Effect of the waxy endosperm gene on germination, agronomic, and malt quality characteristics in
barley (Hordeum vulgare)
by Philip Lyle Bruckner
A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE
in Agronomy
Montana State University
© Copyright by Philip Lyle Bruckner (1981)
Abstract:
A series of four waxy-normal endosperm isogenic pairs developed in three barley (Hordeum vulgare)
lines were used to evaluate the effect of the waxy endosperm gene on certain germination and
agronomic traits during and after kernel maturation as well as on malting quality and speed of
imbibition. Plots in two locations were sampled three times per week from shortly after anthesis to
harvest maturity to evaluate seed size, alpha-amylase activity, and germination characteristics during
kernel maturation. A second set of plots was used to evaluate the effect of the waxy endosperm gene on
yield, malt quality, and other agronomic traits at harvest maturity. Speed of imbibition in four
Compana isotypes grown in three environments was determined in a 48 hour, 20° C, unaerated steep.
Isogenic analysis showed that waxy endosperm isotypes exhibited significantly less dormancy, smaller
seeds, and greater alpha-amylase activity during kernel maturation than did normal endosperm
isotypes. Waxy and normal endosperm isotypes did not vary significantly in germination behavior,
yield, heading date, or in most malting quality characteristics at harvest maturity. Waxy endosperm
isotypes were significantly lower in diastatic power, had significantly lower seed weights, and in
certain genetic backgrounds were shorter than normal isotypes.
Waxy and normal endosperm isotypes did not differ significantly in speed of imbibition although
preliminary information showed that waxy isotypes could reach a 45% moisture level from 9.1 to 14.0
hours sooner than normal Compana isotypes. Naked Compana isotypes imbibed water significantly
faster, yielded 17% less, had a 16% smaller seed weight and exhibited significantly less dormancy and
a greater germination speed during kernel maturation and at harvest maturity than did covered
Compana isotypes. STATEMENT OF PERMISSION TO COPY
In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l l m e n t o f t h e r e q u i r e ­
ments f o r an advanced d e g r e e a t Montana S t a t e U n i v e r s i t y , I a g r e e t h a t
t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r i n s p e c t i o n .
I further
a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e copyi ng o f t h i s t h e s i s f o r
s c h o l a r l y p u r p o s es may be g r a n t e d by my m a jo r p r o f e s s o r , o r , i n
a b s e n c e , by t h e D i r e c t o r o f L i b r a r i e s .
his
I t i s u n d e r s to o d t h a t any
copying o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l no t
be allowed, w i t h o u t my w r i t t e n p e r m i s s i o n .
Signatm
Date
EFFECT OF THE WAXY ENDOSPERM GENE ON GERMINATION,
AGRONOMIC, AND MALT QUALITY CHARACTERISTICS
IN BARLEY ( HORDEUM VULGARE)
by
PHILIP LYLE BRUCKNER
A t h e s i s s u b m i t t e d in p a r t i a l f u l f i l l m e n t
o f t h e r e q u i r e m e n t s f o r t h e d egree
of
MASTER OF SCIENCE
in
Agronomy
Approved:
C h a i r p e r s o n , G rad ua te Committee
Head, Major Department
G rad ua te Dean
z
MONTANA STATE UNIVERSITY
Bozeman, Montana
November, .1981
iii
ACKNOWLEDGEMENT
I
wish t o acknowledge and t h a n k t h e f o l l o w i n g p e o p l e f o r t h e i r
support:
P r o f e s s o r R. F. E s l i c k f o r s e r v i n g a s my m a jo r p r o f e s s o r and
o f f e r i n g e x c e l l e n t s u p e r v i s i o n and a d v i c e t h r o u g h o u t iry g r a d u a t e
training.
. D r s . R. L. D i t t e r l i n e , C. F. McGuire, and J . M. M a r t i n f o r
s e r v i n g on my g r a d u a t e commi tt ee.
The Montana Wheat Resea rc h and M ar k et in g Committee f o r f i n a n c i a l
support.
My f e l l o w b a r l e y g r a d u a t e s t u d e n t s and t h e f a c u l t y o f t h e P l a n t
and S o i l S c i e n c e d e p a r t m e n t f o r f r i e n d s h i p and a s s i s t a n c e th r o u g h t h e
past three years.
My Dad and Mom, my s i s t e r s , Ramona and Rebecca, and my b r o t h e r s ,
Bruce and Roger f o r l o v e , encouragement and s u p p o r t t h r o u g h o u t my
life.
My w i f e , Cindy Meyer B r u ck n er , f o r b e i n g my b e s t f r i e n d and
f o r s u p p o r t i n g me w i t h h e r en co u ra g em en t, a d v i c e , and l o v e when I
needed i t most.
TABLE OF CONTENTS
Page
V I T A ..................................................
ii
ACKNOWLEDGEMENT............................................................
TABLE OF CONTENTS
jii
. . . . ; . ............................................................
LIST OF TABLES.......................................................
LIST OF F I G U R E S ..................................................
iv
vi
.
ABSTRACT.....................................................................................................
ix
xiii
INTRODUCTION..............................................................................
1
LITERATURE REVIEW
2
................................................................
G er m in a tio n C h a r a c t e r i s t i c s o f Developing
B a r l e y G r a i n ................................
A lp h a-a m y las e Development i n Develo pin g
B a r l e y G r a i n ..................................... . . . .......................
B a r l e y S t a r c h i n t h e Mature B a r l e y Kernel ........................
Endosperm M o d i f i c a t i o n and Enzyme Development . . . .
G er m in a tio n ................................................................. . . . . . .
MATERIALS AND METHODS.......................................................
RESULTS AND DISCUSSION . . .......................................................
C h a r a c t e r i s t i c s o f M a l t i n g and
Nonmalting C u l t i v a r s . ...........................
4
8
14
19
39
General Expe ri me nt al P r o c e d u r e s . ................................ . .
S t a t i s t i c a l M e t h o d s ...................................................... . . . . .
Experi ment I ........................................................................................
Expe rime nt 2 .......................
Experi ment 3 ................................................................
Experiment 4 ...........................
Experiment I :
2
39
40
40
43
46
47
50.
.
50
V
Page
Experi ment 2:
-
Kernel Weight, G er mi na tio n
C h a r a c t e r i s t i c s , and Alpha- am yla se
Development During M a t u r a t i o n . . . .
M a t u r a t i o n a s measured by m o i s t u r e p e r c e n t a g e
Kernel w e i g h t s d u r i n g m a t u r a t i o n .......................
G e r m in a ti v e c a p a c i t y d u r i n g m a t u r a t i o n . . .
Dormancy d u r i n g m a t u r a t i o n . . . . . . . . .
G er m in a tio n speed d u r i n g m a t u r a t i o n ...................
A lp ha -am y las e a c t i v i t y d u r i n g m a t u r a t i o n . .
Sum ma ry ................................
Experiment 3:
Experiment 4:
54
54
61
71
74
85
94
99
Agronomic, G e r m i n a t i o n , and Malt
Q u ality T r a i t s a t Harvest
M a t u r i t y .......................
100
Water I m b i b i t i o n i n Compana I s o t y p e s
108
CONCLUSIONS ...........................
117
REFERENCES
120
............................................................
vi
LIST OF TABLES
Page
Table
1
2
3
4
5
6
7
8
Experi ment I .
C la s s ific a tio n of barley c u ltiv a rs
by use and row t y p e (MBIA, 1981).
42
Experi ment I . Mean g e r m i n a t i o n b e h a v i o r and
alpha-amylase a c t i v i t y values f o r sixteen
b a r l e y c u l t i v a r s c l a s s i f i e d by use and row
type.
51
Expe rim ent I . A n a l y s i s o f v a r i a n c e f o r c e r t a i n
germination t r a i t s f o r s ix te e n barley
c u l t i v a r s c l a s s i f i e d by use and row t y p e .
52
Experi ment 2. S t a t i s t i c a l a n a l y s i s u s in g a p a i r e d
t t e s t o f percentage sp ik e m oisture during
kernel m aturation f o r e i g h t barle y lin e s
i s o g e n i c f o r waxy and normal endosperm
a t Bozeman, Montana, 1978.
59
Experiment 2. S t a t i s t i c a l a n a l y s i s u s in g a p a i r e d
t t e s t o f k e r n e l w e i g h t d u r i n g k er n el m a t u r a t i o n
f o r e i g h t b a r l e y l i n e s i s o g e n i c f o r waxy and
normal endosperm a t Bozeman and H u n tl e y ,
Montana, 1978.
70
Experiment 2. S t a t i s t i c a l a n a l y s i s u s in g a p a i r e d
t t e s t o f germin a t i v e c a p a c i t y d u r i n g k e r n e l
maturation f o r eig h t barley lin e s isogenic
f o r waxy and normal endosperm a t Bozeman and
H u n tl e y , Montana, 1978.
75
Experi ment 2. S t a t i s t i c a l a n a l y s i s u s in g a p a i r e d
t t e s t o f dormancy d u r i n g k e r n e l m a t u r a t i o n
f o r e i g h t b a r l e y l i n e s i s o g e n i c f o r waxy and
normal endosperm a t Bozeman and Hu n tle y ,
Montana, 1978.
83
Experi ment 2. S t a t i s t i c a l a n a l y s i s u s in g a p a i r e d
t t e s t o f g e r m i n a t i o n speed d u r i n g k e r n e l m a t u r ­
a t i o n f o r e i g h t b a r l e y l i n e s i s o g e n i c f o r waxy
and normal endosperm a t Bozeman and H u n tl e y ,
Montana, 1978.
93
vii
Table
9
10
11
12
Page
Experiment 2. S t a t i s t i c a l a n a l y s i s u s in g a p a i r e d
t t e s t o f alpha-amylase a c t i v i t y during kernel
maturation f o r e ig h t barley lin e s isogenic
f o r waxy and normal endosperm a t Bozeman and
H u n t l e y , Montana, 1978.
98
Expe rim ent 3. A n a l y s i s o f v a r i a n c e f o r s e v e r a l
agronomic t r a i t s f o r e i g h t b a r l e y l i n e s
i s o g e n i c f o r waxy and normal endosperm and
t h r e e check c u l t i v a r s a t Bozeman, Montana,
1979.
102
Expe rim ent 3. Mean agronomic r e s p o n s e s compared
u s i n g D un can 's New M u l t i p l e Range T e s t and c o ­
e f f i c i e n t s o f v a r i a t i o n f o r v a r i o u s agronomic
t r a i t s f o r e ig h t barley li n e s isogenic f o r
waxy and normal endosperm and t h r e e check
. c u l t i v a r s a t Bozeman, Montana, 1979.
103
Experi ment 3. A n a l y s i s o f v a r i a n c e f o r ger mi n a t i v e
e n e r g y and g e r m i n a t i o n speed f o r e i g h t b a r l e y
l i n e s i s o g e n i c f o r waxy and normal endosperm
and t h r e e check c u l t i v a r s a t Bozeman, Montana,
1979.
105
13
Experiment 3. Mean g e r m i n a t i o n r e s p o n s e s compared
u s i n g D uncan's New M u l t i p l e Range T e s t and
c o e f f i c i e n t s o f v a r i a t i o n f o r germinative
e n e r g y and g e r m i n a t i o n speed f o r e i g h t b a r l e y
l i n e s i s o g e n i c f o r waxy and normal endosperm and
th r ee , check c u l t i v a r s a t Bozeman, Montana,
1979.
106
14
Experiment 3. Mean r e s p o n s e s and s t a t i s t i c a l
a n a ly s is using a paired t t e s t fo r several
m alt q u a l i t y c h a r a c t e r i s t i c s in conventional
p i l o t m a l t s f o r f o u r waxy and f o u r normal
endosperm b a r l e y i s o t y p e s and t h r e e check
c u l t i v a r s a t Bozeman, Montana, 1979.
107
viii
T ab l e
15
16
17
.
Page
Experi ment 4. A n a l y s i s o f v a r i a n c e f o r k ern el
m o i s t u r e p e r c e n t a g e i n a 48 h o u r , 20° C,
u n a e r a t e d s t e e p f o r f o u r Compana i s o t y p e s
grown i n t h r e e e n v i r o n m e n t s .
Ill
Experiment 4. Rate o f w a t e r u p ta k e by f o u r Compana
i s o t y p e s i n a 20° C, u n a e r a t e d s t e e p . Hours
to reach in d ic a te d moisture percentages.
114
Experi ment 4. A n a l y s i s o f v a r i a n c e f o r germin a t i v e
e n e r g y and g e r m i n a t i o n sp ee d f o r f o u r Compana
i s o t y p e s grown in t h r e e e n v i r o n m e n ts . ,
,
116
.
ix
LIST OF FIGURES
Figure
1
2
3
4
.5
6
7
8
Page
Experiment 2. Average s p i k e m o i s t u r e o f f o u r waxy
and f o u r normal endosperm b a r l e y i s o t y p e s
sampled 23 t i m e s (27 J u l y - 23 September 1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
55
Experiment 2. S p ik e m o i s t u r e o f f o u r Compana i s o ­
t y p e s sampled 23 t i m e s (27 J u l y - 23 September
1978) d u r i n g k er n el m a t u r a t i o n a t Bozeman,
Montana.
56
Experiment 2. Sp ik e m o i s t u r e o f two T i t a n i s o t y p e s
sampled 23 t i m e s (27 J u l y - 23 September 1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
57
Experi ment %. Average s p i k e m o i s t u r e o f two s h o r t
awn-naked and two lo n g awn-covered Compana
i s o t y p e s sampled 23 t i m e s (27 J u l y - 23 S e p t ­
ember 1978) d u r i n g k e r n e l m a t u r a t i o n a t
Bozeman, Montana.
.5 8
Experiment 2. Kernel w e i g h t s o f f o u r Compana i s o t y p e s
sampled 23 t i m e s (27 J u l y - 23 September 1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
62
Experiment 2. Kernel w e i g h t s o f f o u r Compana
i s o t y p e s sampled 14 t i m e s (24 J u l y - 22 August
1978) d u r i n g k er n el m a t u r a t i o n a t H u n tl e y ,
Montana.
63
Expe rim ent 2. Average k e r n e l w e i g h t s o f f o u r waxy
and f o u r normal endosperm b a r l e y i s o t y p e s
sampled 23 t i m e s (27 J u l y - 23 September 1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
64
Experiment 2. Average k er n el w e i g h t s o f f o u r waxy
and f o u r normal endosperm b a r l e y i s o t y p e s
sampled 14 t i m e s (24 J u l y - 22 August 1978)
d u r i n g k e r n e l m a t u r a t i o n a t H u n tl e y , Montana.
65
Experiment 2.
Kernel w e i g h t s o f two Bet zes i s o t y p e s
sampled 14 t i m e s (24 J u l y - 22 August 1978)
d u r i n g k e r n e l m a t u r a t i o n a t H u n tl e y , Montana.
66
Expe rime nt 2. Average k e r n e l w e i g h t s o f two s h o r t
awn-naked and two long awn-covered Compana
i s o t y p e s sampled 23 t i m e s (27 J u l y - 23 September
1978) d u r i n g k e r n e l m a t u r a t i o n a t Bozeman,
Montana.
67
Experiment 2. Average k e r n e l w e i g h t s o f two s h o r t
awn-naked and two long awn-covered Compana
i s o t y p e s sampled 14 t i m e s (24 J u l y - 22 August
1978) d u r i n g k e r n e l m a t u r a t i o n a t H u n tl e y ,
Montana.
68
Expe rime nt 2. G e r m in a ti v e c a p a c i t y o f two B et ze s
i s o t y p e s sampled 23 t i m e s (27 J u l y - 23
September 1978) d u r i n g k e r n e l m a t u r a t i o n a t
Bozeman, Montana.
72
Experiment 2. Average ger mi n a t i v e c a p a c i t y o f two
s h o r t awn-naked and two lo n g awn-covered Compana
i s o t y p e s sampled 23 t i m e s (27 J u l y - 23 September
1978) d u r i n g k e r n e l m a t u r a t i o n a t Bozeman,
Montana.
73
Expe rime nt 2. Average dormancy o f f o u r waxy and
f o u r normal endosperm b a r l e y i s o t y p e s sampled
23 t i m e s (27 J u l y - 23 September 1978) d u r i n g
k e r n e l m a t u r a t i o n a t Bozeman, Montana.
77
Experi ment 2. Average dormancy o f f o u r waxy and f o u r
normal endosperm b a r l e y i s o t y p e s sampled 14
t i m e s . (24 J u l y - 22 August 1978) d u r i n g k e r n e l
m a t u r a t i o n a t H u n tl e y , Montana.
78
Experi ment 2. Dormancy o f f o u r Compana i s o t y p e s
sampled 23 ti m es (27 J u l y - 23 S e p t e m b e r .1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
79
xi
Figure
17
18
19
20
21
22
23
24
25
Page
Experiment 2. Dormancy o f f o u r Compana i s o t y p e s
sampled 14 t i m e s (24 J u l y - 22 August 1978)
d u r i n g k e r n e l m a t u r a t i o n a t H u n tl e y , Montana.
80
Experiment 2. Average dormancy o f two s h o r t awnnaked and two long awn-covered Cpmpana i s o t y p e s
sampled 23 t i m e s (27 J u l y - 23 September 1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
81
Expe rim ent 2. Average dormancy o f two s h o r t awnnaked and two long awn-covered Compana i s o t y p e s
sampled 14 t i m e s (24 J u l y - 22 August 1978)
d u r i n g k e r n e l m a t u r a t i o n a t H u n tl e y , Montana.
82
Experiment 2. Average g e r m i n a t i o n speed o f f o u r
waxy and f o u r normal endosperm b a r l e y i s o t y p e s
sampled 23 t i m e s (27 J u l y - 23 September 1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
86
Experi ment 2. Average g e r m i n a t i o n sp eed o f f o u r
waxy and f o u r normal endosperm b a r l e y i s o t y p e s
sampled 14 t i m e s (24 J u l y - 22 August 1978)
d u r i n g k e r n e l m a t u r a t i o n a t H u n tl e y , Montana.
87
Experiment 2. G er m in a tio n speed o f f o u r Compana
i s o t y p e s sampled 23 t i m e s (27 J u l y - 23 Sep­
temb er 1978) d u r i n g k e r n e l m a t u r a t i o n a t
Bozeman, Montana.
88
Experi ment 2. G er mi na tio n speed o f f o u r Compana
i s o t y p e s sampled 14 t i m e s (24 J u l y - 22
August 1978). d u r i n g k e r n e l m a t u r a t i o n a t
H u n t l e y , Montana.
89
Experi ment 2. Ger min at ion speed o f two T i t a n
i s o t y p e s sampled 23 t i m e s (27 J u l y - 23
September 1978) d u r i n g k e r n e l m a t u r a t i o n
a t Bozeman, Montana.
90
Experiment 2. Average g e r m i n a t i o n s p e e d . o f two
s h o r t awn-naked and two long awn-covered
Compana i s o t y p e s sampled 23 t i m e s (27 J u l y 23 September 1978) d u r i n g k er n el m a t u r a t i o n
a t Bozeman, Montana.
91
xii
F ig u r e
26
27
28
.29
'
30
Page
Experiment 2. Average g e r m i n a t i o n speed o f two
s h o r t awn-naked and two long awn-covered
Compana i s o t y p e s sampled 14 t i m e s (24 J u l y . 22 August 1978) d u r i n g k e r n e l m a t u r a t i o n
a t H u n t l e y , Montana.
92
Expe rime nt 2. Average a l p h a - a m y l a s e a c t i v i t y
o f f o u r waxy and f o u r normal endosperm b a r l e y
i s o t y p e s sampled 23 t i m e s (27 J u l y - 23 Sep­
te mb er 1978) d u r i n g k e r n e l m a t u r a t i o n a t
Bozeman, Montana.
95
Experi ment 2. Al pha -am yla se a c t i v i t y o f two
Compana i s o t y p e s sampled 23 t i m e s (27 J u l y 23 September 1980) d u r i n g k e r n e l m a t u r a t i o n
a t Bozeman, Montana.
96
Experi ment 4. P a t t e r n s o f w a t e r u p ta k e d u r i n g a
48 h o u r , 20° C, u n a e r a t e d s t e e p f o r seed from
f o u r Compana i s o t y p e s grown i n t h r e e
environments.
109
Experiment 4. R e g r e s s i o n e q u a t i o n s d e s c r i b i n g
t h e w a t e r u p ta k e d u r i n g a 48 h o u r , 20° C,
u n a e r a t e d s t e e p o f seed from f o u r Compana
i s O t y p e s grown i n t h r e e en v i r o n m e n ts .
113
O
xiii
ABSTRACT
A s e r i e s o f f o u r waxy-normal endosperm i s o g e n i c p a i r s developed
in t h r e e b a r l e y (Hordeum v u l g a r e ) l i n e s w e r e used t o e v a l u a t e t h e
e f f e c t o f t h e waxy endosperm gene on c e r t a i n g e r m i n a t i o n and agronomic
t r a i t s d u r i n g and a f t e r k er n el m a t u r a t i o n as well as on m a l t i n g
q u a l i t y and speed o f i m b i b i t i o n .
P l o t s in two l o c a t i o n s were sampled
t h r e e t i m e s p e r week from s h o r t l y a f t e r a n t h e s i s t o h a r v e s t m a t u r i t y
t o e v a l u a t e seed s i z e , a l p h a - a m y l a s e a c t i v i t y , and g e r m i n a t i o n
c h a r a c t e r i s t i c s d u r i n g k er n el m a t u r a t i o n . A second s e t o f p l o t s
was used t o e v a l u a t e t h e e f f e c t o f t h e waxy endosperm gene on
y i e l d , m a l t q u a l i t y , and o t h e r agronomic t r a i t s a t h a r v e s t m a t u r i t y .
Speed o f i m b i b i t i o n in f o u r Compana i s o t y p e s grown i n t h r e e e n v i r o n ­
ments was d e t e r m in e d in a 48 h o u r , 20° C, u n a e r a t e d s t e e p .
Isogenic
a n a l y s i s showed t h a t waxy endosperm i s o t y p e s e x h i b i t e d s i g n i f i c a n t l y
l e s s dormancy, s m a l l e r s e e d s , and g r e a t e r a l p h a - a m y l a s e a c t i v i t y
d u r i n g k er n el m a t u r a t i o n th a n d i d normal endosperm i s o t y p e s . Waxy
and normal endosperm i s o t y p e s d id n o t v a r y s i g n i f i c a n t l y i n g e r m i n a t i o n
b e h a v i o r , y i e l d , hea d in g d a t e , o r in most m a l t i n g q u a l i t y c h a r a c t e r i s ­
t i c s a t h a r v e s t m a t u r i t y . Waxy endosperm i s o t y p e s were s i g n i f i c a n t l y
lowe r i n d i a s t a t i c power, had s i g n i f i c a n t l y lower seed w e i g h t s , and
i n c e r t a i n g e n e t i c backgrounds were s h o r t e r th a n normal i s o t y p e s .
Waxy and normal endosperm i s o t y p e s d i d n o t d i f f e r s i g n i f i c a n t l y in .
speed o f i m b i b i t i o n a l t h o u g h p r e l i m i n a r y i n f o r m a t i o n showed t h a t waxy
i s o t y p e s co ul d r e a c h a 45% m o i s t u r e l e v e l from 9.1 t o 1 4 .0 hours
s o o n e r th a n normal Compana i s o t y p e s .
Naked Compana i s o t y p e s imbibed
w a t e r s i g n i f i c a n t l y f a s t e r , y i e l d e d 17% l e s s , had a 16% s m a l l e r
s ee d w e i g h t and e x h i b i t e d s i g n i f i c a n t l y l e s s dormancy and a g r e a t e r
g e r m i n a t i o n speed d u r i n g k er n el m a t u r a t i o n and a t h a r v e s t m a t u r i t y
t h a n d i d cov er e d Compana i s o t y p e s .
INTRODUCTION
Waxy b a r l e y s t a r c h i s more r e a d i l y m o d i f i e d by e i t h e r ch em ic a ls
o r enzymes t h a n i s normal b a r l e y s t a r c h .
T h i s and o t h e r unique p r o p e r
t i e s o f waxy b a r l e y s t a r c h i n d i c a t e t h a t waxy b a r l e y may become
i n c re a s in g ly im portant in c e r t a i n i n d u s t r i a l processes.
L ittle in­
f o r m a t i o n has been d ev el o pe d on t h e e f f e c t o f t h e waxy endosperm
gene on agron omi c, g e r m i n a t i o n , and m a l t q u a l i t y c h a r a c t e r i s t i c s
b e f o r e and a f t e r , h a r v e s t m a t u r i t y .
The o b j e c t i v e s o f t h e f o l l o w i n g s t u d i e s were t o d e t e r m i n e th e
e f f e c t o f t h e waxy endosperm gene on g e r m i n a t i o n , dormancy, seed s i z e ,
and a l p h a - a m y l a s e a c t i v i t y d u r i n g k er n el m a t u r a t i o n and on i m b i b i t i o n
and m a l t i n g q u a l i t y i n t h e ma ture g r a i n .
LITERATURE REVIEW
G er m in a tio n C h a r a c t e r i s t i c s o f De vel op in g B a r l e y Grain
I s o l a t e d b a r l e y embryos can g e r m i n a t e a t a v e r y e a r l y s t a g e o f
de v el o p m en t , even as e a r l y as f i v e days a f t e r a n t h e s i s (B is h o p , 1944;
Gordon, T 9 6 9) .
The a b i l i t y o f t h e embryo t o g er m i n a te a t t h i s e a r l y
s t a g e depends on a c r i t i c a l embryo s i z e (Cameron-Mills and D u f f u s ,
1980).
I n t a c t s e e d s , however, c a n n o t g e r m i n a t e i n t h e e a r l y d e v e l o p ­
mental s t a g e s .
Gordon (1969) r e p o r t e d t h a t o n l y a few i n t a c t b a r l e y
s ee ds g e r m i n a te d i n t h e f i r s t 42 days a f t e r a n t h e s i s .
W e l l i n g t o n (1964)
r e p o r t e d no g e r m i n a t i o n i n b a r l e y s ee d s u n t i l 3 - 4 weeks a f t e r a n t h e s i s ,
w h i l e B i l d e r b a c k (1971) showed no g e r m i n a t i o n up t o 20 days a f t e r
anthesis
when t h e s e e d s were im m ed i at el y p l a c e d on m o i s t sand.
S i m i l a r r e s u l t s a r e r e p o r t e d f o r wheat ( W e l l i n g t o n , 1956a, 1956b;
M i t c h e l l e t a l . , 1980).
The seed c a n , however, g e r m i n a te a t a v e r y e a r l y s t a g e i f th e
embryo i s exposed t o t h e a i r by r u p t u r i n g t h e p e r i c a r p and t e s t a .
Gordon (1969) r e p o r t e d a g e r m i n a t i o n r a t e i n b a r l e y o f 75% t e n days
a f t e r a n t h e s i s un der t h e s e c o n d i t i o n s .
Wheat can g e r m i n a t e as e a r l y as
3-4 weeks a f t e r a n t h e s i s when t h e embryo i s exposed m e c h a n i c a l l y
( W e l l i n g t o n , 19 5 6 b) .
effect.
Drying o f t h e immature g r a i n has a s i m i l a r
A i r d r i e d g r a i n g e r m i n a t e s a t an e a r l i e r s t a g e o f m a t u r i t y (10
days a f t e r a n t h e s i s ) and a t a f a s t e r r a t e t h a n u n d r ie d g r a i n
3
( M i t c h e l l e t a l . , 198 0) .
W el li n g t o n r e p o r t e d g e r m i n a t i o n o f d e s i c c a t e d
immature wheat t h r e e weeks a f t e r a n t h e s i s compared t o f i v e weeks a f t e r
a n t h e s i s in u n d r i e d g r a i n ( W e l l i n g t o n , 1 9 5 6 b ) .
The g e r m i n a t i o n c a p a c i t y o f immature g r a i n d ev el o p s e a r l y a f t e r
f e r t i l i z a t i o n , p r o b a b l y w i t h i n t h e f i r s t 10-15 days f o l l o w i n g a n t h e s i s
(Gordon, 1969; LaCrox e t a l . , 1976; Gordon e t a l . , .1979; M i t c h e l l
e t a l . , 1980; T a k a h a s h i , 1980).
The g e r m i n a t i o n c a p a c i t y r i s e s , the n
d e c r e a s e s r a p i d l y w i t h d e c r e a s i n g m o i s t u r e c o n t e n t and t h e i n d u c t i o n o f
dormancy ( T a k a h a s h i , 198 0) .
High t e m p e r a t u r e s d u r i n g seed f o r m a t i o n
(10-20 days p q s t a n t h e s i s ) r e p r e s s dormancy i n d u c t i o n w h i l e low te m p e r ­
a t u r e s enhance t h e i n d u c t i o n o f dormancy ( T a k a h a s h i , 1980).
LaCroix
e t a l . (1976) r e p o r t e d a d e c r e a s e in g e r m i n a t i o n p e r c e n t a g e in s p r i n g
wheat 34^-40 days a f t e r a n t h e s i s .
W e l l i n g t o n (1964) r e p o r t e d a 14%
and 22% r e d u c t i o n in g e r m i n a t i o n o f Domen,and Herta b a r l e y s r e s p e c t ­
i v e l y , as s e c o n d a r y dormancy was imposed.
T h i s dormancy b r e a k s down
w i t h i n c r e a s i n g m a t u r i t y and s t o r a g e .
The p e r i c a r p i s i m p l i c a t e d as havi ng some c o n t r o l o v e r ger mi na­
t i o n in d e v e l o p i n g b a r l e y ( W e l l i n g t o n , 1964; Gordon, 1 969; B r i g g s ,
1978; M i t c h e l l e t a l . , 198 0) .
Water l o s s t h r o u g h t h e p e r i c a r p oc cu rs
w h i l e t h e embryo and r e m a in d e r o f t h e g r a i n i s s t i l l
accumulating water.
The c a p a c i t y t o g e r m i n a t e f i r s t o c c u r s when 50% o f t h e w a t e r has been
l o s t from t h e o u t e r p e r i c a r p ( M i t c h e l l e t a l . , 1980).
The c a p a c i t y t o g e r m i n a t e a t h a r v e s t t i m e and d u r i n g b a r l e y
4
develo pme nt i s a v a r i e t a l c h a r a c t e r t h a t i s s u b j e c t t o e n v ir o n m en ta l
variation.
A s t u d y o f 4 m a l t i n g and 3 n o n m a lti n g b a r l e y v a r i e t i e s
showed i n i t i a l g e r m i n a t i o n c a p a c i t y o c c u r r i n g 25-44 days a f t e r a n t h e s i s
and 50% g e r m i n a t i o n c a p a c i t y o c c u r r i n g between 30 and 60 days a f t e r
a n t h e s i s (LaBerge e t a l . , 1971).
Gordon e t a l .
(1979) showed t h a t a
50% g e r m i n a t i o n p o t e n t i a l i n wheat o c c u r r e d 32-38 days a f t e r a n t h e s i s .
Speed o f g e r m i n a t i o n i n c r e a s e s w i t h i n c r e a s i n g m a t u r i t y i n b a r l e y
( B i l d e r b a c k , 1971) and whe at (LaCroix e t a l . , 1976).
A lp ha -a m yl as e Development i n D eve lop in g B a r l e y Grain
In b a r l e y and whe at a t l e a s t two t y p e s o f a l p h a - a m y l a s e e x i s t
( D au s sa nt and Mayer, 1980; Kru ger, 1980; Gordon, 1980; S a r g e a n t , 1980).
Green a l p h a - a m y l a s e , a l p h a - a m y l a s e I , i s found i n d e v e l o p i n g s e e d s .
Malt a l p h a - a m y l a s e , a l p h a - a m y l a s e I I , i s found p r e d o m i n a n t l y i n germin­
a t i n g s e e d s ( D au s sa nt and Mayer, 1980; Gordon, 1980).
R ece nt e v i d en ce
i n d i c a t e s b o th t y p e s o f a l p h a - a m y l a s e a r e p r e s e n t i n g e r m i n a t i n g
b a r l e y s e e d , a l t h o u g h most o f t h e a l p h a - a m y l a s e a c t i v i t y i s due t o
a l p h a - a m y l a s e I I ( D au s sa nt and Mayer, 1980).
Green a l p h a - a m y l a s e , l o c a t e d i n t h e p e r i c a r p o f d e v e l o p i n g s e e d s ,
i s in d e p e n d e n t o f t h e embryo o r exogenous g i b b e r e l l i c . a c i d f o r
s y n t h e s i s (MacGregor e t a l . , 1972; A l l i s o n e t a l . , 1974; D au ssa nt and
Mayer, 1980; Gordon, 1980; S a r g e a n t , 1980).
The a l e u r o n e l a y e r and
t h e s c u t e l l u m s y n t h e s i z e m a l t a l p h a - a m y l a s e de novo i n r e s p o n s e t o
5
g i b b e r e l l i n s from t h e embryo o r exogenous GA (D aus san t and Mayer, 1980).
The two t y p e s o f a l p h a - a m y l a s e have d i f f e r e n t e l e c t r o p h o r e t i c p r o p e r ­
t i e s , pH optimums, pH and h e a t s t a b i l i t i e s and s t a r c h d i g e s t i n g
p r o p e r t i e s ( D au s sa nt and Mayer, 1980).
Alp ha -a m yl as es i n immature b a r l e y s i n c r e a s e r a p i d l y a f t e r a n t h e s i s ,
t h e n d e c l i n e t o a Tow, s t a b l e l e v e l
( D u f f u s , 1969; LaBerge e t a l . ,
1971; MacGregor e t a l . , 1971; MacGregor e t a l . , 1972; A l l i s o n e t a l ,
1974; Riggs and G o t h a r d , 1976; Gordon, 1980).
Considerable v a r ia tio n
i n a l p h a - a m y l a s e d ev el opm ent al p a t t e r n s e x i s t s due t o e n v i ro nm en ta l and
cultivar characteristics
(MacGregor e t a l . , 1974; LaCroix e t a l . , 1976;
Riggs and G o t h a r d , 1976).
LaBerge e t a l .
(1971) i n a s t u d y o f seven
b a r l e y c u l t i v a r s , i n c l u d i n g f o u r m a l t i n g b a r l e y s , showed t h a t a l p h a am ylase l e v e l s i n c r e a s e d im m ed ia te ly a f t e r a n t h e s i s , peaked i n t h e
f i r s t t e n days f o l l o w i n g a n t h e s i s , t h e n d e c l i n e d t o a low l e v e l by
10-15 days a f t e r a n t h e s i s .
Al I i son e t a l .
(1974) d e m o n s t r a t e d t h a t
p e r i c a r p a n t h e s i s in G o l d f i e l d b a r l e y peaked a b o u t f i f t e e n days a f t e r
anthesis.
Riggs and Gothard (1976) r e p o r t e d peak a l p h a - a m y l a s e
a c t i v i t y 10-16 days a f t e r a n t h e s i s i n s i x b a r l e y c u l t i v a r s a l t h o u g h a
h u l l e s s b a r l e y c u l t i v a r , N a c k t a , showed no d e f i n i t e peak.
Maximum
a l p h a - a m y l a s e a c t i v i t y d i f f e r e d mark ed ly between c u l t i v a r s a l t h o u g h ,
t h e r e were no c u l t i v a r d i f f e r e n c e s i n a l p h a - a m y l a s e a c t i v i t y from 31
days a f t e r a n t h e s i s t o m a t u r i t y .
Conquest b a r l e y showed a peak a l p h a -
amylase a c t i v i t y 11 days a f t e r e a r emergence (two days a f t e r a n t h e s i s )
6
when grown i n t h e f i e l d w h i l e maximum a c t i v i t y o f Conquest and Fergus
b a r l e y grown i n a growth chamber o c c u r r e d 9-10 days and f o u r days a f t e r
a n t h e s i s , r e s p e c t i v e l y (MacGregor e t a l . , 1971; MacGregor e t a l . , 1972)!.
The a l p h a - a m y l a s e a c t i v i t y i n Conquest d e c l i n e d t o 1/10 i t s maximum
a f t e r 28 days and remained c o n s t a n t u n t i l m a t u r i t y .
Duffus (1969)
r e p o r t e d peak a l p h a - a m y l a s e l e v e l s i n b a r l e y grown i n . B r i t a i n o c c u r r e d
20-30 days a f t e r a n t h e s i s and t h a t c h l o r o c h o l i n e c h l o r i d e a p p l i e d
s h o r tly a f t e r a n th e sis in h i b ite d alpha-amylase s y n th e s is .
Sim ilar
enzyme development p a t t e r n s and c u l t i v a r v a r i a t i o n s a r e r e p o r t e d i n
whe at (LaCroix e t a l . , 1976; Gordon e t a l . , 1979; King and G a l e , 1980).
A s e t o f a l p h a - a m y l a s e isozymes which have s i m i l a r i s o e l e c t r i c
p o i n t s t o g e r m i n a t i o n a l p h a - a m y l a s e have been r e p o r t e d i n d e v e l o p i n g
immature w he at i n a d d i t i o n t o t h e g r ee n a l p h a - a m y l a s e n o r m a l ly
p r e s e n t ( K r u g e r , 1980).
The p r e s e n c e o f t h e s e isoenzymes i n d i c a t e s
t h a t some l e a k a g e may o c c u r i n t h e g e r m i n a t i o n c o n t r o l mechanisms and
t h a t c o n t r o l o v e r g e r m i n a t i o n may n o t be 100% e f f e c t i v e .
M a lt in g
b a r l e y s , w i t h c h a r a c t e r i s t i c s t r o n g enzyme systems and s h o r t dormancy
p e r i o d s , showed i n c r e a s e d a l p h a - a m y l a s e a c t i v i t y d u r i n g l a t e r i p e n i n g
i n r e s p o n s e t o r a i n (LaBerge e t a l . , 1971).
Riggs and Gothard (1976)
r e p o r t e d a s t r o n g c o r r e l a t i o n between peak a l p h a - a m y l a s e a c t i v i t y d u r ­
i n g b a r l e y development and g e r m i n a t i o n e n e r g y t h r e e weeks a f t e r h a r v e s t .
The purpose of alpha-amylase in the pericarp during grain develop­
ment and the reasons for i t s disappearance during maturity are
7
unknown (MacGregor e t a l . , 1972; A l l i s o n e t a l . , 1974; Riggs and
G o t h a r d , 1976; D au s sa n t and Mayer, 19 8 0 ).
Al I i son e t a l .
MacGregor e t a l . (1972) and
(1974) s p e c u l a t e d t h a t g r e e n a l p h a - a m y l a s e i n t h e p e r i ­
c a r p may h y d r o l y z e p e r i c a r p s t a r c h e a r l y i n development t o p r o v i d e
en e r g y f o r growing k e r n e l s o r produce s h o r t c h ai n p r i m e r s t o be used
i n dndosperm s t a r c h s y n t h e s i s .
S a r g e a n t (1980) showed t h a t in w hea t,
g r e e n a l p h a - a m y l a s e i n t h e p e r i c a r p i s n o t in v o l v ed i n s t a r c h s y n t h e ­
sis.
D is a p p e a r a n c e o f g r e e n a l p h a - a m y l a s e d u r i n g m a t u r a t i o n may be
due t o i n h i b i t i o n , i n a c t i v a t i o n , i n s o l u b i l i z a t i o n , o r d e g r a d a t i o n o f
en zy m ati c p r o t e i n (MacGregor e t a l . , 1972; Riggs and G o t h a r d i T976;
D au s sa n t and Mayer, 1980).
The a l e u r o n e s y n t h e s i z e s a l p h a - a m y l a s e i n r e s p o n s e t o g i b b e r e l l i c
a c i d (Gordon, 1980).
i n dev el op m en t.
The a b i l i t y t o r e s p o n d in t h i s way a r i s e s e a r l y
Gordon (1980) s t a t e d t h a t t h e a b i l i t y o f a l e u r o n e
l a y e r s t o r e s p o nd t o GA a r i s e s 25-30 days a f t e r a n t h e s i s , a l th o u g h
c u l t i v a r s v a r y c o n s i d e r a b l y in t h i s p r o p e r t y .
The s t a g e o f development
a t which t h e embryo can s y n t h e s i z e g i b b e r e l I i n s remains u n c l e a r
(Gordon, 1980 ).
Cool r i p e n i n g en v i ro n m en ts t h a t slow g r a i n d e h y d r a t i o n
a l s o slow embryo m a t u r a t i o n as well a s t h e a l e u r o n e c e l l s '
produce g er m in a t i v e a l p h a - a m y l a s e .
a b i l i t y to
Marchylo e t a l . (1980) h a r v e s t e d
wheat 25, 32, and 39 days a f t e r f l o w e r i n g and found t h a t t h e embryo
s c u t e l l urn co ul d s y n t h e s i z e a l p h a - a m y l a s e i n t h e ab se nce o r p r e s e n c e
o f GAg 25 days a f t e r f l o w e r i n g .
The immature e n d o s p e r m - a le ur o ne
.
produced a l p h a - a m y l a s e i n r e s p o n s e t o GA3 32 days a f t e r f l o w e r i n g .
At
s u c c e s s i v e d ev el o pm en ta l s t a g e s t h e t i s s u e s s y n t h e s i z e d h i g h e r l e v e l s
o f alpha-amylase.
B i l d e r b a c k (1971) showed t h a t a l e u r o n e l a y e r s i n
Himalaya b a r l e y s t i l l
anthesis.
co ul d n o t res po nd t o exogenous GA3 25 days a f t e r
However, d r i e d immature s ee d s a t l e a s t 20 days o l d when
i n c u b a t e d i n exogenous g i b b e r e l l i c a c i d , produced l a r g e amounts o f
alpha-amylase.
King and Gale (1980) r e p o r t e d no a l p h a - a m y l a s e p ro duc ­
t i o n i n h a l f s ee d s o f whe at a f t e r GA3 i n c u b a t i o n u n t i l 35-40 days
a fte r anthesis.
A r t i f i c i a l l y d r i e d d e t a c h e d h a l f s e e d s res po nde d t o
GA3 as e a r l y as 22 days a f t e r a n t h e s i s .
T h e . r a t e and d u r a t i o n o f
d r y i n g i n f l u e n c e d t h e a b i l i t y o f t h e immature g r a i n t o res p o n d t o
GA3 and prod uce a l p h a - a m y l a s e (King and G a l e , 1980).
B a r l e y S t a r c h in t h e Mature B a r l e y Kernel
S t a r c h , a g l u c a n , forms t h e food r e s e r v e p o l y s a c c h a r i d e in
p l a n t s (Greenwood, 1964).
S t a r c h , t h e most s i g n i f i c a n t chemical
component o f t h e c e r e a l g r a i n c o n s t i t u t e s t w o - t h i r d s o f t h e d ry w ei g h t
o f b a r l e y ( H a r r i s , 1962).
S t a r c h c o m p ri s es 63-65% o f t h e d r y w ei g h t
o f plump, two rowed b a r l e y ( H a r r i s , 1962; B r i g g s , 1978).
The endo­
sperm s t o r e s t h e m a j o r i t y o f t h e s t a r c h i n b a r l e y , making up 85-89%
o f t h i s t i s s u e ( B r i g g s , 1978).
S t a r c h i s e x c l u s i v e t o p l a n t s , b e i n g a m i x t u r e o f two t y p e s o f
g l u c o s e p o ly m e r s , one l i n e a r and t h e o t h e r branched ( H a r r i s , 1962;
9
Bewley and B la ck , 1978; B r i g g s , 1978; Bohli n s k i , 197 9) .
Amylose i s a
s t r a i g h t c h a i n polymer c o n t a i n i n g D - g lu co p yr an o s e u n i t s l i n k e d by
a l p h a ( l - 4 ) g l u c o s i d i c bonds which may be as long a s 2000 g l u c o s e r e s i ­
dues.
Amylopectin i s a much l a r g e r m o l e c u le w it h a h i g h l y branched
s t r u c t u r e i n which t h e a l p h a ( I - 4 ) l i n k e d g lu c o p y r a n o s e c h a i n s a r e
branc he d w i t h a l p h a ( l - 6 ) l i n k a g e s e v e r y 24-26 g l u c o s e r e s i d u e s .
The r e l a t i v e p r o p o r t i o n o f amylose and a m y lo p e c t in can be
e s t i m a t e d by t h e i o d i n e b i n d i n g c a p a c i t y o r i o d i n e a f f i n i t y t e s t ,
c a p i t a l i z i n g on t h e f a c t t h a t amylose b in d s i o d i n e a t c o n s t a n t f r e e
i o d i n e c o n c e n t r a t i o n s up t o a l i m i t i n g v a l u e w h il e a m y lo p e c t in binds
l i t t l e iodine.
S t a r c h , b e i n g a m i x t u r e o f t h e two p o ly m er s , has an
interm ed iate binding ca p a c ity .
The p r o p o r t i o n o f amylose i s e s t i m a t e d
by e x t r a p o l a t i o n o f t h e l i n e a r p o r t i o n o f t h e amylose and s t a r c h
b i n d i n g cu r v e s t o z e r o f r e e i o d i n e and u s in g t h e f o l l o w i n g r e l a t i o n ­
s h i p (Greenwood, 1964):
%
Amylose =
A f f i n i t y o f amy T o s e x ^00
Enzymes d e g r ad e s t a r c h
(Greenwood, 1964; Bewley and B la ck , 1978;
B r i g g s , 1978; B o h i n s k i , 1979).
a r e a l p h a - and b e t a - a m y l a s e .
ent patterns.
The two p r i n c i p l e h y d r o l y z i n g enzymes
Both a t t a c k a l p h a ( l - 4 ) bonds b u t in d i f f e r ­
Alpha- am ylas e c l e a v e s a l p h a ( l - 4 ) bonds a t random p o i n t s
w h i l e b e t a - a m y l a s e a c t i o n removes s u c c e s s i v e m a l t o s e u n i t s b eg i n n in g
a t t h e n o n - r e d u c i n g t e r m i n u s o f t h e g lu c o p y r a n o s e c h a i n .
Neither
a l p h a - no r b e t a - a m y l a s e can remove bran ch p o i n t s , w i t h c l e a v a g e s to p p i n g
\
10
two t o t h r e e g l u c o s e u n i t s from t h e a l p h a ( l - 6 ) bond.
Thus amylose can
t h e o r e t i c a l l y be c o n v e r t e d e n t i r e l y t o g l u c o s e p lu s m a l t o s e and a l p ha
and b e t a d e x t r i n s by t h e combined a c t i o n o f a l p h a - a n d b e t a - a m y l a s e .
The same two enzymes w i l l o n l y p a r t i a l l y d e g r a d e a m y l o p e c t i n .
Even
though t h e t h e o r e t i c a l y i e l d o f m a l t o s e from amylose d i g e s t e d by pur e
b e t a - a m y l a s e i s 100% ( H a r r i s , 1962) t h e a c t u a l y i e l d i s n e a r 73%.
Th is
i n c o m p le t e c o n v e r s i o n o f amylose by b e t a - a m y l a s e i s p r o b a b l y due t o
some m o d i f i c a t i o n i n amylose s t r u c t u r e (Greenwood, 19 6 4 ) , p o s s i b l e
anomalous a l p h a ( 1- 6 ) l i n k a g e s ( B r i g g s , 1978).
Beta-amylase converts
o n l y 58% o f a m y l o p e c t i n t o m a l t o s e (Greenwood, 1964).
S t a r c h g r a i n s a r e l a i d down as i n s o l u b l e p a r t i c l e s .
The s t a r c h
c o n t e n t o f t h e g r a i n d u r i n g g r a i n development r i s e s i n a l o g a r i t h m i c
( H a r r i s , 1962) o r s ig m o i d a l f a s h i o n ( B r i g g s , 1978).
N inety-five
p e r c e n t o f t h e s t a r c h i s d e p o s i t e d in t h e i n i t i a l 11-28 days a f t e r .
s p i k e emergence (MacGregor e t a l . , 1971; B r i g g s , 1978).
Genotype and
e n v i ro n m e n ta l c h a r a c t e r i s t i c s c o n t r o l t h e amount and p r o p e r t i e s o f
s t a r c h ( H a r r i s , 1962).
Amylose and a m y lo p e c t in a r e n o t s y n t h e s i z e d
s i m u l t a n e o u s l y ( H a r r i s , 1962; MacGregor e t a l . , 1971; B r i g g s , 1978).
The amylose c o n t e n t o f t h e s t a r c h i n c r e a s e d from a v a l u e o f 13.8% a f t e r
14 days t o 22.5% and remained c o n s t a n t t o m a t u r i t y , i n d i c a t i n g t h a t
d u r i n g t h e e a r l y s t a g e s o f g r o w t h , t h e am y lo p e c t in f r a c t i o n was s y n t h e ­
s i z e d a t a r e l a t i v e l y f a s t e r r a t e th a n amylose (MacGregor e t a l . , 1971)
The p r o p o r t i o n o f smal l s t a r c h g r a n u l e s i n c r e a s e s d r a m a t i c a l l y w i t h
n
m a t u r i t y (MacGregor e t a l . , 1971; B r i g g s , 1978).
B a r l e y s t a r c h g r a n u l e s a r e g e n e r a l l y round and f o l l o w a b i modal
size d istrib u tio n pattern.
The small and l a r g e s i z e g r a n u l e s bei ng
I . 7 - 2 . 5 urn and 2 2 . 5 - 4 7 . 5 urn i n d i a m e t e r , r e s p e c t i v e l y ( B r i g g s , 1978).
Two d i s t i n c t s t a r c h g r a n u l e s i z e s were found i n w h e a t, t h e l a r g e r
g r a n u l e s b e i n g 25 urn i n d i a m e t e r and t h e small g r a n u l e s 5 urn i n d i a ­
meter.
The small s t a r c h g r a n u l e s a c c o u n te d f o r 90% o f t h e t o t a l number
o f g r a n u l e s b u t comprised o n l y 10% o f t h e t o t a l s t a r c h w e i g h t (Bewley and
B l a c k , 1978).
Small s t a r c h g r a n u l e s have a h i g h e r g e l a t i n i z a t i o n
t e m p e r a t u r e and amylose c o n t e n t (41.3%) t h a n l a r g e g r a n u l e s (26.9%)
( B r i g g s , 1978).
Normal b a r l e y s t a r c h c o n t a i n s a p p r o x i m a t e l y 25% amylose and 75%
a m y lo p e c t in (Bewley and B l a c k , 1978; E s l i c k , 1979).
V ar io u s r e p o r t s
on amylose show i t s r an g e t o be from 11-26% o f t h e s t a r c h ( H a r r i s , 1962;
Greenwood, 1964; B r i g g s , 1978).
G e n e t i c m u t a t i o n s in b a r l e y and i n
o t h e r c e r e a l s have r e s u l t e d i n s t a r c h e s c o n t a i n i n g a l m o s t 100%
a m y l o p e c t i n (Banks e t a l . , 1970; Bewley and B la c k , 1978).
In t h e o r y ,
i
t r u e waxy b a r l e y s c o n t a i n 100% a m y lo p e c t in ( E s l i c k , 1979) a l t h o u g h waxy
endosperm b a r l e y s do c o n t a i n some amylose (0-3%) (Banks e t a l . , 1970;
Goering e t a l . , 1973; B r i g g s , 1978).
High amylose m u t a t i o n s have
a l s o been r e p o r t e d (Greenwood, 1964; B r i g g s , 1978).
Nonwaxy and waxy b a r l e y k e r n e l s and p o l l e n g r a i n s can be d i s t i n ­
g u is h e d by i o d i n e s t a i n i n g ( E r i k s s o n , 1969).
A s i n g l e r e c e s s i v e gene
12
on chromosome one t h a t e x p r e s s e s x e n i a c o n t r o l s t h e waxy endosperm
c h a r a c t e r ( E s l i c k , 1979).
E r i c k s s o n (1969) r e p o r t e d t h e s po nta neo us
m u t a t i o n r a t e t o t h e waxy phenotype i n b a r l e y t o ran ge from 5.1 x l 0 ~ 6
t o 15 x IO"6 .
Many p r o p e r t i e s o f waxy endosperm b a r l e y s have been s t u d i e d and
documented.
A s t u d y o f two J a p a n e s e waxy endosperm b a r l e y c u l t i v a r s
showed bo th t o have l e s s t h a n 0.5% am y lo se , a b e t a - a m y l o l y s i s l i m i t
o f 54% c o n v e r s i o n i n t o m a l t o s e , and an a v e r a g e c h a i n l e n g t h o f 23
g l u c o s e u n i t s (Banks, e t a l . , 1970).
The a v e r a g e m o l e c u l a r w e i g h t o f
t h i s s t a r c h was 300 x 10° and showed a b i modal d i s t r i b u t i o n o f l a r g e
and small s t a r c h g r a n u l e s w i t h a r an ge o f 22 and 3 urn i n d i a m e t e r ,
respectively.
Waxy b a r l e y s t a r c h g e l a t i n i z e s a few d e g r e e s lower th a n
waxy corn s t a r c h .
Waxy endosperm b a r l e y s t a r c h e s a r e more s u s c e p t i b l e t o en zym ati c,
a c t i o n p o s s i b l y b ec a u se t h e p ur e a m y l o p e c t i n s t a r c h g r a n u l e s a r e l e s s
r e s i s t a n t t o en zy m ol ys is t h a n t h e amylose/amyl o p e c t i n h y b r i d g r a n u l e
found i n nonwaxy b a r l e y (Goering e t a l . , 1973; Fox and E s l i c k , 1979).
Go ering e t a l .
(1973) has shown t h a t waxy b a r l e y s t a r c h has a 20°C lower
p a s t i n g t e m p e r a t u r e t h a n normal b a r l e y (7 5 0C v s . 95°C).
In co rn and
sorghum t h e amylose c o n t e n t o f t h e s t a r c h does n o t i n f l u e n c e g e l a t i n i z atio n temperature.
Go ering e t a l .
(1973) a l s o showed waxy Gompana
b a r l e y s t a r c h had a s i m i l a r Br abe nd er co o k i n g c u r v e t o t h a t o f waxy
sorghum s t a r c h b u t had o n l y h a l f t h e s w e l l i n g power and o n e - t h i r d t h e
.
13
s o l u b i l i t y o f Waxy sorghum s t a r c h , i n d i c a t i n g t h a t t h e a m y lo p e c t in
i n waxy Qbmpana was a un iq u e s t a r c h .
Waxy b a r l e y s t a r c h m a l t s more
r a p i d l y t h a n normal b a r l e y s t a r c h when measured by m a l t o s e p r o d u c t i o n
(Fox and E s l i c k , 1979).
Waxy b a r l e y f l o u r i s h i g h e r t h a n normal
barley f l o u r in beta-glucans.
The s t a r c h from waxy s h o r t - a w n nude
Companai grown a t one l o c a t i o n r e t a i n e d s u f f i c i e n t a l p h a - a m y l a s e - 1 i ke
a c t i v i t y t o l i q u i f y i t s e l f and f o u r t i m e s i t s w e i g h t o f waxy o r normal
co r n s t a r c h ( Goering and E s l i c k , 1976).
A new p r o c e s s f o r p r o d u c t i o n
o f u l t r a high m a l t o s e s y r u p from waxy endosperm b a r l e y s i s based on
some o f t h e s e uniq ue p r o p e r t i e s o f waxy b a r l e y s (Goering e t a l . , 1980)
I t was f u r t h e r s u g g e s t e d t h a t t h e e a s e o f I i q u i f i c a t i o n o f waxy b a r l e y
s t a r c h as w e l l as o t h e r c h a r a c t e r i s t i c s make waxy b a r l e y s p o t e n t i a l l y
u s e f u l i n t h e brewing i n d u s t r y (Goering e t a l . , 1973; Goering and
E s l i c k , 1976).
S u l l i n s and.Rooney (1974) d e m o n s t r a t e d t h a t waxy sorghum was
more r a p i d l y s o l u b i l i z e d by a l p h a - a m y l a s e enzymes and by b u f f e r e d
rumen f l u i d t h a n nonwaxy sorghum and t h a t t h e waxy sorghum ke rn el had
l e s s p e r i p h e r a l endosperm.
F u r t h e r m o r e , waxy sorghum had a p e r i ­
p h e r a l endosperm l e s s d e n s e t h a n nonwaxy sorghum, hav in g l a r g e
s t a r c h . g r a n u l e s w i t h a l e s s dens e p r o t e i n m a t r i x more s u s c e p t i b l e t o
enzyme a t t a c k ( S u l I i n s and Rooney, 1975).
They con cl u d ed t h a t t h e pro
p e r t i e s o f t h e p e r i p h e r a l endosperm were r e s p o n s i b l e f o r waxy sorghum
s t a r c h b e i n g more s u s c e p t i b l e t o enzyme a t t a c k .
14
Y ie l d t r i a l s c on d uc te d o v e r 43 en v i ro n m en ts w i t h waxy and normal
i s o g e n i c p a i r s have shown no s i g n i f i c a n t y i e l d r e d u c t i o n in t h e waxy
endosperm genotype ( E s l i c k , 1979).
Y ie l d comparisons o f cove re d and
h u l l e s s i s o g e n i c p a i r s grown i n r e p l i c a t e d y i e l d t r i a l s o v e r 149
en v i ro n m en ts i n d i c a t e an a v e r a g e y i e l d r e d u c t i o n o f 12% f o r t h e h u l l e s s
c h a r a c t e r ( E s l i c k , 1979).
I s o g e n i c com parisons between s h o r t awn
and long awn i s o g e n i c p a i r s i n r e p l i c a t e d y i e l d t r i a l s o v e r 95 e n v i r o n ­
ments have shown no s i g n i f i c a n t d i f f e r e n c e s i n y i e l d ( E s l i c k , 1979).
Endosperm M o d i f i c a t i o n and Enzyme Development
The m o b i l i z a t i o n o f c e r e a l endosperm r e s e r v e s d u r i n g g e r m i n a t i o n
i s r e q u i r e d t o r e p l e n i s h embryo c a r b o h y d r a t e r e s e r v e s d e p l e t e d d u r i n g
t h e f i r s t 24 -4 8 hou rs f o l l o w i n g i m b i b i t i o n (Bewley and B l a c k , 1978).
The embryo c o n t r o l s t h e m o b i l i z a t i o n o f endosperm r e s e r v e s .
The
embryo s y n t h e s i z e s and r e l e a s e s g i b b e r e T l i n t o t h e a l e u r o n e l a y e r
where p r o d u c t i o n and r e l e a s e o f h y d r o l y t i c enzymes o c c u r s (Bewley and
B l a c k , 1978; B r i g g s , 1978).
M o b i l i z a t i o n commences n e a r t h e s c u t e l l u m
a n d s p r e a d s a l o n g t h e endosperm as t h e a l e u r o n e l a y e r b e g i n s enzyme
.
r e l e a s e (Bewley and B l a c k , 1978; Gibbons, 1980).
H y d r o l y s i s o f s t a r c h g r a i n s does n o t t a k e p l a c e i f t h e e n c l o s i n g
ce ll walls are in t a c t.
Wheat c e l l w a l l s a r e composed o f 15% p r o t e i n
and 75% c a r b o h y d r a t e s .
B e t a - g l u c a n s and a r a b i n o x y l a n make up most o f
the carbohydrate f r a c t io n .
P r o t e i n a s e s , a r a b i n o x y l a n a s e s , and
15
p e n t p s a n a s e s a r e s y n t h e s i z e d i n t h e a l e u r o n e l a y e r and r e l e a s e d in
r e s p o n s e t o g i b b e r e l l i n (Bewley and B l a c k , 1978).
Acid p h o s p h a t a s e ,
r i b o n u c l e a s e , and e n d o - b e t a - g l uca na se can be s y n t h e s i z e d i n t h e abs en ce
o f g i b b e r e l l i n b u t t h e i r a c t i v i t i e s a r e enhanced and t h e i r r e l e a s e
c o n t r o l l e d by g i b b e r e l l i n s (Bewley and B l a c k , 1978; B r i g g s , 1978).
B e t a - g l u c a n a s e , a r a b i n o x y l a n a s e s , and p r o t e i n a s e s d e gr ad e c e l l
w a l l c o n s t i t u e n t s and d i s s o l v e c e l l w a l l s .
D e g r a d a t io n o f t h e endosperm
w a ll o c c u r s i n i t i a l l y i n t h e s u b - a l e u r o n e l a y e r s t h e n p r o g r e s s e s t o
t h e c e n t e r o f t h e endosperm.
E r o s i o n o f s t a r c h g r a n u l e s b e g i n s o n ly
a f t e r c e l l w a l l s have been m o d i f i e d .
D is so lu tio n o f c e l l w alls renders
t h e e n c l o s e d s t a r c h a c c e s s i b l e t o e n z y m a ti c a t t a c k (Bewley and Bla ck,
1978).
G i b b e r e l l i n s , r e l e a s e d by t h e embryo, in d u c e t h e a l e u r o n e l a y e r
t o undergo m e t a b o l i c changes r e s u l t i n g i n t h e r e l e a s e o f many enzymes.
Much o f t h e work, howe ver , on b a r l e y enzyme s y n t h e s i s has fo cu s ed on
the sy n th e sis o f alpha-amylase.
Le ve ls o f a l p h a - a m y l a s e a c t i v i t y
■
i n c r e a s e d u r i n g b a r l e y g e r m i n a t i o n (.Kneen, 1944; B r i g g s , 1964; Reynolds
and MacWi 111 am, 1966; B r i g g s , 1968a; P a lm e r , 1969; K r u g e r , 1976;
Bewley and B l a c k , 1978; B r i g g s , 1978; MacGregor, 1978; MacGregor and
D a u s s a n t , 1979; D au s sa n t and Mayer, 1980).
Barley kernels sy n th e siz e
a l p h a - a m y l a s e de novo p r i m a r i l y i n t h e a l e u r o n e l a y e r i n r e s p o n s e t o a
g i b b e r e l l i n t r i g g e r r e c e i v e d from t h e embryo.
De novo a l p h a - a m y l a s e
s y n t h e s i s i s documented and s u p p o r t e d by many f a c t s i n c l u d i n g
.16
(a) t h e p r o d u c t i o n o f a l p h a - a m y l a s e in i s o l a t e d b a r l e y a l e u r o n e l a y e r s
i n r e s p o n s e t o endogenous GA, (b) s u b s e q u e n t d e c l i n e s and i n c r e a s e s
i n enzyme p r o d u c t i o n as t h e hormone i s removed and r e a p p l i e d (B riggs
1964; Bewley and B l a c k , 19 7 8 ) , and (c) immediate s to p p a g e o f a l p h a amylase s y n t h e s i s by p r o t e i n s y n t h e s i s i n h i b i t o r s ( B r i g g s , 1963, 1964;
Bewley and B l a c k , 1^ 78).
D e f i n i t i v e p r o o f o f de novo s y n t h e s i s o f
a l p h a - a m y l a s e was shown by l a b e l i n g amino a c i d s w i t h
IR
0 (Bewley and
B l a c k , 1978) o r r a d i o a c t i v i t y ( B r i g g s , 1964) and s u b s e q u e n t l y d e t e c t i n g
t h e l a b e l e d amino a c i d s i n s y n t h e s i z e d a l p h a - a m y l a s e .
S e v e r a l s t u d i e s have shown s y n t h e s i z e d g i b b e r e l l i n i s in v o l v e d
i n enzyme s y n t h e s i s .
E xpe ri me nt s have shown t h a t e x c i s e d b a r l e y
embryos can r e l e a s e g i b b e r e l l i n up t o 60 hou rs i n v i t r o ( B r i g g s , 1978),
t h a t t h e endosperm o f degermed g r a i n can be m o d i f ie d i n t h e p r e s e n c e o f
exogenous GA w h i l e l i t t l e m o d i f i c a t i o n o c c u r s w i t h o u t t h e GA ( B r i g g s ,
19 6 8 a , 1 9 78 ) , and t h a t t h e embryo can be removed two t o t h r e e days
a f t e r g e r m i n a t i o n b e g i n s , w i t h l i t t l e e f f e c t on enzyme l e v e l
1978).
(Briggs,
Up t o seven isozymes o f a l p h a - a m y l a s e i n c l u d i n g t h e two major
groups o f t h e enzyme a p p e a r i n GA t r e a t e d i s o l a t e d a l e u r o n e l a y e r s and
d u r i n g g e r m i n a t i o n (Bewley and B l a c k , .1978; MacGregor, 1978; MacGregor
and D a u s s a n t , 1979; D a u s s a n t and Mayer, 1980).
During t h e l a g p ha se between g i b b e r e l l i n a r r i v a l a t t h e a l e u r o n e
l a y e r and r a p i d a l p h a - a m y l a s e s y n t h e s i s t h e hormone r e d i r e c t s p r o t e i n
s y n t h e s i s i n t h e a l e u r o n e c e l l s , p o s s i b l y by enh an ci n g s y n t h e s i s o f RNA
17
i n c l u d i n g mRNA f o r a l p h a - a m y l a s e .
.
G i b b e r e l l i n may a l s o enhance a c t i v a ­
t i o n o r p r o t e c t i o n o f mRNA i n t h e a l e u r o n e c e l l s .
e v i d e n c e t h a t GA a c t s a t t h e t r a n s l a t i o n a l
There i s l i t t l e firm
level o f control
(Bewley and
B l a c k , 1978).
The a l e u r o n e l a y e r pr odu ces a b o u t 85% o f t h e a l p h a - a m y l a s e and t h e
s c u t e l l urn 15%.
Malted b a r l e y shows a b o u t 7% o f t h e a l p h a - a m y l a s e i s
l o c a t e d i n t h e embryo w i t h t h e r e m a in in g 93% i n t h e endosperm i n d i c a ­
t i n g t h a t a b o u t h a l f t h e a l p h a - a m y l a s e produced i n t h e embryo i s
r e l e a s e d t o t h e endosperm ( B r i g g s , 1964, 1 9 7 8 . ) .
A lp h a-a m yl as e accum­
u l a t e s i n t h e a l e u r o n e l a y e r b e f o r e i t s r e l e a s e ( B r i g g s , 1978).
S y n th e ­
s i s o f a l p h a - a m y l a s e i s p r o b a b l y l i m i t e d n o t by t h e i n a b i l i t y o f t h e
a l e u r o n e l a y e r t o res p o nd t o g i b b e r e l l i n b u t by t h e s u p p l y o f
g i b b e r e l l i n t o t h e a l e u r o n e l a y e r (Atanda and M i f l i n , 1970; B r i g g s ,
1978).
The d e f i c i e n c y i n g i b b e r e l l i n s u p p ly t o t h e a l e u r o n e l a y e r i s .
p r o b a b l y due t o d e f i c i e n c i e s i n t h e t r a n s p o r t o f g i b b e r e l l i n t o t h e
a l e u r o n e r a t h e r th a n l a c k o f s y n t h e s i s a t t h e embryo s i n c e endosperm
a r e a s d i s t a l t o t h e embryo produce d i s p r o p o r t i o n a t e l y small amounts o f
a l p h a - a m y l a s e (Atanda and M i f l i n , 1970).
High embryo s u g a r l e v e l s may d e p r e s s l e v e l s o f a l p h a - a m y l a s e
.
p r o d u c t i o n ( B r i g g s , 1964) o r p r e v e n t g i b b e r e l l i n p r o d u c t i o n o r r e l e a s e
from t h e embryo ( B r i g g s , 1978).
Enzyme s y n t h e s i s may be c o n t r o l l e d
t h r o u g h a f e e d b a c k loop i n which g i b b e r e l l i n p r o d u c t i o n i s c o n t r o l l e d
by t h e s u g a r l e v e l s i n t h e embryo w h i l e s u g a r l e v e l s a r e c o n t r o l l e d by
18
enzyme s y n t h e s i s and u l t i m a t e l y g i b b e r e l l i n p r o d u c t i o n ( B r i g g s , 1978).
P r o t e o l y s i s , removal o f s t a r c h and c a l c iu m i o n s , and a f a l l i n g pH
c o n t r i b u t e t o d e c l i n i n g enzyme a c t i v i t y ( B r i g g s , 1968a).
Externally
a p p l i e d g i b b e r e l l i n s can r e p l a c e o r augment embryo produced g i b b e r e l l i n
t o i n i t i a t e o r i n c r e a s e a l p h a - a m y l a s e f o r m a t i o n ( B r i g g s , 1963, 1964;
Reynolds and MacWilliam, 1966; B r i g g s , 1968a; P alm er, 1969; Atanda and
M i f l i n , 1970; Bewley and B l a c k , 1978; B r i g g s , 1978; MacGregor, 1978;
Smith and B r i g g s , 1978).
The amount and r a t e o f a l p h a - a m y l a s e prod uc­
t i o n i s a l s o i n f l u e n c e d by b a r l e y g en ot yp e (Atanda and M i f l i n , 1970;
G o th a r d , 1974; Bewley and B l a c k , 1978; MacGregor, 1 9 7 8 ) , t e m p e r a t u r e
and w a t e r c o n d i t i o n s d u r i n g g e r m i n a t i o n (Kneen, 1944; B r i g g s , 1968a;
MacGregor and D a u s s a n t , 1 9 79 ) , oxygen a v a i l a b i l i t y (Smith and B r i g g s ,
1978) and mech anic al damage ( B r i g g s , 1968b).
P r o t e i n a s e s s y n t h e s i z e d de novo i n t h e a l e u r o n e l a y e r i n r e s p o n s e
t o g i b b e r e l l i n , a c t i v a t e b e t a - a m y l a s e , p r e s e n t i n a bound i n s o l u b l e form
i n un ge rm in ate d b a r l e y , by r e d u c i n g t h e number o f d i s u l f i d e bridges,
between t h e enzyme m o l e c u le and i n s o l u b l e p r o t e i n s (Bewley and Bla ck ,
1978; B r i g g s , 1978).
B e t a - a m y l a s e i s n o t s y n t h e s i z e d de novo.
Bet a-
and a l p h a - a m y l a s e s work t o g e t h e r i n s t a r c h breakdown and can c o m p l e t e l y
h y d r o l y z e amylose a l t h o u g h a m y lo p e c t in d i g e s t i o n h a l t s w i t h t h e p r od u c­
tion of lim it dextrins
(Bewley and B l a c k , 1978).
Two d e b r a n c h i n g enzymes a r e r e p o r t e d i n c e r e a l s .
R enzyme, found
i n b a r l e y m a l t , d eb r a n c h e s a m y lo p e c t in and b e t a - l i m i t d e x t r i n s , w h i l e
19
l i m i t d e x t r i n a s e , r e p o r t e d i n P r o c t o r b a r l e y and un g erm in ate d o a t s ,
a t t a c k s a l p h a - and b e t a - l i m i t d e x t r i n s b u t does n o t d eb r an c h a m y lo p ec t in
(Bewley and B la c k , 1978).
The a l e u r o n e l a y e r s y n t h e s i z e s l i m i t
d e x t r i n a s e de novo a t t h e t i m e o f s t a r c h breakdown, i t s a c t i v i t y b ei n g
enhanced 10-15 f o l d between t h e f i r s t and f o u r t h days f o l l o w i n g i m b i b i ­
t i o n (Bewley and B l a c k , 1978).
S t a r c h a m o ly s is pr od uc es two m a jo r p r o d u c t s , a l p h a - and b e t a m altose.
A l p h a - g l u c o s i d a s e , an enzyme p r e s e n t i n t h e q u i e s c e n t b a r l e y
embryo and a l e u r o n e l a y e r s , h y d r o l y z e s t h e s e p r o d u c t s (Bewley and
B l a c k , 1978; B r i g g s i 1978).
The enzyme a c t i v i t y i n c r e a s e s a t both,
s i t e s d u r i n g t h e f i r s t f i v e days f o l l o w i n g i m b i b i t i o n .
Barley h a lf
g r a i n s r e l e a s e a de n o v o ^ s y n t h e s i z e d a l p h a - a m y l a s e from t h e a l e u r o n e
l a y e r w i t h i n 12 hours o f t h e a d d i t i o n o f GA (Bewley and B l a c k , 1978).
G lu c o s e , t h e r e s u l t i n g p r o d u c t o f a l p h a - g l u c o s i d a s e a c t i v i t y , i s
ab so rb ed by t h e s c u t e l l u m , c o n v e r t e d t o s u c r o s e , and t r a n s p o r t e d t o
t h e growing embryo (Bewley and B l a c k , 1978).
G er m in a tio n
The g e r m i n a t i o n p r o c e s s r e s u l t s i n growth o f t h e g r a i n embryo, man­
i f e s t e d by t h e growth o f t h e r o o t and an i n c r e a s e in t h e l e n g t h o f t h e
s h o o t , w i t h c o n c u r r e n t m o d i f i c a t i o n o f t h e c o n t e n t s o f t h e endosperm.
( S c h u s t e r , 1962).
G er m in a tio n b eg i n s as t h e s u r f a c e l a y e r s p ic k up
w a t e r which p e n e t r a t e s t h r o u g h t h e m i c r o p y l e i n t o t h e k e r n e l ( B r i g g s ,
20
1978 ).
The g r a i n s w e l l s d u r i n g t h e f i r s t 24 hours and t h e embryo
becomes t u r g i d and i n c r e a s e s i n s i z e .
Ger min at ion b e g i n s w i t h t h e
emergence o f t h e c o l e o r h i z a , p r i m a r y , and s e co n d ar y seminal r o o t s from
t h e embryo. ( P o l l o c k , 1962; B r i g g s , 1978).
At al m o s t t h e same time t h e
c o l e o p t i l e b r e a k s t h r o u g h t h e t e s t a and b e g i n s e l o n g a t i o n .
The c o l e o p -
t i l e grows up t h e d o r s a l s i d e o f t h e k e r n e l , p r e s s i n g a groo ve i n t h e
endosperm and emerging from t h e apex o f t h e ke rn el o r t h r o u g h t h e lemma
a l o n g one s i d e ( S c h u s t e r , 1962; B r i g g s , 1978).
The o u t s i d e g r a i n
c o v e r i n g s p r o b a b l y r e s t r i c t p h y s i c a l l y t h e e l o n g a t i o n o f t h e plumule
s i n c e t h e e l o n g a t i o n o f t h e plumule i n dehusked g r a i n d u r i n g g e r m i n a t i o n
i s c o n s i d e r a b l y g r e a t e r t h a n i n i n t a c t b a r l e y k e r n e l s ( S c h u s t e r , 1962).
Endogenous r e s e r v e s s u p p o r t i n i t i a l growth o f t h e embryo w h i l e s u b s e ­
q u e n t growth makes use o f p r o d u c t s from t h e endosperm d i s s o l u t i o n
( B r i g g s , 1978). .
Endosperm breakdown b eg i ns im m e d i a te l y below t h e s c u t e l l u m in a
l a y e r o f compressed c e l l s and moves toward t h e g r a i n apex ( S c h u s t e r ,
1962; B r i g g s , 1978).
A f te r a s h o r t p e r io d , a l t e r a t i o n proceeds f a s t e r
im m e d i a te l y below t h e a l e u r o n e l a y e r ( B r i g g s , 1978).
The asymmetry
o f endosperm breakdown r e s u l t s from t h e a n g l e o f t h e s c u t e ! I a r f a c e
.
a g a i n s t t h e endosperm, t h e se quence and l o c a t i o n i n which d e g r a d a t i v e
enzymes a r e fo rmed, and t h e p r o p e r t y o f r e s i s t a n c e t o e n zy m at ic d e g r a d ­
a t i o n by r e s i d u a l w a l l s i n t h e n u c e l l a r s h e a f c e l l s
( B r i g g s , 1978).
Endosperm a l t e r a t i o n b e g i n s w i t h t h e h y d r o l y t i c d e c o m p o s i ti o n o f high
21
m o l e c u l a r w e i g h t m a t e r i a l s by enzymes p r e s e n t i n the . b a r l e y
( S c h u s t e r , 1962).
The s y n t h e s i s o f c e r t a i n enzymes f o l l o w soon a f t e r
th e beginning o f germination (S chuster,
1962).
One o f t h e s e enzymes,
a l p h a - a m y l a s e , d e v e l o p s r a p i d l y i n g e r m i n a t i n g g r a i n , and w i t h b e t a amylase and c e r t a i n o t h e r enzymes a t t a c k s s t a r c h g r a n u l e s , c a u s i n g
g r a n u l e p i t t i n g a n d / o r g r a n u l e e r o s i o n and u l t i m a t e l y s t a r c h g r a n u l e
breakdown ( S c h u s t e r , 1962; B r i g g s , 1978).
The d e g r a d a t i o n p r o d u c t s o f
t h e enzymes r a p i d l y d i f f u s e th r o u g h t h e s c u t e l l u m and a r e used f o r
r e s p i r a t i o n and t h e en e r g y p r o c e s s e s o f growth ( S c h u s t e r , 1962).
G er m in a tio n b e g i n s w i t h w a t e r a b s o r p t i o n and r e h y d r a t i o n o f t h e
kernel
(Brown, 1975; Bewley and B l a c k , 1978).
The k e r n e l r e q u i r e s a
minimum o f 35% w a t e r f o r a c t i v e g e r m i n a t i o n ( E s s e r y e t a l . , 1954;
Kirs op e t a l . , 1967; Brown, 1975; Wainwright and Buckee, 1977).
Ade­
quate kernel m o d ific a tio n f o r m alting b a rle y re q u ire s a f u r t h e r
i n c r e a s e i n w a t e r p e r c e n t a g e t o 42-45% ( K ir s o p e t a l . , 1967) o r 43-46%
(Brookes e t a l . , 1976).
V ar io us r e s e a r c h e r s have conc lu ded t h a t good
m a l t i n g p er f o r m a nc e i s p o s i t i v e l y c o r r e l a t e d w i t h t h e a b i l i t y o f b a r l e y
t o t a k e up w a t e r r a p i d l y (B ro ok es , e t a l . , 1 9 / 6 ; Ulonska arid Baumer,
1976; Wainwright and B u c k e e , 1977).
V ar io us f a c t o r s a f f e c t w a t e r i m b i b i t i o n by t h e b a r l e y s ee d .
Large
k e r n e l s have been r e p o r t e d t o i n i t i a l l y imbibe w a t e r f a s t e r t h a n small
k e r n e l s , a l t h o u g h small k e r n e l s r e a c h t h e a p p r o p r i a t e l e v e l f o r
g e r m i n a t i o n more r a p i d l y , and a f t e r p r o lo n g e d s t e e p i n g have a h i g h e r
22
m o i s t u r e p e r c e n t a g e , t h a n l a r g e k e r n e l s ( P o l l o c k , 1962; Brookes e t a l . ,
1976; Davidson e t a l . , 1976).
B rig g s (1978) r e p o r t e d s m a l l e r k e r n e l s
t a k e up m o i s t u r e f a s t e r and t o a h i g h e r f i n a l l e v e l t h a n l a r g e k e r n e l s .
A p o s i t i v e c o r r e l a t i o n between s t a r c h c o n t e n t and ti m e r e q u i r e d t o
r e a c h a p r e d e t e r m i n e d m o i s t u r e l e v e l has been r e p o r t e d ( P o l l o c k , 1962;
Brookes e t a l . , 1976) as w ell as a c o r r e s p o n d i n g i n v e r s e r e l a t i o n s h i p
between n i t r o g e n c o n t e n t and i m b i b i t i o n r a t e (Brookes e t a l , , 1976).
C o n t r a d i c t o r y r e p o r t s as t o t h e i n f l u e n c e o f i n i t i a l b a r l e y m o i s t u r e
c o n t e n t on w a t e r u p ta k e e x i s t b u t i t i s p r o b a b l e t h a t b a r l e y , l i k e
o t h e r s e e d s , has a v e l o c i t y o f w a t e r u p t a k e i n v e r s e l y p r o p o r t i o n a l t o
t h e amount o f w a t e r p r e v i o u s l y a b s o r b ed (Brookes e t a l . , 1976). Ol d,
d r y b a r l e y seed a b s o r b s w a t e r a t a much s l o w e r r a t e t h a n does f r e s h ,
m o i s t s e e d , however.
Increasing temperature increases the r a te of
i m b i b i t i o n ( P o l l o c k , 1962; MacLeod, 1967; Brookes e t a l . ,
B r i g g s , 1978).
1976;
All b a r l e y s p r o b a b l y have a s i m i l a r t e m p e r a t u r e co­
e f f i c i e n t of im bibition.
A l i n e a r i n v e r s e r e l a t i o n s h i p , e x i s t s between
t e m p e r a t u r e and t h e lo g o f t h e ti m e r e q u i r e d by g r a i n t o r e a c h a
p a r t i c u l a r moisture level
( B r i g g s , 1978).
Water s e n s i t i v i t y
(Brookes e t a l . , 1 97 6 ) , embryo a n d / o r mic r o p y I e s i z e (Davidson e t a l , ,
1976) and v a r i e t y (Ulonska and Baumer, 1976) may a l s o i n f l u e n c e w a t e r
u p ta k e .
Upon immersion o f b a r l e y in w a t e r an immediate m o i s t u r e l a y e r
(2-3% f r e s h w e ig h t ) forms around t h e k e r n e l ( K ir s o p e t a l . , 1967;
23
Brookes e t a l . , 1976; Davidson e t a l . 9 1976; B r i g g s , 1978).
This
f i l m o f w a t e r must be removed f o r a c c u r a t e w a t e r u pta ke s t u d i e s
( B r i g g s , 1978).
Drying by b l o t t i n g f a i l s t o remove a l l w a t e r on t h e
e x t e r n a l s u r f a c e and may i n f l a t e e s t i m a t e s o f w a t e r u p ta k e by 1% o r
more (Davidson e t a l . , 1976).
Surface la y e rs hydrate r a p i d l y , w ithin
t h e f i r s t two hours i n h u l l e d b a r l e y and t h e f i r s t 30 seco nd s in
h u l l e s s g r a i n s ( B r i g g s , 1978).
In naked g r a i n t h e p e r i c a r p condu cts
w a t e r so w e l l t h a t t h e g r a i n i n t e r i o r h y d r a t e s a t t h e same r a t e
w h e t h e r t h e ap ex , t h e b a s e , o r t h e whole g r a i n i s immersed i n w a t e r .
During i m b i b i t i o n t h e m o i s t u r e c o n t e n t i n c r e a s e s r a p i d l y , t h e n a t a
p r o g r e s s i v e l y d e c l i n i n g r a t e u n t i l , i f g e r m i n a t i o n does n o t o c c u r , i t
a p p r o x im a te s a l i m i t i n g v a l u e ( B r i g g s , 1978).
Numerous r e s e a r c h e r s have r e p o r t e d a t r i p h a s i c p a t t e r n o f w a t e r
up ta k e i n g e r m i n a t i n g s e e d s (Brookes e t a l . , 1976; Bewley and Bla ck,
1978; T a k a h a s h i , 1980).
Ph as e I ( i m b i b i t i o n ) i s p u r e l y a p h y s i c a l
p r o c e s s , o c c u r r i n g d u r i n g t h e f i r s t s i x t o t e n hours a f t e r immersion,
c h a r a c t e r i z e d by r a p i d w a t e r u p ta k e a c c o u n t i n g f o r 60% o f t o t a l w a t e r
uptake.
Seed c o l l o i d s imbibe w a t e r p r e v i o u s l y l o s t d u r i n g r i p e n i n g
r e g a r d l e s s o f dormancy o r v i a b i l i t y prob lem s.
s ee d in t e g u m e n t c o n t r o l s t h i s p h as e.
Perm eability o f the
Phase I I (10-20 h o u r s ) i s t h e l a g
o r a c t i v a t i o n p ha se d u r i n g which w a t e r u p ta k e slows o r c e a s e s .
Major
m e t a b o l i c p r o c e s s e s b eg in and w a t e r u p t a k e resumes w i t h i n c r e a s i n g
os m ot i c p r e s s u r e .
Dormant s ee d does n o t undergo t h i s p h as e as c o n t r o l .
24
i s e x e r t e d by embryo dormancy.
Phase I I I
(20+ h o u r s ) c o n s t i t u t e s a
s t e a d y l i n e a r i n c r e a s e i n w a t e r u p ta k e t h a t can be c o r r e l a t e d t o p l a n t
m e ta b o li s m .
T h i s p h a s e , an a c t i v e p r o c e s s , o c c u r s o n l y i n v i a b l e seed
and i n c l u d e s t h e v i s i b l e o n s e t o f g e r m i n a t i o n .
The s u r f a c e l a y e r s o f t h e b a r l e y k e r n e l a r e t h e p r i n c i p l e b a r r i e r s
to water en try .
The t e s t a i s s em i - p er m ea b l e and may r e s t r i c t w a t e r
e n t r y f o r t h e f i r s t few h o u r s .
The p e r i c a r p , however, i s t h e p r i n c i p l e
b a r r i e r t o w a t e r e n t r y (Brookes e t a l . , 1976).
Gaps e x i s t i n t h e p e r i ­
c a r p and t e s t a , e s p e c i a l l y n e a r t h e embryo, which may a l l o w w a t e r
entry.
The embryo p r e f e r e n t i a l l y t a k e s up w a t e r (K irs o p e t a l . , 1967;
MacLeod, 1967; Brookes e t a l . , 1976).
Embryo m o i s t u r e c o n t e n t may
r e a c h 65-70% w h i l e t h e endosperm m o i s t u r e c o n t e n t i s 41%.
Most w a t e r
up ta k e by t h e k e r n e l l i k e l y o c c u r s i n t h e m i c r o p y l a r r e g i o n ( P o l l o c k ,
1962; MacLeod, 1967; Brookes e t a l . , 1976; B r i g g s , 1978).
A b a r l e y i m b i b i t i o n s t u d y con du ct ed a t 13° C i n d i c a t e d t h a t t h e
a x i s o f t h e embryo and t h e s c u t e l l u m a b s o r b w a t e r c o n s i d e r a b l y f a s t e r
t h a n a l l o t h e r k er n el p a r t s e x c e p t t h e husk (Reynolds and MacWiIliam,
1966).
Rapid a b s o r p t i o n o f w a t e r by t h e embryo f o r s i x hours
f o l l o w e d by .a d e c l i n i n g r a t e o f a b s o r p t i o n r e s u l t e d i n a b o u t 58%
m o i s t u r e a f t e r 24 hours in t h e imbibed embryo.
The s c u t e l l u m lagged
behi nd t h e embryo i n w a t e r up ta ke u n t i l a b o u t s i x hours t h e n p a r a l l e l e d
t h e embryo m o i s t u r e c o n t e n t up t o 58% m o i s t u r e a t 24 hours*
The
endosperm a b s o r be d w a t e r more s l o w l y , r e a c h i n g 35% m o i s t u r e a t 24
25
hours.
Water c o n t e n t o f t h e whole g r a i n was 38.4% a f t e r 24 ho urs.
A no th er s t u d y c on d uc te d a t 25° C showed w a t e r c o n t e n t i n whole g r a i n
i n c r e a s i n g from 17.4% t o 23.8%, 26.2%, and 30.5% a f t e r 2 , 4 , 6 , and
8 h o u r s , r e s p e c t i v e l y (Davidson e t a l . , 1976).
Many f a c t o r s a f f e c t t h e g e r m i n a t i o n o f s e e d , one o f t h e most
i m p o r t a n t b e i n g s ee d dormancy.
Seed dormancy can be d e f i n e d t o
i n c l u d e a l l i n s t a n c e s o f i n h i b i t i o n o f g e r m i n a t i o n , w h e t h e r th e y a r e
co n n e c te d w i t h t h e p r o p e r t i e s o f t h e s ee d s t h e m s e lv e s o r w h e t h e r t h e y
a r e d e t e r m in e d by e n v i ro n m e n ta l c o n d i t i o n s .
In t h e b r o a d e s t s e n s e
dormancy i s t h e a b s e n c e o f g e r m i n a t i o n o r as a g r e a t e r o r l e s s e r
r e d u c t i o n o f t h e ger mi n a t i v e c a p a c i t y o f s e e d s , o r f i n a l l y as t h e
m a i n t e n a n c e o f t h e c a p a c i t y t o g e r m i n a t e o n l y w i t h i n a smal l range o f
c o n d i t i o n s ( N i k o l a e v a , 1969).
B a r l e y s e e d s sometimes f a i l t o germin­
a t e due t o p r im a r y ( i n t r i n s i c ) dormancy o r s e co n d ar y dormancy, t h e
l a t t e r o f which i s imposed by e x t e r n a l f a c t o r s ( B r i g g s , 1978).
Dormancy v a r i e s among samples a c c o r d i n g t o c u l t i v a r (Deming and
R o b e r t s o n , 1933; Chang, 1943; B is h o p , 1944, 1945, 1946; E s s e r y e t a l . ,
1954; F i n l a y , 1960a; Bel l and L u p t o n , 1962; Carson and Horne, 1962;
P o l l o c k , 1962; W e l l i n g t o n , 1964; MacLeod, 1967; B e l d e r o k , 1968; Gordon
1969; L a l l u k k a , 1976; B r i g g s , 1978; S t r a n d , 198 0) , w e a t h e r c o n d i t i o n s
d u r i n g growth and h a r v e s t ( B is h op , 1945, 1946; W e l l i n g t o n , 1964;
MacLeod, 1967; B e l d e r o k , 1968; L a l l u k k a , 1976; R e i n e r and Loch, 1976;
B r i g g s , ,1978; D e r e r a , 1980; Gordon, 1980;
S t r a n d , 1980; T a k a h a s h i ,
26
19 80 ), s t o r a g e and h a n d l i n g p r o c e d u r e s (B is h op , 1944, 1945, 1946;
MacLeod, 1967; Gordon, 1969; Brookes e t a l . , 1976; B r i g g s , 1978)* and
t h e methods used t o t e s t g e r m i n a t i o n ( Bi sh op , 1945, 1946; E s s e r y e t a l .
1954; E s s e r y e t a l . , .1955; P o l l o c k e t a l . , 1955a, 1955b; P o l l o c k , 1962;
W e l l i n g t o n , 1964; Gordon, 1969, 1970; B r i g g s , 1978; S t r a n d , 1980). .
Dormancy e x p r e s s e d as a s i n g l e number i s u s u a l l y u n s a t i s f a c t o r y ,
s i n c e t h e g e r m i n a t i o n r a t e , as well a s f i n a l p e r c e n t a g e may change
d u r i n g s t o r a g e , e . g . a b a r l e y lo t. w i t h 100% g e r m i n a t i o n r e a c h e d 50%
g e r m i n a t i o n w i t h i n Si hou rs im m ed i at el y a f t e r h a r v e s t b u t r e q u i r e d o n ly
1 5. 5 hours a f t e r t h r e e weeks o f s t o r a g e (Gordon, 1969).
Thus a d i s ­
c u s s i o n o f dormancy s h ou ld i n c l u d e t h e r a t e as well a s t h e f i n a l
g e r m i n a t i o n p e r c e n t a g e und er a d e f i n e d s e t o f c o n d i t i o n s ( B r i g g s , 1978)
Numerous a t t e m p t s have been made t o a s s i g n s i n g l e d e s c r i p t i v e numbers
to germination t e s t s
( F i n l a y , 1960a, 1960b; Gordon, 1969; Goodchild
and Walker, 1971; Bewley and B la ck , 197 8) .
The b e s t t y p e o f p r e s e n t a ­
t i o n a p p e a r s t o be a graph o f c u m u l a t i v e g e r m i n a t i o n a g a i n s t t i m e f o r
each s e t o f g e r m i n a t i o n c o n d i t i o n s ( B r i g g s , 1978).
A m i x t u r e o f f a c t o r s o c c u r r i n g w i t h i n t h e g r a i n and i t s s u r f a c e
l a y e r s i n t e r a c t i n g w i t h en v i ro n m e n ta l f a c t o r s p r o b a b l y c a u s e b a r l e y
dormancy.
Embryo dormancy in' b a r l e y i s r a r e (Bish op , 1944; P o l l o c k ,
1962; Gordon, T970; B r i g g s , 1978) a l t h o u g h embryo dormancy has been
r e p o r t e d in Hordeum spontaneum (B el de.rok, 1968).
B rig g s (1978) r e ­
p o r t e d a s t u d y i n which i n t a c t b a r l e y g e r m i n a t e d 6% w i t h g e r m i n a t i o n
27
i n c r e a s i n g t o 12%, 46%, and 48% as 25%, 50%, and 75% o f t h e endosperm
was removed, r e s p e c t i v e l y .
Dehusked g r a i n ge rm in at e d a t 12%, 58%,
65%, and 81% un d er t h e same c o n d i t i o n s .
Ger min at ion o f i s o l a t e d
embryos was 100%, i n d i c a t i n g no embryo dormancy and a c e r t a i n germina­
t i o n i n h i b i t i n g e f f e c t a s s o c i a t e d w i t h t h e seed c o v e r i n g s .
The most p r o m i s i n g t h e o r y on b a r l e y dormancy i n v o l v e s t h e i n t e r n a l
l e v e l o f f r e e oxygen in t h e embryo ( P o l l o c k , 1962; B e l d e r o k , 1968;
B r i g g s , 1978).
Dormant and nondormant g r a i n s r e s p i r e a t a b o u t t h e same
r a t e ( P o l l o c k , 1962; B r i g g s , 1978).
The embryos o f dormant g r a i n s , as
shown by e x p e r i m e n t s w i t h i s o l a t e d embryos, have a h i g h e r f r e e oxygen
r e q u i r e m e n t o r r e q u i r e a, h i g h e r oxygen t e n s i o n th a n nondormant embryos.
T h i s oxygen r e q u i r e m e n t o f t h e embryo p r o g r e s s i v e l y d e c l i n e s d u r i n g
a f t e r - r i p e n i n g ( P o l l o c k , 1962; B r i g g s , 1978) o r t h e s ee d c o a t s become
more perme able t o oxygen.
E v e n t u a l l y enough Oxygen r e a c h e s t h e embryo
f o r b ot h g e r m i n a t i o n and growth ( B e l d e r o k , 1968).
R esp irato ry processes
i n t h e embryo compete f o r oxygen w i t h t h e growth p r o c e s s e s ( P o l l o c k ,
1962; B e l d e r o k , 1968).
R e s p i r a t i o n i n dormant seed may r e q u i r e so much
oxygen t h a t l i t t l e may be l e f t f o r g e r m i n a t i o n ( B e l d e r o k , 1968).
The
s u r f a c e s t r u c t u r e o f t h e s e e d , s u r f a c e m o i s t u r e , and m i c r o b i a l pop ula ­
t i o n s on t h e seed l i m i t t h e oxygen s u p p ly t o t h e embryo ( B r i g g s , 1978).
The seed s u r f a c e l a y e r s r e s t r i c t oxygen f l o w , so dormancy may be broken
o r red uc e d by damaging t h e p e r i c a r p m e c h a n i c a l l y .
The s u r f a c e w a t e r
f i l m r e d u c e s oxygen u pt a k e bec a u se o f t h e t i m e t a k e n f o r oxygen t o
28
d i s s o l v e i n t o w a t e r , t h e t i m e t o d i f f u s e i n t o t h e g r a i n , and t h e lower
oxygen c o n t e n t in water, a s compared t o a i r .
M ic r o b i a l p o p u l a t i o n s on
t h e s ee d i n f l u e n c e s ee d dormancy by t h e i r high consumption o f oxygen
( B r i g g s , 1978).
The p r o d u c t i o n o f g i b b e r e l l i n s i n p l a n t t i s s u e s
require aerobic conditions.
The embryo r e q u i r e s oxygen in o r d e r t o
form g i b b e r e l l i n s o r t o c o n v e r t bound g i b b e r e l l i n s t o f r e e g i b b e r e l l i n s
( B e l d e r o k , 1968).
Pronounced dormancy may be s e p a r a t e d i n t o t h r e e p has es i n b a r l e y
( B e l d e r o k , 1968).
The f i r s t i s an im mediate p o s t - h a r v e s t ph as e i n
which p r a c t i c a l l y no g r a i n s g e r m i n a t e i n t h e g e r m i n a t i o n t e s t .
The .
second is, a t r a n s i t i o n a l p ha se f o l l o w i n g t h e a f t e r - r i p e n e d s t a t e in
which dormancy t e r m i n a t e s i n g r a d u a l l y i n c r e a s i n g numbers o f g r a i n s .
In t h e t h i r d ph as e g r a i n s f u l l y g e r m i n a t e a t optimum m o i s t u r e , but
c a n n o t do so i f e x c e s s w a t e r i s p r e s e n t .
T h i s l a t t e r b e h a v i o r demon­
s t r a t e s water s e n s i t i v i t y .
(1954) f i r s t d e t e c t e d w a t e r
Essery e t a l .
s e n s i t i v i t y when t h e y found c e r t a i n b a r l e y s would n o t g e r m i n a t e
under normal s t e e p i n g c o n d i t i o n s .
Thes e b a r l e y s showed normal germina­
t i v e en er g y und er c o n d i t i o n s o f t h e a c c e p t e d t e s t , b u t i f t h e amount o f
w a t e r was i n c r e a s e d from 4ml t o 8ml g e r m i n a t i o n d e c l i n e d ( P o l l o c k
e t a l . , 1955b).
Water s e n s i t i v e b a r l e y s f a i l t o g e r m i n a t e bec a u se t h e
embryos f a i l t o res p o nd t o t h e low i n t e r n a l oxygen t e n s i o n r e s u l t i n g
from t h e p r e s e n c e o f an unduly t h i c k w a t e r f i l m (MacLeod, 1967).
g e r m i n a t i v e en e r g y may a l s o r e f l e c t a d e f i c i e n c y o f oxygen i n th e
Low
v i c i n i t y o f t h e embryo (Gordon, 1969).
F i n l a y ( 1 9 6 0 a ) , however, found
no w a t e r s e n s i t i v i t y i n h i s s t u d y o f t h e g e n e t i c and en v i ro n m en ta l
v a r i a t i o n s i n g e r m i n a t i o n b e h a v i o r i n 800 c u l t i v a r s .
In f a c t , 8ml o f
w a t e r a c c e l e r a t e d t h e g e r m i n a t i o n r a t e o v e r t h e use o f 4mI o f w a t e r in
the t e s t .
Ra te o f w a t e r a b s o r p t i o n ( B e l d e r o k , 1968; B r i g g s , 1978) and
n i t r o g e n c o n t e n t (B is h o p , 1946; B e l d e r o k , 1968) do n o t i n f l u e n c e
dormancy.
The f o l l o w i n g t r e a t m e n t s r e p o r t e d l y b r e a k dormancy: d r y i n g w i t h
h e a t (B is h o p , 1944; P o l l o c k , 1962; B e l d e r o k , 1968; B r i g g s , 1978),
g i b b e r e l l i n t r e a t m e n t (MacLeod, 1967; B e l d e r o k , 1968; Brookes e t a l . ,
1976; B r i g g s , 1 9 78 ) , removal o f seed c o a t o r me chanical damage (Bish op ,
1944, 1945; P o l l o c k e t a l . , 1955a, 1955b; W e l l i n g t o n , 1964; B e l d e r o k ,
1968; Gordon, 1970; B is h o p , 197 8) , f r e e z i n g , s t r a t i f i c a t i o n o r col d
t e m p e r a t u r e s (B is h o p , 1944; B r i g g s , 1 9 7 8 ) , g e r m i n a t i o n i n oxygen
( B is ho p, 1944, 1945; P o l l o c k , e t a l . , 1955b; B r i g g s , 1978) and v a r i o u s
chemical t r e a t m e n t s (B is h o p , 1944, 1945; P o l l o c k e t a l . , 1955b;
P o l l o c k , 1962; Brookes e t a l . ,
1976; B r i g g s , 1978).
One o r two r e c e s ­
s i v e g e n e t i c f a c t o r s r e p o r t e d l y c o n t r o l dormancy in b a r l e y (B e l d e r o k ,
1968).
The w a t e r c o n d i t i o n s d u r i n g a g e r m i n a t i o n t e s t a l s o a f f e c t t h e
f i n a l germination o f the barley l o t .
In a d d i t i o n t o c o n d i t i o n s f a v o r ­
i n g w a t e r s e n s i t i v i t y and w a t e r i m b i b i t i o n as p r e v i o u s l y d i s c u s s e d ,
t h e p o s i t i o n o f t h e embryo r e l a t i v e t o t h e w a t e r l e v e l , w a t e r
30
t e m p e r a t u r e , and d i s s o l v e d io n s may a f f e c t g e r m i n a t i o n .
Gordon (1969)
r e p o r t e d s i g n i f i c a n t d i f f e r e n c e s in g e r m i n a t i o n in a f a c t o r i a l e x p e r i ­
ment comparing t a p and d i s t i l l e d w a t e r .
T em p er at u re a l s o i n f l u e n c e s g e r m i n a t i o n .
Kneen (1944) r e p o r t e d
t h e r e l a t i v e growth r a t e o f wheat and sorghum, as measured by av era ge
c o l e o p t i l e l e n g t h i n c r e a s e d as g e r m i n a t i o n t e m p e r a t u r e was i n c r e a s e d
from 14° C t o 30° C.
Gordon (1969) r e p o r t e d t h a t t h e g e r m i n a t i o n temp­
e r a t u r e i n f l u e n c e d t h e e x p r e s s i o n o f t o t a l g e r m i n a t i o n un d er e x c e s s i v e
m o i s t u r e c o n d i t i o n s b u t t h a t i t had l i t t l e e f f e c t on t h e f i n a l
g e r m i n a t i o n p e r c e n t a g e un d er optimum m o i s t u r e c o n d i t i o n s .
The r a t e o f
w a t e r a b s o r p t i o n in b a r l e y depends on t e m p e r a t u r e ( P o l l o c k , 1962).
S p e c i f i c t e m p e r a t u r e s have been n o te d such as 5 ° C'as m i n i m a l , 29° C as
o p t i m a l , and 38° C as maximal f o r b a r l e y g e r m i n a t i o n ( B r i g g s , 1978).
Such f i g u r e s a r e m i s l e a d i n g s i n c e samples o f g r a i n v a r y w i d e l y in r e s ­
ponse t o d i f f e r e n t g e r m i n a t i o n c o n d i t i o n s .
Within l i m i t s m a tu r e g r a i n
g e r m i n a t e s more r a p i d l y a t h i g h e r t e m p e r a t u r e s ( B r i g g s , 1978).
One
s t u d y showed r o o t l e t a p p e a r a n c e i n s i x days a t 5° C, t h r e e days a t
10. 5° C, two days a t 1 5 . 5 ° C, and one and t h r e e - f o u r t h days a t 17 .8 ° C.
Dormant g r a i n , however, g e r m i n a te s b e t t e r a t lower t e m p e r a t u r e s .
Most dormant b a r l e y w i l l g e r m i n a te a t 2 - 7 ° C.
As t h e g r a i n m a t u r e s ,
t h e t e m p e r a t u r e ran ge o v e r which g e r m i n a t i o n o c c u r s widens ( B r i g g s ,
1978).
Fixed t i m e o r t e m p e r a t u r e t e s t s may be m i s l e a d i n g .
Germination
o f one g r a i n sample showed t h a t g e r m i n a t i o n i n f i v e days was b e s t a t
31
12° C (67%).
The same seed sample g er m i n a te d b e t t e r (95%) i n an
e l e v e n day t e s t a t 5° C.
In t h e l o n g e r t e s t g e r m i n a t i o n a t 12° C was
o n l y 86%.
M e c h a n i c a l , h e a t , and p r e g e r m i n a t i o n damage r ed uc e g e r m i n a t i o n
c a p a c i t y o f b a r l e y ( P o l l o c k , 1962).
Microorganisms i n f l u e n c e germina­
t i o n by i n c r e a s i n g dormancy o r by c a u s i n g seed o r s e e d l i n g d e a t h
( B r i g g s , 1978).
Aging o f s ee d l e a d s t o a d i s a p p e a r a n c e o f dormancy and
a slow d e g e n e r a t i o n o f t h e embryo l e a d i n g t o e v e n t u a l d e a t h ( P o l l o c k ,
1962).
G u l t i v a r c h a r a c t e r i s t i c s and s t o r a g e c o n d i t i o n s a f f e c t
b a r l e y ger mi n a t i v e c a p a c i t y and l i f e ( P o l l o c k , 1962; B r i g g s , 1978).
A ssessmen t o f g e r m i n a t i o n c h a r a c t e r i s t i c s o f g r a i n g e n e r a l l y f a l l s
i n t o t h r e e groups o f t e s t s :
germination c a p a c ity t e s t s , germination
e n e r g y t e s t s , and s p e c i a l g e r m i n a t i o n t e s t s such as t h e w a t e r s e n s i t i ­
v i t y t e s t ( P o l l o c k , .1962).
G erm ination en e r g y t e s t s a s s e s s t h e
p e r c e n t g e r m i n a t i o n o f a g iv e n seed l o t a t a p a r t i c u l a r t i m e under
s t a n d a r d c o n d i t i o n s (B is h o p , 1944; B e l d e r o k , 1968; B r i g g s , 1978;
B r o o k e s , 1980).
G er mi na tio n c a p a c i t y t e s t s d e t e r m i n e t h e v i a b i l i t y o f
t h e seed l o t a s t h e p e r c e n t a g e o f s e e d , b o th dormant and nondormant
(B is h o p , 1944; B e l d e r o k , 1968; B r i g g s , 1978; Brookes, 1980).
The
d i f f e r e n c e between germin a t i v e ener gy and germin a t i v e c a p a c i t y d e t e r ­
mines t h e amount o f dormancy in t h e sample ( B r i g g s , 1978).
ence between g e r m i n a t i o n w i t h
8 ml
The d i f f e r ­
4 ml o f w a t e r and g e r m i n a t i o n w i t h
o f w a t e r has been d e f i n e d as w a t e r s e n s i t i v i t y ( E s s e r y e t a l . ,
.
32
1955; Wainwright and Buckee5 1977; B r i g g s 5 1978).
Many s t a n d a r d i z e d g e r m i n a t i o n methods e x i s t a l t h o u g h many have
s e r i o u s l i m i t a t i o n s ( B is h o p , 1944, 1945, 1946; E s s e r y e t a l . , 1954,
1955; P o l l o c k e t a l . , 1955a, 1955b; P o l l o c k , 1962; MacLeod, 1967;
B e l d e r o k , 1968; Gordon, 1969; Wainwright and Buckee, 1977; B r i g g s , 1978;
Gordon e t a l . , 1979).
T e s t s and c r i t e r i a f o r g e r m i n a t i o n d i f f e r de­
pendi ng on i n t e n d e d use o f t h e seed ( B r i g g s , 1978).
M altsters require
r a p i d g e r m i n a t i o n such as 50% in one t o two days and 95-100% in t h r e e
days and s c o r e g r a i n s as g e r m i n a te d as soon as t h e c o l e o r h i z a a p p e a r s .
For s ee d t e s t i n g p u r p o s es t h e seed must produ ce a w ho le , no rmal ,
v i g o r o u s s e e d l i n g w i t h an a d e q u a t e r o o t s y s t e m , a c o l e o p t i l e , and a t
l e a s t one s e e d l i n g l e a f ( B r i g g s , 1978).
M a lt in g g e r m i n a t i o n t e s t s
g e n e r a l l y r e q u i r e o n l y t h r e e t o f o u r days w h i l e seed t e s t i n g germina­
t i o n r e q u i r e 7- 14 days ( B r i g g s , 1978).
R eliable germination r e s u l t s
r e q u i r e r e p l i c a t e d su bsamples under r i g i d l y s t a n d a r d i z e d c o n d i t i o n s
o f t e m p e r a t u r e , amount o f w a t e r , and t e s t d u r a t i o n ( B r i g g s , 1978). .
I n a d e q u a t e l y c o n t r o l l e d c o n d i t i o n s may l e a d t o s e r i o u s d i s c r e p a n c i e s
between v a r i o u s g e r m i n a t i o n t e s t s
(Essery e t a l . ,
1954; B r i g g s , 1978).
M ic r o - or g an is m i n f e c t i o n s can ca u s e mold growth and r o t t i n g d u r i n g
t e s t i n g ( B r i g g s , 1978).
Most m i c r o b i a l i n f e c t i o n s can be c o n t r o l l e d by
s ee d t r e a t m e n t .
G e r m in a ti v e en er g y t e s t s a r e u s u a l l y con ducted a t 15-20° C and a r e
a b o u t 72 hours in d u r a t i o n a l t h o u g h some may t a k e l o n g e r ( E s s e r y e t a l . ,
33
1954).
Some o f t h e common germin a t i v e en erg y t e s t s i n c l u d e t h e
J
S c h o n f e ld t e s t , t h e Aubry method, t h e Coldewe o r Schonjahn method, and
t h e Buch in gor t e s t ( B is h o p, .1944; E s s e r y e t a ] . , 1954; B r i g g s , 1978).
More s a t i s f a c t o r y t e s t s can be done in f l a t d i s h e s , on f i l t e r p a p e r s ,
i n grad ed sand o r s o i l t h a t i s as unifo rm as p o s s i b l e t o which e x a c t l y
measured p r o p o r t i o n s o f w a t e r a r e added ( B r i g g s , 1978).
No d i f f i c u l ­
t i e s a r i s e when d e t e r m i n i n g g e r m i n a t i v e en er g y in f u l l y m a tu r e b a r l e y
a l t h o u g h t h e p r e c i s e en vi ron m ent d u r i n g t h e t e s t d e t e r m i n e s g e r m i n a ti o n
i f some d e g r e e o f dormancy e x i s t s in t h e b a r l e y sample ( P o l l o c k , 1962).
G er mi na tio n c a p a c i t y t e s t s d e t e r m i n e v i a b i l i t y d i r e c t l y by f o r c i n g
dormant s e e d s t o g e r m i n a t e o r i n d i r e c t l y by d e t e r m i n i n g v i a b i l i t y in
some o t h e r way ( P o l l o c k , 1962; B r i g g s , 1978).
D i r e c t germ in ati on, ca p a ­
c i t y t e s t s i n v o l v e p r e t r e a t m e n t t o e l i m i n a t e dormancy.
Common
methods i n c l u d e s t e e p i n g in d i l u t e hydrogen p e r o x i d e (Thunaeus t e s t )
( P o l l o c k , 1962; Wainwright and Bu ck ee, 1977; B r i g g s , 1 9 7 8 ) , c u t t i n g
t h e g r a i n s i n h a l f t r a n s v e r s e l y f o l l o w e d by g e r m i n a t i o n ( Eck ha rd t
test)
( B is h o p , 1944; B r i g g s , .1978), t r e a t m e n t w i t h g i b b e r e l l i c a c i d
( P o l l o c k , 19 6 2 ), removal o f t h e husk and p e r i c a r p w i t h s u l f u r i c a c i d
( P o l l o c k e t a l . , 1955a; P o l l o c k , 1962; B r i g g s , 197 8) , me cha nic al
p e e l i n g ( B is h o p, 1944, 1945, 1946; P o l l o c k , 1962; B r i g g s , 1 9 7 8 ) , and
g e r m i n a t i o n i n a s o l u t i o n o f p ot a ss iu m n i t r a t e (0.2%) ( B r i g g s , 1978;
Gordon e t a l . , 1979).
I n d i r e c t measurements o f v i a b i l i t y use chemical
s u b s t r a t e s to determine the v ia b le p ro p o rtio n o f seed.
Dead se eds
34
t a k e up barium c h l o r i d e and r e s a z u r i n o r in d i g o carm ine s t a i n s and
t h e s e have been used t o d e t e r m i n e g e r m in a t i v e c a p a c i t y ( B r i g g s , 1978).
More s u c c e s s f u l i n d i r e c t methods d e t e c t l i v i n g t i s s u e s by t h e a b i l i t y
o f t h e i r endogenous enzymes and s u b s t r a t e s t o r ed uc e m a t e r i a l s such as
d i n i t r o b e n z e n e (B is h o p , T944; B r i g g s , 19 7 8 ) , s a l t s o f s e le n i u m
( B is h o p , 1944, 1945, 1946; P o l l o c k , 1962; B r i g g s , 1 9 7 8 ) , t e l l u r i u m
( B r i g g s , 19 7 8 ), o r t e t r a z o l i urn s a l t s
(B is h o p , 1946; P o l l o c k , 1962;
MacLeod, 1967; Wainwright and Buckee, 1977; B r i g g s , 1978) t o c o l o r e d ,
i n s o l u b l e s u b s t a n c e s which s t a i n v i a b l e t i s s u e s .
Tetrazolium t e s t s
a r e t h e most common, t h e chemical b e i n g redu ce d t o h i g h l y i n s o l u b l e ,
b r i g h t red f o r a z a n s in v i a b l e t i s s u e ( B r i g g s , 1978).
Measurement o f s ee d dormancy may i n v o l v e d e t e r m i n i n g t h e l e n g t h o f
t h e dormant p e r i o d , d e t e r m i n i n g dormancy i n t e n s i t y {% dormant seed ) o r
b ot h ( S t r a n d , 1980).
The l e n g t h o f dormancy i s t h e number o f days
between t h e h a r v e s t s t a g e and t h e t i m e when a give n p e r c e n t a g e o f
g r a i n ( e . g . , 50%, 85%, 98%) i s c a p a b l e o f g e r m i n a t i n g un der s e l e c t e d
t e s t c o n d i t i o n s ( B e l d e r o k , 1968).
S t r a n d (1980) d e f i n e d t h e l e n g t h
o f t h e dormant p e r i o d as t h e number o f s t o r a g e days a t 20° C r e q u i r e d
t o r e d u c e dormancy t o an a c c e p t a b l e l e v e l .
Dormancy l e n g t h t e s t s
g e n e r a l l y i n v o l v e e a r - g e r m i n a t i o n t e s t s which begi n a t h a r v e s t r i p e n e s s
and a r e c on d uc te d a t r e g u l a r i n t e r v a l s u n t i l dormancy i s gone o r germin­
a tio n reaches a predetermined level
M a t t s s o n , 1976).
( B e l d e r o k , 1968; O ls so n and
Olsson and M at ts s o n ( 1 976) con ducted a s t u d y on t h e
I
35
l e n g t h o f t h e dormancy p e r i o d i n wheat by g e r m i n a t i n g s ee d s a t 18° C
t w i c e p e r week from f u l l r i p e n i n g u n t i l 50% g e r m i n a t i o n .
They found
l a r g e c u l t i v a r d i f f e r e n c e s in t h e l e n g t h o f t h e dormancy p e r i o d .
Dormancy i n t e n s i t y can be d e f i n e d as t h e p e r c e n t a g e o f dormant s eed s i n
a sample.
Dormancy i n t e n s i t y d e t e r m i n a t i o n may i n v o l v e g e r m i n a t i o n a t
v a r i o u s t e m p e r a t u r e s w i t h t h e s e n s i t i v i t y o f t h e t e s t dep en di n g on
g e r m i n a t i o n t e m p e r a t u r e ( S t r a n d , 1980).
O t h e r dormancy i n t e n s i t y
t e s t s i n c l u d e hanging g r a i n b u nd le s i n a c l o s e d room, kee p in g them
m o i s t and e v a l u a t i n g t h e e x t e n t o f g e r m i n a t i o n a t 7 , 10, o r 14 days
by use o f a p r e d e t e r m i n e d s c a l e o r a l t e r n a t e l y by t e r m i n a t i n g germi na­
t i o n a f t e r 3-5 days and e s t i m a t i n g t h e amount o f g e r m i n a t i o n by an
a l p h a - a m y l a s e t e s t ( B e l d e r o k , 1968).
A c c u r a t e dormancy d e t e r m i n a t i o n
r e q u i r e s t e s t i n g a t t h e same m a t u r i t y s t a g e ( B e l d e r o k , 1968; S t r a n d ,
19 8 0 ) , c a r e f u l t h r e s h i n g t o av o id k e r n e l damage ( S t r a n d , 19 8 0 ),
low m o i s t u r e l e v e l s t o e l i m i n a t e w a t e r s e n s i t i v i t y ( S t r a n d , 1980),
ca re fu l a t t e n t i o n to germination tem peratures
( S t r a n d , 1980) and s t a n ­
d a r d i z e d s t o r a g e o f l o t s t o be t e s t e d (Olsson and M a t t s s o n , 1976;
S t r a n d , 1980 ).
Length o f wheat dormancy p e r i o d s i n c r e a s e d from 12 t o
15 t o 50 days as s t o r a g e t e m p e r a t u r e d e c r e a s e d from 22° C t o 18° C t o
2° C, r e s p e c t i v e l y (Olsson and M a t t s s o n , 1976).
Noll and Czarnecki
(1980) r e p o r t e d a c c u r a t e dormancy t e s t i n g co u ld be d e l a y e d f o r up t o
4- 5 months in wheat by s t o r a g e a t -15 ° C o r by i n c r e a s i n g t h e germina­
t i o n t e m p e r a t u r e t o 30° C.
The same v a r i e t a l r a n k i n g f o r dormancy was
36
a c h i e v e d Under t h e s e c o n d i t i o n s as was found im m ed i at el y a f t e r
harvest.
R e s u l t s from s p i k e and g r a i n g e r m i n a t i o n t e s t s show t h a t
dormancy depends p r i m a r i l y on g r a i n p r o p e r t i e s w h i l e s p i k e t y p e ( e r e c t
o r n o d d i n g ) , d e n s i t y o f t h e head , and t h e p r e s e n c e o f glumes have a
min or e f f e c t on g e r m i n a t i o n b e h a v i o r ( B e l d e r o k , 1968).
B r ee d i n g p o p u l a t i o n s can be s c r e e n e d f o r dormancy i n t h e F2 o r
l a t e r g e n e r a t i o n s by p l a n t i n g s e e d s i n m o i s t sand in a bench and a l l o w ­
ing th e seeds to germinate.
Upon t e r m i n a t i o n o f t h e g e r m i n a t i o n th e
s ee d s a r e s i f t e d from t h e sand ( S t r a n d , 198 0) .
The g e r m i n a te d s eed s
a r e d i s c a r d e d and t h e dormant seed saved and d r i e d f o r s u b s e q u e n t
planting.
S e l e c t i o n p r e s s u r e i s r e g u l a t e d by t h e dormancy l e v e l in t h e
p o p u l a t i o n a t t h e t i m e o f t h e t e s t and t h e p e r c e n t a g e o f t h e p o p u l a t i o n
expected to su rv iv e th e t e s t .
The l e v e l o f dormancy o f t h e p o p u l a t i o n
i s a fu n c tio n o f c l im a t ic c o n d itio n s during rip e n in g , the g enetic level
o f dormancy, s t o r a g e t e m p e r a t u r e , and t h e ti m e from m a t u r i t y t o t e s t i n g .
The t e s t i s . f r o m 5 -1 0 days in d u r a t i o n a t t e m p e r a t u r e s from 10-20° C.
The h i g h e r t e m p e r a t u r e s m a n i f e s t more dormancy and a r e a p p l i e d t o low
dormancy m a t e r i a l o r f o r a low s e l e c t i o n p r e s s u r e tow ard nondormancy
( S t r a n d , 1 980).
G er m in a tio n p e r c e n t a g e o b t a i n e d un der s p e c i f i e d c o n d i t i o n s i s t h e
most commonly used mea sur e o f g e r m i n a t i o n .
I t r e v e a l s n o t h i n g , however,
a b o u t t h e r a t e o r u n i f o r m i t y o f g e r m i n a t i o n (Bewley and B l a c k , 1978).
A no th er commonly used g e r m i n a t i o n measure i s t h e g e r m i n a t i o n r a t e which
37
can be e x p r e s s e d f o r a s i n g l e s e e d , f o r a p o p u l a t i o n , o r a p r o p o r t i o n
o f the population,
t h e mean g e r m i n a t i o n r a t e o f a p o p u l a t i o n may be
e x p r e s s e d by Ko tow ski1s c o e f f i c i e n t o f v e l o c i t y (Cy ) (Bewley and
B l a c k , 1978).
V ar io u s a t t e m p t s have been made t o combine b o th t h e
g e r m i n a t i o n r a t e and f i n a l g e r m i n a t i o n v a l u e i n t o a s i n g l e numerical
value.
C z a b a t o r 1s g e r m i n a t i o n v a l u e (C) and Timson' s g e r m i n a t i o n in d e x
have been c r i t i c i z e d b e c a u s e s i m i l a r v a l u e s may be o b t a i n e d from
d i f f e r e n t c u m u l a t i v e g e r m i n a t i o n c u r v e s (Bewley and B l a c k , 1978).
F i n l a y ' s g e r m i n a t i o n b e h a v i o r v a l u e (G) ( F i n l a y , 1960a) and Gordon's
g e r m i n a t i o n r e s i s t a n c e ( G . R . ) and u n i f o r m i t y f a c t o r ( U . F . )
(Gordon,
1969) p r o v i d e s i n g l e n u m e ri ca l v a l u e s e x p r e s s i n g g e r m i n a t i o n b e h a v i o r .
Goodchild and Walker (1971) combined mean g e r m i n a t i o n r a t e , t o t a l
g e r m i n a t i o n , and v a r i a t i o n s in r a t e i n t o a p o l y g o n i a l r e g r e s s i o n
method
o r c u r v e f i t t i n g w h i l e J a n s s e n ad v o c a te d a method u s i n g t h e
a v e r a g e g e r m i n a t i o n t i m e , t h e s t a n d a r d d e v i a t i o n , and t h e t o t a l accum­
u l a t e d sum o f t h e normal c u r v e (Bewley and B l a c k , 1978).
B a r l e y g e r m i n a t i o n b e h a v i o r i s q u i t e v a r i a b l e and f a l l s i n t o
t h r e e broad c l a s s i f i c a t i o n s based on a g e r m i n a t i o n b e h a v i o r v a l u e (G)
( F i n l a y , 1960a).
The f i r s t group (G=460) has f a s t and even g e r m i n a ti o n
and i s composed a l m o s t e n t i r e l y o f naked b a r l e y t y p e s a l t h o u g h a few
e x c e p t i o n a l h u l l e d v a r i e t i e s a p p r ox im at e d t h i s r a t e o f g e r m i n a t i o n .
m a j o r i t y o f b a r l e y v a r i e t i e s f a l l i n t o a medium c a t e g o r y (G=300) o f
The
38
germination.
(G=145 ) .
A few b a r l e y v a r i e t i e s g e r m i n a t e s lo w ly and uneve nl y
MATERIALS AND METHODS
General Expe ri men ta l P r o c e d u r e s
In t h e s e e x p e r i m e n t s s e e d s were g e r m i n a te d between m o i s t b l o t t e r
p a p e r s i n p l a s t i c g e r m i n a t i o n boxes.
The boxes were p l a c e d in p l e x ­
i g l a s s g e r m i n a t i o n chambers w i t h t e m p e r a t u r e m a i n t a i n e d between 20 .
and .25°.C and t h e r e l a t i v e h um i d it y n e a r 100%.
a s needed t o keep t h e b l o t t e r p a p e r s m o i s t .
Each box was w at er e d
T r i p l i c a t e samples o f
one hundred s e e d s .were g er m i n a te d from each seed l o t .
t e s t s l a s t e d seven d a y s .
Al I germination,
Seeds were c o n s i d e r e d g e r m i n a te d a t t h e
f i r s t s i g n o f embryo growth.
Counts were made a f t e r seven days o r
a f t e r s p e c i f i c days o f g e r m i n a t i o n as i n d i c a t e d i n S p e c i f i c e x p e r i ­
m e nt s .
•
Base l e v e l s o f a l p h a - a m y l a s e , d e f i n e d in t h i s e x p e r i m e n t as
t h a t a l p h a - a m y l a s e p r e s e n t in t h e k er n el p r i o r t o any g e r m i n a t i o n , were
e s t i m a t e d u s i n g a gel d i f f u s i o n - s t a r c h d i g e s t i o n t e c h n i q u e d e s c r i b e d
by Fox and E s l i c k ( 1 98 0 ) .
Areas o f s t a r c h d i g e s t i o n r i n g s were
c o n v e r t e d t o ng dye r e l e a s e / m i n u t e / m g sample by c a l c u l a t i n g a
r e g r e s s i o n l i n e f o r each p l a t e from t h r e e check samples o f known
a l p h a - a m y l a s e a c t i v i t y and s u b s e q u e n t l y d e t e r m i n i n g enzyme a c t i v i t y
f o r each sample.
Where a p p l i c a b l e , a l p h a - a m y l a s e a c t i v i t y was con­
v e r t e d t o ng dye r e l e a s e / m i n u t e / k e r n e l .
.
.
40
S t a t i s t i c a l Methods
. The s t a t i s t i c a l a n a l y s e s u t i l i z e d v a r i e d w i t h t h e e x p e r i m e n t .
An F t e s t a n d / o r Duncan's New M u l t i p l e Range T e s t were used, t o
compare mean r e s p o n s e s among groups ( S t e e l and T o r r i e , I 9 6 0 ; .
Sn ed ec or and Cochran, 1967).
R e g r e s s i o n and c o r r e l a t i o n methods,
were a l s o used where a p p l i c a b l e (Sned eco r and Cochran, 1967; Sokal
and Rohlf , 196 9) .
P a i r e d c o m p a r is o n s . w e r e made u s i n g a p a i r e d t t e s t
( Sn ede cor and Cochran, 1967).
Some o f t h e d a t a v i o l a t e d t h e a n a l y s i s o f v a r i a n c e as sumpti ons,
o f n o r m a l i t y and homogeneity o f v a r i a n c e .
and a n a l y z e d p a r a m e t r i c a l l y o r a n a l y z e d
tics
(Sokal and R o h l f 5 1969).
Such d a t a were t r a n s f o r m e d
using
nonparametric s t a t i s ­
P a i r e d n o n p a r a m e t r i c co m par iso ns were
made u s i n g t h e s i g n t e s t o r W i l c o x s o n ' s Signed -R an k T e s t ( S t e e l
^and T o r r i e , 1 960; Sned eco r and Co ch ra n i, 1967; Sokal and R o h l f , 1969).
U nl es s d i f f e r e n t r e s u l t s were o b t a i n e d by a n a l y z i n g t r a n s f o r m e d d a t a
o r using nonparametric techniques only th e param etric a n a l y s i s of
o rig in al data is reported.
Experiment I
The o b j e c t i v e o f t h i s ex p e r i m e n t was t o c h a r a c t e r i z e t h e
dormancy i n t e n s i t y and g e r m i n a t i o n b e h a v i o r o f b a r l e y .
F ifty barley
c u l t i v a r s i n c l u d i n g 2 5 two-row and 25 s i x - r o w c i i l t i v a r s r e p r e s e n t i n g
commercial m a l t i n g and f e e d b a r l e y s were p l a n t e d 18 A p r i l 1978 a t
•i
41
Bozeman, Montana.
The b a r l e y was damaged by h a i l on 16 J u l y , d u r i n g
th e heading p erio d .
Heads from 16 c u l t i v a r s , presumably r e p r e s e n t i n g
a wide r an g e o f g e r m i n a t i o n b e h a v i o r , were h a r v e s t e d 30 A u g u s t ^
s h o r t l y a f t e r h a r v e s t r i p e n e s s (14% m o i s t u r e ) .
The heads were a i r d r i e d one week a t 20°C, th e n t h r e s h e d and
germinated.
G er m in a ti on Counts were made a f t e r days f i v e and seven.
.
Speed o f g e r m i n a t i o n was d e f i n e d as t h e r a t i o o f p e r c e n t
g e r m i n a t i o n on day f i v e t o t h e f i n a l g e r m i n a t i o n p e r c e n t on t h e
s e v e n t h day.
Re sid u a l s ee d from t h e s e c u l t i v a r s was s t o r e d a t 20°C
f o r f i v e m on th s, t h e n t e s t e d f o r g e r m i n a t i o n a second t i m e .
The
d i f f e r e n c e between f i n a l g e r m i n a t i o n p e r c e n t a g e Fe br uar y 1979
(Germin a t i v e C a p a c i t y ) , and f i n a l g e r m i n a t i o n p e r c e n t a g e Sep tem ber,
T978 (Germin a t i v e I n t e n s i t y ) , was d e f i n e d as t h e p e r c e n t a g e o f d o r ­
mancy t h a t had broken down d u r i n g f i v e months o f s t o r a g e .
Base a l p h a -
amylase a c t i v i t y l e v e l s were d e t e r m in e d f o r a l l c u l t i v a r s .
E i g h t m a l t i n g . a n d e i g h t f e e d b a r l e y c u l t i v a r s (MBIA, 1981) were
e q u a l l y d i v i d e d between two- and s i x - r o w t y p e s (Table I ) .
was used t o compare mean r e s p o n s e s among g r ou p s .
An F t e s t
The e r r o r mean
s q u a r e was used t o t e s t v a r i a t i o n w i t h i n c l a s s i f i c a t i o n s and v a r i a t i o n
among C u l t i v a r s .
The w i t h i n c l a s s i f i c a t i o n mean s q u a r e was used t o
t e s t v a r i a t i o n among c l a s s i f i c a t i o n s , between m a lt and f e e d b a r l e y s ,
between two- and s i x - r o w b a r l e y s , and t h e i n t e r a c t i o n among
classifications.
T h e . d a t a was a l s o a n a l y z e d u s in g a l o g a r i t h m i c
42
Table I .
Ex per im ent I .
C ultivar
C l a s s i f i c a t i o n o f b a r l e y c u l t i v a r s by
use and row t y p e (MBIA, 1981).
P r i n c i p l e Use
2 o r 6 -Row
Be tz es
Erbet
Klages
Piroline
Malt
Malt
Malt
Malt
2
2
2
2
Dickson
barker
T raill
Trophy
Malt
Malt
Malt
Malt
6
6
6
6
Compana
Dekap
H ec to r
Ingrid
Feed
Feed
Feed
Feed
2
2
2
2
Galt
. Steptoe
T r eb i
Vantage
Feed
Feed
Feed
Feed
6
6
6
6
43
t r a n s f o r m a t i o n a l t h o u g h no d i f f e r e n c e i n r e s u l t s was o b t a i n e d .
Experiment 2
T h i s e x p e r i m e n t was cond uct ed t o e v a l u a t e t h e e f f e c t o f t h e waxy
endosperm gene on dormancy, g e r m i n a t i o n , and a l p h a - a m y l a s e a c t i v i t y
l e v e l s during kernel m a tu ra tio n .
Four waxy-normal endosperm n e a r
i s o g e n i c p a i r s , d ev el o pe d i n t h e T i t a n , B e t z e s , and Compana c u l t i v a r s ,
were grown a t Bozeman and H u n t l e y , Montana i n p l o t s 1 . 2 m e t e r s wide
and 3 5 . 0 m e t e r s l o n g .
All i s o g e n i c s i n v o l v e d i n t h i s e x p e r i m e n t were
d ev el o p ed by b a c k c r o s s i n g t h e waxy endosperm gene seven g e n e r a t i o n s
i n t o each c u l t i v a r .
F i f t y t o s e v e n t y - f i v e random s p i k e s were t a k e n from each p l o t
e v e r y two t o t h r e e days from s h o r t l y a f t e r head in g u n t i l h a r v e s t
m a t u r i t y ( l e s s t h a n 14% m o i s t u r e ) .
Twenty-three samples were t a k en
d u r i n g t h e p e r i o d from 27 J u l y t o 23 September a t Bozeman.
samples were c o l l e c t e d a t Hun tley (24 Ju ly, t o 22 A u g u s t ) .
Four tee n
Sp ike s
were w e ig h e d , a i r d r i e d f o r one week a t 2 0 °C in p a p e r b a g s , r e ­
weig hed , t h r e s h e d , and g e r m i n a t e d .
S p ik e m o i s t u r e was e s t i m a t e d
on a f r e s h w e i g h t b a s i s u s i n g t h e f o l l o w i n g e q u a t i o n :
(
F r e s h w e i g h t - Dry w e ig h t
) x 100 = % s p i k e m o i s t u r e
Fresh weight
Sp ik e m o i s t u r e was d e t e r m i n e d o n ly a t Bozeman.
Physiological
m a t u r i t y was d e f i n e d a s t h e p o i n t i n ti m e a t which m o i s t u r e had
44
d e c r e a s e d t o 40%.
s ev en .
G er m in a tio n c o u n t s were made a f t e r days t h r e e and
G er m in a ti o n speed was d e f i n e d by t h e f o l l o w i n g e q u a t i o n :
( I g e r m i n a t i o n day 7 > x 100 = G e m i n a t i o n Speed Index
Seed w e i g h t f o r each sample ( m g / K e r n e l) , was c a l c u l a t e d by
c o u n t i n g and w e ig h i ng two l o t s o f one hundred a i r d r i e d s e e d s .
mination c a p a c i t y was d e t e r m i n e d a f t e r f i v e months o f s t o r a g e .
Ger­
Seeds
which d i d n o t g e r m i n a t e i n t h e seven day c o n v e n t i o n a l g e r m i n a t i o n
t e s t were c u t i n h a l f l e n g t h w i s e and p l a c e d i n t e t r a z o l i u m c h l o r i d e
(TZ) s o l u t i o n f o r 30 m i n u t e s .
were c o n s i d e r e d v i a b l e .
Seeds w i t h b r i g h t l y s t a i n e d embryos
G er mi na tio n c a p a c i t y was d e f i n e d as t h e
sum o f p e r c e n t g e r m i n a t i o n i n t h e c o n v e n t i o n a l g e r m i n a t i o n t e s t p lu s
v i a b l e seed a s d e t e r m in e d by t h e TZ t e s t .
Dormancy o f t h e d e v e l o p ­
in g seed was e s t i m a t e d by s u b t r a c t i n g t h e p e r c e n t ger mi n a t i v e
i n t e n s i t y , d e t e r m in e d one week a f t e r s a m p l i n g , from t h e p e r c e n t
germinative cap acity .
Base l e v e l a l p h a - a m y l a s e a c t i v i t y , i n t h e
un ge rm in at e d s e e d , was d e t e r m in e d f o r ea ch c u l t i v a r - d a t e c o m b in at io n .
Data from t h e 13 September sample grown a t Bozeman was o m i tt e d
from s t a t i s t i c a l a n a l y s e s b e ca us e o f c o n s i d e r a b l e s p r o u t i n g damage.
A p p r ox im at el y two i n c h e s o f r a i n f a l l f e l l
s h o r t l y b e f o r e samp ling .
The heads were h a r v e s t e d wet and i m p r o p e r l y d r i e d r e s u l t i n g in
d r a m a t i c a l l y i n c r e a s e d a l p h a - a m y l a s e l e v e l s and d e p r e s s e d g e r m i n a t i v e
e n e r g y and c a p a c i t y .
45
I s o g e n i c a n a l y s e s between waxy and normal endosperm b a r l e y s
were made by p a i r e d co m par iso ns o f waxy-nonwaxy l i n e s a t each d a t e
using a paired t t e s t .
S i m i l a r co m par iso ns were a l s o made between
s h o r t awn-nude Compana i s o t y p e s and normal
(lon g awn-cov ere d) Compana
i s o t y p e s and between Washonupana (waxy s h o r t awn-nude) and Compana
(normal endosperm long a w n - c o v e r e d ) .
P a i r e d t t e s t s were made f o r
each c h a r a c t e r i s t i c a t each l o c a t i o n w i t h i n each g e n e t i c background
th e n a c r o s s e n v i r o n m e n t s , and a c r o s s g e n e t i c back g ro u n ds .
The waxy-
normal endosperm com par iso ns a c r o s s g e n e t i c backgrounds were made by
a v e r a g i n g waxy and normal endosperm v a l u e s a t each d a t e and s u b s e ­
q u e n t l y comparing t h e means ( p a i r e d by d a t e ) .
Paired t t e s t s across
e n v i ro n m e n ts were made sim p l y by i n c r e a s i n g t h e number o f p a i r s in
t h e t e s t t o i n c l u d e both e n v i r o n m e n t s .
I s o g e n i c a n a l y s e s were a l s o
performed u s i n g t h e s i g n and W i l c o x s o n ' s Ranked Sign t e s t s .
G r a p h ic a l p r e s e n t a t i o n s o f t h e t i m e c o u r s e s o f v a r i o u s expe ri me n­
t a l o b s e r v a t i o n s were made u s in g a t h r e e - s a m p l e moving a v e r a g e to
smooth and s i m p l i f y d a t a c u r v e s .
Bozeman d a t a i s p r e s e n t e d u s in g t h e
.
p e r c e n t a g e o f s p i k e m o i s t u r e as a m a t u r i t y in d e x .
presented ch ro nologically.
H u n tl e y d a t a i s
The s i g n o f t h e t s t a t i s t i c p r e s e n t e d in
t a b l e s 4-9 in d ic a te s th e r e l a t i v e p o s iti o n of is o ty p e s .
Normal i s o t y p e
v a l u e s were always s u b t r a c t e d from m ut ant i s o t y p e v a l u e s i n t h e p a i r e d
t test.
Thus a p o s i t i v e t s t a t i s t i c i n d i c a t e s t h e m u ta nt i s o t y p e
v a l u e i s g r e a t e r t h a n t h e normal i s o t y p e v a l u e and v i c e v e r s a .
46
Experi ment 3
The p u r p o s e o f t h i s e x p e r i m e n t was t o d e t e r m in e t h e e f f e c t o f
t h e waxy endosperm gene on dormancy, g e r m i n a t i o n , and m a l t q u a l i t y
c h a r a c t e r i s t i c s a t h a r v e s t m a t u r i t y ( l e s s t h a n 14% m o i s t u r e ) .
Four
waxy-normal endosperm i s o g e n i c p a i r s p l u s t h r e e check c u l t i v a r s ,
P i r o l i n e , S h a b e t , and Klages were p l a n t e d on r e c r o p p e d s o i l a t
Bozeman, Montana i n an e f f o r t t o m a i n t a i n p r o t e i n c o n t e n t w i t h i n
acceptable m alting li m it s .
The e x p e r i m e n t was p l a n t e d a s a randomized
c o m pl et e b lo c k w i t h f o u r r e p l i c a t i o n s .
30 cm between rows.
P l o t s were f o u r rows wide w i t h
The rows were t h r e e m e te r s long and were p l a n t e d
a t t h e r a t e o f 3 .2 5 grams p e r m e t e r .
Heading d a t e f o r ea ch p l o t was
r e c o r d e d a s t h e days a f t e r I J a n u a r y when t h e f i r s t f l o r e t o f t h e main
t i l l e r r e a c h e d t h e f l a g l e a f b l a d e on 50% o f t h e p l a n t s .
Plant
h e i g h t (cm) was measured from t h e crown t o t h e t o p f l o r e t a t t h e
hard dough s t a g e .
At h a r v e s t r i p e n e s s 1 . 4 8 s q u a r e m e t e r s from t h e c e n t e r two rows o f
each p l o t were h a r v e s t e d f o r y i e l d , g e r m i n a t i o n , and m a l t q u a l i t y
evaluations.
Y i e l d , g r a i n w e i g h t p e r u n i t a r e a , was c o n v e r t e d t o
q u in tals per hectare.
T e s t w e i g h t s were d et e r m in e d u s i n g t h e
l Ohaus T e s t Weight S c a l e 1 and c o n v e r t e d t o K g / h e c t o l i t e r .
Kernel
w e i g h t s (grams/1000 k e r n e l s ) were d e t e r m i n e d by we ig hi n g and c o u n t i n g
30 grams o f b a r l e y seed and t h e n c a l c u l a t i n g t h e w e ig h t o f 1000 k e r n e l s .
Malt e v a l u a t i o n s were made on 350 gram s a m p l e s , bulke d i n equal
47
p r o p o r t i o n s from each r e p l i c a t i o n , a t t h e USDA-ARS North C e n t r a l
Region B a r l e y and Malt L a b o r a t o r y a t Madison, Wisc ons in.
G erm ination
b e h a v i o r was e v a l u a t e d on I O ct o b er and 3 December o f t h e same h a r v e s t
year.
D a i l y g e r m i n a t i o n c o u n t s were made i n t h e t e s t s .
Germination
speed was q u a n t i f i e d u s i n g F i n l a y ' s g e r m i n a t i o n b e h a v i o r in d e x (G)
( F i n l a y , 1960a).
S t a t i s t i c a l a n a l y s e s i n v o l v e d an F t e s t t o compare g e r m i n a t i o n
and agronomic t r a i t s o f m ut an t i s o t y p e s , a p a i r e d t t e s t t o compare
m a l t q u a l i t y c h a r a c t e r i s t i c s o f waxy and normal endosperm i s o t y p e s ,
and Duncan's M u l t i p l e Range T e s t t o compare d i f f e r e n c e s among
c u l t i v a r means.
Experi ment 4
T h i s e x p e r i m e n t was con du ct ed t o d e t e r m i n e t h e e f f e c t o f t h e
waxy endosperm gene on t h e r a t e o f w a t e r i m b i b i t i o n .
Seed from f o u r
Compana i s o t y p e s - Washonupana, Shonupana, Wapana, and Compana,
grown i n t h r e e e n v i ro n m e n ts was used i n t h e s t u d y .
c o n t e n t o f t h e seed was 7 . 24 -9. 05% .
I n i t i a l moisture
Seed l o t s from each en v i ro n m en t-
c u l t i v a r co m b in a ti o n were immersed i n 2 0 °C, u n a e r a t e d w a t e r i n t h r e e
r e p l i c a t i o n s and sampled a f t e r 0 . 2 5 , 0 . 5 0 , 0 . 7 5 , 1 . 0 0 , 2 . 0 0 , 4 . 0 0 ,
8 . 0 0 , 36 . 0 0 and 4 8 . 0 0 h ou rs o f s t e e p t i m e .
At each sampl ing t i m e ,
a p p r o x i m a t e l y 1000 s ee d s were removed from t h e w a t e r , i m m e d i a t e l y
b l o t t e d t o remove s u r f a c e w a t e r , w eig he d , and th e n d r i e d i n a f o r c e d
48
a i r oven a t 8 0 ° C.
F in a l oven d r y w e i g h t s were o b t a i n e d when no
f u r t h e r m o i s t u r e l o s s (measured by d e c r e a s i n g w e ig h t ) o c c u r r e d .
M o is tu r e p e r c e n t a g e was c a l c u l a t e d on a f r e s h w ei g h t b a s i s .
Equat ion s
d e s c r i b i n g w a t e r u p ta k e f o r each i s o t y p e and f o r each env ironm ent
were d ev el op ed u s i n g r e g r e s s i o n t e c h n i q u e s .
s i m i l a r t o t h o s e d e r i v e d by Shu ll
These e q u a t i o n s a r e
(1920) f o r Xanthium s e e d s .
The
e q u a t i o n t a k e s t h e form Y=mlog^Q(X+l)+b i n which Y=the t o t a l p e r c e n ­
t a g e o f m o i s t u r e i n t h e s e e d , and X=the h o ur s o f s t e e p t i m e , m and b
be in g c o n s t a n t s , r e p r e s e n t i n g t h e s l o p e and Y - i n t e r c e p t , r e s p e c t i v e l y .
Seeds from t h e same i s o t y p e s were a l s o t e s t e d f o r g e r m i n a t i o n
s pee d.
Seed from a l l t h r e e e nv iro n m en ts had been s t o r e d f o r a minimum
o f two y e a r s a t 20 C, t h u s r e d u c i n g dormancy t o a minimal l e v e l .
G er m in a tio n c o u n t s were made d a i l y f o r seven days.
G er m in a tio n speed
was c a l c u l a t e d a s t h e g e r m i n a t i o n promp tne ss index (GPI) i n which
t h e p e r c e n t a g e g e r m i n a t i o n on days one t h r o u g h s e v e n , r e s p e c t i v e l y ,
a r e weighed by a f a c t o r o f seven on day one t o one on day s e v e n , and
summed.
Data were s t a t i s t i c a l l y a n a l y z e d u s i n g an F t e s t t o compare mean
r e s p o n s e s between waxy and normal Compana i s o t y p e s and between s h o r t
awn-nude and long awn-covered Compana i s o t y p e s .
I s o t y p e and s t e e p
t i m e were f i x e d e f f e c t s , and en v iro n m en t was c o n s i d e r e d a random
e f f e c t . . Mean r e s p o n s e s among i s o t y p e s were t e s t e d u s i n g t h e e n v i r o n ­
ment by i s p t y p e i n t e r a c t i o n mean s q u a r e .
S te e p ti m e r e s p o n s e s were
49
t e s t e d u s i n g t h e en vi ro nm en t by s t e e p ti m e i n t e r a c t i o n mean s q u a r e .
The s t e e p t i m e by i s o t y p e i n t e r a c t i o n was t e s t e d u s i n g t h e mean
s q u a r e o f t h e second o r d e r i n t e r a c t i o n .
t h e r e s i d u a l mean s q u a r e .
All o t h e r F t e s t s inv o lv ed
RESULTS AND DISCUSSION
Experiment I .
C h a r a c t e r i s t i c s o f M a l t i n g and Nonmalting C u l t i v a r s ,
P e r c e n t a g e g e r m in a t i v e c a p a c i t y ( T a b l e s 2 and 3) v a r i e d s i g n i f i ­
c a n t l y among c u l t i v a r s b u t n o n s i g n i f i c a n t l y between m a l t and f e e d
t y p e s o r between two- and s i x - r o w b a r l e y s .
No s i g n i f i c a n t i n t e r ­
a c t i o n between t h e m a l t - f e e d and t w o - s i x row c l a s s i f i c a t i o n s was
detected.
S i g n i f i c a n t v a r i a t i o n w ith in th e six-row c l a s s i f i c a t i o n
b u t n o t w i t h i n t h e two-row c l a s s i f i c a t i o n was o b s e r v e d .
P e r c e n t a g e dormancy ( T a b l e s 2 and 3) v a r i e d s i g n i f i c a n t l y
among c u l t i v a r s , a f a c t w e ll documented (Deming and R o b e r t s o n , 1933;
B e l d e r o k , 1968).
feed barleys.
Malt b a r l e y s had s i g n i f i c a n t l y l e s s dormancy th a n
A s h o r t dormancy p e r i o d (LaBerge e t a l . , 1971) a n d / o r
a low dormancy, i n t e n s i t y (M a lt in g B a r l e y Improvement A s s o c i a t i o n ,
1981) a r e c h a r a c t e r i s t i c o f m a l t b a r l e y s .
d i d n o t v a r y s i g n i f i c a n t l y f o r dormancy.
Two- and s i x - r o w b a r l e y s
The i n t e r a c t i o n between
m a l t - f e e d and t w o - s i x row c l a s s i f i c a t i o n s was a l s o n o n s i g n i f i c a n t .
S i g n i f i c a n t v a r i a t i o n in dormancy e x i s t e d w i t h i n all. c l a s s i f i c a t i o n s .
e x c e p t t h e m a l t two-row c l a s s i f i c a t i o n .
S ig n ific a n t v a r ia tio n w ithin
t h e f e e d c l a s s i f i c a t i o n s would be e x p e c t e d .
By d e f i n i t i o n , m a lt
b a r l e y s must meet r i g i d s t a n d a r d s f o r g e r m i n a t i o n w h i l e f e e d b a r l e y s
i n c l u d e a l l b a r l e y s n o t m e e ti n g m a l t s t a n d a r d s .
G e r m in a tio n speed ( T a b l e s 2 and 3) v a r i e d s i g n i f i c a n t l y among
51
T ab l e 2.
Experi ment I .
Mean g e r m i n a t i o n b e h a v i o r and a l p h a - a m y l a s e
a c t i v i t y values fo r six te en b arle y c u l tiv a r s
c l a s s i f i e d by use and row t y p e .
T
r
G erm inative•
Capacity
‘ Dormancy
C lassification
%
'
a
i
t
G erm ination
Speed
A lpha-am ylase
A ctivity
Ring .
diameter
100
(mm) .
%
7.9
7.6
.
0.3 .
Malt
Feed
D ifference
(M al t-F ee d )
96 .8
88.4
8.4
7:8
2 5 .5
-17.7
96 .0
73.1
22.9
Two-Row
Six-Row
Difference
(2-row T 6-row)
98.5
86 .7
n .s
17.9
15.4
2.5
8 1 .6
87 .5
-5.9
7.6
7.9
-0.3
Malt
Malt
Feed
Feed
99.1
94 .5
98.0
78.8
5.4
10.2
30.4
2 0 .5
97 .4
94.5
65.7
80 .4
7.6
8.1
7. 5
7.8
92.6
16.7
8 4 .5
7.7 5
2-row
6 - row
2-row
6 - row
O v e r a l l means
.
■
52
T a b l e 3.
Experiment T.
A nalysis o f v aria n ce f o r c e r t a i n germination
t r a i t s fo r sixteen barley c u ltiv a r s c l a s s i ­
f i e d by use and row t y p e .
So urce o f V a r i a t i o n
df
C ultivars
15
Among c l a s s i f i c a t i o n s
Malt vs Feed
2 vs 6 - row
M vs F x 2 vs 6-row
63 0.7**
...
G erm ination
Speed
M.S.
807.9**
1084.7**
1057.0
841 .7
1692.0
63 8 .0
1492.8
37 63.0*
77.5
63 8 .0
2543.4*
6291.0*
41 9 .5
•
916.6
3
3
3
3
524.1**
1.0
15 3.2**
18.3
1923.7**
63 6.7**
67.0
590;5**
1258.3**
63 1 .3 * *
720.8**
18.6
38.1
1320.8**
1505.7**
9.5
2 9 .6
12
32
Dormancy
M.S.
I
I
I
3
Wi thin c l a s s i f i c a t i o n s
Ma lt 2-row
. Malt Srrow
Feed 2-row
Feed 6-row
Error
. G er m in a ti v e
Capacity
M.S.
* , ** S i g n i f i c a n t a t t h e P=O.05 and P=O.01 p r o b a b i l i t y l e v e l s ,
respectively.
38.3 .
53
c u l t i v a r s and between m a l t and f e e d t y p e s .
This agrees w ith p r i o r
r e s e a r c h ( F i n l a y , 1960a; Ulonska and Baumer, 1976) r e p o r t i n g wide
v a r i a t i o n in germ ination speed.
Two- and s i x - r o w b a r l e y s d i d no t
vary s i g n i f i c a n t l y f o r germination speed.
Feed b a r l e y s had s i g n i f i ­
can t v a r i a t i o n w ithin c l a s s i f i c a t i o n s , but not the malt b a rle y s.
L e v e ls o f b as e a l p h a - a m y l a s e a c t i v i t y d id no t v a r y much among
classifications
(Tab le 2) and among c u l t i v a r s .
S t a t i s t i c a l analyses
w ere n o t c on d uc te d f o r a l p h a - a m y l a s e a c t i v i t y due t o i n a d e q u a t e
replication.
A v a i l a b l e i n f o r m a t i o n s u p p o r t s t h e f i n d i n g o f Riggs and
Gothard (1 9 7 6) .
They r e p o r t e d t h a t a l p h a - a m y l a s e l e v e l s r e a c h e d a
peak s h o r t l y a f t e r a n t h e s i s , d e c l i n e d t o a n e g l i g i b l e l e v e l by
31 days p o s t a n t h e s i s , and th e n remained s t a b l e u n t i l m a t u r i t y .
No
s i g n i f i c a n t d i f f e r e n c e s were r e p o r t e d among seven b a r l e y c u l t i v a r s
f o r a l p h a - a m y l a s e a c t i v i t y i n t h e p e r i o d from 31 days a f t e r a n t h e s i s
to m aturity.
T h i s e x p e r i m e n t c o n f ir m s t h a t g e r m i n a t i o n b e h a v i o r v a r i e s
w i d e l y among b a r l e y c u l t i v a r s and between m a l t and f e e d b a r l e y s .
These r e s u l t s a l s o i n d i c a t e t h a t s c r e e n i n g f o r m a lt b a r l e y s could
i n v o l v e t e s t i n g f o r dormancy, g e r m i n a t i o n s p e e d , o r b o t h .
i t s e l f g i v e s no i n d i c a t i o n o f g e r m i n a t i o n b e h a v i o r .
Row ty p e
.
.
54
Experiment 2:
Kernel Weight, G er mi na tio n C h a r a c t e r i s t i c s , and
A lp h a- am y la s e Development During M a t u r a t i o n
M a t u r a t i o n a s measured by m o i s t u r e p e r c e n t a g e
.
P e r c e n t a g e s p i k e m o i s t u r e o f a l l b a r l e y l i n e s sampled t h r o u g h o u t
k e r n e l m a t u r a t i o n a t Bozeman ( F i g u r e s 1 -4 ) p a r a l l e l s p a t t e r n s o f
g r a i n m o i s t u r e c o n t e n t d u r i n g k er n el development r e p o r t e d f o r b a r l e y
'
.
( W e l l i n g t o n , 1964; MacGregor e t a l . , 1971) and wheat (Gordon e t a l . ,
1979);
Isogenic a n a ly sis
(Table 4) showed s p i k e m o i s t u r e t o be
s i g n i f i c a n t l y h i g h e r f o r t h e waxy endosperm l i n e s th a n f o r t h e normal
endosperm l i n e s .
Waxy endosperm T i n e s av e r a g e d one t o two p e r c e n t
h i g h e r s p i k e m o i s t u r e t h a n d i d normal endosperm l i n e s a t each sampling
date (Figure I ) .
During k e r n e l m a t u r a t i o n Washonupana and Watan had
s i g n i f i c a n t l y h i g h e r s p i k e m o i s t u r e t h a n Shonuparia and T i t a n , r e s p e c ­
t i v e l y (Tab le 4 ) .
Washonupana had a 2-16% h i g h e r s p i k e m o i s t u r e p e r ­
c e n t a g e t h a n Shonupana ( F i g u r e 2) w h i l e Watan was 0 - 1 1% h i g h e r in
s p i k e m o i s t u r e p e r c e n t a g e t h a n T i t a n d u r i n g ke rn el m a t u r a t i o n ( F ig u r e
3).
No s i g n i f i c a n t d i f f e r e n c e s in s p i k e m o i s t u r e e x i s t e d between
Wapana and Compana and between Wabet and B e t z e s d u r i n g t h i s p e r i o d .
P a i r e d com pa ris o n s among t h e f o u r . Compana i s o l i n e s showed t h a t
t h e s h o r t awn-naked, i s o l i n e s w er e, i n b o th c a s e s , s i g n i f i c a n t l y
h i g h e r in s p i k e m o i s t u r e d u r i n g k e r n e l m a t u r a t i o n th a n t h e long awncov er e d i s o l i n e s
(Table 4 ) .
The s h o r t awn-naked i s o l i n e s , Washonu-
pana and Shonupana a v e r a g e d 2-14% h i g h e r i n s p i k e m o i s t u r e th a n
.
55
% S p ik e M o i s t u r e ( f r e s h w e ig h t b a s i s )
Mean o f f o u r waxy endo­
sperm i s o t y p e s .
Mean o f f o u r normal
endosperm i s o t y p e s .
Sampling
Figure I.
Date
Experiment 2. Average s p i k e m o i s t u r e o f f o u r waxy and
f o u r normal endosperm b a r l e y i s o t y p e s sampled 23 ti me s
(27 J u l y - 23 September 1978) d u r i n g ke rn el m a t u r a t i o n
a t Bozeman, Montana.
56
Washonupana
Shonupana
Wapana
% Sp ik e M o is tu r e ( f r e s h w e i g h t b a s i s )
Compana
Sampling Date
Figure 2.
Experiment 2. Spike moisture of four Compana isotypes
sampled 23 times (27 July - 23 September 1978) during
kernel maturation at Bozeman, Montana.
57
Watan
Titan
Sampling Date
Figure 3.
Experiment 2. Spike moisture of two Titan isotypes
sampled 23 times (27 July - 23 September 1978) during
kernel maturation at Bozeman, Montana.
58
Mean o f two s h o r t awnnaked i s o t y p e s .
Mean o f two long awncovered i s o t y p e s .
V)
-Q
4->
CB
-C
i
-C
t /l
(I)
5-
M-
<U
S3
4->
V>
I
o;
CL
on
as
Sampling Date
Figure 4.
Experiment 2. Average spike moisture of two short awnnaked and two long awn-covered Compana isotypes sampled
23 times (27 July - 23 September 1978) during kernel
maturation at Bozeman, Montana.
59
T a b l e 4.
Experiment 2 .
S t a t i s t i c a l a n a l y s i s u s in g a p a i r e d t t e s t
o f p e r c e n t a g e s p i k e m o i s t u r e d u r i n g k er n el
. maturation fo r e ig h t barley lin e s isogenic
f o r waxy and normal endosperm a t Bozeman,
Montana, 1978.
Bozeman
. 22 d f
Comparison
Mutant
isotype
Washonupana
Wapana
Watan
Wabet
Waxy (mean)
. Normal
isotype
Sign o f t +
S.L.+ +
+■
-
'* *
NS .
**
NS
Shonupana
Cpmpana
Titan
. Bet zes
Normal
■
+
(mean)
+
**
+
+
**
* ..
Washonupana
Shonupana
Wapana
Compana
S h o r t awnnaked (mean)
Long awncov er e d (mean)
+
**
Washonupana
Compana
+
**
.
+ Sign o f t s t a t i s t i c i n p a i r e d t t e s t where normal i s o t y p e v a l u e s were
s u b t r a c t e d from m ut an t i s o t y p e v a l u e s . .
++ S .L . = S i g n i f i c a n c e l e v e l (one t a i l ) NS, * , .** d e n o t e n o n s i g n i f i c a n c e
and s i g n i f i c a n c e a t t h e P=O.05 arid P =0 .01 p r o b a b i l i t y l e v e l s ,
respectively.
60
Wapana and Compana d u r i n g k e r n e l m a t u r a t i o n ( F i g u r e s 2 and 4 ) .
A vail­
a b l e co m p ar iso n s d i d n o t p e r m i t t h e d e t e r m i n a t i o n o f w h e t h e r t h e
h i g h e r s p i k e m o i s t u r e s i n t h e s h o r t awn-naked i s o l i n e s were due t o
t h e naked gene o r t h e s h o r t awn g en e, o r b o t h .
Washonupana, c a r r y i n g
t h e waxy, s h o r t awn, and naked g e n e s , m a i n t a i n e d s i g n i f i c a n t l y h i g h e r
s p i k e m o i s t u r e t h a n Compana ( F i g u r e 2 and Ta bl e 4 ) .
The f a c t t h a t waxy endosperm and s h o r t awn-naked b a r l e y i s o t y p e s
m a i n t a i n e d h i g h e r l e v e l s o f s p i k e m o i s t u r e d u r i n g k er n el m a t u r a t i o n
t h a n d i d normal endosperm and long awn-covered i s o t y p e s , r e s p e c t i v e l y ,
i n d i c a t e s t h a t b a r l e y s c a r r y i n g t h e waxy gene a n d / o r t h e s h o r t awn
and naked genes may l a g in m a t u r i t y when compared t o b a r l e y s n o t
c a r r y in g th e s e genes.
D e f i n i n g h a r v e s t m a t u r i t y a s t h e p o i n t in
t i m e a t which m o i s t u r e i n t h e g r a i n f a l l s below 14%, a one t o two
day l a g i n m a t u r i t y c o u l d be e x p e c t e d i n waxy endosperm o r s h o r t awnnaked b a r l e y s .
A no the r e x p e r i m e n t showed a l l f o u r Compana i s o t y p e s
t o have s t a t i s t i c a l l y i d e n t i c a l h e ad i n g d a t e s (Experiment 3, Tabl e 11)
C o n s e q u e n t l y , i t can be assumed t h a t t h e p e r i o d from a n t h e s i s t o
h a r v e s t m a t u r i t y i s l o n g e r i n t h e waxy endosperm and s h o r t awn-naked
isotypes.
T h i s l a g i n m a t u r i t y coul d be due t o d i f f e r e n c e s i n d r y -
down r a t e s a l t h o u g h s p i k e m o i s t u r e d i f f e r e n c e s were a p p a r e n t d u r i n g
t h e g r a i n f i l l i n g p e r i o d ( g r e a t e r t h a n 40% m o i s t u r e ) ( F i g u r e s I and
4).
61
Kernel w e i g h t s d u r i n g m a t u r a t i o n
.
Kernel w e i g h t s o f normal i s o t y p e s grown a t Bozeman i n c r e a s e d . ,
r a p i d l y u n t i l p h y s i o l o g i c a l m a t u r i t y (40% m o i s t u r e ) and th e n s t a b i l ­
ized (Figure 5).
Kernel w e i g h t s o f s h o r t awn a n d / o r waxy endosperm
. is o ty p e s grown a t Bozeman c o n t i n u e d t o i n c r e a s e as m o i s t u r e c o n t e n t ..
d e c r e a s e d t o 30% o r l e s s ( F i g u r e s 5 , 7 , 10 ).
Growth p a t t e r n s
s i m i l a r t o t h o s e o f t h e normal i s o t y p e s grown a t Bozeman a r e r e p o r t e d
i n wheat and b a r l e y (MacGregor e t a l . , 1971; Riggs and G o t h a r d , 1976;
Gordon e t a l . ,
1979).
MacGregor e t a l . ,
(1971) showed t h a t t h e
m o i s t u r e c o n t e n t o f b a r l e y samples was a b o u t 40% 32 days a f t e r
anthesis.
They f u r t h e r showed t h a t mg d r y m a t t e r / k e r n e l , mg p r o t e i n /
k e r n e l , f a t , a s h , f i b e r , and mg s t a r c h / k e r n e l a l l i n c r e a s e d t o
some p o i n t n e a r 32 days a f t e r a n t h e s i s and the n l e v e l e d o r d e c r e a s e d
a s t h e g r a i n app ro ac he d m a t u r i t y .
Kernel w e i g h t s o f b a r l e y grown
a t H un tle y remained r e l a t i v e l y s t a b l e t h r o u g h o u t the p e r i o d o f
s am pl ing ( F i g u r e s 6 , 8 , 9, 11 ).
The l a c k o f i n c r e a s i n g k er n el
w e i g h t s d u r i n g t h e e a r l y sampl ing d a t e s a t Huntley i n d i c a t e t h a t
s am pl ing d i d n o t b eg in u n t i l a f t e r p h y s i o l o g i c a l m a t u r i t y (40%
m oisture).
T h i s s h o u ld be c o n s i d e r e d when i n t e r p r e t i n g d a t a from
Hu nt le y.
P a i r e d s t a t i s t i c a l com parisons o f waxy and n o r m a l , endosperm i s o ­
t y p e s r e v e a l e d t h a t w i t h t h e e x c e p t i o n o f Wabet and B e t z e s i n both
e n v i r o n m e n t s , and Watan arid T i t a n a t H u n t l e y , waxy endosperm
,
Kernel Weight - mg
62
Washonupana
Shonupana
Wapana
Compana
I Sp ik e M o ist u re
Figure 5.
Experiment 2. Kernel weights of four Compana isotypes
sampled 23 times (27 July - 23 September 1978) during
kernel maturation at Bozeman, Montana.
63
Kernel w e ig h t - mg
..""ZZ..
Washonupana
Shonupana
Wapana
Compana
8/7
Sampling Date
Figure 6.
Experiment 2. Kernel weights of four Compana isotypes
sampled 14 times (24 July - 22 August 1978) during kernel
maturation at Huntley, Montana.
64
Mean o f f o u r waxy
endosperm i s o t y p e s .
Mean o f f o u r normal
endosperm i s o t y p e s .
I Sp ik e M o is tu r e
Figure 7.
Experiment 2. Average kernel weights of four waxy and
four normal endosperm barley isotypes sampled 23 times
(27 July - 23 September 1978) during kernel maturation
at Bozeman, Montana.
Kernel w e i g h t - mg
65
Mean o f f o u r waxy endosperm
isotypes.
Mean o f f o u r normal endosperm
isotypes.
8/7
Sampling Date
Figure 8.
Experiment 2. Average kernel weights of four waxy and
four normal endosperm barley isotypes sampled 14 times
(24 July - 22 August 1978) during kernel maturation at
Huntley, Montana.
Kernel w e i g h t - mg
66
Wabet
Betzes
Sampling Date
Figure 9.
Experiment 2. Kernel weights of two Betzes isotypes
sampled 14 times (24 July - 22 August 1978) during
kernel maturation at Huntley, Montana.
Kernel Weight - mg
67
Mean o f two s h o r t awnnaked i s o t y p e s .
Mean o f two lo n g awncovered i s o t y p e s .
% Sp ik e M o ist u re
Figure 10.
Experiment 2. Average kernel weights of two short awnnaked and two long awn-covered Compana i sotypes sampled
23 times (27 July - 23 September 1978) during kernel
maturation at Bozeman, Montana.
68
Mean o f two s h o r t awn-naked i s o t y p e s .
" Mean o f two long awn-covered i s o t y p e s .
Sampling Date
Figure 11.
Experiment 2. Average kernel weights of two short awnnaked and two long awn-covered Compana isotypes sampled
14 times (24 July - 22 August 1978) during kernel
maturation at Huntley, Montana.
69
i s o t y p e s had s i g n i f i c a n t l y s m a l l e r k e r n e l w e i g h t s t h a n normal
endosperm i s o t y p e s (Tab le 5 ) .
Wabet had lo w er , though n o n s i g n i f i c a n t
k e r n e l w e i g h t s a t Bozeman b u t s i g n i f i c a n t l y h i g h e r k e r n e l w e i g h t s
th a n B e t z e s a t H u nt le y ( F i g u r e 9) t h r o u g h k er n el m a t u r a t i o n .
Normal endosperm i s o t y p e s had s i g n i f i c a n t l y l a r g e r k e r n e l w e ig h t s
t h a n waxy endosperm i s o t y p e s when a n a l y s e s were e x t en d ed o v e r e n v i r o n
ments e x c e p t f o r t h e Wabet-Betzes comparison (Table 5 ) .
Mean kernel
w e i g h t s d u r i n g m a t u r a t i o n were lo w er i n t h e waxy endosperm l i n e s a t
Bozeman ( F i g u r e 7 ) , H un tle y ( F i g u r e 8 ) , and a c r o s s e n v i r o n m e n t s .
I t can be con cl ud ed t h a t k e r n e l w e i g h t s a r e s m a l l e r i n waxy th a n
in normal endosperm i s o t y p e s a t s i m i l a r m a t u r i t y s t a g e s .
The f a c t
t h a t Wabet had a s i g n i f i c a n t l y g r e a t e r k e r n e l w ei g h t t h a n Be tz es
a t H unt le y c a n n o t be e x p l a i n e d .
A l a t e r ex p e r i m e n t showed t h a t
Wabet, grown a t Bozeman, had a s i g n i f i c a n t l y s m a l l e r k e r n e l w ei g h t
t h a n B e t z e s , and t h a t normal endosperm i s o t y p e s , in t h e same f o u r
i s o g e n i c p a i r s , had k e r n e l w e i g h t s 1 . 0 0 - 4 . 1 4 mg/kernel g r e a t e r
t h a n t h e waxy endosperm i s o t y p e s a t h a r v e s t m a t u r i t y (Exp eri men t 3,
T ab l e 1 1 ) .
S t a t i s t i c a l a n a l y s e s on t h e Compana i s o l i n e s showed s h o r t awnnaked i s o t y p e s had s i g n i f i c a n t l y s m a l l e r ke rn el w e i g h t s t h a n long
awn-covered i s o t y p e s i n each and a c r o s s both e n v ir o n m en ts (Table 5 ) .
E s l i c k (1979) r e p o r t e d an a v e r a g e y i e l d l o s s o f 12% f o r naked
i s o t y p e s i n r e p l i c a t e d y i e l d t r i a l s o v e r 149 en v i ro n m en ts and t h a t
,
T a b l e 5.
Ex per im ent 2.
S t a t i s t i c a l a n a l y s i s u s i n g a p a i r e d t t e s t o f k er n el
weight during kernel m atu ratio n f o r e i g h t b a rle y l i n e s
i s o g e n i c f o r waxy and normal endosperm a t Bozeman and
H u n t l e y , Montana, 1978. ____________ ■
____________
Bozeman
22 d f ,
Compari son
Mutant
isotype
. N o rm al .
isotype
Washonupana
Wapana
Watan .
Wabet
Shonupana
. Cbmpana
Titan
Betzes
sign
of t
s i gn
o f t"f . S.L.
Waxy (mean)
Normal
WaShonupana
Shonupana
Wapana
Compana
S h o r t awnnaked (mean)
Long awnc o v e r e d (mean)
,**
** .
*
NS
-
(mean)
.
-
**
**
-
**
-
Across e n v i r o n m e n ts
36 d f
S.L.
**
. .**
NS
.**'
_
4.
**
-
H u n tl e y
13 d f
■ s ig n
of t
S.L.
+
**
** .
*
NS
**
-
**
**
**
-
**
. **
**
_
**
**
_
**
:
.
-
Washonupana
Compana
-
**
Sign o f t s t a t i s t i c i n p a i r e d t t e s t where normal i s o t y p e v a l u e s were s u b t r a c t e d .
from m u ta n t i s o t y p e v a l u e s . .
.
S .L . = S i g n i f i c a n c e l e v e l (one t a i l ) NS, * , ** d e n o t e n o n s i g n i f i c a n c e and s i g n i f i ­
ca n ce a t t h e P=O.05 and P=0. 01 p r o b a b i l i t y l e v e l s , r e s p e c t i v e l y - .
s h o r t awn i s o t y p e s have s m a l l e r k e r n e l s t h a n long awn i s o t y p e s .
Thus i t would be e x p e c t e d t h a t s h o r t awn-naked i s o t y p e s would have
lo w er k e r n e l w e i g h t s t h a n long awn-covered i s b t y p e s .
Long awn-
cov er e d i s o t y p e s had k e r n e l w e i g h t s 4 - 5 mg/kernel h i g h e r d u r i n g
k e r n e l m a t u r a t i o n t h a n s h o r t awn-naked i s o t y p e s a t Huntley ( F i g u r e s
6 and 1 1 ) .
At Bozeman, d i f f e r e n c e s i n k e r n e l w e i g h t s between
Cpmpana i s o l i n e s f i r s t a p p e a r e d when s p i k e m o i s t u r e was i n t h e 50-55%
r an g e ( F i g u r e 5 ) .
During t h e dry-down p e r i o d from 50% t o 10% s p i k e
m o i s t u r e a t Bozeman k er n el w e i g h t s o f long awn-covered Compana
i s o t y p e s remained a b o u t 10 mg /k er ne l g r e a t e r th a n in t h e s h o r t
a w n - n a k e d . i s o t y p e s . ( F i g u r e TO).
Germinative c a p a c ity during m a tu ratio n
The p a t t e r n s o f development f o r g er m in a t i v e c a p a c i t y ( F i g u r e s
12 and 13) a r e s i m i l a r t o t h o s e r e p o r t e d in t h e l i t e r a t u r e
( W e l l i n g t o n , 1964; Gordon, 1970; LaBerge e t a l . , 1971; Gordon e t a l . ,
1979; M i t c h e l l e t a l . , 1980).
These p a t t e r n s o f dev el o p m en t,
however, ap p r o x im at e o n l y t h e l a t e r p o r t i o n s o f p r e v i o u s l y r e p o r t e d
patterns.
G e r m in a ti v e c a p a c i t y , d e f i n e d i n t h i s e x p e r i m e n t a s th e
t o t a l p e r c e n t a g e o f k e r n e l s a b l e t o g e r m i n a t e in t h e a b s e n c e o f
dormancy, te n d e d t o be much h i g h e r d u r i n g t h e e a r l i e r s t a g e s o f
k e r n e l devel opment th a n had been p r e v i o u s l y been r e p o r t e d .
Th is
d i s c r e p a n c y may have been due t o a d i f f e r e n c e in t e c h n i q u e s i n c e i t
was r e p o r t e d t h a t a i r d r y i n g o f immature g r a i n i n c r e a s e d g e r m i n a b i T i t y
% G e r m in a ti v e C a p a c i t y
72
Wabet
Betzes
% Sp ike M o is tu r e
F ig u r e 12.
Experiment 2. G er m in a tiv e c a p a c i t y o f two Bet zes i s o ­
t y p e s sampled 23 t i m e s (27 J u l y - 23 September 1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
73
KXU
>>
-M
U
fO
CL
<T3
O
90,
<D
>
Mean o f two s h o r t awn-naked
isotypes.
-M
fO
C
E
<u
Mean o f two long awn-covered
isotypes.
CD
85.
80
5&
4«
si
J)
I t
I
% Spike M o is tu r e
Figure 13.
Experiment 2. Average germinative capacity of two short
awn-naked and two long awn-covered Compana isotypes
sampled 23 times (27 July - 23 September 1978) during
kernel maturation at Bozeman, Montana.
74
( M i t c h e l l e t a l . , 1980).
In g e n e r a l , g erm in a t i v e c a p a c i t y was s i m i l a r f o r waxy and normal
endosperm b a r l e y i s o t y p e s .
All i s o g e n i c comparisons made in t h e
Bozeman en v iro n m en t e x c e p t f o r Wabet and Bet zes showed no s i g n i f i c a n t
d i f f e r e n c e s i n p a t t e r n s o f g e r m i n a t i v e c a p a c i t y between waxy and
normal endosperm i s o t y p e s (Table 6 ) .
Wabet had a s l i g h t l y g r e a t e r
g er m in a t i v e c a p a c i t y a t Bozeman ( F i g u r e 12 ).
At H u n tle y a l l d i f f e r ­
ence s between waxy and normal endosperm i s o g e n i c p a i r s were non­
s i g n i f i c a n t e x c e p t f o r Watan and T i t a n .
i n ger mi n a t i v e c a p a c i t y t h a n T i t a n .
Watan was s i g n i f i c a n t l y lower
Across env iro nm en ts and g e n e t i c
backgrounds a l l d i f f e r e n c e s between waxy and normal endosperm
i s o t y p e s were, n o n s i g n i f i c a n t (Tab le 6 ) .
In a l l c a s e s s h o r t awn-naked Compana i s o l i n e s were h i g h e r in
g e r m i n a t i v e c a p a c i t y t h a n long awn-covered Compana i s o l i n e s
(Table.6).
T h i s r e l a t i o n s h i p was, however, s t a t i s t i c a l l y s i g n i f i c a n t o n l y f o r
t h e Washpnupana-Wapana comparison a t Bozeman and a c r o s s en vi ron m ent s
and f o r t h e means o f t h e s h o r t awn-naked and long awn-covered i s o t y p e s
a t Bozeman ( F i g u r e 13) and a c r o s s e n v i r o n m e n t s .
Washonupana had a
s i g n i f i c a n t l y g r e a t e r g e r m i n a t i v e c a p a c i t y th a n Compana a t Bozeman .
b u t n o t a t HuntTeyi
Dormancy d u r i n g m a t u r a t i o n
The g e n e r a l p a t t e r n s o f dormancy d u r i n g k e r n e l . m a t u r a t i o n a t
Bozeman ( F i g u r e s 14, 16, 18) showed dormancy i n c r e a s e d d u r i n g t h e
T a b l e 6.
Experiment 2.
S t a t i s t i c a l a n a l y s i s u s in g a p a i r e d t t e s t o f g e r m i n a t i ve
c a p a c ity during kernel m atu ratio n fo r e ig h t barle y l i n e s
i s o g e n i c f o r waxy and normal endosperm a t Bozeman and .
H u n t l e y , Montana, 1978.
Bdzeman
22 d f
Compari son
H unt le y
13 d f
sign
o f f ""
S . L . ++
sign
of t
Shonupana
Compana
Titan
Betzes
+
NS
NS
NS.
*
+
+
.. -
NS
. NS
*
Waxy (mean)
Normal
+
NS
+
NS
Washonupana
Shbnupana
Wapana
Compana
+
+
*
NS
.+
+
S h o r t awnnaked (mean)
Long awnc o v e r e d (mean)
+
*
+
Washonupana
Compana
+
*
+
Mutant
isbtype
Normal
isotype
Washonupana
Wapana
Watan
Wabet
(mean)
.
.
S.L.
Across e n v i ro n m e n ts
, 36 d f
. sign
of t
+ ■
+
+
NS.
NS
*
*
+
NS .
NS
NS
+
+
*
NS
NS
+
*
NS
+
*
. NS
.
S.L.
,
V
+
Sign o f t s t a t i s t i c i n p a i r e d t t e s t where normal i s o t y p e v a l u e s were s u b t r a c t e d
from m u t a n t i s o t y p e v a l u e s .
++ S . L. = S i g n i f i c a n c e l e v e l (one t a i l ) NS, *, ** d e n o t e n o n s i g n i f i c a n c e and s i g n i f i ­
canc e a t t h e P=O.05 and P=Q.01 p r o b a b i l i t y l e v e l s , r e s p e c t i v e l y .
76
p e r i o d s h o r t l y a f t e r a n t h e s i s u n t i l p h y s i o l o g i c a l m a t u r i t y (40%
m o i s t u r e ) , p eak ed , th e n d e c r e a s e d s t e a d i l y w i t h i n c r e a s i n g m a t u r i t y .
.
C o n s i d e r i n g dormancy p a t t e r n s d u r in g , k e r n e l development and m a tu r a ­
t i o n t o be e s s e n t i a l l y t h e i n v e r s e o f g er m in a t i v e e n e r g y devel op mental
p a t t e r n s , t h i s e x p e r i m e n t s u p p o r t s B i s h o p ' s i n t e r p r e t a t i o n o f ca r m in ­
a t i v e power o f b a r l e y a t d i f f e r e n t m a t u r i t y s t a g e s ( B is h o p , 1944).
B i s h o p ' s i n t e r p r e t a t i o n showed l i t t l e dormancy a t t h e m i l k s t a g e ,
i n c r e a s i n g dormancy u n t i l n e a r p h y s i o l o g i c a l m a t u r i t y , t h e n a p r o g r e s s i v e dormancy d e c l i n e w i t h m a t u r i t y .
.
T h i s e x p e r i m e n t d i d no t
s u p p o r t G o r d o n 's i n t e r p r e t a t i o n o f e a r l i e r work t o change B i s h o p ' s
c u r v e s o f g e r m i n a t i v e power a t d i f f e r e n t m a t u r i t y s t a g e s (Gordon,
1970).
Gordon s u g g e s t e d t h a t g e r m i n a t i v e en er g y remained n e a r ze r o
u n t i l p h y s i o l o g i c a l m a t u r i t y , th e n i n c r e a s e d r a p i d l y t o m a t u r i t y .
Dormancy devel op men ta l p a t t e r n s i n t h e Hun tley en v iro nm ent ( F i g u r e s
T5, 17, 19) showed dormancy d e c l i n e d s t e a d i l y .
Th is i s a d d i t i o n a l
e v i d e n c e t h a t sampl ing a t H un tle y began a f t e r p h y s i o l o g i c a l m a t u r i t y .
I s o g e n i c a n a l y s e s o f dormancy d u r i n g k e r n e l m a t u r a t i o n (Table 7)
showed dormancy was s i g n i f i c a n t l y low er i n waxy endosperm i s o t y p e s
th a n i n normal endosperm i s o t y p e s when a v e r a g e d a c r o s s g e n e t i c back­
grounds and t a k e n a c r o s s en v i r o n m e n ts .
Waxy endosperm i s o t y p e s i n t h e
Compana background b u t n o t i n t h e T i t a n and Bet zes bac kgrounds were
s i g n i f i c a n t l y low er i n dormancy in and a c r o s s both e n v i ro n m e n ts th a n
normal endosperm i s o t y p e s (Table 7 ) .
Major dormancy d i f f e r e n c e s . .
77
Mean o f f o u r waxy endosperm
isotypes.
% Dormancy
Mean o f f o u r normal endosperm
isotypes.
F i g u r e 14.
% Spike M o is tu r e
Experiment 2. Average dormancy o f f o u r waxy and f o u r normal
endosperm b a r l e y i s o t y p e s sampled 23 ti m es (27 J u l y 23 September 1978) d u r i n g k er n el m a t u r a t i o n a t Bozeman,
Montana.
78
Mean o f f o u r waxy endosperm
isotypes.
% Dormancy
Mean o f f o u r normal endosperm
isotypes.
8 /7
Sampling Date
F i g u r e 15.
Experiment 2. Average dormancy o f f o u r waxy and f o u r
normal endosperm b a r l e y i s o t y p e s sampled 14 t i m e s
(24 J u l y - 22 August 1978) d u r i n g ke rn el m a t u r a t i o n
a t H u n t l e y , Montana.
79
Washonupana
Shonupana
Wapana
% Dormancy
Compana
% Spike M o is tu r e
F i g u r e 16.
Experiment 2. Dormancy o f f o u r Compana i s o t y p e s sampled
23 ti me s (27 J u l y - 23 September 1978) d u r i n g ke rn el m a t u r ­
a t i o n a t Bozeman, Montana.
80
"" Washonupana
Shonupana
Wapana
•i Compana
S a m p l i n g
F ig u r e 17.
Experiment 2.
D a t e
Dormancy o f f o u r Compana i s o t y p e s sampled
14 ti m es (24 J u l y - 22 August 1978)
during kernel m aturation a t Huntley,
Montana.
81
Mean o f two s h o r t awnnaked i s o t y p e s .
Dormancy
Mean o f two long awncove re d i s o t y p e s .
Io Sp ik e M o ist u re
Figure 18.
Experiment 2. Average dormancy of two short awn-naked
and two long awn-covered Compana isotypes sampled 23
times (27 July - 23 September 1978) during kernel
maturation at Bozeman, Montana.
82
% Dormancy
Mean o f two s h o r t awn-naked
i sotypes .
Mean o f two long awn-covered
isotypes.
Sampling Date
Figure 19.
Experiment 2. Average dormancy of two short awn-naked
and two long awn-covered Compana isotypes sampled 14
times (24 July - 22 August 1978) during kernel maturation
at Huntley, Montana.
T a b l e 7.
Experi ment 2.
S t a t i s t i c a l a n a l y s i s u s i n g a p a i r e d t t e s t o f dormancy d u r i n g
k e r n e l m a t u r a t i o n f o r e i g h t b a r l e y l i n e s i s o g e n i c f o r waxy
and normal endosperm a t Bozeman and HUntle y , Montana, 1978.
Bozeman
22 d f
Compari son
H u n tle y
13 d f
Mutant
isotvoe
Normal
isotype
sign
of t +
Washonupana
Wapana
Watan.
Wabet
Shonupana
Compana
Titan
Betzes
+
**
**
NS
NS
+
*
**
NS
NS
Waxy (mean)
Normal
-
**
-
Washonupana
Shonupana
Wapana
Compana
—
**
**
S h o r t awnnaked (mean)
Long awnc o v e r e d (mean)
-
**
Washonupana
Compana
-
**
+
++ ’
(mean)
sign
of t
S . L . ++
s ig n
o ft
S.L.
._
S.L.
+ .
**
**
NS
NS
**
_
**.
—
-
NS
**
-
**
**
-
**
**
-
**
**
—
-
Across e n v i ronments
36 d f
.
.
'
Sign o f t s t a t i s t i c i n p a i r e d t t e s t where normal i s o t y p e v a l u e s were s u b t r a c t e d
from m u t a n t i s o t y p e v a l u e s .
S.L . = S i g n i f i c a n c e l e v e l (one t a i l ) NS., *, ** d e n o t e n o n s i g n i f i c a n c e and s i g n i f i ­
can c e a t t h e P=O.05 and R=0.01 p r o b a b i l i t y l e v e l s , r e s p e c t i v e l y .
84
between waxy and normal endosperm i s o t y p e s were f i r s t o b s e r v e d when
s p i k e m o i s t u r e was n e a r 45% a t Bozeman ( F i g u r e s 14 and 1 6 ) .
At
H u n t l e y , dormancy d i f f e r e n c e s between waxy and normal endosperm i s o ­
t y p e s were a p p a r e n t t h r o u g h o u t sampl ing b u t were small a t h a r v e s t
m a t u r i t y ( F i g u r e 15 and 17).
S h o r t awn-naked Compana i s o t y p e s e x h i b i t e d s i g n i f i c a n t l y l e s s
dormancy in a l l b u t one comparison t h a n long, awn-covered Compana
i s o t y p e s (Tab le 7 ) .
T h i s r e l a t i o n s h i p h e l d t r u e a c r o s s env iro nm ent s
and when a v e r a g e d a c r o s s i s o t y p e s a t ea ch envi ron me nt ( F i g u r e s 18
and 19 ) .
Although t h e e f f e c t s o f t h e s h o r t awn and naked genes
c o u l d n o t be s e p a r a t e d i n t h i s e x p e r i m e n t , i t i s p r o b a b l e t h a t t h e
l e s s e r dormancy i n t h e s h o r t awn-naked i s o t y p e s was caus ed by t h e
naked c h a r a c t e r .
Numerous r e s e a r c h e r s have r e p o r t e d t h a t t h e dormancy
mechanism i n wheat and b a r l e y i s a t l e a s t p a r t i a l l y c o n t r o l l e d by t h e
surface layers of the k e rn e l.
Dormancy i s a r e s u l t o f t h e i n t e r n a l
l e v e l o f f r e e oxygen a t t h e embryo ( P o l l o c k , 1962; B e l d e r o k , 1968;
B r i g g s , 1978) a n d / o r a f u n c t i o n o f g r a i n d e h y d r a t i o n d u r i n g k er n el
m a t u r a t i o n ( W e l l i n g t o n , 1964; Gordon, 1970; Gordon e t a l . , 1979;
M i t c h e l l e t a l . , 1980).
Whatever t h e dormancy mechanism, t h e p e r i ­
c a r p in naked i s o t y p e s would be a l e s s e r b a r r i e r t o oxygen u p ta ke
a n d / o r g r a i n d e s s i c a t i o n t h a n t h e t e s t a - p e r i c a r p s u r f a c e l a y e r s in
cov er e d b a r l e y i s o t y p e s .
85
G er m in a ti o n speed d u r i n g m a t u r a t i o n
Speed o f g e r m i n a t i o n o f seed h a r v e s t e d a t d i f f e r e n t . s t a g e s o f
k e r n e l devel opment g e n e r a l l y i n c r e a s e d w i t h i n c r e a s i n g k e r n e l m a t u r i t y
(Figures 20-26).
R e p r e s s i o n o f g e r m i n a t i o n speed may be c o n s i d e r e d
a n o t h e r form o f dormancy (Gordon, 1969).
S t a t i s t i c a l analyses in d i­
c a t e d t h a t g e r m i n a t i o n speed d u r i n g k e r n e l m a t u r a t i o n was s t r o n g l y
i n f l u e n c e d by en vi ro nm en t and g e n e t i c background (Table 8 ) .
Germina­
t i o n speed d i f f e r e n c e s between waxy and normal endosperm i s o t y p e s
were i n c o n s i s t e n t .
Mean g e r m i n a t i o n speed o f waxy endosperm i s o t y p e s
d u r i n g k e r n e l m a t u r a t i o n was s i g n i f i c a n t l y s lo w er a t Bozeman and
s i g n i f i c a n t l y f a s t e r a t H un tle y th a n t h e mean g e r m i n a t i o n speed o f
normal endosperm i s o t y p e s (Tab le 8 ) .
Mean g e r m i n a t i o n speed
d i f f e r e n c e s between waxy and normal endosperm i s o t y p e s were i n c o n s i s ­
t e n t a t Bozeman ( F i g u r e 20) b u t more c o n s i s t e n t a t H un tle y ( F i g u r e 21)
Wapana g e r m i n a te d f a s t e r t h a n Compana in b o th en vi ron m ent s ( F i g u r e s
22 and 23 ) .
Washonupana g er m i n a te d s i g n i f i c a n t l y f a s t e r th a n
Shonupana a t H u nt le y b u t n o t Bozeman (Tab le 8 ) .
T i t a n g er m i n a te d
f a s t e r th a n Watan d u r i n g k er n el m a t u r a t i o n a t Bozeman ( F i g u r e 24)
.
e s p e c i a l l y w i t h i n t h e p e r i o d when s p i k e m o i s t u r e dropped from 30% t o
10%.
S h o r t awn-naked Compana i s o t y p e s , w i t h o u t e x c e p t i o n , g er m i n a te d
s i g n i f i c a n t l y f a s t e r t h a n long awn-covered Compana i s o t y p e s (Table 8 ) .
Washonupana and Shonupana g e r m in at e d f a s t e r th a n Wapana and Compana,
86
Mean o f f o u r normal endosperm i s o t y p e s .
G e r m in a ti o n Speed Index
( ^ ^ r m i n a i o n day 7 x 10t»
Mean o f f o u r waxy endosperm i s o t y p e s .
% Spike M o is tu r e
Figure 20.
Experiment 2. Average germination speed of four waxy and
four normal endosperm barley i sotypes sampled 23 times
(27 July-23 September 1978) during kernel maturation at
Bozeman, Montana.
87
Mean o f f o u r waxy endosperm
isotypes.
Mean o f f o u r normal endosperm
i sotypes .
8 /7
Sampling d a t e
Figure 21.
Experiment 2. Average germination speed of four waxy
and four normal endosperm barley isotypes sampled 14
times (24 July - 22 August 1978) during kernel maturation
at Huntley, Montana.
88
Washonupana
Shonupana
Wapana
Compana
I Spike M o ist u re
Figure 22.
Experiment 2. Germination speed of four Compana isotypes
sampled 23 times (27 July - 23 September 1978) during
kernel maturation at Bozeman, Montana.
89
Washonupana
Shonupana
Wapana
Compana
8/7
Sampling Date
Figure 23.
Experiment 2. Germination speed of four Compana isotypes
sampled 14 times (24 July - 22 August 1978) during kernel
maturation at Huntley, Montana.
G er m in a ti o n Speed Index ( |
^
^ , lo o)
90
Watan
i. T i t a n
Sp ik e Mo ist ur e
Figure 24.
Experiment 2. Germination speed of two Titan isotypes
sampled 23 times (27 July - 23 September 1978) during
kernel maturation at Bozeman, Montana.
91
Mean o f two s h o r t awn-naked i s o t y p e s .
G er m in a ti o n Speed Index ( ^ . g e r m i n a t i o n day 3
Mean o f two long awn-covered i s o t y p e s .
% Spike M o is tu r e
Figure 25.
Experiment 2. Average germination speed of two short awnnaked and two long awn-covered Compana isotypes sampled
23 times (27 July - 23 September 1978) during kernel
maturation at Bozeman, Montana.
G er m in a ti o n Speed Index ( |
^
^
xlOO)
92
Mean o f two s h o r t awnnaked i s o t y p e s .
Mean o f two long awncovere d i s o t y p e s .
8 /7
Sampling
F ig u r e 26.
Date
Experiment 2. Average g e r m i n a t i o n speed o f two s h o r t
awn-naked and two long awn-covered Compana i s o t y p e s
sampled 14 ti m es (24 J u l y - 22 August 1978) d u r i n g
k er n el m a t u r a t i o n a t H u n t l e y , Montana.
T a b l e 8.
Experiment 2.
S t a t i s t i c a l , a n a l y s i s using a paire d t t e s t o f germination
speed d u r i n g k e r n e l m a t u r a t i o n f o r e i g h t b a r l e y l i n e s
i s o g e n i c f o r waxy and normal endosperm a t Bozeman and
H u n t l e y , Montana, 1,978.
Bozeman
22 d f
Compari son
Mutant
i sotvoe
Normal
isotype
sign
o f t"f
Washonupana
Wapana '
Watan
Wabet
Shonupana
Compana
Titan
Betzes
- .
+
Waxy (mean)
Normal
Washonupana
Shonupana
S . L. ++
H un tle y
13 df.
sign
of t
Across e n v i r o n m e n t s
36 d f
Si.L.
s ig n
of t
S.L.
+
+
+
*
**
NS
NS
+
**
NS
*
+
**
+
NS
+
+
**
**
+
+
*
**
+
+
**
**
Long awnc o v e r e d (mean)
+
**
+
**
.+
**
Compana
+
**
+
**
+
**
+
+
+
NS
**
**
• NS
-
Wapana
Compana
S h o r t awnnaked (mean)
Washonupana
(mean)
-
-
-
NS
irk
Sign o f t s t a t i s t i c i n p a i r e d t t e s t where normal i s o t y p e v a l u e s were s u b t r a c t e d
from m ut an t i s o t y p e v a l u e s .
S.L . = S i g n i f i c a n c e l e v e l (one t a i l ) NS, * , ** d e n o t e n o n s i g n i f i c a n c e and s i g n i f i ­
canc e a t t h e P=O.05 and P =0 .01 p r o b a b i l i t y l e v e l s , r e s p e c t i v e l y .
94
r e s p e c t i v e l y , d u r i n g k e r n e l m a t u r a t i o n a t both l o c a t i o n s ( F i g u r e s
22 and 23) and when av e r a g e d a t each l o c a t i o n ( F i g u r e s 25 and 26 ).
Naked b a r l e y s may g e r m i n a t e f a s t e r t h a n covered b a r l e y s b e c a u s e o f a
f a s t e r r a t e o f w a t e r i m b i b i t i o n ( B r i g g s , 1978) o r , i f r e p r e s s i o n o f
g e r m i n a t i o n speed i £ a form o f dormancy, by a l e s s e r d e g r e e o f
dormancy i n naked b a r l e y s as p r e v i o u s l y d i s c u s s e d .
Ulonska and
Baumer (1976) in a s t u d y o f 14 s p r i n g b a r l e y c u l t i v a r s grown i n two
e n v i ro n m e n ts r e p o r t e d N a c k t a , a naked c u l t i v a r , had t h e h i g h e s t germ­
i n a t i o n speed o v e r s i x days g e r m i n a t i o n and 11 d i f f e r e n t s t e e p i n g
tim es.
I t would a p p e a r t h a t h u l l t y p e has t h e s t r o n g e s t i n f l u e n c e on
speed o f g e r m i n a t i o n a l t h o u g h endosperm t y p e , g e n e t i c bac kground,
e n v i r o n m e n t , and t h e i r i n t e r a c t i o n s may have a l e s s e r i n f l u e n c e .
A lp h a-a m yl as e a c t i v i t y d u r i n g m a t u r a t i o n
I
1
P a t t e r n s o f a l p h a - a m y l a s e a c t i v i t y d u r i n g k er n el m a t u r a t i o n
( F i g u r e s 27 and 28) a r e s i m i l a r t o t h o s e r e p o r t e d i n t h e l i t e r a t u r e
i n which a l p h a - a m y l a s e a c t i v i t y peaked s h o r t l y a f t e r a n t h e s i s (4 t o
30 days p o s t a n t h e s i s ) t h e n d e c l i n e d t o low s t a b l e l e v e l s u n t i l
m a t u r i t y ( D u f fu s , 1969; LaBerge e t a l . , 1971; MacGregor e t a l . , 1971;
MacGregor e t a l . , 1972; Al I i son e t a l . ,
1976; Gordon, 1980).
1974; Riggs and G o t h a r d ,
Sampling i n t h i s ex p e r i m e n t began a t Bozeman
s h o r t l y a f t e r a n t h e s i s d u r i n g t h e p e r i o d when a l p h a - a m y l a s e a c t i v i t y
was d e c r e a s i n g r a p i d l y .
Samples o b t a i n e d n e a r h a r v e s t m a t u r i t y
(10-20% m o i s t u r e ) showed i n c r e a s e d a l p h a - a m y l a s e a c t i v i t y i n r e s p o n s e
A lp h a-a m yl as e A c t i v i t y ( I o g 10 ng dye r e l e a s e / m i n u t e / k e r n e l )
95
Mean o f f o u r waxy endosperm
isotypes.
Mean o f f o u r normal endosperm
isotypes.
Spike M o is tu re
F ig u r e 27.
Experiment 2. Average a l p h a - a m y l a s e a c t i v i t y o f f o u r
waxy and f o u r normal endosperm b a r l e y i s o t y p e s sampled
23 ti m es (27 J u l y - 23 September 1978) d u r i n g kern el
m a t u r a t i o n a t Bozeman, Montana.
A lp h a- am yl as e A c t i v i t y ( I o g l n ng dye r e l e a s e / m i n u t e / k e r n e l )
96
Washonupana
Shonupana
% Spike M o is tu r e
F i g u r e 28.
Experiment 2. A lph a-a m yla se a c t i v i t y o f two Compana
i s o t y p e s sampled 23 t i m e s (27 J u l y - 23 September 1978)
d u r i n g k e r n e l m a t u r a t i o n a t Bozeman, Montana.
97
t o r a i n s i m i l a r t o t h a t p r e v i o u s l y r e p o r t e d (LaBerge e t a l . , 1971).
S t a t i s t i c a l an alyses of alpha-amylase a c t i v i t y during kernel
m a t u r a t i o n showed waxy endosperm i s o t y p e s had g r e a t e r a l p h a - a m y l a s e
a c t i v i t y t h a n normal endosperm i s o t y p e s , a l t h o u g h most o f t e n t h e
d i f f e r e n c e s were n o t s i g n i f i c a n t (Table 9 ) .
Mean a l p h a - a m y l a s e
a c t i v i t y was g r e a t e r i n waxy endosperm t y p e s a t Bozeman ( F i g u r e 27)
b u t n o t a t H u n tle y.
Washonupana e x h i b i t e d g r e a t e r a l p h a - a m y l a s e
a c t i v i t y t h a n Shonupana a t Bozeman ( F i g u r e 2 8 ) .
Goering and E s l i c k
(1976) r e p o r t e d t h a t t h e same c u l t i v a r , Washonupana, grown i n one
e n v i r o n m e n t , r e t a i n e d s u f f i c i e n t a l p h a - a m y l a s e - l i k e a c t i v i t y on i t s
s t a r c h g r a n u l e s t o l i q u i f y n o t o n ly i t s e l f b u t f o u r t i m e s i t s w ei g h t
in e i t h e r waxy o r normal un modified co r n s t a r c h when h e a t e d i n t h e
Brabender amylograph.
All a l p h a - a m y l a s e a c t i v i t y d i f f e r e n c e s between
waxy and normal endosperm i s o t y p e s a t Hun tley were n o n s i g n i f i c a n t
(Tab le 9 ) .
Kernel m a t u r i t y a t H u n tl e y , as d e t e r m in e d by k er n el
w e i g h t s and dormancy l e v e l s , was advanced well p a s t t h e s t a g e o f
p h y s i o l o g i c a l m a t u r i t y when sampling began.
Riggs and Gothard (1976)
s t u d i e d a l p h a - a m y l a s e a c t i v i t y i n seven b a r l e y c u l t i v a r s and showed
t h a t , although s i g n i f i c a n t alpha-amylase a c t i v i t y d if f e r e n c e s e x iste d
between c u l t i v a r s from a n t h e s i s t o 31 days p o s t a n t h e s i s , a l l c u l t i ­
v a r d i f f e r e n c e s had d i s a p p e a r e d by 31 days a f t e r a n t h e s i s .
Thus, we
c o u l d assume t h a t any a l p h a - a m y l a s e a c t i v i t y d i f f e r e n c e s , i f p r e s e n t .
T a b l e 9.
Experiment 2.
S t a t i s t i c a l a n a l y s i s using a paired t t e s t o f alpha-amylase
a c t i v i t y during kernel m aturation f o r e i g h t b a rle y l i n e s
i s o g e n i c f o r waxy and normal endosperm a t Bozeman and
H u n t l e y , Montana, 1978.
Bozeman
22 d f
Compari son
sign
of t f
H u n tle y
13 d f
sign
of t
s ig n
of t
+
NS
NS
NS
NS
+
+
+
+
*
*
NS
*
+
NS
+
**
NS
NS
—
NS
NS
_
Normal
i sotype
Washonupana
Wapana
Watan
Wabet
Shonupana
Compana
Titan
Betzes
+
+
+
+
**
NS
NS
NS
+
+
Waxy (mean)
Normal
+
**
Washonupana
Shonupana
Wapana
Compana
-
S h o r t awn. naked (mean)
Washonupana
-
Across en v i ro n m en ts
36 d f
S.L.
Mutant
isotype
(mean)
•
S . L . ++
-
-
Long awnc o ve r e d (mean)
-
NS
_
NS
Compana
+
NS
-
NS
-
S.L.
NS
*
NS
+
■ NS
Sign o f t s t a t i s t i c in p a i r e d t t e s t where normal i s o t y p e v a l u e s were s u b t r a c t e d
from m ut an t i s o t y p e v a l u e s .
S.L . = S i g n i f i c a n c e l e v e l (one t a i l ) NS, *, ** d e n o t e n o n s i g n i f i c a n c e and s i g n i f i ­
can c e a t t h e P=O..05 and P =0 .01 p r o b a b i l i t y l e v e l s , r e s p e c t i v e l y .
/
99
were missed a t H un tle y b ec a u se o f t h e m a t u r i t y s t a g e d u r i n g sampling.
Even though d i f f e r e n c e s , i n a l p h a - a m y l a s e a c t i v i t y a t H un tle y were
s m a l l , waxy endosperm i s o t y p e s e x h i b i t e d s i g n i f i c a n t l y g r e a t e r a l p h a amylase a c t i v i t y , w i t h one e x c e p t i o n , th a n normal endosperm i s o t y p e s
when a n a l y s e s were e x t e n d e d a c r o s s both e n v ir o n m en ts ( Ta bl e 9 ) .
S h o r t awn-naked Compana i s o t y p e s and long awn-covered Compaha i s o t y p e s
did not vary s i g n i f i c a n t l y f o r alpha-amylase during kernel m aturation
(Table 9 ) .
Tt would a p p e a r h u ll t y p e has a n e g l i g i b l e e f f e c t oh
a l p h a - a m y l a s e a c t i v i t y w h i l e endosperm t y p e has a small b u t o f t e n
s i g n i f i c a n t e f f e c t on a l p h a - a m y l a s e a c t i v i t y .
Summary
The waxy endosperm i s o t y p e i n t h e Be tz es b ac kg ro un d, Wabet,
had a s i g n i f i c a n t l y g r e a t e r g e r m i n a t i v e c a p a c i t y and a l p h a - a m y l a s e
a c t i v i t y during kernel m aturation than B etzes.
Wabet and Betzes d id
not d i f f e r during kernel m aturation f o r spike m o istu re, kernel weight,
dormancy, o r g e r m i n a t i o n sp eed .
The waxy and normal endosperm i s o t y p e s
i n t h e T i t a n background d i d n o t d i f f e r f o r dormancy o r f o r a l p h a am ylase a c t i v i t y .
Watan has s i g n i f i c a n t l y h i g h e r l e v e l s o f s p i k e
m o i s t u r e , and was s i g n i f i c a n t l y low er i n ke rn el w e i g h t , g e r m i n a t i v e
c a p a c i t y , and g e r m i n a t i o n speed d u r i n g k e r n e l m a t u r a t i o n th a n T i t a n .
All waxy endosperm i s o t y p e s i n t h e Compana background were
s i g n i f i c a n t l y low er f o r k er n el w e i g h t and dormancy, s i g n i f i c a n t l y
h i g h e r in a l p h a - a m y l a s e a c t i v i t y , and d i d n o t d i f f e r f o r . g e r m i n a t i v e
100
c a p a c i t y d u r i n g k e r n e l m a t u r a t i o n from normal endosperm Compana
isotypes.
Spike m o i s t u r e d u r i n g k e r n e l m a t u r a t i o n d id n o t d i f f e r
between Wapana and Compana b u t was s i g n i f i c a n t l y h i g h e r in Washonupana t h a n i n Shonupapa.
G er m in a tio n speed d u r i n g k er n el m a t u r a t i o n
was s i g n i f i c a n t l y h i g h e r i n Wapana t h a n i n Compana b u t d i d n o t v ar y
between Washonupana and Shonupana.
All s h o r t awn-naked i s o t y p e s i n t h e Compana background were
s i g n i f i c a n t l y h i g h e r f o r s p i k e m o i s t u r e and g e r m i n a t i o n s p e e d , and
s i g n i f i c a n t l y lo w er f o r k e r n e l w e ig h t and dormancy d u r i n g k er n el
m a t u r a t i o n th a n t h e lo ng awn-covered Compana i s o t y p e s .
Washonupana
showed a s i g n i f i c a n t l y g r e a t e r g er m in a t i v e c a p a c i t y t h a n Wapana bu t
d i d n o t d i f f e r from Wapana f o r a l p h a - a m y l a s e a c t i v i t y d u r i n g
kernel m a tu ratio n .
Shonupana had l e s s a l p h a - a m y l a s e a c t i v i t y d u r i n g
k e r n e l m a t u r a t i o n th a n Compana b u t d i d n o t d i f f e r from Compana fo r.,
g er m in a t i v e c a p a c i t y .
Washonupana (waxy e n d o s p e r m - s h o r t awn-naked)
was s i g n i f i c a n t l y h i g h e r f o r s p i k e m o i s t u r e , g e r m i n a t i v e c a p a c i t y ,
and g e r m i n a t i o n s p e e d , had s i g n i f i c a n t l y low er k er n el w e i g h t and
dormancy l e v e l s , and cjid n o t v a r y f o r a l p h a - a m y l a s e a c t i v i t y d u r i n g
ker nel , m a t u r a t i o n from Compana (normal endosperm-long a w n - c o v e r e d ) .
Experi ment 3:
Agronomic, G e r m in a ti o n , and Malt Q u a l i t y T r a i t s
a t Harvest M aturity
The a n a l y s i s o f v a r i a n c e f o r s e v e r a l agronomic t r a i t s a t h a r v e s t
m a t u r i t y showed t h a t s i g n i f i c a n t c u l t i v a r d i f f e r e n c e s e x i s t e d f o r
101
hea di ng d a t e , p l a n t h e i g h t , y i e l d , t e s t w e i g h t , and 1000 k er n el
w e i g h t (Tab le 1 0 ) .
The c u l t i v a r r e s i d u a l mean s q u a r e , which
i n c l u d e d a l l v a r i a t i o n n o t ac c o u n te d f o r by endosperm and h u l l t y p e ,
was s i g n i f i c a n t f o r a l l t r a i t s .
All waxy endosperm i s o t y p e s had a
lowe r t e s t w e i g h t and lo w er k er n el w e i g h t th a n t h e i r normal i s o t y p e s
a l t h o u g h n o t a s i g n i f i c a n t l y lowe r k e r n e l w e i g h t i n t h e T i t a n geno­
t y p e (Ta bl e 1 0 ) .
The waxy endosperm i s o t y p e o f Bet zes was e a r l i e r
and s h o r t e r t h a n t h e normal i s o t y p e .
The naked i s o l i n e s i n t h e
Compana c u l t i v a r y i e l d e d l e s s , had s i g n i f i c a n t l y h i g h e r t e s t w ei g h ts
and s i g n i f i c a n t l y low er k e r n e l w e i g h t s t h a n t h e cove re d i s o l i n e s ,
as c o u l d be e x p e c t e d .
Endosperm t y p e by h u ll t y p e i n t e r a c t i o n s were
n o n s i g n i f i c a n t i n t h e Compana c u l t i v a r (Tab le 10 ).
D uncan's M u l t i p l e
Range T e s t (Tab le 11) f u r t h e r i n d i c a t e d t h a t Washonupana and Wabet
were s i g n i f i c a n t l y s h o r t e r and had a s i g n i f i c a n t l y lower k e r n e l w ei g h t
t h a n Shonupana and B e t z e s , r e s p e c t i v e l y .
The check c u l t i v a r s f e l l
w i t h i n t h e ran ge o f t h e e i g h t waxy-normal endosperm i s o t y p e s f o r a l l
agronomic t r a i t s w i t h t h e e x c e p t i o n o f head in g d a t e .
Klages headed
s i g n i f i c a n t l y l a t e r t h a n a l l o t h e r c u l t i v a r s (Table 1 1 ) .
The v a l u e s o b t a i n e d i n t h i s e x p e r i m e n t r e l a t i n g t o k er n el s i z e
and y i e l d a r e s i m i l a r t o t h o s e r e p o r t e d e a r l i e r by E s l i c k (19 79 ).
He
showed t h a t t h e y i e l d r e d u c t i o n s t h a t c o u l d be e x p e c te d by i n c o r p o r ­
a t i o n o f t h e waxy endosperm and h u l l e s s genes i n t o a g en ot ype were
3% and 12%, r e s p e c t i v e l y , when compared t o normal
endosperm and
T a b l e 10.
Expe rim ent 3.
A n a l y s i s o f v a r i a n c e f o r s e v e r a l agronomic t r a i t s f o r
e i g h t b a r l e y l i n e s i s o g e n i c f o r waxy and normal
endosperm and t h r e e check c u l t i v a r s a t Bozeman,
Montana, 1979.
df
S ou rce o f v a r i a t i o n
3
Blocks
10
C u l t i v a r s and i s o t y p e s
Compana endosperm type!
Compana h u l l t y p e
Compana endosperm
t y p e x h u ll t y p e
T i t a n endosperm t y p e
Be tz es endosperm t y p e
C u ltiv ar residual
Error
30
T ot al
44
*
**
t r a i t
A g r o n o m i c
Heading
Plant
Test
Y ie l d
Date
Height
Weioht
M.S.
M.S.
M.S.
M.S.
1000 Kernel
Weight
M.S.
I
I
0.15
30 .5 4* *
0.56
3.06
10.57
61 .70**
14.06
5 .0 6
3.78
1 4. 16 *
5.68
2 5 .7 8 *
0.26* *
0.73* *
0. 1 5 *
3.74* *
17.29**
170.20**
26.42**
265.40**
I
I
I
5
0.06
0 .1 3
4.50*
59 .42**
10.56
0 .1 3
55 .13**
106.41**
0.26
10.15
1.75
19.60 *
0.0 2
0. 1 6 *
0. 14 *
0.62* *
9.86
5.6 6
23.56*
274.22**
1.07
3.87
6.04
0 .0 3
S i g n i f i c a n t a t P=O.05, P=O.01 p r o b a b i l i t y l e v e l s , r e s p e c t i v e l y .
3.27
Experiment 3.
C u ltiv a r or isotype
Washonupana
Shonupana
Wapana
Compana ( d e r i v e d )
Watan
T itan (derived)
Wabet ‘
Betzes (derived)
P iroline
S h ab et
Klages
C.V. 0L
Mean agronomic r e s p o n s e s compared u s i n g Duncan's New
M u l t i p l e Range T e s t + and c o e f f i c i e n t s o f v a r i a t i o n f o r
v a r i o u s agronomic t r a i t s f o r e i g h t b a r l e y l i n e s i s o g e n i c f o r
waxy and normal endosperm and t h r e e check c u l t i v a r s a t
Bozeman, Montana, 1979.
A 9 r o n o m i c
t r a i t
Plant
Test
Heading
1000 ke rn el
height
Y ie ld
Weight
date
Weight
Julian
quintals/
kg /
cm
hectoliter
days
hectare
grams
12 .4 8 b
191.25 de
47.7 5 d
8.79 a
39.1 9 c
13.42 b
9.0 5 a
43 .3 3 b
191.5 0 cde 51.2 5 C
7 . 8 9 cd
190.25 e f
5 0 . 5 0 cd
14.77 b
48.91 a
50.75 cd
16.21 ab
8.01 c
190.75 e
49.91 a
13 .2 9 b
7.69 d
188.75 f
56.25 b
29.9 3 e
189.00 f
56.50 b
15.5 4 ab
7.9 7 C d
31.61 e
7.8 2 cd
14.21 b
192.50 bed 55.2 5 b
32 .6 6 e
8.09 c
19.4.00 b
60 .5 0 a
36.1 0 d
15.14 b
192.75 bed 56 .0 0 b
16.61 ab
8.49 b
39.45 c
7 . 9 8 Cd
193.00 be
57.0 0 b
19.32 a
40.3 6 c
14 .8 8 b
8.05 c
198.75 a
5 8 . 5 0 ab
40.67 be
0.55
3.60
16.2 9
2.2 2
+ S e p a r a t e l e t t e r s d e n o t e s i g n i f i c a n t l y d i f f e r e n t means ( P=O.05).
4.6 0
EOl
T a b l e 11,
104
cov er e d i s o t y p e s o v e r many e n v i r o n m e n t s .
In t h i s e x p e r i m e n t , in a
s i n g l e e n v i r o n m e n t , t h e y i e l d r e d u c t i o n s caused by t h e waxy endosperm
and h u l l e s s gen ot ype s were 9% and 17%, r e s p e c t i v e l y .
The c o e f f i c i e n t
o f v a r i a t i o n f o r y i e l d i n t h i s e x p e r i m e n t was u n e x p l a i n a b l y high
(Tab le 1 1 ) .
The a v e r a g e t e s t w e i g h t and k e r n e l w e i g h t o f t h e waxy
endosperm i s o t y p e s were 97% and 93%, r e s p e c t i v e l y , o f t h e av e r a g e
t e s t w e i g h t and k e r n e l w e i g h t o f t h e normal endosperm i s o t y p e s .
The
t e s t w e i g h t s and k e r n e l w e i g h t s o f t h e naked Compana i s o t y p e s
a v e r a g e d 112% and 84%, r e s p e c t i v e l y o f t h e s i m i l a r w e i g h t s o f t h e
c o v er e d Compana i s o t y p e s .
The a n a l y s i s o f v a r i a n c e f o r ger mi n a t i v e en er g y and g e r m i n a t i o n
speed ( Ta bl e 12) showed t h a t endosperm t y p e had no s i g n i f i c a n t e f f e c t
on g e r m i n a t i o n c h a r a c t e r i s t i c s a t h a r v e s t m a t u r i t y in a l l g e n e t i c
back gr ou n d s.
Hull t y p e i n t h e Compana c u l t i v a r had a h i g h l y s i g n i f i ­
c a n t e f f e c t on both g e r m i n a t i v e en er g y and g e r m i n a t i o n speed (Table
12).
Naked Compana i s o l i n e s g er m i n a te d s i g n i f i c a n t l y f a s t e r th a n
c o v er e d Compana i s o t y p e s (Table 13 ).
Washonupana and Shonupana had
s i g n i f i c a n t l y g r e a t e r g e r m i n a t i v e e n e r g y t h a n Compana (Ta b le 13 ).
M a lt in g q u a l i t y o f waxy endosperm i s o t y p e s , as d e t e r m i n e d in
c o n v e n t i o n a l p i l o t m a l t s , was g e n e r a l l y i n f e r i o r t o m a l t i n g q u a l i t y
o f t h e normal endosperm i s o t y p e s (Table 14 ).
Mean d i a s t a t i c power
and t h e s o l u b l e t o t o t a l p r o t e i n r a t i o was s i g n i f i c a n t l y lo w er f o r
waxy endosperm i s o t y p e s th a n f o r normal endosperm i s o t y p e s .
Waxy
O
105
T a b l e 12.
Experiment 3.
A n a l y s i s o f v a r i a n c e f o r g er m in a t i v e ener gy
and g e r m i n a t i o n speed f o r e i g h t b a r l e y
l i n e s i s o g e n i c f o r waxy and normal endo­
sperm and t h r e e check c u l . t i v a r s a t
Bozeman, Montana, 1979.
Source o f v a r i a t i o n
df
G er m in a ti v e
en er g y
M.S.
Block
3
1 .0 9
C u l t i v a r s and i s o t y p e s
10
Compana endosperm
type
Compana h u l l t y p e
Compana endosperm
type x hull type
T i t a n endosperm ty p e
Bet zes endosperm ty p e
C u ltiv ar residual
Error
30
Total
44
*, **
G er mi na tio n
speed
M.S.
7136.7**
2.69* *
13268.0**
I
I
0.33
5.88* *
306.3
101800.0**
I
I
I
5
0 .3 3
0 .6 6
0.91
3 .7 5* *
1600.0
10.1
1596.0
5477.5**
0 .7 5
1169.1
S i g n i f i c a n t a t t h e P =0 .05, P =0 .01 p r o b a b i l i t y l e v e l s ,
respectively.
106
T a b l e 13.
Experiment 3.
C u ltiv ar or isotype
Washonupana
Shonupana
Wapana
Compana
Watan
Titan
Wabet
Betzes
Piroline
Sh ab et
Klages
C.V. %
+
Mean g e r m i n a t i o n r e s p o n s e s compared u sin g
Duncan's New M u l t i p l e Range T e s t + and co­
e f f i c i e n t s o f v a r i a t i o n f o r g e r m in a t i v e
en er g y and g e r m i n a t i o n speed f o r e i g h t
b a r l e y l i n e s i s o g e n i c f o r waxy and normal
endosperm and t h r e e check c u l t i v a r s a t
Bozeman, Montana, 1979.
•
G e r m in a ti v e
en er g y
■
%
Ger mi na tio n
speed
. F i n l a y ' s G Index
99.85
99.85
98.92
98.3 5
98.42
99.00
97.92
97.25
98.92
97 .9 0
98.0 0
4 6 0. 75
4 72 .0 0
321.25
2 9 2 .5 0
426.75
4 29 .0 0
4 0 7 .0 0
378.7 5
3 4 4. 50
358.5 0
420.0 0
0.89
a
a
ab
be
abc
ab
be
c
ab
be
be
ab
a
fg
g
abc
abc
bed
cde
efg
def
abc
8.72
S e p a r a t e l e t t e r s d e n o t e s i g n i f i c a n t l y d i f f e r e n t means (P =0 .0 5 ).
T a b l e 14.
Expe rim ent 3.
Barley
Protein
%
Mean r e s p o n s e s and s t a t i s t i c a l a n a l y s i s u s in g a p a i r e d
t t e s t f o r s e v e r a l m a l t q u a l i t y c h a r a c t e r i s t i c s in con­
v e n t i o n a l p i l o t m a l t s f o r f o u r waxy and f o u r normal
endosperm b a r l e y i s o t y p e s and t h r e e check c u l t i v a r s
a t Bozeman, Montana, 1979.
Kernel , Plump
Weight B a r l ey
%
mg
Fi neMalt
course
Extract d if f .
%
. %
Protein
Wort
ratio
D i a s t a t i c AlphaProtein S o l/to ta l
Power amylase
%
%
degrees 2 0 °u n its
Waxy endosperm
isotypes X
10 .9 8
36.3 3
66.5 5
80.40
3.5 3
3.82
34. 2 8
96.30
30 . 7 8
Normal endosperm
isotypes X
11.15
37.73
69.1 3
81 .2 8
3.58
3 .9 0
35.63
122.80
29 . 2 3
T statistic
(3 d f )
-2.05
-2.76
-0.63
-2.88
-0.23
-0.85
-3.58
-7.23
2.21
0.13
0.0 7
0.5 7
0.06
0 .8 3
0.46
0.04
0.01
0.1 2
P i r o l in e
11.10
35.80
86 .9 0
79 .6 0
3 .3 0
3.34
31.9 0
133.00
26.0 0
S h ab et
10 .8 0
39.00
68 .8 0
80.70
3.50
3.80
37.00
119.00
25.3 0
Klages
10.9 0
39.00
71.0 0
82.80
2.70
4 .5 3
42.90
173.00
41. 8 0
p - v a l u e f o r Mn:
Waxy=normal•
108
endosperm i s o t y p e s produced more, a l t h o u g h n o t s i g n i f i c a n t l y more,
a l p h a - a m y l a s e d u r i n g m a l t i n g th a n normal i s o t y p e s .
In a l l m a l t i n g
c h a r a c t e r i s t i c s , b o th waxy and normal endosperm i s o t y p e s were much
i n f e r i o r t o K la g e s , . t h e c u r r e n t m a lt b a r l e y s t a n d a r d i n t h e a r e a .
The f a c t t h a t waxy endosperm b a r l e y s t a r c h i s more r e a d i l y modi­
f i e d by e i th e r ] enzymes o r c h e m ic a ls t h a n normal b a r l e y s t a r c h
(Goering e t a l . , 1980) had l e d t o t h e h y p o t h e s i s t h a t waxy endosperm
b a r l e y s s h ou ld be s u p e r i o r t o normal endosperm b a r l e y s f o r m a l t i n g .
T h i s h y p o t h e s i s was f u r t h e r s u p p o r t e d by e x p e r i m e n t s which showed
waxy endosperm b a r l e y s have l e s s dormancy t h a n and i n some c a s e s .
g e r m i n a t e f a s t e r th a n normal endosperm b a r l e y s , a t l e a s t d u r i n g
kernel m a tu ratio n .
A p p a r e n t l y waxy endosperm b a r l e y s
are
not
s u p e r i o r t o normal endosperm b a r l e y i n m a l t i n g q u a l i t y a s d e te r m in e d
in conventional m a lting t e s t s .
Per hap s m o d i f ie d m a l t i n g t e c h n i q u e s
a r e n e c e s s a r y t o e x p l o i t t h e uniq ue s t a r c h p r o p e r t i e s i n waxy endo­
sperm b a r l e y s .
Experiment 4:
Water I m b i b i t i o n i n Compana I s o t y p e s
The g e n e r a l p a t t e r n s o f w a t e r u p ta k e by f o u r Compana i s o t y p e s in
a 48 h o u r , 20° C, u n a e r a t e d s t e e p a r e s i m i l a r t o t h o s e p r e v i o u s l y
r e p o r t e d ( Kirs op e t a l . , 1966; Reynolds and MacWiIliam, 1967;
Brookes e t a l . , 1976).
I n i t i a l w a t e r u p t a k e was r a p i d f o l l o w e d by a
g r a d u a lly d e c re a sin g r a t e . ( F i g u r e 29).
The a n a l y s i s o f v a r i a n c e f o r
% Gra in M o is tu r e
109
Washonupana
Shonupana
Wapana
Compana
Stee p Time ( h o u r s )
Figure
29
.
Experiment 4. Patterns of water uptake during a 48 hour,
20° C, unaerated steep for seed from four Compana
isotypes grown in three environments.
no
t h e w a t e r u p ta k e o f f o u r Compana i s o t y p e s grown i n t h r e e env iro nm en ts
r e v e a l e d t h a t w a t e r u p ta k e was s i g n i f i c a n t l y i n f l u e n c e d by t h e
e nv i ro n m en t i n which t h e g r a i n was grown, by i s o t y p e , h u l l t y p e , and
s t e e p t i m e (Table 1 5 ) .
Waxy endosperm i s o t y p e s to o k up w a t e r f a s t e r
t h a n normal endosperm i s o t y p e s d u r i n g t h e s t e e p b u t n o t by a s i g n i f i ­
c a n t amount.
Naked Compana i s o t y p e s imbibed w a t e r s i g n i f i c a n t l y
f a s t e r t h a n t h e cov er e d Compana i s o t y p e s (Table 15 and F i g u r e 2 9 ) .
The h u l l t y p e by endosperm t y p e i n t e r a c t i o n was n o n s i g n i f i c a n t .
The i s o t y p e by s t e e p ti m e i n t e r a c t i o n s were s i g n i f i c a n t bec ause
o f t h e d i f f e r e n t i a l r e s p o n s e o f t h e f o u r Compana i s o t y p e s e a r l y in
t h e s t e e p a s compared t o l a t e r i n t h e s t e e p , o r bec a u se o f expe ri me n­
tal error.
B rig g s (1978) r e p o r t e d i n i t i a l w a t e r u p ta k e was much
f a s t e r in naked th a n i n cov er e d b a r l e y .
Davidson e t a l . ,
(1976)
r e p o r t e d t h a t b l o t t i n g t h e seed d r y f a i l e d t o remove a l l t h e w a t e r
h e l d by t h e s u r f a c e l a y e r s o f t h e k er n el and c o n s e q u e n t l y o v e r ­
e s t i m a t e d w a t e r u p ta k e by a b o u t V L -
S in c e i n i t i a l m o i s t u r e d i f f e r e n ­
t i a l s were s m a l l , t h i s i n t e r a c t i o n may be s i g n i f i c a n t b e c a u s e o f
e x p e r i m e n t a l t e c h n i q u e s which removed more o f w a t e r from t h e s u r f a c e
l a y e r s o f t h e naked b a r l e y th a n from t h e cov er e d b a r l e y .
S i g n i f i c a n t e n v i ro n m e n ta l i n t e r a c t i o n s may be e x p l a i n e d by
v a r i a b i l i t y i n t h e m e t a b o l i c a c t i v i t y o r v i a b i l i t y o f t h e seed s i n c e
t h e g er m in a t i v e e n e r g y and g e r m i n a t i o n speed d id vary s i g n i f i c a n t l y
between e n v i r o n m e n ts (Tab le 1 7 ) .
T h i s v a r i a b i l i t y c o u l d be due t o
m
T a b l e 15.
Expe rime nt 4.
A n a l y s i s o f v a r i a n c e f o r k er n el m o i s t u r e
p e r c e n t a g e i n a 48 h o u r , ZO0 C, u n a e r a t e d
s t e e p f o r f o u r Compana i s o t y p e s grown in
t h r e e e n v i r o n m e n ts .
So urce of. v a r i a t i o n
df
Replication
Environment.
Isotype
Hull t y p e
Endosperm t y p e
Hull t y p e x endosperm t y p e
2
2
3
Environment x i s o t y p e
Environment x h u l l t y p e
Environment x endosperm t y p e
Environment x ( h u l l type, x
endosperm t y p e )
6
S t e e p ti m e
Environment x s t e e p ti m e
I s o t y p e x s t e e p ti m e
Hull t y p e x s t e e p ti m e
Endospermtype x s t e e p time
(Hull t y p e x endosperm t y p e )
x s t e e p ti m e
10
20
30
M.S.
I
I
I
27.20**
20 .17**
5 2. 69 *
12 3.50**
33.78
0.74
2
2
5 .8 0* *
8 . 24 **
0.62
2
8 .5 4* *
10
10
3739.51**
1 .2 6* *
16.85**
44 .2 7* *
5.58* *
10
0.71
Environment x i s o t y p e x s t e e p time
. 60
0 .4 5* *
Resi dua l
262
0 .2 6
* , ** S i g n i f i c a n t a t t h e P=O.05, P=O.01 p r o b a b i l i t y l e v e l s ,
respectively.
112
seed age o r p o s s i b l y d i f f e r e n t i a l
one o r more environments.
k e r n e l damage i n seed l o t s from
Naked b a r l e y k e r n e l s a r e more s e n s i t i v e
t o embryo damage d u r i n g t h r e s h i n g th a n mos% cove re d b a r l e y k e r n e l s .
R e g r e s s i o n e q u a t i o n s , f i t t e d t o c u m u l a t i v e w a t e r u p ta k e c u r v es
f o r each o f t h e f o u r Compana i s o t y p e s , were used t o summarize w at er ,
im b ib itio n (Figure 30).
S i m i l a r e q u a t i o n s were used t o d e s c r i b e
w a t e r up ta k e p a t t e r n s in Xanthium s ee d s ( S h u l l , 1920).
Times
r e q u i r e d t o r e a c h give n m o i s t u r e p e r c e n t a g e s , were c a l c u l a t e d from
t h e r e g r e s s i o n e q u a t i o n o f each i s o t y p e (Table 16 ).
Waxy endosperm
and naked Compana i s o t y p e s , a t l e a s t un d er t h e c o n d i t i o n s o f t h i s
s t e e p , r e a c h e d t h e m o i s t u r e c o n d i t i o n s n e c e s s a r y f o r g e r m i n a t i o n and
f o r s a t i s f a c t o r y m o d i f i c a t i o n d u r i n g m a l t i n g b e f o r e normal endosperm
and cove re d Compana i s o t y p e s .
required fo r
active
Minimum w a t e r c o n t e n t s i n t h e kern el
g e r m i n a t i o n and s a t i s f a c t o r y m o d i f i c a t i o n d u r in g
m a l t i n g a r e n e a r 35% and 45%, r e s p e c t i v e l y (Brown, 1975; Brookes
e t a l . , 197 6) .
T h i s b e i n g t h e c a s e , Washonupana, Shonupana, Wapana,
and Compana would r e q u i r e 9 . 4 , 1 0 . 9 , 1 3 . 0 , and 14 .8 h o u r s , r e s p e c t ­
i v e l y , t o r e a c h m o i s t u r e l e v e l s n e c e s s a r y f o r g e r m i n a t i o n and 3 2 . 2 ,
4 1 . 3 , 5 8 . 4 , and 7 2 . 4 h o u r s , r e s p e c t i v e l y t o r eac h 45% m o i s t u r e ,
n e a r optimum f o r s a t i s f a c t o r y m o d i f i c a t i o n d u r i n g m a l t i n g (Table 16).
Of c o u r s e , w a t e r u p ta k e i s a f u n c t i o n o f t e m p e r a t u r e and o t h e r s t e e p
c o n d i t i o n s so would v a r y somewhat un d er a d i f f e r e n t s e t o f s t e e p
conditions.
Assuming t h e m a l t s t e r r e q u i r e s a covered b a r l e y t y p e ,
.
(Y) % Grai
20
Y=mlogln (X+l)+b
r
Y -Intercept
—
,
,,
0
I
0
1
Slope
r2
Washonupana
14.85
19.81
.999
Shonupana
15.55
18.11
.998
Wapana
16.7 9
15.90
.997
Compana
17.01
15.00
.997
I
2
I
4
—i-------------- 1 "
8
16
24
- t-
-I
36
48
(X) Hours S te e p Time (Log S c a l e )
F i g u r e 30.
Experiment 4. R e g r e s s i o n e q u a t i o n s d e s c r i b i n g t h e w a t e r
u pt a k e d u r i n g a 48 h o u r , 20° C, u n a e r a t e d s t e e p o f seed
from f o u r Compana i s o t y p e s grown i n t h r e e en v i r o n m e n ts .
114
T a b l e 16.
Isotype
Experiment 4.
■
Ra te o f w a t e r u p ta k e by f o u r Compana
i s o t y p e s i n a 20° C u n a e r a t e d s t e e p .
Hours t o r e a c h i n d i c a t e d m o i s t u r e
percentages.
N o i
s t u r e
25
P e r c
e n t v
35
.40
.
9.4
17 .6
32.2
10 .9
21.4 .
4 1 .3
45
Washonupana
2.2
Shonupana
2.3
Wapana
2.3
1 3 .0
27.8
5 8 .4
Compana
2.4
1 4 .8
33.1
72.4
.
115
t h i s e x p e r i m e n t i n d i c a t e s t h a t s t e e p t i m e co u l d be s h o r t e n e d su b­
s t a n t i a l l y (14 hours a t 20° C i n t h e Corripana c u l t i v a r ) by u s i n g
waxy endosperm i s o t y p e s f o r m a l t i n g i n s t e a d o f normal endosperm i s o ­
types.
Uniform m o i s t u r e d i s t r i b u t i o n w i t h i n t h e k er n el i s a l s o
important.
The a n a l y s i s o f v a r i a n c e f o r ger mi n a t i v e en er g y and g e r m i n a t i o n
speed
o f f o u r Compana i s o t y p e s grown i n t h r e e en v i ro n m en ts r e v e a l e d
s i g n i f i c a n t e f f e c t s on g e r m i n a t i o n b e h a v i o r were caused by t h e growing
e nv i ro n m en t (Tab le 1 7 ) .
S i g n i f i c a n t en v iro n m en t by i s o t y p e i n t e r ­
a c t i o n s were a p p a r e n t a l t h o u g h t h e e f f e c t o f i s o t y p e on g e r m i n a t i o n
b e h a v i o r was n o n s i g n i f i c a n t .
N e i t h e r endosperm ty p e nor h u l l t y p e
s i g n i f i c a n t l y influenced germination behavior.
Naked Compana i s o t y p e s
d i d , however, g e r m i n a t e f a s t e r th a n c o ve r e d Compana i s o t y p e s .
This
was n o n s i g n i f i c a n t bec a us e t h e mean s q u a r e o f t h e e n v io rn m en t by
i s o t y p e i n t e r a c t i o n , which was used t o t e s t t h e e f f e c t o f h u l l t y p e
on g e r m i n a t i o n s p e e d , was so l a r g e (Tab le 17 ).
Rat es o f w a t e r u p ta k e do v a r y between waxy and normal endo­
sperm and between naked and cove re d i s o t y p e s .
The d i f f e r e n c e in
r a t e s o f w a t e r u p ta k e between naked and cove re d i s o t y p e s may e x p l a i n
why naked b a r l e y s g e r m i n a t e f a s t e r t h a n cove re d b a r l e y s .
The f a c t
t h a t waxy b a r l e y s t a k e w a t e r up f a s t e r , a l t h o u g h n o t by a s i g n i f i c a n t
amount, t h a n normal b a r l e y s may be an i m p o r t a n t c o n s i d e r a t i o n i n t h e
f u t u r e o f waxy b a r l e y s a s m a l t i n g b a r l e y s .
T a b l e 17.
Experiment 4.
A n a l y s i s o f v a r i a n c e f o r g er m in a t i v e
en er g y and g e r m i n a t i o n speed f o r f o u r
Compana i s o t y p e s grown in t h r e e
en v i ro n m e n ts .
So urce o f v a r i a t i o n
df
G e r m in a ti v e
en er g y
M.S.
Environment
2
267.6**
14246.2**
Isotype
HulI t y p e
Endosperm t y p e
Hull t y p e x endosperm t y p e
3
I
I
I
31 .2
9.4
84.0
0.0
1692.3
3 3 96. 9
1666.0
14.1
Environment x i s o t y p e
Environment x h u l l t y p e
Environment x endosperm
type
Environment x ( h u l l t y p e
x endosperm t y p e )
6
2
30.3* *
15.5*
1354.0**
7 3 3. 1*
2
75.1* *
3160.4**
Resi dua l
* , **
.
2
24
Ger min at ion
speed
M.S.
0.4
168 .6
4.5
21 5 .4
S i g n i f i c a n t a t t h e P=O.05 and P=O.01 p r o b a b i l i t y l e v e l s ,
respectively.
CONCLUSIONS
C o n s i d e r a b l e v a r i a t i o n in g e r m i n a t i o n b e h a v i o r does e x i s t
among b a r l e y g e n o t y p e s .
G e n e r a l l y , m a l t b a r l e y s g e r m i n a te d f a s t e r ,
and e x h i b i t e d l e s s dormancy o r a t l e a s t a s h o r t e r dormancy p e r i o d
t h a n b a r l e y s used f o r f e e d .
Screening barle y s fo r malt p o te n tia l
co ul d i n v o l v e g e r m i n a t i o n speed t e s t s a n d / o r dormancy t e s t s , a l t h o u g h
such t e s t s a r e t i m e consuming and l a b o r i o u s .
Waxy endosperm b a r l e y i s o t y p e s d i f f e r from normal endosperm
b a r l e y i s o t y p e s i n c e r t a i n g e r m i n a t i o n and agronomic t r a i t s d u r i n g
t h e p e r i o d o f k e r n e l development and m a t u r a t i o n and a t h a r v e s t m a t u r ­
ity .
During k e r n e l m a t u r a t i o n waxy endosperm i s o t y p e s e x h i b i t e d
s i g n i f i c a n t l y l e s s dormancy, a s m a l l e r seed s i z e , g r e a t e r a l p h a - a m y l a s e
a c t i v i t y , and m a i n t a i n e d a h i g h e r p e r c e n t a g e o f m o i s t u r e i n t h e s p i k e
.
t h a n normal endosperm i s o t y p e s .
The h i g h e r m o i s t u r e c o n t e n t o f waxy
endosperm i s o t y p e s may be e v i d e n c e t h a t t h e p e r i o d from a n t h e s i s t o
h a r v e s t m a t u r i t y i s l o n g e r i n waxy t y p e s t h a n i n normal t y p e s .
In
s p e c i f i c g e n e t i c backgrounds waxy endosperm i s o t y p e s g e r m i n a te d f a s t e r
t h a n normal endosperm i s o t y p e s .
By h a r v e s t m a t u r i t y d i f f e r e n c e s
between waxy and normal endosperm i s o t y p e s i n dormancy and g e r m i n a t i o n
sp eed were no l o n g e r a p p a r e n t .
Waxy endosperm i s o t y p e s were n o t
s i g n i f i c a n t l y d i f f e r e n t from normal endosperm i s o t y p e s f o r y i e l d o r
d a t e o f h ea d i n g .
Waxy endosperm i s o t y p e s in s p e c i f i c g e n e t i c
I
ns
backgrounds were s h o r t e r th a n normal endosperm i s o t y p e s .
The t e s t
w e i g h t s and k e r n e l w e i g h t s o f waxy endosperm i s o t y p e s were
s i g n i f i c a n t l y lower t h a n s i m i l a r w e i g h t s i n normal endosperm i s o t y p e s .
In a 48 h o u r , 20° C, u n a e r a t e d s t e e p waxy endosperm i s o t y p e s took up
w a t e r f a s t e r , b u t n o t s i g n i f i c a n t l y f a s t e r , th a n normal endosperm
isotypes.
In t h e Compana g e n e t i c b ack gr ou nd , waxy endosperm i s o t y p e s
r e a c h e d 45% m o i s t u r e , n e a r optimum f o r s a t i s f a c t o r y m o d i f i c a t i o n d u r ­
i n g m a l t i n g , from 9 . 1 - 1 4 . 0 h ou rs q u i c k e r t h a n i n normal endosperm
isotypes.
D e s p i t e t h e a p p a r e n t a d v a n t a g e s f o r m a l t i n g p o s s e s s e d by
waxy endosperm b a r l e y s , namely more r a p i d s t a r c h m o d i f i c a t i o n by
enzymes o r c h e m i c a l s , l e s s dormancy, and f a s t e r u p ta ke o f w a t e r , waxy
endosperm i s o t y p e s were i n f e r i o r t o normal endosperm i s o t y p e s f o r
m a l t i n g q u a l i t y as d e t e r m in e d by c o n v e n t i o n a l p i l o t m a l t s .
Normal
b a r l e y i s o t y p e s were s i g n i f i c a n t l y h i g h e r i n d i a s t a t i c power and
had a h i g h e r s o l u b l e p r o t e i n t o t o t a l p r o t e i n r a t i o .
S h o r t awn-naked and long awn-covered Compana i s o t y p e s a l s o
d i f f e r e d d u r i n g k e r n e l m a t u r a t i o n and a t h a r v e s t m a t u r i t y .
Naked
Compana i s o t y p e s had s m a l l e r s e e d s , l e s s dormancy, g e r m i n a te d f a s t e r ,
and m a i n t a i n e d a h i g h e r s p i k e m o i s t u r e p e r c e n t a g e t h r o u g h o u t ke rn el
m a t u r a t i o n t h a n d i d c o v er e d Compana i s o t y p e s .
Hull t y p e had no
e f f e c t on hea d in g d a t e o r p l a n t h e i g h t b u t s i g n i f i c a n t l y i n f l u e n c e d
y i e l d , t e s t w e i g h t , seed w e i g h t , g er m in a t i v e en er g y and g e r m i n a t i o n
speed a t m a t u r i t y .
Naked Compana i s o t y p e s y i e l d e d 17% l e s s th a n
c o v er e d Compana i s o t y p e s .
Seed s i z e i n t h e naked i s o t y p e s was
-7
119
16% l e s s t h a n i n t h e c o v e r e d i s o t y p e s .
isotypes
S h o r t awn-naked Compana
g er m i n a te d f a s t e r and had l e s s dormancy t h a n lo n g awn-
cov er e d Compana i s o t y p e s a t h a r v e s t m a t u r i t y .
In a 48 h o u r , 20° C,
u n a e r a t e d s t e e p naked Compana i s o t y p e s imbibed w a t e r s i g n i f i c a n t l y ...
f a s t e r t h a n cov er e d Compana i s o t y p e s .
&
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