level.
44
Field Performance - 1981
Tillering Capacity
Seed size did not affect tiller production per plant at North
Havre in 1981 (Table 10).
'Ingrid' produced more tillers per plant
than lKlages1.
Grain Yield
Grain yield was not affected by seed size, cultivar or the size .
x cultivar interaction.
Plant populations among large and small seed plantings in both
cultivars were nearly equal.
Extreme plot variabiIity/wi/thin treatments was obvious, both from
examination of the raw data by replication and from the coefficients of
variation computed.
Field experiments covering extremely large land
areas, nearly .65 hectares in this case, will require special design
considerations for control of experimental error.
45
T a b l e 10.
E f f e c t s o f 'two se ed size c l a s s e s and u n s i z e d se ed on the
n u m b e r of t U l e r s p r o d u c e d p e r p l a n t f o r t w o b a r l e y
c u l t i v a r s at H a v r e , 1981.
S ize Class or Cultivar_ _ _ _ _ _ _ _ _ _ _
Size Class
Large
Tillers/plant.
■_ _ _ _ _ _ _ _ _ _ (no.)_ _ _ _
. 5.35 a
Small
5.12 a
Unsized
4.64 a
Cultivar
Ingrid
5.66 a
Klages
4.41 b
c.v.(%) = 26.1
(VrEMSZx)(IOO)
,
Means followed by a common letter within a single effect group are
not statistically different at the 5% significance level.
CHAPTER II
SEED SIZE AND EMBRYO SIZE RELATIONSHIPS WITH
SEEDLING PERFORMANCE IN BARLEY
Introduction
Seed size influence on plant performance was recognized at least
300 years ago (14).
Early agriculturalists advocated that farmers
should employ techniques to separate smaller, inferior seeds from their
seed lots before sowing (14, 21).
Crop response to seed lot sizing
varies with the separation method used (I, 33).
Dimensional separation,
that method which is most commercially feasible for cereal grains
might not select for the characters of seed mass having the most influ­
ence on plant performance.
The relative proportions and functions of embryo and endosperm in
cereal grains have been studied (34, 42, 47), but their relationships
with plant performance as influenced by seed size have not.
Barley plants can be cultured from excised embryos (8, 23, 24)
whereby performance can be studied free of endosperm influence.
Our objectives were (I) to determine if embryo size in barley
differs significantly among seed size classes separated with a commer­
cial precision sizer, and (2) to determine if excised embryos from sized
seeds contribute significantly to the seed size influence on plant
performance shown by other research.
47
Materials and Methods
Embryo Excision Procedures
Over 1 ,000 barley embryo were used for investigation in this study.
Several procedures were evaluated to establish .a standard excision
technique that.would afford reasonable excision speed with minimum embryo
injury.
Different pre-excision soaking times, and mechanical techniques
for seed coat removal 'were evaluated and a suitable method was developed.
Embryos for this study were excised after the whole seeds were
soaked in water for 8 hours at room temperature.
coats were then removed with a small forceps.
The palea and seed
Excision was performed
by carefully applying pressure on the softened endosperm adjacent to
the embryo until the forceps could be slipped under the embryo.
The
embryo was then gently removed with a single point of the forceps
The embryo is removed with relative ease as there is no true connection
to sever between the scutellum and.the endosperm (23).
Embryo Size
Seed lots utilized were the same, as those used in whole seed
evaluations (Chapter I), and consisted of four size classes and the
unsized control within each of the two cultivars ( 1Ingrid1 and lKlages1)
studied.
Size classes obtained by separation with a single-cylinder
Carter Precision Sizer, were (I) > 6/64, large; (2) > 5.75/64, medium;
(3) > 5.5/64, medium-small; and (4) < 5.5/64,small.
48
Samples consisting of 10 seeds from each of the ten sized treat­
ments were oven-dried at 50°C for 36 hours and weighed.
The samples
were then soaked in water for 8 hours and the embryos excised.
The
endosperm portions were again oven-dried and weighed for determination .
of embryo weights by subtraction.
Means are the average of six repli­
cations totalling 120 embryos per size class and 300 per cultivar.
These data were evaluated by factorial analysis of variance in a random­
ized complete block design.
Embryo Respiration
Fifty-seed samples from the large and small seed size classes for .
each cultivar were air-dried, w eighed, soaked 8 hours in sterile water;
and the embryos excised.
Forceps were dipped in ethanol, flame steri­
lized and cooled in sterile water between excisions.
Embryos were
stored in sterile water until all excising was completed.
Respiration
active flasks were filled with 20 undamaged embryos which were selected
from each seed lot and assigned at random to the stations of a Gilson
Differential Respirometer.
The active flasks were prepared according
to standard procedure prescribed by the manufacturer, and were allowed
to equilibrate for 20 minutes in a 25°C water bath with mild agitation.
Two active flasks without seed were affixed to the remaining stations to
serve as system controls.
for 2 hours.
Oxygen uptake was recorded every 15 minutes
Average uptake per interval, adjusted to standard
49
atmospheric pressure and temperature was expressed as ul
gram embryo weight per !minute.
replications.
uptake per
Treatment means are the average of three
These data were evaluated by factorial analysis of vari­
ance in a completely random design.
Vegetative Production from Cultured
Embryos
Samples from the large and small seed size classes for each cultivar were soaked eight hours in sterile water; and the embryos excised
from 50 seeds.
The embryos were placed in water-filled, aerated beakers
until all 200 excisions were completed.
A culture medium of 16 ml of pure liquid coconut endosperm was
added to each in a series of 15 x 100 mm sterile petri dishes using a
filtered air-flow hood to reduce contamination.
A 47 mm mi Ilipore
filter disc with a 47u pore size was floated on the liquid as each dish
was filled, and the dish covered.
Excised embryos were surface steri­
lized in a 1% sodium hypochlorite solution for 30 seconds followed/by a
series of 11 sterile water rinses.
Embryos were individually bathed in
a separate source of coconut endosperm and placed ventral surface down
on the filter discs.
The general technique employed for this procedure
was reported by Jensen using another media (24).
positioned oh the disc.
Five embryos were
Each dish was covered immediately after the
embryos had been positioned, and sealed with paraffin laboratory film.
The dishes were wrapped with aluminum foil since light provokes
50
precocious germination (24).
Extreme care was required in handling the
dishes to avoid splashing medium onto the disc.
When liquid splashing
occurred, the disc and embryos generally sank immediately.
The dishes were placed in a growth chamber at 10°C.
One dish per
treatment was designated for daily inspection of embryo development.
When, after four days, adequate differentiation of shoot and root growth
was noted in the inspection dishes; the remaining dishes were unwrapped
and exposed to a 12-hour, low intensity light regime for an additional
three days.
Thirty, w e 11-defferentiated embryos for each size treatment were
removed from the coconut endosperm culture on the eighth day after
excision.
Plumule rupture of the coleoptiIe had'not yet occurred.
These seedlings were placed in glass vials, 17 x 68 mm, covered with
aluminum foil and filled with Hoagland1s #1 nutrient solution (22)
modified by reducing the amount of IM C a t N O g ^ from 5 to 3 ml per liter.
Each developing seedling was wrapped with a narrow strip of cotton form­
ing a collar at the juncture of the coleoptiIe and seminal roots.
The
cotton collar held the seedling in position at the top of the vial and
served as a wick for uptake of nutrient solution.
Aluminum foil caps
with small punctures allowing protrusion of the coleoptiIes were affixed
to the vials.
The vials were randomly arranged in a test tube rack and
returned to the growth chamber at IO0C with a 16-hour photoperiod at low
51
light intensity.
The vials were aerated daily.
Most seedlings developed
a normal first leaf within 15 days after excision.
Eighteen seedlings per size treatment were selected at random and
transferred to foil-covered test tubes, 25 x 200 mm, on the 15th day
after excision.
Techniques used were the same as those for the small
vials, except the cotton collars were replaced with split-foam plugs
and the seedlings were placed in a larger growth chamber at 10°C.
Photoperiod was/increased to 16 hours with 8 hours under cool white
flourescent light and 8 hours under a combination of cool white f Iourescent and mercury vapor lamps.
aerated daily.
The tubes containing seedlings were
These seedlings, dependirjg..ppon:treatment, had developed
2-3 normal leaves, and had attained heights of 10-20 cm within 29 days
after excision.
Twelve plants from each size treatment were randomly selected and
removed from the test tubes 29 days after excision and placed into, holes
drilled in a masonite panel.
apart in a grid pattern.
Holes in the
panel were spaced 7.5 cm
The panel was mounted over a shallow vat con­
taining Hoagland's #1 (22) modified nutrient solution.
The plants were
placed so that the foam collars were just above the liquid surface, and
the roots were immersed in the solution.
An aquarium aeration pump
fitted with two, triple-split manifolds was installed to provide contin­
uous aeration at six locations in the vat.
The plants were then returned
52
t o t h e g r o w t h c h a m b e r u n d e r t h e c o n d i t i o n s p r e v i o u s l y d e s c r i b e d fo r
c u l t u r e in t h e t e s t tu bes.
The plants were harvested 60 days after embryo excison to evaluate
vegetative growth.
The plants were separated into top and root portions
by cutting immediately above the crown.
Leaf and stem area measurements
were taken on fresh top growth using an electronic leaf-area-analyzer.
Top and root materials for all plants were then oven-dried at 79°C for
36 hours and weighed.
Means were determined from an unequal number Of
observations per treatment and were evaluated by factorial analysis of
variance in a completely random design using an unweighted means pro­
cedure (45).
Results and Discussion
Embryo Excision
The use of a modified blender for seed coat removal to facilitate
excision resulted in unacceptable levels of embryo injury.
Barley
embryos were removed more efficiently, and with less embryo injury,
when the whole seeds were soaked for a minimum of 6, and a maximum of
8 hours prior to excision.
Embryo Size
Embryo weight increased as whole seed weight increased (Table 11)
with significant differences shown among embryo weight means for the two
seed size classes a n d .two cultivars. Embryo weight of cultivars was
Table 11.
Effects of embryo size on performance of seedlings from isolated embryos
of sized seed of two barley cultures.
Weight/Seed
Treatment Combination
mg
%
Seed
Embryo
Weight/Embryo
mg
Ingrid-Large
40.61 b
2.70 b
6.6
Ingrid-Medium
31.43 d
2.54 be
8.1
- 27.88 e
2.31 c
8.3
21.94 f
1.90 d
8.7
Ingrid-Medium small
Ingrid-Small
-
Embryo
Respiration
uI Og/g/min
in vitro Embryo Culture
Shoot 0. M.
Leaf & Stem Area
Root U.M.
mg/plant
cm2/plant
mg/plant
.033 b
273.9 a
1603.0 a
253.5 a
.046 a
102.3 c
588.6 c
122.9 c
.042 a
. 168.0 b
1166.0 b
181.9 b
.042 a
151.6 b
1105.0 b
181.6 b
7.3
Ingrid-Unsizeda
33.08 d
2.40 c
Klages-Large
47.58 a
3.06 a
6.4
Klages-Medium
35.69 c
2.34 c
6.6
KIages-Mediurn small
32.42 d
2.02 d
6.2
Klages-SmaIl
26.17 e
1.77 d
6.8
Klages-Unsizedb
39.01 b
2.45 be
6.3
Ingrid
30.99 b
2.37 a
7.6
.039 a
188.1 a
1096.0 a
188.2 a
Klages
36.17 a
2.33 a
6.4
.042 a
159.8 a
1135.0 a
181.8 a
.037 b
220.9 a
1384.0 a
217.7 a
.044 a
126.9 b
846.6 b
. 152.2 b
13.54
15.73
Cultivar
Size Class
Large
44.09 a
2.88 a
6.5
Medium .
33.56 c
2.44 b
7.3
Medium-Small
30.15 d
2.16 c
7.2
Small
24.05 e
1.84 d
7.7
Unsized
36.05 b
2.42 b
6.7
c.V.(%) (VEMS/ "x )(100)
5.56
. 9.38
-
8.65
11.34
Means followed by a common letter within any single group are not statistically different at the 5% significance level.
.Jhe' unsized Ingrid seed lot contained 75.48% large kernels.
The unsized Klages seed lot contained 62.36% large kernels.
54
similar.
The cultivar x size interaction was significant.
'Ingrid'
embryos were heavier than those of lKIages1 among small, medium-small
and medium seed size classes, but lKlages1 embryos were heavier than
those of 'Ingrid' within the large seed size class.
As seed size decreased, the percent embryo dry weight increased
within the cultivar 'Ingrid 1 (Table 11).
However, the percent embryo
dry weight among different seed size classes remained nearly constant
within the 'Klages'cultivar.
The general belief that embryos occupy
relatively greater portions of the total seed mass as seed size de­
creases, was supported in this study by one cultivar and not the other.
Embryo Respiration
Oxygen uptake by embryos, expressed by ulOg/gram/minute, increased
with decreasing embryo weight (Table 11).
Gas exchange was signifi­
cantly higher with small embryos from small seed than it was with large
embryos from large seed.
Respiration rate of cultivars was similar.
The cultivar x size interaction was significant.
Embryos from small
seeds of the cultivar 'Ingrid' exhibited greater gas exchange than
embryos from large seed.
However, large and small embryos of 'Klages'
had similar rates of gas exchange even though difference in 'Klages'
embryo size from large to small was greater than that of 'Ingrid'.
Further work to include chemical assay of embryo tissues would aid in de
termining why the embryo size responses vary among these two cultivars.
55
Vegetative Production
Embryo weight affected all vegetative growth characters evaluated.
Large 1Ingrid1 embryos produced 2.7 times more top and root growth
than small embryos (Table 11).
Large embryos produced plants with leaf
and stem areas 2.1 times that of small embryos.
Embryo weight affected
vegetative growth in the same manner as seed size in lIngrida described
in Chapter I , although differences were more pronounced with the
cultured embryos. This could be due to greater stress occurring within
the small embryos when isolated from their natural endosperms.
The
greatest plant death loss throughout the embryo culture experiment was
noted within the 1Ingrid-small1 treatment.
Embryo size did not affect top growth, root growth or leaf and
stem area of lKIages1 at 60 days (Table 11).
Vegetative performance means, over both embryo sizes, did not.
statistically differ among cultivars.
The cultivar x size interaction
was significant for leaf and stem areas, root dry matter; and for dry
matter top growth.
From these results I conclude (I) that embryo weight
is.positively correlated with seed weight in both of the cultivars
studied, (.2) seed size influence on seedling performance in the malting
cultivar lKIages1 is associated with endosperm effects - quality,
quantity, or both; and (3) seed size influence on seedling performance
in the feed barley 'Ingrid' is at least partially attributable to
embryo effects.
LITERATURE CITED
1.
A r n y , A. C. and R. J. Garber. 1918. Variation and correlation
in wheat, with special reference to weight of seed planted]
J. Agric. Res. 14(9): 359-392.
!
2.
Austenson, H. M. and P. D. Walton. 1970. Relationships between
initial seed weight and mature plant characters in spring wheat.
Can. J. Plant S c i . 50: 53-58.
3.
Baniaameur, F. and J. L. Caddel. 1976. Barley kernel size in
relation to seedling vigor, yield and yield components. Rev.
text, a paper presented at the 1976 meetings of A m e r. S o c . jof
Agr o n . Houston, TX. 15 p.
j
4.
Barr, E. L. 1976. Evaluation of barley cultivars for gibberellic
acid activity. M. S. thesis. Montana State University, Plant
& Soil S c i . D e p t . , Bozeman, MT. (unpublished). 38 p.
|
5.
Bonnett, 0. T. and C. M. Woodworth. 1931. A yield analysis of
three varieties of barley. J. Amer. S o c . Agron. 23: 311-326.
6.
Boyd, W. J. R., A. G. Gordon and L. J. LaCroix. 1971. Seed size,
germination resistance and seedling vigor in barley. C a n . J .
Plant S c i . 51: 93-99.
i
7.
B r o w n , R. 1943. Studies in germination and seedling growth:
I. The water content, gaseous exchange, and dry weight of I
attached and isolated embryos of barley. Ann. B o t . 7(25):;93-113.
8.
Cameron-Mi I Is, V. and C. M. Duffus. 1977. The in vitro culture
of immature barley embryos on different culture media. Ann. B o t .
41: 1117-1127.’
i
I
9.
10.
Carver, M. F. F. 1977. The influence of seed size on the!per­
formance of cereals in variety trials. J. Agric. S c i . 89: j247-249.
CeccarelIi, S. and M. T. Pegiati. 1980. Effect of seed weight
on coleoptiIe dimensions in barley. Can. J. Plant S c i . 60: 221225.
■
i
I
57
11.
C h i n g , I. M . , S. Hedtke, M. C. Boulger and W. E. Kronstad.
1977. ■ Correlation of field emergence rate and seed vigor
criteria in barley cultivars. Crop S c i . 17(2): 312-314.
12.
Dasgupta, P. R. and H. M. Austenson. 1973. Relations between
estimates of seed vigor and field performance in wheat. Can.
J. Plant S c i . 53: 43-46.
13.
Demirlicakmak1 A., M. I. Kaufmann and I. P. V. Johnson. 1963.
The influence of seed size and seeding rate on yield and yield
components of barley. Can. J. Plant S c i . 43: 330-337.
14.
Derr, H. B. 1910. The separation of seed barley/by the specific
gravity method. C ire. 62. Bur. Plant Ind. USDA. U. S. Govern­
ment Printing Office. Washington, DC. 6 p.
15.
Eslick, R. F. 1957. Within variety competitive effects on pro­
tein and seed number per head as influenced by seed size. Montana
Agricultural Experiment Station. Bozeman, MT (unpublished).
16.
Evans, I. E . and G. M. Bhatt. 1977. Influence of seed size,
protein content and cultivar on early seedling vigor in wheat.
Can. J. Plant S c i . 57: 929-935.
17.
Paris, D. G. and A. A. Guitard. 1967. Method of determining
seeding rate in barley yield trails. Can. J. Plant S c i . 47: 219220,
18.
Guitard, A. A., J. A. Newman and P. B. Hoyt. 1961. The influence
of seeding rate on the yield and the.yield components of wheat,
oats and barley. Can. J. Plant S c i . 41: 751-758.
19.
Hadjichristodoulou, A. D. and J. Photiades. 1977. Effect of
sowing depth on plant establishment, tillering capacity and
other agronomic characters of cereals. J. Agric. S c i . 89: 161167.
20.
Hampton, J. G. 1981. The extent and significance of seed size
variation in New Zealand wheats. N i Z. 0. Exp. Agric. 9: 179-183.
21.
Hicks, G. H. and J. C. Dabney. 1896. The superior value of
large, heavy seed. Yearbook of the U. S. Department of Agricul­
ture. 305-322.
58
22.
Hoagland, D. R. and D. I . Ar n o n . 1938. The water-culture method
for growing plants without soil. C ire. 347. Agric. Exp: S t a .
Univ. of Calif. Berkley, CA. 39 p.
23.
J a m e s , W. 0. and A. I. James. 1940. The respiration of barley
germinating in the dark. New Phytol. 39(2): 145-176.
24.
Jensen, C. J. 1975. Barleyymonoploids and doubled monoploids:
techniques and experience. P roc. of 3rd International Barley
Genetics Symposium, Garshing.
25.
Kaufmann, M. L. 1958. Seed size as a problem in genetic studies
of barley. P roc. of Genetics Society of Canada. 3(2): 30-32.
26.
Kaufmann, M. I. and A. D. McFadden. 1963. The influence of seed
size on results of barley yield trials. Can. J. Plant S c i . 43:
51-58.
27.
Kaufmann, M. I. and.A. A. Guitard. 1967. The effect of seed
size on early plant development in barley. Can. J. Plant S c i .
47: 73-77.
28.
Kaufmann, M. L. and A. D. McFadden. 1960. The competitive
interaction between barley plants grown from large and small
seeds. Can. J . Plant S c i . 40: 623-629.
29.
Kiesselbach, T. A. and C . A. Helm. 1917. Relation of size of
seed and sprout value to the yield of small grain crops. Res.
. Bull. no. 11. Agric. Exp. S t a . Univ. of Nebraska. Lincoln, NE.
73 p.
30.
Kiesselbach, T. A. 1924. Relation of seed size to the yield
of small grain crops. J. A m e r . S o c . Agron. 16: 670-682.
31.
Lebsock, K. L. 1948. Differential yield due to difference in
size of seed of barley varieties grown in yield trials. B. §.
thesis. Montana State College, Plant & Soil S c i . Dept. Bozeman,
MT (unpublished). 16 p.
32.
Leonard, W. H. and J. H. Martin.
Macmillan Company, New York.
1963.
Cereal crops.
The
59
33.
Lil l , J. G. 1910. The relation of size, weight and density of
kernel to germination of wheat. Giro. no. 11. Exp. Sta. Kansas
State Agricultural College. Manhattan, K S . 8 p.
34.
Lowe, L. B. and S. K. Rie s . 1973. Endosperm protein of wheat
seed as a determinant of seedling growth. Plant Physiol. 51:
57-60.
35.
Maguire, J. D. 1962. Speed of germination - aid in selection
and evaluation for seedling emergence and vigor. Crop S c i . 2(2):
176-177.
36.
McFadden, A. D. 1963. Effect of seed source on comparative
test results in barley. Can. J. Plant S c i . 43: 295-300.
37.
Mc N e a l , F. H., M. A. Berg, A. L. Dub b s , J. L. Krall, D. E.
Baldridge and G. P. Hartman. 1960. The evaluation of spring
wheat seed from different sources. Agron. J. 52: 303-304.
38.
Montgomery, E. G. 1912. Competition in cereals. Bull. no. 127.
Agric. Exp. Sta. University of Nebraska, Lincoln, NE. 22 p.
39.
Muchena, S. C. and C. 0. Grogan. 1977. Effects of seed size on
germination of corn (Zea mays) under simulated water stress
conditions. ■' Can. J. Plant S c i . 57: 921-923.
40.
Montana Department of Agriculture.
statistics. Volume XVITl.
41.
Ogilvie, I . S. and P. J. Kaltsikes. 1977. The relationship
between seed size, embryo size and mature plant characters in
hexaploid triticale. Z. P f lanzenzuchtung. 79(2): 105-109.
. 42.
Paluska, M. M., A. K. Ddbrenz and R. T. Ramage. 1979. Seed
size and seedling components in arivat barley. J. Ariz. N e v .
Acad. S c i . 14(3): 88-90,
43.
Sarquis, A. V., B. B. Fischer, F. G. Parsons and M. D. Miller.
1961. Geographic origin of barley seed produces no effect on
yield. California Agriculture. April, 1961. p. 3.
44.
Singh, V. P . , I. D. Tripathi and R. K. Chowdhury. 1975. Effect
of seed size on seedling growth and mature plant, characters in
barley (Hordeum vulqare L.). Haryana Agric. Univ. J. Res.
5(1): 48-51.
1980.
Montana agricultural
60
45.
Snedecor, G. W. and W. G. Cochran. 1967.
The Iowas State University Press, Ames.
Statistical methods.
46.
Sprague, H. B. and N. F. Farris. 1931. The effect of uniformity
of spacing seed on the development and yield of barley. J. Amer.
S o c . Agron. 23: 516-533.
47.
Tallberg, A. 1977. The amino-acid composition:in endosperm and
embryo of a barley variety and its high lysine mutant. Hereditas.
87: 43-46.
48.
Tanakamaru, S. and J. Inouye. 1976. Studies on the emergence in
crops - Effects of compaction of covering soil on the strength of
plumule elongation in two-rowed barley. P roc. Crop S c i . Soc.
Japan. 45(1): 57-62.
49.
Welch, R. W. 1977. Seedling vigour and grain yield of cereals
grown from seeds of varying protein contents. J. Agr i c . S c i .
88: 119-125.
50.
Whitcomb, W. 0.
its seed value.
51.
Wood, D. W., P. C. Longden and R. K. Scott. 1977. Seed size
variation; its extent, source and significance in field crops.
Seed S c i . & Technol. 5: 337-352.
1936. Weight per bushel of wheat in relation to
Proc..Assoc. Off. Seed Anal. 28: 59-61.
MONTANA STATE UNIVERSITY LIBRARIES
stks [email protected]
Seed and embryo size relationships with
RL
3 1762 00106265 O
N378
C197
cop.2
DATE
Carlson, G. R.
Seed and embr y o size
relationships with
s eedling and mature ...
ISSUED
TO
C / 1??
(L^ X
Download