A study of the inheritance of awnedness, aleurone color, growth habit, and spike density in barley
by John M Green
A THESIS Submitted to the Graduate Committee in partial fulfillment of the requirement for the
degree of Master of Science in Agronomy
Montana State University
© Copyright by John M Green (1943)
Abstract:
The objective of this study was to determine the mode of inheritance and linkage relationships of four
characters in barley. The mode of inheritance was determined by observing the F1 generation plants
and by studying segregation in the F2 and F3 generations. Linkage intensities were calculated by the
product method using the combined F2 and F3 data.
The inheritance of awnedness and growth habit ms studied in crosses of Arlington Aimless, C. I. 702,
with the two Atrada varieties, C. I. 6641 and C. I. 5638. In addition the inheritance of aleurone color
and spike density was studied in the cross with Atrada, C. I. 6638.
Although a two-factor difference for awnedness was observed in each cross, a total of three different
factor pairs affecting awnedness were present in the two crosses studied. A factor pair for normal
versus reduced lateral awns, which affected length of central awns also, was carried in the dominant
condition in each Atrada variety and in the recessive condition in Arlington Awnless. Two factor pairs
for awn length were carried in the dominant condition in Arlington Awnless; one was dominant in
Atrada, C. I. 5638, and recessive in Atrada, C. I. 5641; and the other was recessive in Atrada, C. I.
5638, and dominant in Atrada, C. I. 5641.
Normal lateral awns were partially dominant over reduced and long awns were apparently completely
dominant over short. Growth habit, aleurone color, and spike density were each inherited on a
single-factor basis, although additional modifying factors not detected in this study may have affected
growth habit in the cross Arlington Awnless x Atrada, C. I. 5638. Blue aleurone color was dominant
over white and xenia was observed in the inheritance of this character. Erect growth habit was
dominant over decumbent , and lax spikes were dominant over dense.
In Arlington Awnless x Atrada, C. I, 5641, the two factors for awnedness were inherited independently
of each other and independently of growth habit. In Arlington Awnless x Atrada, C. I. 5658, long
versus short awns were linked with lax versus dense spikes with 24.18±6.30 percent crossing over. The
linkage relationships of growth habit in this cross were not determined because the ratio observed for
this character did not fit a monohybrid ratio, although segregation in the Fg generation indicated a
single factor difference. All other characters segregated independently of each other. A STUDY OF THE INHERITANCE OF
AWNEDIiESS, ALEURONE COLOR, GROWTH HABIT,
AND SPIKE DENSITY IN BARLEY
by
JOHN M, GREEN
A THESIS
x
S ub m itted t o th e G raduate Committee
in
p a r t i a l f u l f i l l m e n t o f th e req u irem en t*
f o r th e d e g re e o f
M aster o f Soienee i n Agronomy
at
Montana S ta te C ollege
Approved*
C hairm an, Examining Coixdb to e
r a a h , G raduate C om nittoe
Bozeman, Montana
—
! /3 7 8
fi.g S .3 x L .
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^
—
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ACKUOlVLEDGlfflNT
The w r i t e r w ishes to acknowledge h i s in d e b te d n e ss to Mr. S . C.
L itz e n b e rg e r f o r p ro v id in g th e m a te r ia l used i n t h i s s tu d y and to
e x p re ss h is a p p r e c ia tio n t o him and t o D r. R . H. Bamberg and D r. R. P .
Murphy f o r t h e i r a s s is ta n c e i n th e c l a s s i f i c a t i o n o f t h i s m a te r ia l and
i n th e a n a ly s is and f i n a l arran g em en t o f th e d a t a .
The w r i t e r a ls o
w ish es to e x p re ss h is a p p r e c ia tio n to th e D iv isio n o f C e re a l Crops and
D iseases f o r f i n a n c i a l a s s is ta n c e p ro v id ed th ro u g h th e F ello w sh ip main­
ta in e d by t h a t agency a t Montana S ta te C o lle g e .
4
7 0 6 4 3
—5—
TABLE OP C0NTE1JTS
Page
LIST OF TABLES .......................................................................... .... ..........................
5
ABSTRACT..................................
7
INTRODUCTION . . . . .
........................................................................................
8
REVIEW OF LITERATURE
.....................
8
Avm Length
......................................
8
Normal v e rs u s Reduced L a te r a l Avms
B lue v e rsu s W hite A leurone C olor
. . . . . . . . . . . .
10
. . . . . . . . . . . . .
11
S p rin g v e rs u s W in ter H a b it o f G r o w t h ............................................
13
Lax v e rs u s Dense S p ik e s . . . . . . . . .
14
...................... . . .
Linkage Groups i n B a rle y . . . . . . . . . . . . . . . . .
15
MATERIALS AND METHODS........................................................................................
D e s c r ip tio n o f P a re n ts and C h a ra c te rs S t u d i e d .....................
.
16
16
Method o f Growing th e F i l i a l G e n e r a t i o n s ......................... • • •
17
Methods o f C l a s s i f i c a t i o n
18
. . . . . . . . . . . .
Symbols f o r G en etic C h a r a c t e r s .....................
.................
• • •
A n a ly sis o f D a t a .......................................
EXPERIMENTAL RESULTS
21
•
21
........................................................................................
23
V a r ia tio n i n Awn L ength . . . . . . . . . . . . . . . . . .
23
I n h e r ita n c e o f Awnedness
23
. . . . . . . . . . .
...................
A rlin g to n A im less x A tra d a , C. I . 5641 ......................
23
A rlin g to n A im less x A tra d a , C. I . 5638 . . . . . . . .
26
I n h e r ita n c e o f A leurone C olor i n
A rlin g to n A im less x A tra d a , C. I • 5638
.......................................
32
Page
I n h e r ita n c e o f Growth H a b it in
A rlin g to n Armless x A tra d a » C. I* 5641
33
I n h e r ita n c e o f Growth H a b it i n
A rlin g to n Awnless x A tra d a , C. I . 5638 ............................................
34
I n h e r ita n c e o f D e n s ity o f S p ik e i n
A rlin g to n Awnless x A tra d a , C. I . 5638 . . . . . . . . . . .
35
Linka g e R e la tio n s h ip s i n A rlin g to n Avmless x
A tra d a , C. I . 5641
37
C h a ra c te rs i n h e r i t e d in d e p e n d e n tly
. . . . .
..........
37
Linkage R e la tio n s h ip s i n A rlin g to n Awnless x
A tra d a , 0 . I . 5638 . . . . . . . . .
........................... . . . . .
37
C h a ra c te rs i n h e r i t e d in d e p e n d e n tly . . . . . . . . . .
37
C h a ra c te rs lin k e d i n
39
in h e r ita n c e
. . . . . . . . . . .
DISCUSSION.................................................................
42
SUMMARY
46
..........................................................................................................................
LITERATURE CITED AHD CONSULTED ..................................................... . . . . .
DESCRIPTION OF P L A T E S ..................................................................
PLATE I
PLATE I I
...........................................
48
51
52
53
5LIST OF TABLES
Page
T able I
T ab le I I
T able I I I
T ab le 17
T able V
T able T I
T able V II
T able V III
T ab le I I
T able I
H easu ren en ts re c o rd e d and th e a n a ly s is o f v a ria n c e
c a lc u la te d on c e n t r a l awn le n g th s a s a p a r t o f th e
s tu d y o f v a r i a t i o n i n aim le n g th w ith in th e A rlin g ­
to n Awnless v a r i e t y
24
O bserved and c a lc u la te d F2 p h en o ty p ic r a t i o s f o r
awn ty p e s in A rlin g to n A m le ss x A tra d a , C. I . 5641
25
O bserved and c a lc u la te d F2 g e n o ty p ic r a t i o s f o r awnedness as d eterm in ed by th e F , s e g r e g a tio n i n A rlin g ­
to n Avciless x A tra d a , C. I . 5641
26
O bserved and c a lc u la te d F2 p h en o ty p ic r a t i o s f o r
axvodness i n A rlin g to n Awnloss x A tra d a , C. I . 5638
27
Observed and c a lc u la te d F2 g e n o ty p ic r a t i o s f o r awnedneee a s d e term in e d b y th e F j s e g r e g a tio n i n
A rlin g to n A im less x A tra d a , Ce I . 563 8
28
Frequency d i s t r i b u t i o n o f c e n t r a l aim le n g th s i n Fg
f a m ilie s grown from f i f t e e n F2 p la n ts c l a s s i f i e d a s
h aving th e A rlin g to n A m le s a , o r 2 , awn ty p e
29
H y p o th e tic a l genotypes and o b serv ed b re e d in g
b e h a v io r o f th e F2 g e n e r a tio n s e g re g a te s i n
A rlin g to n A im less x A tra d a , C. I* 5641, and
A rlin g to n A im less x A tra d a , C. I . 5638
31
Observed and c a lc u la te d F2 g e n o ty p ic r a t i o s f o r
b lu e v e rs u s w h ite a le u ro n e as d eterm in ed by th e
Fg s e g r e g a tio n o f A rlin g to n Awnless x A tra d a ,
C. I . 5638
33
O bserved F2 p h en o ty p ic r a t i o s f o r s p rin g v e rs u s
w in te r grow th h a b i t i n A rlin g to n Awnless x A tra d a ,
Ce I • 5 6 3 8 , and A rlin g to n A im less x A tra d a , Ce Ie
5641
34
Observed Fg g e n o ty p ic r a t i o s f o r s p rin g v e rs u s w in te r
grow th h a b x t a s determ in ed b y th e F j s e g r e g a tio n in
A rlin g to n Awnless x A tra d a , Ce I , 5638, and
A rlin g to n Awnless x A tra d a , Ce I , 5641
35
T able H
O bserved and c a lc u la te d Fg p h en o ty p ic r a t i o s f o r
la x v e rs u s dense sp ik e i n A rlin g to n Awnless x
A tra d a , Ce I . 5638
T able X II
Observed and c a lc u la te d Pg g e n o ty p ic r a t i o s f o r
la x v e rs u s dense sp ik e a s d eterm in ed b y th e Fg
s e g r e g a tio n i n A rlin g to n Awnless x A tra d a ,
C. I , 5638
T able X III
Observed and c a lc u la te d Fg g e n o ty p ic r a t i o s f o r
s p rin g v e rs u s w in te r h a b it o f grow th and two f a c t o r s
f o r awnedness as d eterm in ed by th e F3 s e g r e g a tio n o f
A rlin g to n Awnless x A tra d a , C. I . 5641
T able XIV
Observed and c a lc u la te d Fg g e n o ty p ic r a t i o s a s
d eterm in ed by th e Fg s e g r e g a tio n f o r c h a r a c te r s
in h e r ite d in d e p e n d e n tly i n A rlin g to n Awnless x
A tra d a , C. I . 5638
T able XV
Observed and c a lc u la te d Fg g e n o ty p ic r a t i o s a s
d eterm in ed b y th e Fg s e g r e g a tio n f o r lo n g v e rs u s
s h o r t awns and la x v e rs u s dense s p ik e s in A rlin g to n
Awnless x A tra d a , C. I* 5638
T able XVI
O bserved and c a lc u la te d Fg p h en o ty p ic r a t i o s f o r
lo n g v e rs u s s h o r t awns and la x v e rsu s dense s p ik e s
i n A rlin g to n Awnless x A tra d a , C. I . 5638
A S tu d y o f th e I n h e r ita n c e o f
Awnednees, A leurone C o lo r, Growth H a b it,
and S pike D en sity i n B a rle y
ABSTRACT
The o b je c tiv e o f t h i s s tu d y was to d eterm in e th e node o f in h e r ita n c e
and lin k a g e r e la t i o n s h i p s o f fo u r c h a r a c te r s i n b a r l e y . The node o f in ­
h e r ita n c e was d eterm in ed by o b s e rv in g th e
g e n e ra tio n p la n ts and by
s tu d y in g s e g r e g a tio n i n th e Fg and Fg g e n e r a tio n s . Linkage i n t e n s i t i e s
were c a lc u la te d by th e p ro d u c t method u s in g th e combined Fg and Fg d a ta .
The in h e r ita n c e o f awnedness and grow th h a b it was s tu d ie d i n c ro s s e s
o f A rlin g to n A w nless, C. ! • 702, w ith th e two A tra d a v a r i e t i e s , C. I . 5641
and C. I . 5638. In a d d itio n th e in h e r ita n c e o f a le u ro n e c o lo r and sp ik e
d e n s ity was s tu d ie d in th e c ro s s w ith A tra d a , C. I . 5638.
A lthough a tw o - f a c to r d if f e r e n c e f o r awnedness was o bserved i n each
c r o s s , a t o t a l o f th r e e d i f f e r e n t f a c t o r p a ir s a f f e c t i n g awnedness were
p re s e n t i n th e two c ro s s e s s tu d ie d . A f a c t o r p a i r f o r norm al v e rsu s re ­
duced l a t e r a l aw ns, which a f f e c t e d le n g th o f c e n t r a l awns a l s o , was c a r r ie d
i n th e dom inant c o n d itio n i n each A tra d a v a r i e t y and i n th e r e c e s s iv e con­
d i t i o n i n A rlin g to n A w nless. Two f a c t o r p a ir s f o r awn le n g th were c a r r ie d
i n th e dom inant c o n d itio n i n A rlin g to n A w nless; one was dom inant i n A tra d a ,
C. I . 5638, and r e c e s s iv e i n A tra d a , C. I . 5641; and t h e o th e r was re c e s s iv e
i n A tra d a , C. I . 5638, and dom inant i n A tra d a , C. I . 5641.
Normal l a t e r a l awns were p a r t i a l l y dom inant ovor red u ced and long
awns were a p p a r e n tly c o m p le te ly dom inant o v o r s h o r t . Growth h a b i t , a le u ro n e
c o l o r , and s p ik e d e n s it y were each i n h e r ite d on a s i n g l e - f a c t o r b a s i s , a l ­
though a d d itio n a l m odifying f a c to r s n o t d e te c te d i n t h i s s tu d y may have
a f f e c t e d grow th h a b it i n th e c ro s s A rlin g to n Awnless x A tra d a , C. I . 5638.
Blue a le u ro n e c o lo r was dom inant o v e r w h ite and x e n ia was o b serv ed i n th e
in h e r ita n c e o f t h i s c h a r a c t e r . E r e c t grow th h a b it was dom inant ovor de­
cum bent, and la x s p ik e s w ere dom inant o v e r d e n se .
I n A rlin g to n Awnless x A tra d a , C. I . 5641, th e two f a c t o r s f o r awned­
n e ss were in h e r ite d in d e p e n d e n tly o f each o th e r and in d e p e n d e n tly o f grow th
h a b i t . I n A rlin g to n Awnless x A tra d a , C. I . 5638, lo n g v e rs u s s h o r t awns
were lin k e d w ith la x v e rs u s dense s p ik e s w ith 24.18+ 6.30 p e rc e n t c ro s s in g
o v e r . The lin k a g e r e l a t i o n s h i p s o f grow th h a b it i n t h i s c ro s s were n o t
d eterm in ed b ecau se th e r a t i o o b serv ed f o r t h i s c h a r a c te r d id n o t f i t a
monohybrid r a t i o , a lth o u g h s e g r e g a tio n i n th e Fg g e n e ra tio n in d ic a te d a
s in g le f a c t o r d i f f e r e n c e . A ll o th e r c h a r a c te r s se g re g a te d in d e p e n d e n tly
o f each o t h e r .
A S tu d y o f th e I n h e r ita n c e o f
A nnednoss, A leurone C o lo r, Growth H a b it,
and Spike D e n sity i n B a rle y
John M, Green
INTRODUCTION
One o f th e f i r s t g e n e tic s tu d ie s i n b a r l e y , th e r e s u l t s o f which
w ere p u b lish e d i n 1901, was conducted i n A u s tria b y von T sc h eraa k ,
S in ce t h a t t i n e th e p o s s i b i l i t i e s a ffo rd e d by b a r le y f o r such s tu d ie s
have a t t r a c t e d th e a t t e n t i o n o f many s tu d e n ts o f g e n e tic s and p la n t b re e d ­
in g .
At th e p re s e n t tim e , g e n e tic s t u d ie s w ith s e v e ra l d i f f e r e n t b a r le y
c ro s s e s a r e b e in g conducted a t th e Montana A g r ic u ltu r a l Experim ent S t a t i o n .
The r e s u l t s o f one o f th e s e s t u d i e s , a s tu d y o f th e in h e r ita n c e o f awnedn e s s , a le u ro n e c o l o r , grow th h a b i t , and s p ik e d e n s ity in two c r o s s e s , a re
p re s e n te d i n t h i s p a p e r.
REVIEW QF LITERATURE
Awn Length
The in h e r ita n c e o f awn le n g th i n th e progeny o f numerous c ro s s e s
was s tu d ie d by von U bisch ( 2 0 ) l / .
He co ncluded t h a t awn le n g th was con­
t r o l l e d by th r e e f a c t o r p a ir s which he d e s ig n a te d Aa, Uu, and Vv.
The
genotype A -U -w gave r i s e t o awns o f e x tr e e le n g th ; A -u u w , A-uuV-, and
aaU -V -, lo n g awns; a& U -w , aauuV -, and a a u u w , s h o r t aw ns.
D e n sity o f
l / F ig u re s i n p a r e n th e s is r e f e r to ^ L i t e r a t u r e c ite d and c o n s u lte d '', page 4 8 .
-
3-
s p ik e was c lo s e ly a s s o c ia te d w ith awn le n g th i n th e c ro s s e s stu d ie d #
Miyake and Im ai (12) a ls o found th r e e f a c t o r p a ir s in v o lv e d i n th e
in h e r ita n c e o f awn le n g th i n some c ro s s e s s tu d ie d .
I n o th e r c ro s s e s a
s i n g l e - f a c t o r d if f e r e n c e betw een lo n g and s h o r t awns was o b s e rv e d .
Long
v e rs u s s h o r t awns was found to be lin k e d w ith h u lle d v e rs u s naked seed
w ith 5 p e rc e n t c r o s s in g o v er and w ith awned v e rs u s aw n less l a t e r a l f l o r e t s .
In c ro s s e s i n w hich th r e e f a c t o r p a ir s f o r awn le n g th were in v o lv e d , awn
le n g th was lin k e d w ith two row v e rs u s s i x row , awned v e rs u s aw nless l a t e r a l
f l o r e t s , norm al v e rs u s c u rle d (a dw arf c h a r a c t e r ) , and p ro b a b ly lin k e d
w ith p u rp le v e rs u s w h ite s e e d .
Ikeno (9 ) re p o rte d a tw o -f a c to r d if f e r e n c e f o r awn le n g th i n Klnukawa,
a lo n g awned v a r i e t y , c ro s s e d w ith N ogenhasi, a v a r i e t y w hich i s g e n e r a lly
a w n le s s , b u t som etim es has s h o r t c e n t r a l aw ns.
In f o u r d i f f e r e n t c ro s s e s
M yler (14) a ls o found a tw o - f a c to r d if f e r e n c e f o r awnedness when aw nless
and awned ty p e s were c r o s s e d .
I n th r e e o f th e s e c ro s s e s lo n g awned v a r­
i e t i e s were c ro s s e d w ith A w nless, C. I# 5 6 3 1 ,^ / an aw nless v a r i e t y .
w ere six -ro w ed b a r l e y s .
A ll
The two awn f a c t o r s f o r w hich s e g r e g a tio n was
o b serv ed were d e s ig n a te d Lk and Lk^ by l t y l e r •
S e g re g a te s c a r ry in g b o th
f a c t o r s i n th e dom inant c o n d itio n were long-aw nedj th o se c a r r y in g o n ly Lk
i n th e dom inant c o n d itio n were s h o r t awned; th o s e c a r ry in g o n ly Lk^ i n th e
dom inant c o n d itio n were " a w n le tte d " ; and th o s e re c e s s iv e f o r b o th f a c t o r
p a i r s were a w n le s s .
The " a w n le tte d ” ty p e had awns on th e c e n t r a l s p ik e l e ts
2 / C. I . number r e f e r s to th e a c c e s s io n number o f D iv is io n o f C ereal
Crops and D is e a s e s .
•»10 —
o n ly .
I n th e f o u r th c r o s s , R e d ra c h is , C. I . 5649, x A ra ile ss, a 1 5 :1 r a t i o
f o r aimed to aw nless was o b s e rv e d .
R ed rach is i s a tw o-row ed, aimed v a r i e t y .
A s i n g l e - f a c t o r d if f e r e n c e betw een lo n g and s h o r t awns i n a c ro s s
o f A tra d a , C. 1 . 5658 x T re b i-V e lv e t was re p o rte d b y S tu m ( 1 9 ) .
He
found th e f a c t o r p a i r f o r awn le n g th (L k^Ik^) to b e in h e r i t e d independ­
e n t l y o f rough v e rs u s sm ooth awns (R r) and t o b e lin k e d w ith la x v e rsu s
d ense s p ik e s (L gly ) w ith 23 p e rc e n t c r o s s in g o v e r .
G linyany (6 ) found a s in g le f a c t o r p a i r a f f e c t in g awn le n g th in
N u d ih a x to n i, a v a r i e t y w ith norm al c e n t r a l awns b u t no l a t e r a l aw ns, when
c ro sse d w ith a hooded v a r i e t y .
The f a c t o r p a i r (Nh) f o r lo n g v e rsu s s h o r t
awns was h y p o s ta tic t o a f a c t o r p a i r p re s e n t which c o n tr o lle d th e d ev elo p ­
ment o f l a t e r a l awns (A a).
Normal v e rs u s Reduced L a te r a l Awns
Ikono (9) o b serv ed a 1 :2 :1 r a t i o f o r absence o f l a t e r a l aw ns, in ­
te rm e d ia te l a t e r a l aw ns, and f u l l y developed l a t e r a l awns i n th e Fg pro­
geny o f a c ro s s o f Einukawa x N ogenhasi.
Kinukawa Is a f u l l y awnod v a r­
i e t y w h ile K ogenhasi i s g e n e r a lly a im le ss b u t sometimes has s h o r t c e n tr a l
aw ns.
He concluded t h a t th e f a c t o r r e s p o n s ib le was a p a r t i a l l y dominant
in h ib ito r fa c to r.
S im ila r s e g r e g a tio n was ob serv ed b y G linyany (6 ) i n a
c ro s s o f N udihaxtoni tim e s a hooded v a r i e t y .
He a ls o concluded t h a t th e
f a c t o r r e s p o n s ib le was an i n h i b i t o r and found t h a t i t was e p i s t a t i c to a
f a c t o r f o r awn le n g th p r e s e n t i n th e c r o s s .
A s i n g l e - f a c t o r d if f e r e n c e was a ls o r e p o r te d by Bngeldow ( 3 ) , Miyedca
and Im ai (1 2 ) , end Leonard (1 1 ) .
Engeldow s tu d ie d a c ro s s o f H a x to n i, a
11
■ variety s i m i l a r to N u d ih a x to n i, w ith a lo n g aimed v a r i e t y .
Miyake and
Im al s tu d ie d s e v e r a l c ro s s e s o f norm al aimed v a r i e t i e s on v a r i e t i e s hav­
in g no awns on th e l a t e r a l s p i k e l e t s .
They found th e f a c t o r f o r normal
v e rs u s reduced l a t e r a l awns to be lin k e d w ith norm al v e rs u s c u rle d (d w a rf),
and p ro b a b ly lin k e d w ith p u rp le v e rsu s w h ite s e e d .
They p la ce d th e f a c t o r
p a i r f o r norm al v e rs u s red u ced l a t e r a l awns i n lin k a g e group I I .
Leonard s tu d ie d c ro s s e s o f N udihaxtoni on th r e e hooded v a r i e t i e s ,
C o lse ss IV , C o lse ss V, and A ntrum .
He d e s ig n a te d th e f a c t o r p a i r con­
t r o l l i n g l a t e r a l awn developm ent as L r l r , and found i t lin k e d w ith g reen
v e rs u s orange s e e d lin g c o lo r (O ro r) w ith 3 3 .5 8 * 1.2 0 p e rc e n t c ro s s in g
o v e r.
The f a c to r p a i r L r l r was in h e r ite d in d e p e n d e n tly o f b la c k v e rsu s
w h ite f l o r a l b r a c ts (B h ), covered v e rsu s naked seed (N n), hoods v e rsu s
awns (Kk), lo n g - v e rs u s s h o r t- h a ir e d r a c h l l l a ( S s ) , g reen v e rs u s x an th a
s e e d lin g c o lo r (X0X0 ) , and g reen v e rs u s c h lo r in e s e e d lin g s (Fc f 0 ) .
Leonard concluded t h a t th e f a c t o r p a i r L r l r was i n lin k a g e group I .
Blue v e rs u s W hite A leurone C olor
H a rla n (? ) re p o rte d t h a t c o lo rs in b a r le y a re caused b y two pigm ents;
a n th o e y a n in and a m e la n in -lik e compound.
The an th o o y an in i s v i o l e t i n i t s
a c id c o n d itio n and b lu e i n i t s a lk a l in e c o n d itio n , and th e m e la n in -lik e
compound i s b la c k .
These pigm ents may o c c u r in th e p e r i c a r p , h u l l s ,
a le u ro n e l a y e r , and o c c a s io n a lly in th e endosperm .
The p re se n c e o f
a n th o o y an in i n th e p e r ic a r p g iv e s a v i o l e t c o lo r ; i n th e a le u r o n e , b lu e
c o lo r ; and i f p r e s e n t i n b o th th e p e r ic a r p and a le u r o n e , a p u rp le c o lo r
re s u lts .
I n th e absence o f th e pigm ent i n b o th th e p e r ic a r p and a le u ro n e
I
•12-
th e k e r n e l i s ig h ite .
The r e s u l t s o f two d i f f e r e n t s tu d ie s o f t h e ae;v,e n a t e r i e l were
p u b lis h e d j o i n t l y by ItLytizam., and So and I m i (1 3 ) .
The e a r l i e r s tu d y
was made by Miyazavra., who concluded t h a t th e b lu e c o lo r was in h e r ite d a s
a m osaic i n a c ro s s o f S o ld .to ri, a Jap an ese b lu e v a r i e t y , tim e s GoldenmeIo n ,
an A u s tr a lia n v a r i e t y w ith p a le y e llo w k e r n e l s .
o f b lu e k e rn e ls to w h ite on in d iv id u a l
He o b serv ed v a ry in g r a t i o s
heads b u t when he co u n ted th e
k e r n e ls on a l l heads he found 1009 b lu e and 1019 p a le y e llo w , a p p ro x im a te ly
a I i l ra tio .
So and Im ai s tu d ie d Miyazawa*s m a te r ia l and concluded t h a t
th e c o lo r was n o t a m osaic b u t an endosperm c h a r a c te r c a r r ie d i n th e
a le u ro n e l a y e r .
From t h e i r c l a s s i f i c a t i o n o f t h e Fg p o p u la tio n th e y ob­
ta in e d a 3 :1 r a t i o f o r b lu e to w h ite k e r n e l s .
They co ncluded t h a t th e
c h a r a c te r showed x e n ia and vras in h e r ite d a s a s i n g l e - f a c t o r d if f e r e n c e .
S im ila r r e s u l t s were re p o rte d b y B uckley ( 2 ) , who d id n o t l i s t th e
c ro s s e s s tu d ie d , and by R o b e rtso n , Doming, and Koonce ( 1 7 ) , who s tu d ie d
a c ro s s o f C o lse ss IV x M n n e s o ta 7 2 -8 .
B uckley found a le u ro n e c o lo r to
be in d ep en d e n t o f b la c k v e rs u s w h ite g lum es, two row v e rs u s s i x row , lo n g
v e rs u s s h o r t r a c h i l l a h a i r s , h u lle d v e rs u s naked c a r y o p s is , and p ro b ab ly
in d ep en d e n t o f s t r a i g h t v e rs u s curved p e d u n cle and p u rp le v e rs u s w h ite
lemma.
He found a le u ro n e c o lo r lin k e d w ith hooded v e rsu s awned w ith
41 p e rc e n t c r o s s in g o v e r and p la ce d th e f a c t o r p a i r f o r b lu e v e rsu s
w h ite i n lin k a g e group I I I .
R o b ertso n , Doming, and Koonce a ls o found
a le u ro n e c o lo r t o b e i n h e r ite d in d e p e n d e n tly o f long v e rs u s s h o r t r a c h i l l a
h a i r s and lin k e d w ith hooded v e rs u s awned.
c r o s s in g o v e r .
They found 22.58± 0 .8 2 p e rc e n t
-
13-
Ify le r and S ta n fo rd (15) found a s i n g l e - f a c t o r d if f e r e n c e f o r b lu e
v e rs u s w h ite a le u ro n e i n c ro s s e s o f Kwan (b lu e ) x N epal (w h ite ), A lg e ria n
( b lu e ) x N ep al, and Awnless ( b lu e ) x N ep al, b u t th e y found t h a t th e c o lo r
was a c t u a l l y dependent on tiro com plem entary f a c t o r s .
I n a c ro s s o f two
w h ite v a r i e t i e s , G o ld fo il x N ep al, th e y o b serv ed a 9*7 r a t i o f o r b lu e t o
w h ite i n th e Fg g e n e r a tio n .
They co ncluded t h a t i n c ro s s e s where o n ly a
s i n g l e - f a c t o r d if f e r e n c e i s observed th e b lu e p a re n t has t h e f a c to r s
B lB lB ljB l^ and t h a t th e w h ite p a re n t has e i t h e r B lB lb ljb ]^ o r b lb lB l^ B l^ •
The f a c t o r p a i r B lb l was found to be lin k e d w ith hooded v e rs u s awned w ith
2 4.72 ± 1 .7 3 p e rc e n t c r o s s in g o v e r .
M yler and S ta n fo rd co ncluded t h a t t h i s
was th e san e f a c t o r s tu d ie d by B uckley (2) and R o b ertso n , Doming, and Koonce
(1 7 ), and t h a t i t vjas lo c a te d i n lin k a g e group IV .
The f a c t o r p a i r B ljb l^
was found to b e lin k e d w ith h u lle d v e rs u s naked (Nn) w ith 9 .8 8 ± 0 .4 4 p e r­
c e n t c r o s s in g o v e r and was p la ce d in lin k a g e group I I I .
S p rin g v e rs u s W in te r H a b it o f Growth
G aines (5 ) o bserved w in te r h a b it p la n ts i n th e s e g re g a tin g g enera­
t io n s o f two c r o s s e s . R ice x B e a rd le ss and R ice x E x c e ls i o r , a l l s p rin g
v a rie tie s .
He o b serv ed a r a t i o o f 13 s p r in g to 3 w in te r p la n ts i n th e
Fg g e n e r a tio n and concluded t h a t two f a c t o r s , one an i n h i b i t o r , c o n tr o lle d
h a b i t o f g ro w th .
The o c c u rre n c e o f w in te r h a b it s e g re g a te s in th e progeny o f a c ro s s
o f two s p rin g v a r i e t i e s was a ls o r e p o rte d b y N eatby (1 6 ) .
He concluded
t h a t th r e e f a c t o r p a ir s c o n tr o lle d grow th h a b it i n Guy Mayle x Canadian
Thorpe and t h a t i n th e w in te r - h a b it s e g re g a te s a l l th r e e f a c t o r p a ir s
-
14 -
•were homotygous r e c e s s i v e .
Lax v e rs u s Dense S p ik es
B iffe n ( l ) o b serv ed a s i n g l e - f a c t o r d if f e r e n c e f o r d e n s it y o f sp ik e
w ith la x dom inant o v e r d en se i n th r e e c ro s s e s s tu d ie d .
Similar r e s u l t s
•were re p o rte d by Sturm (1 9 ) , who found t h a t la x v e rsu s dense was i n h e r i t ­
ed in d e p e n d e n tly o f rough v e rs u s smooth awns (E r) and was lin k e d w ith lo n g
v e rs u s s h o r t awns (L kglk^) w ith a p p ro x im a te ly 23 p e rc e n t c ro s s in g o v e r.
In two d i f f e r e n t c r o s s e s , Miyake and Im ai (12) observ ed a s i n g l e - f a c t o r
d if f e r e n c e f o r le x v e rs u s dense s p ik e s .
I n one c ro s s th e d e n s ity f a c t o r
(I q I j ) was lin k e d w ith covered v e rs u s naked seed w ith 13 p e rc e n t c ro s s in g
o v e r , and i n th e o th e r c ro s s th e d e n s it y f a c t o r (L glg) was lin k e d w ith
co vered v e rs u s naked w ith 23 p e rc e n t c ro s s in g o v e r .
N eatby (1 6 ) re p o rte d t h a t a s in g le f a c t o r p a i r w ith m inor m odifying
f a c t o r s c o n tr o lle d d e n s ity i n a c ro s s o f Guy Mayle x Canadian T horpe.
Spike d e n s ity was in h e r ite d in d e p e n d e n tly o f e a r l i n e s s i n t h i s c r o s s , b u t
b o th d e n s it y and e a r l i n e s s were lin k e d w ith l a t e r a l f l o r e t f e r t i l i t y .
A tw o - f a c to r d if f e r e n c e f o r d e n s ity was re p o rte d b y W oxelsen (2 1 ) .
He d e s ig n a te d th e f a c t o r p a ir s L j l 1 and L glg and found t h a t th e f a c t o r
p a i r Lglg was lin k e d w ith rough v e rs u s smooth awn (E r) w ith 10 p e rc e n t
c ro s s in g o v e r .
In a l a t e r p a p e r, Vfexelsen (22) re p o rte d s i n g l e - f a c t o r
and tw o - f a c to r d if f e r e n c e s i n some c r o s s e s s tu d i e d .
One o f th e f a c to r
p a ir s f o r d e n s ity (L ^ l^ ) i n Aspltmd x Smooth awn, C. I . 4 1 5 2 , was lin k e d
w ith th e f a c t o r f o r f e r t i l i t y (Z s) w ith 40 p e rc e n t c r o s s in g o v e r.
Von D bisch (20) coneludod t h a t th r e e f a c t o r p a ir s c o n tr o lle d d e n s ity
in. c ro s s e s t h a t he s tu d ie d •
He found th e la x c o n d itio n dom inant o v er
d e n s e , w ith th e le n g th o f s p ik e d i r e c t l y p r o p o r tio n a l to th e number o f
dom inant f a c t o r s p r e s e n t .
D e n sity was found to be c l o s e l y a s s o c ia te d
w ith awn le n g th .
In s tu d ie s by Hayes and H arlan (8 ) s i n g l e - f a c t o r d if f e r e n c e s were
o b serv ed w ith com plete dominance o f dense o v e r la x i n some c a se s and in ­
com plete dominance i n o t h e r s .
th r e e -fa c to r d iffe re n c e .
I n o th e r c ro s s e s s tu d ie d , th e y observed a
Minor m odifying f a c t o r s w ere p r e s e n t i n some
c ro sse s.
Linkage Groups i n B arley
Seven lin k a g e groups have been e s ta b lis h e d f o r c u l t i v a t e d b a r le y .
The l i t e r a t u r e f o r t h e s e groups has been review ed by R o b e rtso n , Wiobe,
and Im io r (1 8 ) , and f a c t o r p a ir s p re v io u s ly re p o rte d were lo c a te d in
lin k a g e groups w henever p o s s i b l e .
The c h a r a c te r p a ir s in c lu d e d i n t h i s
s tu d y and th e lin k a g e groups i n w hich th e y were p laced a r e g iv en below :
Linkage Groups
I
III
IV
C h a ra c te r P a ir
Long v e rsu s s h o r t awns
Normal v e rs u s reduced
la te r a l s p ik e le t
appendages
Dense v e rs u s la x s p ik e s
Dense v e rs u s la x s p ik e s
Symbol
L klk
L rlr
LI
L414
Dense v e rs u s la x s p ik e s
Dense v e rs u s la x s p ik e s
Dense v e rsu s la x sp ik es
Dense v e rs u s la x s p ik e s
Long v e rs u s s h o r t awns
LI
l L1I
V a
L2I 2
Lklk
Dense v e rs u s la x s p ik e s
Blue v e rs u s w h ite a le u ro n e
LI
B lb l
-
16 -
MATERIALS Aim METHODS
D e s c r ip tio n o f P a re n ts and C h a ra c te rs S tu d ie d
The th r e e v a r i e t i e s u sed a s p a re n ts i n th e c ro s s e s s tu d ie d ware
A rlin g to n A w nless, C. ! • 702, A tra d a , Ce I * 6641, and A tra d a , Ce I e 5638.
A d e s c r ip ti o n o f th e s e v a r i e t i e s f o llo w s .
A rlin g to n Aemless i s c h a r a c te r iz e d by a decumbent ty p e o f growth i n
th e s e e d lin g s t a g e , b lu e a le u r o n e , la x s p ik e s , o c c a s io n a l awn p o in ts on
u s u a ll y a im le s s l a t e r a l s p i k e l e t s , and s h o r t awns on th e c e n t r a l s p i k e l e t s .
The modal c l a s s f o r le n g th o f c e n t r a l awns i s 3 5 .0 mm. t o 3 9 ,9 mm.
A tra d a , C. I . 5641, h as an e r e c t ty p e o f grow th i n t h e s e e d lin g s t a g e ,
b lu e a le u r o n e , la x s p ik e s , and s h o r t c e n t r a l and l a t e r a l aw ns.
The modal
c la s s f o r le n g th o f c e n t r a l awns i s 5 0 .0 mm. to 54 .9 mm., and f o r le n g th o f
l a t e r a l awns i s 3 0 .0 m , t o 3 4 .9 m i.
A tra d a , C. I . 5638, has an e r e c t ty p e o f growth i n th e s e e d lin g s t a g e ,
w h ite 'a le u r o n e , dense s p ik e s , and s h o r t c e n t r a l and l a t e r a l aw ns.
The
mo d a l c l a s s f o r le n g th o f c e n t r a l awns i s 5 0 .0 ram. to 5 4 .9 mm., and fo r
th e le n g th o f l a t e r a l awns i s 3 0 .0 ram. to 3 4 .9 ram.
The decumbent Iype o f grow th made i n th e s e e d lin g s ta g e b y th e
A rlin g to n Awnless v a r i e t y i s s im ila r to t h a t produced b y most w in te r
v a rie tie s of c e re a l c ro p s.
The e r e c t ty p e o f grow th a s o b serv ed i n th e
A tra d a v a r i e t i e s i s s im ila r to th e ty p e o b serv ed i n s p r in g c e r e a l c ro p s .
A lthough i t i s n o t known w h e th e r th e ty p e o f grow th i n th e s e e d lin g s ta g e
i s e n t i r e l y a s s o c ia te d w ith s p r in g and w in te r h a b i t , f o r th e purpose o f
t h i s s tu d y i t w i l l b e assumed t h a t such i s th e c a s e .
T h e re fo re , th ro u g h o u t
t h i s p a p er e r e c t v e rs u s decumbent h a b it o f grow th w i l l be r e f e r r e d t o a s
•17 .
s p r in g v e rsu s w in te r h a b i t .
A rlin g to n Awnless was c ro s se d w ith each o f th e A tra d a v a r i e t i e s i n
1939 a t th e Montana A g r ic u ltu r a l E xperim ent S t a t i o n , Bozeman, M ontana.
The c o n tr a s ti n g c h a r a c te r s s tu d ie d i n each c ro s s a re l i s t e d below :
A rlin g to n Awnless x A tra d a , C. I . 6641
Long v e rs u s s h o r t awns
Normal v e rs u s reduced l a t e r a l awns
S p rin g v e rs u s w in te r h a b it
A rlin g to n Awnless x A tra d a , C. I . 5638
Long v e rs u s s h o r t awns
Normal v e rs u s red u ced l a t e r a l awns
Blue v e rs u s w h ite a le u ro n e
S p rin g v e rs u s w in te r h a b i t
Lax v e rs u s dense s p ik e s
Method o f Growing th e F i l i a l G en eratio n s
The
g e n e r a tio n was grown d u rin g th e w in te r o f 1939-40 i n th e
greenhouse i n W ashington, D. C ., by D r. G. A. Wiebe o f th e D iv is io n o f
C erea l Crops and D is e a s e s .
The Fg and Fg g e n e ra tio n s w ere grown a t th e
Montana A g r ic u ltu r a l Experim ent S ta tio n as a p a r t o f t h e b a r le y improve­
ment program .
The Fg g e n e ra tio n was seeded i n 1940 i n space p la n te d rows w ith
th e seed spaced t h r e e in c h e s a p a r t to a llo w f o r p la n t s e p a r a tio n .
The
decumbent p la n ts were marked i n th e f i e l d d u rin g th e t h i r d week fo llo w ­
in g em ergence.
The p la n ts were p u lle d j u s t b e fo re rip e n in g to be s to re d
18i n th e la b o r a to r y f o r c l a s s i f i c a t i o n o f o th e r c h a r a c t e r s .
The e r e c t and
decumbent p la n ts wore k e p t s e p a ra te when p u lle d *
The P3 g e n e r a tio n was grown i n 1941 j i t -fjos re p e a te d i n 1942 be­
cause th e f a m ilie s grown i n 1941 were so b a d ly w eathered t h a t c o lo r
eo u ld n o t be d e te rm in e d .
The 1941 p la n tin g was made w ith see d from a
random sample o f heads from each ?2 p l a n t .
The seed p la n te d i n 1942 was
from th e Pg heads n o t used f o r s e e d in g i n 1941.
The seed from each Pg
p la n t was sp ace p la n te d i n an e ig h te e n - f o o t row w hich gave an F3 fa m ily .
The F3 f a m ilie s were p u lle d j u s t b e fo re r ip e n in g and were s to r e d f o r
c la s s ific a tio n .
The Fg and F3 g e n e ra tio n s w ere seeded i n th e s p r in g .
Both s p rin g
and w in te r s e g re g a te s headed and m atured when seeded i n th e s p r in g .
Methods o f C l a s s i f i c a t i o n
The F|. p la n ts o f each c ro s s were c l a s s i f i e d f o r th o c h a r a c te r s b e in g
s tu d ie d .
A d e s c r ip ti o n o f t h e F^ ty p e i n each c ro s s f o llo w s :
A rlin g to n Awnless x A tra d a , C. I . 5641
C e n tra l s p i k e l e t s a p p ro x im a te ly tw o - th ir d s f u l l y owned
L a te r a l s p i k e l e t s b e a r in g awns a p p ro x im a te ly o n e -h a lf as
lo n g as th e c e n t r a l awns
A leurone b lu e
P la n ts e r e c t i n th e s e e d lin g s ta g e
S pikes la x
*
A rlin g to n Awnless x A tra d a , C. I . 5638
C e n tra l s p i k e l e t s a p p ro x im a te ly tw o -th ird s f u l l y awned
19 L a te r a l s p i k e l e t s b e a rin g awns a p p ro x im a te ly o n e -h a lf as
lo n g a s t h e c e n t r a l awns
B lue and w h ite a le u ro n e on th e sane s p ik e s , b lu e predom inat­
in g
P la n ts e r e c t i n th e s e e d lin g s ta g e
S p ik es la x
A p re lim in a ry c l a s s i f i c a t i o n o f th e Fg g e n e ra tio n p la n ts was made
on th e b a s is o f t h e i r p h e n o ty p es; t h i s c l a s s i f i c a t i o n was c o rre c te d and
th e Fg genotypes were determ ined by ch eck in g t h e b re e d in g b e h a v io r o f
each Fg p la n t in th e F3 g e n e r a tio n .
C l a s s i f i c a t i o n f o r grow th h a b it was made in th e f i e l d on th e b a s is
o f ty p e o f grow th e x h ib ite d by th e p la n ts d u rin g th e second o r t h i r d week
fo llo w in g em ergence.
I t was c o n sid e re d t h a t th e s e g re g a te s making an
e r e c t ty p e o f grow th were s p rin g h a b it p l a n t s , and th e s e g re g a te s t h a t
made a decumbent ty p e o f grow th were w in te r h a b it p l a n t s .
C l a s s i f i c a t i o n f o r aw nedness, a le u ro n e c o lo r , and d e n s ity o f sp ik e
was made i n th e la b o r a to r y .
I n o rd e r t o e s t a b l i s h p h e n o ty p ic awn c la s s e s
i t was n e c e s s a ry to s tu d y v a r i a t i o n i n awn le n g th .
I t was e v id e n t t h a t
such a s tu d y was n e c e s s a ry from v a r i a t i o n s observ ed i n th e F% g e n e ra tio n
and from observed v a r i a t i o n s w ith in th e A rlin g to n Awnless v a r i e t y .
Ten
p la n ts o f th e A rlin g to n Awnless p a r e n ta l v a r i e t y were s e le c te d a t random
from a group o f s e v e n ty grown i n a space p la n te d row i n 1941.
were ta k e n from each p la n t f o r awn m easurem ent.
Ten heads
The f o u r t h s p i k e l e t from
th e b a s e o f th e h e a d , c o u n tin g s p i k e l e t s on o n ly one s id e o f th e r a o h is ,
was a r b i t r a r i l y chosen as th e one on w hich to measure th e c e n t r a l awn.
—20—
The nean le n g th o f c e n t r a l avcia on each p la n t and th e s ta n d a rd e r r o r o f
each Iaeem m s d e te rm in e d .
F i s h e r ’s a n a ly s is o f v a ria n c e method and th e
F and t t e s t s were used t o d e term in e w h eth er o r n o t d if f e r e n c e s betw een
th e means w ere s i g n i f i c a n t .
The le n g th o f th e lo n g e s t l a t e r a l awn p o in t
i n th e c e n tr a l p o r tio n o f each head was re c o rd e d i n o rd e r t o d eterm in e th e
fre q u e n c y o f o c c u rre n c e .
On th e b a s i s o f in fo rm a tio n o b ta in e d re g a rd in g v a r i a b i l i t y o f awn
le n g th and fre q u e n c y o f o c c u rre n c e o f awn p o in ts and on th e b a s i s o f th e
Fg and Fg s e g r e g a tio n , th e s e g re g a te s w ere d iv id e d in to s i x p h en o ty p ic
awn c la s s e s as d e s c rib e d below :
D e s c rip tio n
L a te r a l Awns
C e n tra l Awns
I
Awnless
None
None o r p o in ts
2
A rlin g to n
Awnless ty p e
None o r p o in ts
Modal c la s s f o r
le n g th 5 5 .0 nm.
-3 9 .9 mm.
S
Reduced A tra d a
ty p e
Modal c la s s f o r
le n g th 5 .0 mm.9 .9 mm.
Modal c la s s f o r
le n g th 2 5 .0 mm.
-2 9 .9 mm.
4
A trad a ty p e
Modal c l a s s f o r
le n g th 3 0 .0 mm.3 4 .9 mm.
Modal c la s s f o r
le n g th 4 5 .0 mm.
- 5 4 .9 mm.
5
f I ty p e —
C e n tra l awns
tw ic e a s long
as l a t e r a l s
Modal le n g th
a p p ro x im a te ly 40 mm.
Modal le n g th
a p p ro x im a te ly
80 mm.
6
F u lly awned
Modal le n g th
a p p ro x im a te ly HO mm.
Modal le n g th
a p p ro x im a te ly
115 nm.
C la ss No.
Heads o f b a r le y r e p r e s e n ta tiv e o f th e s e awn c la s s e s a r e shown in
p la te I I .
-
21 -
The s e g r e g a te s vmre grouped i n t o two p h en o ty p ic c la s s e s f o r a le u ro n e
c o lo r*
The homozygous b lu e and h e tero zy g o u s p la n ts w ere in c lu d e d i n th e
b lu e c la s s and t h e homozygous w h ite p la n ts com prised th e w h ite c la s s *
Two p h en o ty p ic c la s s e s f o r d e n s it y o f s p ik e were o b s e rv e d .
The
s e g r e g a te s were c l a s s i f i e d a s la x o r dense on a v is u a l b a s i s .
Symbols f o r G en etic C h a ra c te rs
A ll g e n e tic symbols e x c e p t th e one f o r s p rin g v e rs u s w in te r h a b it
were ta k e n from th e l i s t o f symbols recommended by R o b e rtso n , W iebe, and
Immer ( 1 8 ) .
The s u b s c r ip t numbers used i n m ost c ase s in d ic a te t h a t th e s e
f a c t o r p a ir s a re n o t n e c e s s a r ily th e same ones re p o rte d b y p re v io u s w o rk e rs.
The f a c t o r p a i r s f o r awn le n g th and la x v e rs u s dense s p ik e s i n th e c ro s s
A rlin g to n Awnless x A tra d a , C. I . 5638, were found to be th e same ones r e ­
p o rte d by Sturm (19) and were a ss ig n e d th e same s u b s c r ip t numbers used by
him*
The g e n e tic symbols used a re l i s t e d below :
C h a ra c te r P a i r :
Symbols Used:
Long v e rs u s s h o r t awns
Normal v e rs u s re d u c ed l a t e r a l awns
Blue v e rs u s w h ite a le u ro n e c o lo r
S p rin g v e rs u s w in te r h a b it
Lax v e rs u s dense s p ik e s
^4 , Lk5I k 5
Lr1I r 1
B lg b l2
Be
l S1S
A n a ly sis o f D ata
A ll p h en o ty p ic r a t i o s o bserved i n t h e Pg g e n e ra tio n and a l l geno­
ty p ic r a t i o s a s determ ined by th e Fg s e g r e g a tio n were compared to c a l­
c u la te d t h e o r e t i c a l r a t i o s .
The o b serv ed r a t i o i n each c ase was te s t e d
f o r goodness o f f i t t o th e c a lc u la te d r a t i o b y use o f th e C h i-sq u are t e s t .
-
22-
A ll P v a lu e s w ere ta k e n fro m th e t a b l e o f C h i-sq u a re p re p a re d b y F is h e r
(4 ) .
To t e s t f o r lin k a g e betw een th e v a rio u s c h a r a c te r s s tu d ie d , th e
o b serv ed g e n o ty p ic r a t i o f o r each c h a r a c te r was combined i n a d ih y b rid
r a t i o w ith th e o b serv ed g e n o ty p ic r a t i o f o r e v e ry o th e r c h a r a c te r s tu d i e d .
Each o f th e s e d ih y b rid r a t i o s was compared w ith a c a lc u la te d It2 i2 i4 * l* 2 *
1*2:1 r a t i o by u se o f th e C h i-sq u are t e s t .
Iihen th e o b serv ed r a t i o f i t
th e c a lc u la te d r a t i o c l o s e l y , th e f a c t o r p a ir s b ein g t e s t e d w ere c o n s id e r­
ed in d ep en d en t o f each o t h e r .
I f a poor f i t t o th e c a lc u la te d r a t i o was
o b ta in e d , th e f a c t o r p a ir s were assumed t o be lin k e d .
C ro sso v er v a lu e s were determ ined by th e p ro d u c t m ethod.
c a l c u l a t i o n , th e ta b le s p re p a re d by limner (10) were u s e d .
To f a c i l i t a t e
The observed
r a t i o was compared w ith t h e r a t i o e x p ec te d w ith th e c a lc u la te d p e rc e n t­
age o f G ro s s in g o v e r by u se o f t h e C h i-sq u a re t e s t f o r goodness o f f i t .
KIPERIMEHTAL RESULTS
V a r ia tio n i n Avm Length
V a r ia tio n i n awn le n g th was s tu d ie d a s a p re lim in a ry s te p in
e s t a b l i s h i n g p h en o ty p ic awn c l a s s e s .
The d a ta o b ta in e d on th e p la n ts
s e le c te d f o r s tu d y from th e A rlin g to n Awnless p a re n t a p p ea r i n ta b le I ,
Some o f th e d if f e r e n c e s betw een mean le n g th s o f c e n t r a l awns were found
to be s i g n i f i c a n t , in d ic a tin g t h a t en v iro n m e n ta l f a c t o r s d e f i n i t e l y a f f e c t ­
ed awn dev elo p m en t,
Awn p o in ts on l a t e r a l s p ik e le ts were o b serv ed on as
many a s s i x o f t h e te n heads ta k e n from some o f th e p l a n t s ,
T o leran ce
w ith in awn c la s s e s i s b ased on th e r e s u l t s o f t h i s s tu d y .
I n h e r ita n c e o f Awnednesa
S in c e i t was n e c e s s a ry to summarise th e r e s u l t s o b ta in e d i n b o th
c ro s s e s b e fo re th e node o f in h e r ita n c e c o u ld b e e x p la in e d s a t i s f a c t o r i l y ,
th e r e s u l t s o b ta in e d w ith b o th c ro s s e s w i l l be p re s e n te d f i r s t and w ill b e
fo llo w e d by an e x p la n a tio n o f th e mode o f i n h e r i t a n c e ,
A rlin g to n Awnless x A tra d a , C, I , 5641. -
The
progeny o f t h i s c ro s s had
lo n g e r awns th a n e i t h e r p a r e n t, in d ic a tin g t h a t each p a re n t c a r r ie d dom inant
o r p a r t i a l l y dom inant genes f o r th e developm ent o f awns n o t c a r r ie d b y th e
o th e r.
The c e n t r a l awns were a p p ro x im a te ly tw o -th ird s f u l l y owned, and
th e l a t e r a l awns w ere a p p ro x im a te ly o n e - h a lf as long a s th e c e n t r a l awns
( P la te I ) ,
T ra n s g re s s iv e s e g r e g a tio n f o r awnedness was ob serv ed i n th e Fg
g e n e r a tio n , th e s e g re g a te s ra n g in g from aw nless to f u l l y owned (P la te I I ) ,
The o b serv ed and c a lc u la te d Fg p h en o ty p ic r a t i o s a r e g iv en i n t a b l e I I ,
24 T able I
¥ la n t
number
I
2
3
4
5
6
7
8
9
10
M easurem nta re c o rd e d and th e a n a ly s is o f v a ria n c e
c a lc u la te d on c e n t r a l a m le n g th s as a p a r t o f th e
s tu d y o f v a r i a t i o n i n a m le n g th w ith in th e A rlin g to n
A m le s s v a r i e t y
2
I
0
0
7
0
5
5
0
20
5
0
3
Length o f
0
0
0
0
0
0
0
0
0
0
0
7
0
0
0
15
0
0
10
15
Head number
5
6
I
T~
8
S
10
l a t e r a l awn p o in ts i n m illim e te rs
15
0
0
0
0
0
0
5
0
0
0
0
0
0
0
0
0
0
5
7
10
0
0
0
0
5
0
0
0
5
0
0
10
5
15
7
0
0
0
7
0
0
5
7
10
0
15
15
8
7
0
0
6
0
0
12
0
10
5
0
5
0
0
16
12
0
0
5
7
0
Mean S .E .
Length o f c e n t r a l a m s i n m illim e te rs
I
2
3
4
5
6
7
8
9
10
25
40
45
25
30
25
35
50
46
50
45
25
25
35
20
45
25
65
50
45
30
25
25
35
40
20
45
45
40
55
40
35
30
50
45
25
40
50
35
35
45
50
40
20
40
25
50
30
25
55
40
25
40
so
60
15
50
35
20
45
7
40
35
25
30
20
40
25
25
35
35
36
50
25
35
40
40
35
25
56
15
25
40
25
40
30
50
50
30
45
20
40
40
6
35
35
40
35
10
40
30.2+ 4.15
3 2 .0 * 2 .1 3
3 7 .0 * 2 .6 0
2 7 .5*3.67
3 7 .5 * 3 .3 5
2 8 .0 * 3 .0 0
4 1 .5 * 2 .4 8
4 2 .0 * 5 .0 6
30 e5±3 #83
4 6 .0 * 2 .4 5
A n a ly sis o f v a ria n c e on le n g th o f c e n t r a l a m s
V a r ia tio n due t o t
P la n ts
Heads
In te ra c tio n
T o ta l
Sum o f sq u ares
9
9
81
99
3759.56
1052.56
8317.04
13129.16
Mean sq u are
417.73
116.95
102.68
V ariance F
4.07**
1 .1 4
10.13
**F v a lu e s i g n i f i c a n t a t th e 1% p o in t
S eE eX ■ 3 .3 8
®e® * d iffe “ 4 .7 7
L ev el o f S ig n ific a n c e (S?£) * 9.3 5
t - 1.95996
25 The c a lc u la te d 3 * 6 tl:2 :3 $ l r a t i o f o r th e awn ty p e s 6 , 5 , 4 , 3 , 2 , and I i s
th e r a t i o e x p ec te d w ith awnedness in h e r i t e d a s a tw o - f a c to r d if f e r e n c e
w ith com plete dominance i n one f a c t o r p a i r and in co m p lete dominance i n
th e o t h e r .
When th e o bserved and c a lc u la te d r a t i o s wore co mpared, a P
v a lu e o f 0 .6 6 was o b ta in e d in d ic a tin g t h a t th e o b serv ed r a t i o f i t th e
c a lc u la te d r a t i o c l o s e l y .
T ab le I I
Item
Observed and c a lc u la te d Pg p h en o ty p ic r a t i o s f o r awn
ty p e s i n A rlin g to n Awnless x A tra d a , C. I . 5641
F u lly
awned
(6)
Observed
co u n ts
19
C a lc u la te d
3 :6 * 1 ;2 ;3 ;1
1 8.19
ra tio
Number o r in d ic a te d
A tiada Beduoed
F1
ty p e ty p e
A trad a
ty
p e (3)
(5)
(4)
phenotype
A rlin g to n
Awnless
ty p e (2 )
Awnless
(I)
T o ta ls
42
6
13
15
3
97
36.38
6 .0 6
12.12
18.19
6.0 6
97.00
X2
3.258
P
0 .6 6
The o b serv ed Fg g e n o ty p ic r a t i o a s d eterm in ed by th e Fg s e g re g a tio n
and th e c a lc u la te d g e n o ty p ic r a t i o a r e g iv e n i n t a b l e I I I .
The c a l c u l a t ­
ed I i 2 i 2 t 4 s l s 2 i l s 2 i l g e n o ty p ic r a t i o f o r awnedness i s th e r a t i o ex p ected
w ith in h e r ita n c e on a tw o - f a c to r b a s i s w ith in d ep en d en t a s s o rtm e n t o f
th e two f a c to r p a i r s .
The observed r a t i o f i t th e c a lc u la te d r a t i o c lo s e ly ,
a P v a lu e o f 0 .7 1 b e in g o b ta in e d .
26T able I I I
Observed and c a lc u la te d Fg g en o ty p ic r a t i o s f o r awnedness
a s determ ined by th e Fg s e g r e g a tio n i n A rlin g to n Awnless
x A tra d a , C. I . 5641
C a lc u la te d
li2 t2 i4 ili2 tL i2 tl
ra tio
N um erical
awn c la s s
Observed
c o u n ts
L rjL r1Lk6Lk5
6
6
6.0625
Lr1L rl Lk6I k 5
6
13
12.1250
Lr1I r 1Lk6Lk6
5
11
12.1250
Lr1I r 1Lk6I k 6
5
31
24.2500
L r1Lr1Ik 6I k 6
4
5
6.0625
Lr1I r 1I k 5I k 5
3
13
12.1250
I r 1I r 1 Lk5Lk5
2
7
6.0625
I r 1I r 1Lk5I k 5
2
8
12.1250
I r 1I r 1I k 5Ik 5
I
3
6.0625
97
97.0000
Genotypes
T o ta ls
A rlin g to n Avmlsss x A tra d a , C. I . 5638 . -
X2
p v a lu e
5.392
0.71
The F1 progeny o f t h i s c ro s s had
lo n g e r awns th a n e i t h e r p a re n t in d ic a tin g t h a t i n t h i s c ro s s a ls o each
p a re n t c a r r ie d dom inant o r p a r t i a l l y dom inant genes f o r th e developm ent o f
awns n o t c a r r ie d by th e o t h e r .
The c e n t r a l s p ik e l e ts were a p p ro x im a te ly
tw o - th ir d s f u l l y awned, and th e l a t e r a l awns were a p p ro x im a te ly o n e -h a lf
a s long as th e c e n t r a l awns ( P la te I ) .
The awn ty p e s o b serv ed i n th e Fg g e n e ra tio n were 2 , 3 , 4 , 5 , and 6
( P la te I I ) •
The o b serv ed and c a lc u la te d p h en o ty p ic r a t i o s a r e g iv en i n
-
t a b l e IVe
27 -
When th e o b serv ed r a t i o was compared w ith a c a lc u la te d
5 t 6 t l : 2 i 4 r a t i o f o r th e aim ty p e s 6 , 5 , 4 , 3 , and 2 , a P v a lu e o f 0 .8 3 m s
o b ta in e d , in d ic a tin g t h a t th e o b serv ed r a t i o f i t th e c a lc u la te d r a t i o
c lo s e ly .
The c a lc u la te d 3:6:1 * 2 * 4 r a t i o i s th e r a t i o e x p e c te d i f awned-
neos i s i n h e r i t e d as a tw o - f a c to r d if f e r e n c e w ith com plete dominance in
one f a c t o r p a i r and in co m p lete dominance i n th e o th e r w ith th e I r ^
and
I r ^ l k 4 phenotypes i n d i s tin g u is h a b l e .
T able IV
Observed and c a lc u la te d Pg p h en o ty p ic r a t i o s f o r awnedn e s s i n A rlin g to n Awnless x A tra d a , C. I . 5638
Humber o f in d ic a te d phenotype
P1
A trada Reduced
A rlin g to n
ty p e
A trad a
Awnless ty p e
(2 )
T o ta ls
ty p e (3 )
(5)
(S T
Item
F u lly
awned
(6)
Observed
co u n ts
15
34
6
C a lc u la te d
3 :6 :1 :2 :4
ra tio
15.19
30.38
5.06
9
10.12
17
81
20.25
81.00
X2
1.484
P
0 .8 3
The Fg g e n o ty p ic r a t i o as d eterm in ed b y th e Pg s e g r e g a tio n and th e
c a lc u la te d g e n o ty p ic r a t i o a re g iv en i n t a b l e V .
The c a lc u la te d 1 ;2 * 2 :4 :
1 :2 :4 r a t i o f o r awnedness i s th e r a t i o e x p ec te d w ith awnedness in h e r ite d
a s a tw o - f a c to r d if f e r e n c e w ith th e tiro f a c t o r p a ir s in d e p e n d e n tly a s s o r te d
when th e I r 1Ir^L k 4Lk4 , I r 1I r 1Lk4 Ik 4 , and I r ^ l r 1 Ik4Ik 4 g enotypes can n o t be
s a tis fa c to rily d iffe re n tia te d .
When th e o b serv ed and c a lc u la te d r a t i o s
w ere compared a P v a lu e o f 0 .6 2 was o b ta in e d .
T his agreem ent betw een th e
observed and t h e o r e t i c a l r a t i o s i n d i c a t e s t h a t th e assu m p tio n o f a tvrof a c t o r d if f e r e n c e f o r aw nedness i s p ro b a b ly c o r r e c t .
-
28-
T able V O bserved and c a lc u la te d Fg g e n o ty p ic r a t i o s f o r atm ednesa
a s d eterm in ed by th e Fg s e g r e g a tio n in A rlin g to n Awnless
x A tra d a , C. I . 5638
Awn
c la s s
Genotype
L riL riL k jL k j
L r iL r iL k jlk j
L f jlr iL k jL k j
L rilriL k jlk j
L riL fjlk jlk j
L f j l r j Ik ^ lk j
IrjlfjL k jL k j
IrilriL k jlk j
l r i l r i Ik jlk j
T o ta ls
6
6
6
5
4
3
2
2
2
Observed
c o u n ts
C a lc u la te d
Ii2i2 :4 tl:2 :j
ra tio
3
12
7
27
6
9
6.0625
10.1250
10.1250
20.2500
5.0625
10.1250
17
20.2500
81
81.0000
X2
5 .193
p v alu e
0 .52
An a tte m p t was made to s e p a r a te th e th r e e g e n o ty p es, Ir ilr iL k ^ L k j.,
I r i l r i L k j l k j * and 1*1 I r i I k j l k j , t h a t were grouped in to th e p h en o ty p ic awn
c la s s 2 ,
The c e n t r a l awns o f f i f t e e n Fg fa m ilie s grown from Fg p la n ts
in c lu d e d i n t h i s group were m easured.
The le n g th s re c o rd e d wore grouped
in to c la s s e s o f 1 0 .0 nan. and th e freq u e n cy d i s t r i b u t i o n o f each fa m ily
was compared to th e d i s t r i b u t i o n o f awn le n g th s i n th e A rlin g to n Awnless
p a re n t v a r i e t y .
The freq u e n cy d i s t r i b u t i o n o f c e n tr a l awn le n g th s in
th e s e Fg fa m ilie s and i n A rlin g to n Awnless a r e p re se n te d i n ta b l e VT•
From th e s e d i s t r i b u t i o n s i t i s e v id e n t t h a t most o f th e s e f a m ilie s were
d i f f e r e n t from A rlin g to n A w nless, b u t i t w ould be n e c e s s a ry to grow an
a d d itio n a l g e n e r a tio n to d eterm in e w h eth er o r n o t th e genotypes co u ld be
d is tin g u is h e d .
-
T able TI
F am ily
number
29-
Frequency d i s t r i b u t i o n o f c e n t r a l aim le n g th s i n Fg
f a m ilie s groim from f i f t e e n Fg p la n ts c l a s s i f i e d as
h av in g th e A rlin g to n A im le ss, o r 2 , aim ty p e
Length i n m illim e te r s
2 0 .0 -2 9 .9 3 0 .0 -3 9 .9 4 0 .0 -4 9 .9
0 .0 - 9 .9
1 0 .0 -1 9 .9
5
17
TT
I
0
6
12
5
4
I
4
0
0
I
0
8
?
24
"SG
15
TZ
TZ
11
11
6
6
6
0
5
0
0
8
12
15
10
11
18
ZZ
TZ
—
7
9
2
4
0
0
6
2
7
10
7
13
8
6
10
To
ZZ
TZ
-z
6
0
0
I
0
4
5
5
6
2
2
3
8
13
8
ZZ
0
I
0
0
I
0
0
0
0
0
0
I
7
I
6
0
I
0
5
2
2
57
7
8
14
72
73
Tl
4
9
5
28
2
75
3
74
A rlin g to n
A im less
5 0 .0 —59 .9
The r e s u l t s in d ic a te t h a t i n each c ro s s awnednoss was in h e r ite d as
a tw o - f a c to r d if f e r e n c e w ith com plete dominance i n one f a c t o r p a i r and
in co m p lete dominance i n th e o t h e r .
I n each p a re n t i n th e two c ro s s e s one
o f th e f a c t o r p a i r s was in th e dom inant and th e o th e r i n th e r e c e s s iv e
c o n d itio n .
On th e b a s is o f s e g r e g a tio n o b s e rv e d , i t was concluded t h a t
i n each c ro s s one f a c t o r p a ir a f f e c t e d l a t e r a l awn developm ent p rim a rily
and th e o th e r f a c t o r p a i r a f f e c t e d awn le n g th o n ly .
The f a c t o r p a i r f o r norm al v e rs u s reduced l a t e r a l awns was d e sig n a te d
L r^ lr^ .
S in ce th e A rlin g to n Awnless p a re n t had no l a t e r a l aw ns, i t was
assumed t h a t i t c a r r ie d th e f a c to r p a i r f o r l a t e r a l awn developm ent i n th e
r e c e s s iv e c o n d itio n ( I r - ^ lr ^ ) .
-
30-
A lthough th e aims o f th e two A tra d a p a re n ts a re s i m i l a r , th e se v a r­
i e t i e s c a r r y d i f f e r e n t dom inant f a c t o r s f o r aim le n g th ^ /.
The f a c t o r f o r
a m le n g th c a r r ie d i n th e r e c e s s iv e c o n d itio n i n A tra d a , C. I , 6638, m s
r e p o r te d by Sturm (1 8 ), who d e sig n a te d i t Lk4Ik 4 .
This v a r i e t y c a r r ie d
one f a c t o r f o r aim le n g th i n th e dom inant c o n d itio n , w hich i s d e sig n a te d
i n t h i s s tu d y .
On th e b a s is o f th e s e f a c t s tmd on th e assum ption
t h a t A rlin g to n A im less c a r r i e s Lr^
ty p e s o f th e A trad a p a re n ts would b e:
th e r e c e s s iv e c o n d itio n , th e geno­
A tra d a , C. I . 5641, L r1Lr1Lk4Lk4
I k 5I k 5 , and A tra d a , C. I . 5638, L r iL r iI k 4 Ik 4Lk5Lk5 .
S in ce th e r e s u l t s
in d ic a te d a tw o - f a c to r d if f e r e n c e i n each c r o s s , th e genotype o f A rlin g to n
Awnless m s assumed to be I r i l r i L k 4Lk4Lk5Lk5 .
H y p o th e tic a l genotypes o f
th e Fg g e n e ra tio n s e g re g a te s were b ased on th e s e p a r e n ta l g e n o ty p es.
These Fg genotypes and th e s e g re g a tio n observ ed in th e F5 g e n e ra tio n a re
g iv e n i n ta b l e V I I .
The c lo s e n e s s o f f i t o f th e p h en o ty p ic and g e n o ty p ic r a t i o s observed
i n th e two c ro s s e s to th e r a t i o s e x p ec te d on th e b a s is o f th e h y p o th e sis
fo rm u la te d in d ic a te t h a t t h i s h y p o th e sis i s p ro b a b ly c o r r e c t .
The p re se n c e o f th e dom inant awn le n g th f a c t o r Lk4Lk4 i n th e a im le ss
s e g re g a te s from th e c ro s s A rlin g to n Awnless x A tra d a , C. I . 5641, can be
s a t i s f a c t o r i l y e x p la in e d i f i t i s assumed t h a t t h i s f a c t o r p a i r (Lk4 ) i s
d ependent on th e p re se n c e o f Lr1 i n th e dom inant c o n d itio n i n o rd e r to
produce any e f f e c t .
C o n v erse ly , th e absence o f any a im le ss s e g re g a te s i n
5 / U npublished d a ta on awn in h e r ita n c e s tu d ie s by S . C. L itz e n b e rg e r,
Montema A g r ic u ltu r a l E xperim ent S t a t i o n , Bozeman, Montima.
-
Table V lI
31 -
H y p o th e tic a l genotypes and ob serv ed b re e d in g b e h a v io r
o f th e Fg g e n e r a tio n s e g re g a te s i n A rlin g to n Avmloss x
A tra d a , C. I* 5641, and A rlin g to n Avmless x A tra d a ,
C. I . 5638
Grenotypic
ra tio
Fg genotype
N um erical
a m c la s s
A rlin g to n Awnless x A tra d a , C. I . 5641
IriIriL kflIikgL ksL ks
I
66 I
L r1LriiLk4Lk^Lk5I k 5
2
2
L r1I r 1Lk^Lk^LkgLkg
H ien o ty p ie S e g re g a tio n ObseiiV-'
ed i n th e FJj gom ratim
ra tio
3
5
—
6
4
Lr j l r ^Lk^Lk^Lkglkg
5
I
Lr1L r1Lk4Lk4I k 5Ik 5
4
1
2
L r1I r 1Lk4Lk4I k 5I k 5
3
2
I
I r 1I r 1I k 4Lk4LkgLkg
2
2
I r 1I r 1Lk4Ik4 Lk5I k 5
2
3
I r 1I r 1Lk4Lk4 Ik 5I k 5
I
I
A rlin g to n A m le s s x A tra d a , Ce I . 5638
6
Lr1L r1I k 4Lk4Lk5Lk5
I
1
True b re e d in g .
3
2
Lr1L r1Ik 4Ik 4LkgLk5
6
2
Lr1I r 1L k ^ k 4Lk5Lk5
5
4
L rl I r l Lk4 Ik 4Lk5Lk5
5
I
L r1Lr1 Ik 4Ik 4Lk5I k 5
4
I
2
L r1I r 1Ik 4Ik 4Lk6Lk5
3
2
I r 1I r I^Ik4Ik 4Lk5I k 5
2
6
4
l r l l r l Lk4l k 4Lk5Lk5
l r I l r I l lc4Bc4Lk5Lk5
2
2
True b re e d in g .
S e g re g a tin g f o r
c la s s e s 4 and 6 .
S e g re g a tin g f o r
c la s s e s 2 ,5 and 6 .
S e g re g a tin g f o r a l l
c l a s s e s , I to 6 ,
True b re e d in g (A trad a
ty p e )
S e g re g a tin g f o r
c la s s e s 1 ,3 , and 4 .
True b re e d in g (Arl i n g to n Avmless ty p e ) .
S e g re g a tin g f o r
c la s s e s I and 2 .
True b re e d in g .
4
S e g re g a tin g f o r
c la s s e s 4 and 6 .
S e g re g a tin g f o r
c la s s e s 2 ,5 , and 6 .
S e g re g a tin g f o r
c la s s e s 2 to 6 .
True b re e d in g (A trada
ty p e ).
S e g re g a tin g f o r
c la s s e s 2 ,3 , and 4 .
True b re e d in g (A r lin g to n Avmless ty p e ) .
A p p a re n tly t r u e b re e d ­
in g .
True b re e d in g .
-
32-
th e progeny o f A rlin g to n Awnless x A tra d a , C. I . 5638, can be e x p la in e d
by th e p re se n c e o f th e le n g th f a c t o r LkgLkg i n th e dom inant c o n d itio n i f
t h i s f a c t o r i s assumed to be in d ep en d e n t o f Lr% i n i t s e x p re ssio n #
P ro n in s p e c tio n o f th e genotypes l i s t e d i t can be see n t h a t norm al
l a t e r a l awns was p a r t i a l l y dom inant o v e r re d u c ed s in c e th e s e g re g a te s
c a r r y in g L r ^ lr^ i n th e h etero zy g o u s c n d i t i o n w ere le s s awned th a n th o s e
c a r r y in g t h i s f a c t o r p a i r i n th e homozygous dom inant c o n d itio n .
I t can
a ls o be seen b y com paring th e s e g r e g a te s i n c la s s e s 2 , 5 , and 6 , which
c a r r i e d l r ^ l r ^ , L r ^ lr ^ , and Lr^Lr^ r e s p e c tiv e ly t h a t t h i s f a c t o r p a i r
a f f e c t e d le n g th o f c e n t r a l awns w ith lo n g awns p a r t i a l l y dom inant over
s h o rt#
The c e n t r a l awns i n c l a s s 2 were s h o r t , i n c la s s 5 , in te r m e d ia te ,
and i n c la s s 6 , lo n g .
I n each o f th e f a c t o r p a ir s a f f e c t i n g awn le n g th o n ly (Lk^lk^ and
L kblkg) lo n g "tmS a p p a r e n tly c o m p le te ly dom inant o v e r s h o r t .
t h a t c a r r i e d th e le n g th f a c t o r (Lk*, o r Lkg) i n th e
The s e g re g a te s
homozygous dominant
c o n d itio n c o u ld n o t be d is tin g u is h e d on a v i s u a l b a s is from th o s e t h a t
were h etero zy g o u s f o r th e same f a c t o r p a ir#
I n h e r ita n c e o f A leurone C olor
i n A rlin g to n Awnless x A tra d a , C. I , 5638
S e g re g a tio n f o r b lu e and w hite a le u ro n e was o bserved on th e
h e a d s,
b u t no a tte m p t was made to an aly z e t h i s s e g r e g a tio n i n t h i s g e n e r a tio n .
R a tio s were determ ined on th e p la n t b a s is i n th e Fg g e n e r a tio n and wore
c o r r e c te d a f t e r c h ec k in g s e g r e g a tio n i n th e Fg g e n e r a tio n .
O f th e 80 Fg
p la n ts c l a s s i f i e d , 60 were c l a s s i f i e d a s b lu e and 20 as w h ite .
The o b serv ed
<
-3 5 r a t i o f i t a c a lc u la te d 3 :1 r a t i o e x a c tly , in d ic a tin g a s i n g l e - f a c t o r
d iffe re n c e e
The b re e d in g b e h a v io r o f 77 o f th e F2 p la n ts m s o b serv ed i n th e
F3 g e n e r a tio n .
The o b serv ed and c a lc u la te d F2 g e n o ty p ic r a t i o s as de­
te rm in e d by th e F3 s e g r e g a tio n a re g iv en in t a b l e V I I I .
A P v a lu e o f
0 .7 2 m s o b ta in e d , i n d ic a tin g t h a t th e o b serv ed r a t i o f i t th e c a lc u la te d
1 :2 :1 r a t i o c l o s e l y .
T his c lo s e n e s s o f f i t to a monohybrid r a t i o in d ic a te s
t h a t a le u ro n e c o lo r was in h e r ite d a s a s in g le —f a c t o r d i f f e r e n c e .
T able VTII
Observed and c a lc u la te d F2 g en o ty p ic r a t i o s f o r b lu e
v e rs u s ■white a le u ro n e as d eterm in ed b y th e F3
s e g r e g a tio n o f A rlin g to n Awnless x A tra d a , C . I . 5638
Number o f in d ic a te d genotype
^ l 2B l2
B lgblg
b lg b lg
O bserved
c o u n ts
C a lc u la te d
1 :2 :1
ra tio
T o ta ls
17
42
18
77
1 9 .25
38.50
19.25
77.00
X2
0.662
P
0 .72
I n h e r ita n c e o f Growth H a b it in
A rlin g to n Awnless x A tro d a , C. I* 5641
The p la n ts o f th e F^ g e n e r a tio n made a n e r e c t ty p e o f g ro w th , in ­
d i c a t i n g t h a t s p r in g h a b it o f grow th was dom inant o v er w in te r .
The F2 p h en o ty p ic and g e n o ty p ic r a t i o s a s d eterm in ed b y th e Fg
s e g r e g a tio n a r e g iv en i n t a b l e s IX and X r e s p e c t i v e l y .
The p h en o ty p ic
r a t i o f i t a c a lc u la te d 3 :1 r a t i o c l o s e l y , a P v a lu e o f 0 .5 0 b e in g o b ta in e d .
The g e n o ty p ic r a t i o f i t a c a lc u la te d 1 :2 :1 r a t i o c lo s e ly s in c e a P v alu e
o f 0.61 was o b ta in e d
-34 -
I t Tsas concluded t h a t g r o w t h h a b i t was i n h e r i t e d a s a s i n g l e - f a c t o r
d if f e r e n c e i n t h i s c r o s s .
S p rin g h a b i t o f grow th was a p p a r e n tly com plete­
l y dom inant o v e r w in te r*
T able H
Observed Pg ph en o ty p ic r a t i o s f o r s p rin g v e rs u s w in te r
grow th h a b it i n A rlin g to n Awnless x A tra d a , C. I* 5638,
and i n A rlin g to n Awnless x A tra d a , C. I . 5641
Number o f in d ic a te d phenotype a /
S p rin g
W in te r t o t a l s
Cross
X2
P
A rlin g to n Awnless x
A tra d a , C. I* 5641
76
21
97
0 .5 0 1
0 .5 0
A rlin g to n Awnless x
A tra d a , C. I* 5638
66
15
81
1 .8 1 5
0 .1 8
Compared w ith a c a lc u la te d 3 :1 r a t i o *
I n h e r ita n c e o f Growth H a b it i n
A rlin g to n Awnless x A tra d a , C* I . 6638
The
p la n ts o f t h i s c ro s s a ls o made an e r e c t ty p e o f gro w th , in ­
d ic a t in g t h a t s p rin g h a b i t was dom inant o v e r w in te r .
The o bserved and c a lc u la te d Fg p h e n o ty p ic r a t i o s a r e g iv en i n
t a b l e IX*
Of th e 81 Fg p la n ts c l a s s i f i e d , 66 were o f th e e r e c t ty p e and
15 w ere decumbent*
A P v a lu e o f 0*18 was o b ta in e d when th e o b serv ed r a t i o
was compared w ith a c a lc u la te d 3 :1 r a t i o .
A lthough t h i s i s a r e l a t i v e l y
poor f i t , th e s e g r e g a tio n o b serv ed i n th e Fg g e n e ra tio n in d ic a te d t h a t
th e in h e r ita n c e o f grow th h a b i t was on a m ajo r s i n g l e - f a c t o r b a s i s •
The o bserved and c a lc u la te d Fg g e n o ty p ic r a t i o s a s d eterm in ed by
th e Fg s e g r e g a tio n a re g iv e n i n t a b l e X .
Of th e p h e n o ty p ic a lI y s p rin g
h a b i t p la n ts 29 b re d tr u e and 37 se g re g a te d f o r s p rin g and w in te r h a b i t .
-
35-
and tn e 16 w in te r h a b it p la n ts b re d t r u e .
When t h i s o b serv ed r a t i o xvas
compared w ith a c a lc u la te d 1 :2 :1 r a t i o , a P v a lu e o f 0 .0 7 was o b ta in e d .
On th e b a s is o f th e b re e d in g b e h a v io r o f th e F2 p la n ts i t was concluded
t h a t t h i s c h a r a c te r was in h e r ite d a s a s in g le - m a jo r - f a c to r d i f f e r e n c e .
The p oor f i t t o a monohybrid r a t i o may have been caused by o th e r f a c to r s
n o t d e te c te d i n t h i s s tu d y .
A d d itio n a l work w ith t h i s c ro s s would be
n e c e s s a ry to d e te rm in e w h eth er o r n o t t h i s i s t r u e .
T ab le X Observed F2 g en o ty p ic r a t i o s f o r s p rin g v e rs u s w in te r
grow th h a b i t as d eterm in ed b y th e F* s e g r e g a tio n i n
A rlin g to n Awnless x A tra d a , C. I . 5638 and in A rlin g to n
Awnless x A tra d a , C. I . 5641
Number o f in d ic a te d genotype a /
S p rin g H eterozygous W in te r T o ta ls
Item
X2
P
A rlin g to n Awnless
x A trad a 5641
28
48
21
97
1.021
0 .6 1
A rlin g to n Awnless
x A trad a 5638
29
37
15
81
5 .4 4 5
0 .0 7
a / Compared w ith a c a lc u la te d 1 :2 :1 r a t i o .
I n h e r ita n c e o f D e n sity o f Spike i n
A rlin g to n Awnless x A tra d a , C. I . 5638
The s p ik e s o f th e
p la n ts were l a x , in d ic a tin g t h a t la x was
dom inant o v e r d e n s e .
The observed and c a lc u la te d F2 p h en o ty p ic r a t i o s a r e p re s e n te d i n
t a b l e X I.
Of th e 81 F2 p la n ts grown, 65 were c l a s s i f i e d as la x «nd 16
as d en se.
When t h i s o bserved r a t i o was compared w ith a c a lc u la te d 3:1
-
36-
r a t i o , a P v a lu e o f 0*30 i.as o b ta in e d , in d ic a tin g t h a t th e o b serv ed r a t i o
f i t a monohybrid r a t i o f a i r l y w e ll.
T able XI
Observed and c a lc u la te d Fg p h en o ty p ic r a t i o s f o r la x
v e rs u s dense s p ik e i n A rlin g to n A im less x A tra d a ,
C . I . 6638
Number oi1 in d ic a te d phenotype
Item __________Lax_____ Dense______________T o ta ls ________ _____________P
O bserved c o u n ts
65
C a lc u la te d
3 :1 r a t i o
6 0 .7 5
16
81
2 0 .2 5
81.00
1 .1 8 9
0 .3 0
The o b serv ed and c a lc u la te d Fg g e n o ty p ic r a t i o s a s d eterm in ed by
th e Fg s e g r e g a tio n a r e p re s e n te d i n t a b l e X I I .
When th e o b serv ed r a t i o
o f 24 homozygous l a x , 41 h e te ro z y g o u s , and 16 homozygous dense was com­
p a re d w ith a c a lc u la te d 1 :2 :1 r a t i o , a P v a lu e o f 0 .4 6 was o b ta in e d .
T able X II
Item
O bserved and c a lc u la te d Fg g en o ty p ic r a t i o s f o r la x
v e rs u s dense s p ik e as d eterm in ed by th e Fg s e g re g a tio n
i n A rlin g to n Awnless x A tra d a , C. I . 5638
Number o f in d ic a te d genotype
la x
H eterozygous
Dense
LgLs
LglG
ie ie
T o ta ls
O bserved co u n ts
24
41
16
81
C a lc u la te d
1 :2 :1 r a t i o
20.25
4 0 .50
20.25
81.00
X2
p
1.593
0.46
I t was concluded t h a t a s in g le f a c t o r p a i r c o n tr o lle d th e in h e r ita n c e
o f sp ik e d e n s ity i n t h i s c ro s s and t h a t th e la x c o n d itio n was dominant
o v er d e n se .
-
37 -
Linkage R e la tio n s h ip s i n
A rlin g to n Awnlese x A tra d a , C. I . 5641
C h a ra c te rs i n h e r i t e d in d e p e n d e n tly . -
The o b serv ed and c a lc u la te d g en o ty p ic
r a t i o s f o r th e c h a r a c te r s in h e r i t e d in d e p e n d e n tly i n t h i s c ro s s a re given
in ta b le X III.
The c a lc u la te d d ih y b rid g e n o ty p ic r a t i o e x p ec te d w ith in ­
d ep en d en t a ss o rtm e n t i s 1 * 2 :2 :4 :1 :2 : 1 :2 :1 .
The ob serv ed s e g r e g a tio n be­
tw een c h a r a c te r p a ir s was compared w ith t h i s t h e o r e t i c a l r a t i o .
The th r e e c h a r a c te r s s tu d ie d i n t h i s c r o s s , norm al v e rs u s reduced
l a t e r a l aw ns, lo n g v e rsu s s h o r t aw ns, and grow th h a b i t , were a l l in ­
h e r i t e d in d e p e n d e n tly o f each o t h e r .
The r a t i o f o r norm al v e rs u s r e ­
duced l a t e r a l awns and lo n g v e rs u s s h o r t awns (L r^lr^ L k g lk g ) f i t th e
c a lc u la te d r a t i o c l o s e l y , a P v a lu e o f 0 .7 1 b e in g o b ta in e d .
When th e
r a t i o f o r each o f th e s e c h a r a c te r s was combined i n a d ih y b rid r a t i o w ith
s p rin g v e rs u s w in te r h a b i t , good f i t s to in d ep en d en t r a t i o s were o b ta in e d ,
th e P v a lu e i n b o th c a se s b e in g 0 .9 0 .
Ho lin k a g e s were o b serv ed in t h i s c r o s s .
Linkage R e la tio n s h ip s in
A rlin g to n Awnless x A tra d a , C. I . 5658
No a tte m p t was made to d e term in e th e lin k a g e r e l a t i o n s h i p s o f s p rin g
v e rs u s w in n er h a b it i n t h i s c r o s s .
A lthough t h i s c h a r a c te r ap p eared t o
be i n h e r i t e d a s a s in g le - m a jo r - f a c to r d i f f e r e n c e , th e o b serv ed r a t i o i n
th e Fg g e n e r a tio n d id n o t f i t a monohybrid r a t i o c lo s e ly enough to j u s t i f y
i t s use i n lin k a g e d e te r m in a tio n s .
C h a ra c te rs i n h e r ite d in d e p e n d e n tly .-
The o b serv ed and c a lc u la te d Pg
g e n o ty p ic r a t i o s f o r th e c h a r a c te r s i n h e r ite d in d e p e n d e n tly i n t h i s c ro s s
T able X III
Observed and c a lc u la te d Pg g en o ty p ic r a t i o s f o r s p rin g v e rs u s w in te r h a b it o f growth
and two f a c to r s f o r awnednoss as determ in ed by th e P3 s e g re g a tio n o f A rlin g to n
Awnless x A tra d a , Ce I . 5641
Genotype
s tu d ie d
_______________ Number o f in d ic a te d genotype
AaBb
AAbb Aabb
AABB AABb
AaBB
aaBB
Observed counts
L r1I r 1Lk5I k 5
L r1I r 1E e
Lk5I k 5E e
C a lc u la te d
ra tio
T able XIT
13
13
11
11
16
15
31
27
28
5
5
7
13
11
9
6 .0 6
12.13
12.13
24.24
6.06
12.13 6.0 6
7
6
7
8
8
9
12.13
aabb
T o ta ls
3
6
6
97
97
97
6.06
97.00
X2
5.392
3.496
3.454
P
0.71
0 .9 0
0 .9 0
O bserved and c a lc u la te d Fg g en o ty p ic r a t i o s as d eterm in ed by th e Pg s e g re g a tio n f o r
c h a r a c te r s i n h e r ite d in d e p e n d e n tly i n A rlin g to n Awnless x A tra d a , C# I e 5638
Genotype
s tu d ie d
Observed co u n ts
Lr1I r 1Lk4Ik 4
l f I 1f I l
6
6
6
aaBb
G 1G
C a lc u la te d
ra tio
Observed counts
Lf 11f 1b 12l 1 2
LglgB lgblg
C a lc u la te d r a t i o
Observed counts
Lk4 Ik 4B lg b l2
C a lc u la te d r a t i o
AABB AASb
Number o f in d ic a te d genotype
AaBB
AaBb
AAbb
Aabb aaBB
1
a
aaBb
aabb
T o ta ls
—
I
81
5.193
0.52
81
6.842
0.66
X2
P
3
12
7
27
6
9
—
17
5
12
11
21
4
11
8
8
5.06
10.13
10.13
20.24
5.06
10.13 5.06
10.13
6.06
81.00
6
3
4 .8 1
11
12
9.63
9
10
9.63
23
23
19.24
4
8
4 .8 1
9
2
6
4
9 .63 4 .8 1
8
7
9.63
5
4
4.81
77
77
77.00
3.430
6.612
0.90
0.58
8
10
5
16
4
6
2
8
5
64
7.375
0.5 0
4
8
8
16
4
8
4
8
4
64
-
a r e g iv e n i n t a b l e XIV.
39 -
A ll o f th e o b serv ed r a t i o s e x c e p t one vrore com­
p a re d w ith c a lc u la te d 1 i 2 i 2 i 4«1 i 2 i 1 i 2 i 1 g e n o ty p ic r a t i o s .
Die observed
r a t i o f o r norm al v e rs u s red u ced l a t e r a l awns and lo n g v e rs u s s h o r t awns
(L r^ lr^ L k ^ lk ^ ) was compared w ith a c a lc u la te d I i 2 : 2 t 4 : l : 2 : 4 r a t i o , s in c e
th e th r e e genotypes I r 1I r 1Lk4Lk4 , I r 1I r 1Lk4I k 4 , and I r 1I r 1Ik 4 Ik 4 co u ld
n o t be d is tin g u is h e d .
When th e observed and c a lc u la te d r a t i o s f o r th e genotype Lr1I r 1Lk4Ik4
were com pared, a P v a lu e o f 0 .5 2 was o b ta in e d , i n d ic a tin g t h a t th e s e two
c h a r a c te r s w ere i n h e r i t e d in d e p e n d e n tly .
Lax v e rs u s dense s p ik e s (L glg)
and b lu e v e rs u s w h ite a le u ro n e (B lg b lg ) wore a ls o in h e r ite d in d ep en d en t­
l y o f norm al v e rs u s reduced l a t e r a l aw ns.
The P v a lu e s o b ta in e d f o r
th e s e com parisons were 0 .5 6 f o r L r1I r 1Lglg and 0 .9 0 f o r L r1I r 1B lg b lg .
The o bserved r a t i o f o r sp ik e d e n s ity and a le u ro n e c o lo r (L glgB lgblg)
gave a P v a lu e o f 0 .5 8 when compared w ith t h e c a lc u la te d r a t i o w hich
in d ic a te d t h a t th e s e c h a r a c te r s w ere i n h e r i t e d in d e p e n d e n tly .
A leurone
c o lo r was found t o be i n h e r i t e d in d e p e n d e n tly o f th e f a c t o r p a i r f o r
awn le n g th (Lk4l k 4 ) a l s o , a s in d ic a te d b y th e P v a lu e o f 0 .5 0 .
In th is
o b serv ed r a t i o o n ly 64 in d iv id u a ls o f th e Fg p o p u la tio n were u s e d .
It
was n e c e s s a ry t o om it th e 17 p la n ts grouped in awn c la s s 2 b ecau se th e
g enotypes in c lu d e d i n t h i s group c o n ta in e d th e th r e e co m b in atio n s o f th e
f a c t o r p a i r f o r a m le n g th , I k 4Lk4 , Lk4I k 4 , and Ik 4Ik 4 .
C h a ra c te rs lin k e d i n in h e r i t a n c e . -
The o b serv ed and c a lc u la te d Fg geno­
ty p i c r a t i o s f o r long v e rs u s s h o r t awns and la x v e rsu s dense s p ik e s a re
g iv e n i n t a b l e XV.
Vfhen th e observed and c a lc u la te d r a t i o s w ere compared,
-
a P v a lu e o f 0 .0 6 was o b ta in e d .
w ere p ro b a b ly lin k e d .
40 -
T his would in d ic a te t h a t th e s e c h a r a c te r s
The p e rc e n ta g e o f c ro s s in g o v e r c a lc u la te d b y th e
p ro d u c t method was 24.18 ± 6 .3 0 p e r c e n t.
The o bserved p h en o ty p ic r a t i o
and th e c a lc u la te d r a t i o s w ith in d ep en d e n t a ss o rtm e n t and w ith 24.18
p e r c e n t c ro s s in g o v e r a re g iv e n i n t a b l e XVI.
The o b serv ed r a t i o f i t
th e c a lc u la te d 9 : 3 i 3 t l r a t i o p o o rly , th e P v a lu e b e in g betw een 0 .0 1 and
0 .0 2 .
A c lo s e f i t to th e r a t i o ex p ected w ith 24.18 p e rc e n t c ro s s in g
o v e r was o b ta in e d .
The P v a lu e f o r t h i s com parison was 0 .9 5 , in d ic a t­
in g t h a t th e s e c h a r a c te r s were lin k e d .
T able XV Observed and c a lc u la te d Pg g e n o ty p ic r a t i o s a s determ ined
by th e Fg s e g r e g a tio n f o r lo n g v e rsu s s h o r t awns and la x
v e rs u s dense s p ik e s i n A rlin g to n Awnless x A tra d a , C. I .
5638
Fg genotype
Lk4Lk4L6L6
Observed
co u n ts
C a lc u la te d
1 i 2 i 2 i 4 i 1 s2 : l i 2 t l
ra tio
Uc4Lk4L6I 6
^ c4Ik 4I16L6
6
6
10
4
8
8
Lk4 Ik 4L6I 6
21
16
Lk4Lk4I 6I 6
Lk4Ik 4Ig lg
I k 4Ik 4LgLg
I k 4I k 4L6I 6
I k 4Ik 4I 6I 6
0
7
I
5
8
4
8
4
8
4
64
64
T o ta ls
X2
P v a lu e
15.043
0.0 6
—41 —
T ab le XVI
O bserved and c a lc u la te d Pg ph en o ty p ic r a t i o s f o r
lo n g v e rs u s s h o r t aims and la x v e rs u s d en se s p ik e s
i n A rlin g to n A m le s s x A tra d a , C. I . 5638
Humber o f in d ic a te d phenotype
S h o rt awns
Long awns
Dense
Lax
Lax
Dense
T o ta ls
Observed c o u n ts
C a lc u la te d
9 t3 i3 il
ra tio
43
7
6
8
64
36
12
12
4
64
C a lc u la te d r a t i o
w ith 2 4.18 p e r
c e n t c ro s s in g
over
4 1 ,2
9 .2
6 4 .0
6 .8
6 .8
X2
P
10.444
.0 1 -.0 2
0 .3 3 5
0 .9 5
-
42 .
DISCUSSION
I n each o f th e tiro c ro s s e s s tu d ie d , awtiedness vas i n h e r i t e d a s a
tir o - f a c to r d i f f e r e n c e .
I n A rlin g to n A im less x A tra d a , C. I . 6630, th e
s e g re g a te s ranged f r o n long-aim ed t o th e A rlin g to n A im less ty p e , and i n
A rlin g to n A im less x A tra d a , C. I . 5641, th e s e g r e g a te s ran g ed from lo n g aimed to a w n le s s .
A tw o - f a c to r d if f e r e n c e betw een lo n g -aim ed and aim­
l e s s was r e p o r te d by M yler (1 4 ) .
I n c ro s s e s o f long-aim ed v a r i e t i e s on
an a im le ss o n e , he o b serv ed in te rm e d ia te t r u e b re e d in g ty p e s t h a t wore
v e ry s im ila r i n awnedness t o th e A tra d a and A rlin g to n A im less v a r i e t i e s .
However, H y le r d id n o t r e p o r t e i t h e r f a c t o r a s p r im a r ily a f f e c t i n g
l a t e r a l aim developm ent.
Tfhether o r n o t he ob serv ed th e e f f e c t s o f
th e same f a c t o r s o p e ra tin g i n A rlin g to n A im less x A tra d a , C. I . 5641,
can be d eterm in ed o n ly b y f u r tlie r s tu d y .
A s i n g l e - f a c t o r d if f e r e n c e f o r norm al v e rs u s reduced l a t e r a l awns
w i t i norm al p a r t i a l l y dom inant o v e r re d u c ed was o b serv ed i n e ac h c ro s s
i n t ils s tu d y .
T his f a c t o r , w hich was d e s ig n a te d L r1 , a ls o a f f e c t e d th e
le n g th o f c e n t r a l aw ns.
Ikono ( 9 ) , G linyany ( 6 ) , Engeldow ( 3 ) , Miyake
and Im ai (1 2 ), and Leonard (11) re p o rte d a s in g le f a c t o r d if f e r e n c e f o r
t h i s c h a r a c te r w ith p a r t i a l dom inance, b u t none o f th e s e w orkers re p o rte d
any e f f e c t o f t h i s f a c t o r on c e n t r a l awn le n g th .
Two o f th e s e w o rk e rs,
(9 ) and ( 6 ) , concluded t h a t th e f a c t o r o p e ra te d as an i n h i b i t o r and was
dom inant when l a t e r a l awns w ere re d u c e d .
A lthough s e g r e g a tio n f o r o n ly two f a c t o r p a ir s was ob serv ed i n each
o f th e two c r o s s e s , i t was concluded t h a t t h r e e f a c t o r p a i r s f o r awnedness
were p r e s e n t i n each o f th e p a r e n ta l v a r i e t i e s .
I n a d d itio n to th e f a c t o r
43p a i r f o r l a t e r a l a m dev elo p m en t, L r1 , two f a c t o r p a ir s a f f e c t i n g a m
le n g th o n ly , Lk^ and Lkg, were p r e s e n t.
Ih e a m le n g th f a c t o r , Lk^,
f o r w hich s e g r e g a tio n was o bserved i n A rlin g to n Awnlees x A tra d a , C. I .
5638, was a p p a r e n tly th e saiie f a c t o r r e p o rte d by S tu m ( 1 9 ) .
He o b serv ­
ed a s i n g l e - f a c t o r d if f e r e n c e betw een lo n g and s h o r t awns i n A tra d a ,
C. I . 5630, x I r e b i- V e lv o t.
A s i n g l e - f a c t o r d if f e r e n c e betw een lo n g and
s h o r t awns has a ls o been re p o rte d b y G linyany (6) and Miyalce and Imai
(1 2 ).
A t o t a l o f t h r e e f a c t o r p a ir s a f f e c t i n g awnedness lias boon r e ­
p o rte d by von Ubisoh ( 2 0 ) , Miyake and Im ai (1 2 ) , and Ikeno ( 9 ) .
The in h e r ita n c e o f b lu e v e rs u s w h ite a le u ro n e on a s i n g l e - f a c t o r
b a s i s , a s o b serv ed i n A rlin g to n Awnless x A tra d a , C. I . 5638, h as been
p r e v io u s ly r e p o r te d by M iyazawa, S o, and Im ai (1 3 ) , B uckley ( 2 ) , R obert­
s o n , Doming, and Koonce (1 7 ) , and Ttylor and S ta n fo rd (1 5 ) .
Btyler and
S ta n fo rd a ls o r e p o r te d a 9 :7 r a t i o f o r b lu e to w h ite i n a c ro s s o f two
w h ite v a r i e t i e s .
X enia was observed i n t h i s s tu d y and was a ls o re p o rte d
by a l l o f th e s e w o rk e rs.
S p rin g v e rs u s w in te r h a b it was a p p a r e n tly in h e r i t e d on a m ajor
s i n g l e - f a c t o r b a s is i n b o th c ro s s e s s tu d ie d , b u t d i f f i c u l t y i n c l a s s i f i ­
c a tio n and t h e poor f i t o f th e o bserv ed r a t i o to a nonohybrid r a t i o i n
A rlin g to n Avmless x A tra d a , C. I . 5638, In d ic a te d t h a t o t h e r f a c to r s
may have a f f e c t e d t h i s c h a r a c te r i n t h i s c r o s s .
S p rin g v e rs u s w in te r
h a b it was p re v io u s ly re p o rte d to be in h e r i t e d as a tw o - f a c to r d if f e r e n c e
b y G aines (6 ) and a s a t h r o e - f a c t o r d if f e r e n c e by N eatby ( 1 6 ) .
The in h e r ita n c e o f la x v e rs u s dense s p ik e s on a s i n g l e - f a c t o r b a s is
w ith la x dom inant o v o r d e n se , as o b serv ed i n A rlin g to n Awnless x A tra d a ,
- 44 -
C. I . 5638, i s i n agreem ent w ith r e s u l t s r e p o rte d by B iffe n ( l ) , S tu ra
(1 9 ) , Miyake and Im ai (1 2 ) , and W exelsen (2 1 ) .
a tw o - f a c to r d if f e r e n c e i n some c ro s s e s s tu d ie d .
W exelsen (22) ob serv ed
N eatby (16) re p o rte d
a s i n g l e - f a c t o r d if f e r e n c e w ith m inor m odifying f a c to r s p r e s e n t , and
von U bisch (20) re p o rte d a t h r e e - f a c t o r d i f f e r e n c e .
Hayes and H arlan
(8 ) found dense dom inant o v e r la x i n c r o s s e s t h a t th e y s tu d ie d .
The d a ta o b ta in e d a re n o t s u f f i c i e n t to p la c e th e f a c t o r p a ir s i n
lin k a g e groups b e ca u se none o f t h e c h a r a c te r s s tu d ie d w ere c o n tr o lle d b y
known f a c t o r s o f known l o c a t i o n .
Those c h a r a c te r s shown t o be in h e r ite d
in d e p e n d e n tly can be c o n sid e re d to be i n d i f f e r e n t lin k a g e groups o r o v e r
50 c ro s s o v e r u n i t s a p a r t on th e sane chromosome.
Those c h a r a c te r s found
t o b e lin k e d a r e i n th e same lin k a g e g ro u p .
*
Because o f th e d i f f i c u l t y o f c l a s s i f i c a t i o n and th e r e s u l t a n t skew­
ed monohybrid r a t i o f o r s p rin g v e rs u s w in te r h a b it in A rlin g to n Aimless
x A tra d a , C . I . 5638, no a tte m p t was made to d e term in e th e l i nkage r e ­
l a tio n s h ip s o f t h i s c h a r a c te r i n t h i s c r o s s .
The o n ly c h a r a c te r s t h a t were shown t o be lin k e d were la x v e rsu s
dense s p ik e s and lo n g v e rs u s s h o r t aw ns.
These c h a r a c te r s were lin k e d
i n th e c o u p lin g phase w ith 24.18± 6.30 p e rc e n t c ro s s in g o v er i n A rlin g ­
to n Awnless x A tra d a , C. I . 5638.
S tu m (19) observ ed t h i s same lin k a g e
w ith a p p ro x im a te ly 23 p e rc e n t c ro s s in g o v e r i n A tra d a , C. I . 5638 x
T r e b i- V e lv e t.
S in c e th e A tra d a p a re n t o c c u rre d in b o th c ro s s e s and
s in c e th e c ro s s o v e r p e rc e n ta g 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 , i t
was concluded t h a t th e sane f a c t o r p a ir s p ro b a b ly c o n tr o lle d th e s e
c h a r a c te r s in b o th c r o s s e s .
-
45 -
The lin k a g e r e la tio n s h ip s o f th e c h a r a c te r s s tu d ie d i n th e two
c ro s s e s a r e summarized b elo w .
A rlin g to n Awnless x A tra d a , C. I . 5641
Long v e rs u s s h o r t awns in h e r ite d in d e p e n d e n tly o f
Normal v e rs u s reduced l a t e r a l awns
S p rin g v e rs u s w in te r h a b i t
Normal v e rs u s reduced l a t e r a l awns in h e r ite d in d e p e n d e n tly o f
S p rin g v e rs u s w in te r h a b it
A rlin g to n Awnless x A tra d a , Ce I# 5658
Long v e rsu s s h o r t awns i n h e r i t e d in d e p e n d e n tly o f
Normal v e rs u s reduced l a t e r a l awns
B lue v e rs u s w h ite a le u ro n e
Normal v e rsu s red u ced l a t e r a l awns in h e r ite d in d e p e n d e n tly o f
Blue v e rs u s w h ite a le u ro n e
Lax v e rs u s dense s p ik e s
Lax v e rsu s dense sp ik es i n h e r i t e d in d e p e n d e n tly o f
B lue v e rs u s w h ite a le u ro n e
Long v e rs u s s h o r t awns lin k e d i n in h e r ita n c e w ith
Lax v e rs u s dense s p ik e s w ith 2 4 .1 8 ± 6 .3 0 p e rc e n t c ro s s in g
over
S p rin g v e rs u s w in te r h a b it
L inkage r e la tio n s h ip s w ere n o t d eterm in ed f o r t h i s
c h a r a c te r i n t h i s c ro s s
-46
SUMMAHT
Tho in h e r ita n c e o f awnedness and grow th h a b it i n A rlin g to n Awn­
l e s s x A tra d a , C. I . 5641, and th e in h e r ita n c e o f aw nedness, grow th
h a b i t , a le u ro n e c o l o r , and sp ik e d e n s ity i n A rlin g to n Awnless x A tra d a ,
Ce I , 5638, were s tu d ie d .
Three d i f f e r e n t f a c t o r s f o r awnedness were found i n th e two
c ro s s e s s tu d ie d ,
Awnedness was in h e r ite d a s a tw o -f a c to r d if f e r e n c e
i n each c r o s s , w ith a p p a re n t com plete dominance i n a f a c t o r p a i r f o r
le n g th o f awns and p a r t i a l domianoe i n a f a c t o r p a i r f o r norm al v e rsu s
red u ced l a t e r a l awns and le n g th o f aw ns.
The f a c t o r f o r norm al v e rs u s
red u ced l a t e r a l awns was d e s ig n a te d L r^ ,
T h is f a c to r was c a r r ie d i n th e
r e c e s s iv e c o n d itio n i n A rlin g to n Avmless and i n th e dom inant c o n d itio n in
th e two A trad a v a r i e t i e s .
Lk^ and Lkg.
The f a c to r s f o r le n g th o f awns were d e sig n a te d
A rlin g to n Awnless c a r r ie d b o th o f th e s e f a c t o r s i n th e
dom inant c o n d itio n ; A tra d a , C. 1 , 5641, c a r r i e d Lk^ i n th e dom inant
c o n d itio n and Lkg i n th e r e c e s s i v e ; and A tra d a , C, I , 5638, c a r r ie d
Lk^ i n th e r e c e s s iv e c o n d itio n and Lkg i n th e d o m in an t.
long-aw ned ty p e s were o b ta in e d i n each c r o s s .
f a c t o r s i n th e dom inant c o n d itio n .
T ru e-b ree d in g
These c a r r i e d a l l th r e e
T ru e-b ree d in g aw nless s e g re g a te s
c a r r y in g Lr^ and Lkg i n th e re c e s s iv e and Lk^ i n th e dom inant c o n d itio n
were o b ta in e d i n A rlin g to n Awnless x A tra d a , C. I , 5641,
Mo aw nless
s e g r e g a te s were o b ta in e d i n A rlin g to n Awnless x A tra d a , C. I , 5638; th e
s e g r e g a te s c a r r y in g Lr^ and Lk^ i n th e r e c e s s iv e and Lkg i n th e dom inant
c o n d itio n had awns s im ila r t o th o s e o f th e A rlin g to n Awnless p a r e n t.
- 47 -
Blue v e rs u s w h ite a le u r o n e , s p rin g v e rs u s w in te r h a b i t , and la x
v e rs u s dense s p ik e s were each i n h e r i t e d on a s in g l e - f a c t o r b a s i s .
each c a s e , th e dom inant c h a r a c te r i s l i s t e d f i r s t .
In
X enia was observed
i n th e in h e r ita n c e o f a le u ro n e c o l o r .
The lin k a g e r e la t i o n s h i p s o f s p rin g v e rs u s w in te r h a b i t i n A rlin g ­
to n Awnless x A tra d a , C. I . 5638, w ere n o t d eterm in ed b ecau se th e r a t i o
o b ta in e d f o r t h i s c h a r a c te r i n th e Pg g e n e r a tio n d id n o t f i t a monohybrid
r a t i o c l o s e l y , a lth o u g h th e Pg s e g r e g a tio n in d ic a te d a s i n g l e - f a c t o r
d if f e r e n c e .
Long v e rs u s s h o r t awns was lin k e d w ith la x v e rs u s dense s p ik e s w ith
2 4 .18 ± 6 .3 0 p e rc e n t c r o s s in g o v e r.
A ll o th e r co m b in atio n s o f c h a r a c te rs
s tu d ie d showed in d ep en d en t a sso rtm e n t*
The genotypes o f t h e p a re n t v a r i e t i e s a s d eterm in ed f o r th e c h a r a c te r s
used i n t h i s s tu d y are*
A leurone
c o lo r
Spike
d e n s ity
Growth
h a b it
Lk4 Lk4 I k 6 I k 5
B l2B l2
l Gl
B B
lrIlrI
Lk4 Lk4 Lkg Lkg
B l2B l2
Lr^Lr^
Ik 4 Ik 4 Lkg Lkg
b l 2b l 2
V a rie ty
L a te r a l
awns
A tra d a , C. I . 5641
Lr^ Lr^
A rlin g to n Awnless
A tra d a , C. I . 5638
Am
le n g th
S
e o
1B1B
E E
-•
48 -
LITERATURE CITED AKD COKSULTED
I* B if f e n , R . H .
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1 0 i 460-492.
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O liv e r and Boyd.
E dinburgh
e d . 3 .2 8 3 p p .
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38 p p .
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B u i. 869.
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1918.
-
10# lE rter, Fe Re
49 -
F o iiiu lae and ta b le s f o r c a lc u la tin g lin k a g e in ­
te n s itie s e
l i e L eonard, W# He
G e n e tic s , 1 5 i 8 1 -9 8 #
1950e
I n h e r ita n c e o f red u ced l a t e r a l s p i k e l e t appendages
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S o c e Agrone, 3 4 :2 1 1 -2 2 1 ,
1 2 , M iyake, K ,, and Im a i, Y,
Jour# Amere
1942,
G en etic s tu d ie s i n b a r le y , I . D ot, Mag,
(T okyo), 3 6 :2 5 -3 8 ,
1922.
( T r a n s la tio n o b ta in e d from
D r, G, A, W iebe, Bureau P la n t In d u s try )
1 5 , Miy&zava, B ,, S o , I I ,, and Im a i, Y ,
C ro sses betw een b a r le y w ith b lu e
g r a in and b a r le y w ith p a le y e llo w g r a in i n Jap an ;
A pparent s e g r e g a tio n i n m osaic i n th e F^ e x p la in e d
by x e n ia .
I n t . R , S c i . and P ra c . A g ., 1 0 :5 4 5 -5 4 7 ,
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1 4 . Myler , J . L ,
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412.
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1942.
1 5 . I ty le r , J . L , , and S ta n f o r d , E , He
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Amer. Soo, A g ro n ., 3 4 :4 2 7 -4 3 5 .
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c h a r a c te r s and lin k a g e i n b a r l e y s .
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J o u r . k?;r. R e s ., 4 4 :4 4 5 -4 6 6 .
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501 9 . S tu m , J . J .
I n h e r ita n c e o f awn le n g th , d e n s ity o f s p ik e and rough­
2 0 . TJbisoh, G. von
n ess o f a m i n a b a r le y c r o s s .
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t h e s i s , Montana S ta te C o lle g e .
25 p p .
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A g ., 10:1104-1113 .
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2 2 . ____________
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H e r e d ita s , 1 7 :3 2 3 -3 4 1 .
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51DESCRIPTION OF PLATES
P la te I .
R e p re s e n ta tiv e heads o f each o f th e p a re n t v a r i e t i e s and th e
F l ty p e o f A rlin g to n Awnleas x A tra d a , C. I . 6638, and o f
A rlin g to n Awnless x A tra d a , C. I • 5641.
P la te I I . Heads o f b a r le y r e p r e s e n ta tiv e o f each o f th e s i x p h en o ty p ic
awn c la s s e s e s ta b lis h e d f o r t h i s s tu d y . The number o f each
f ig u r e i n t h e p la te c o rre sp o n d s to th e number o f th e awn c la s s
r e p r e s e n te d . F ig u re I , aw nless ty p e ; f ig u r e 2 , A rlin g to n
Awnless ty p e ; f ig u r e 3 , reduced A trad a ty p e ; f i g u r e 4 , A trada
ty p e ; f ig u r e 5 , Fi ty p e ; and f ig u r e 6 , f u l l y awned ty p e .
PLATE I
PLATE I I