Jan. 1.1925 
A Study of Variability in the Burt Oat 
47 
STUDY IN 1921 
Because of the injury caused by 
chinch bugs at Manhattan no data on 
kernel color are presented for the crop 
grown there in 1921. The data from 
Akron, given in Table X, indicate that 
some of the kernels classed as black 
and dark brown probably are similar 
in breeding behavior. The color de¬ 
scribed as dark brown in many cases 
probably is the result of the imperfect 
development of black. The results 
obtained in 1921 are similar to those 
of 1920 in that the dark-colored parental 
kernels show a very strong tendency to 
produce dark-colored kernels in their 
progenies. 
The light brown color class probably 
contains many genetic reds, which, 
due to physiological influences, appear 
as light brown. The fact that the 
parental kernels described as light 
brown produced about 71 per cent of 
red kernels in their progenies supports 
this statement. Red was the most 
stable of the kernel colors. Red 
kernels produced only small percent¬ 
ages of other colors in their progenies. 
A few light brown and yellow kernels 
were produced in the progenies of red 
kernels, which may have been due in 
part to the effect of physiological fac¬ 
tors, which favor an intensification in 
the one case and a dilution or incom¬ 
plete development of red color in the 
other. Many parental kernels which 
were described as yellow apparently 
were genetic reds, in which the red 
color for some reason did not attain its 
normal development. 
Comparatively few yellows bred true, 
most of them producing reds of varying 
intensities, and including occasional ker¬ 
nels described as light brown. Kernels 
classified as white appear to be of two 
classes, those which for physiological 
reasons did not fully develop their 
normal color and thus appeared white, 
although genetically really colored, 
and those which w r ere genetically 
white. Comparatively few (26.2 per 
cent) of the kernels in the progenies of 
parental white kernels were described 
as white. It appears difficult to 
obtain strains of Burt oat which will 
breed true for white kernel color. This 
is not an unexpected condition when it 
is remembered that this variety is 
known to contain factors for black, 
several shades of brown, red, yellow, 
and probably gray kernel colors. It 
may be supposed that all of these 
factors would have to be absent or in 
the recessive condition to permit the 
production of homozygous white 
kernels. 
The occurrence of dark-colored gray 
and brown kernels in the cross Burt 
(red) X Sixty-Day (yellow) is ex¬ 
plained by Fraser (37) as probably due 
to reversion or to mutation. The 
results obtained in these experiments 
clearly indicate that the dark-colored 
kernels which occur in Burt oat are the 
result of genetic factors for dark color, 
carried by many strains in this variety. 
The advisability of assigning only two 
color factors for the variety Burt, as 
Fraser has done, is questioned, though 
probably he meant only to indicate 
that these were the particular factors 
considered in his experiments and not 
necessarily the only ones present in 
the variety. Further and more care¬ 
fully controlled experiments are needed, 
for as Fraser has stated— 
Considerable variation in color is to be noted 
even within the same pure line during different 
seasons, or under strikingly different environmental 
conditions. 
The results obtained in these experi¬ 
ments indicate that the Burt oat not 
only contains the “R” and “ Y” color 
factors mentioned by Fraser (37) in 
the strain with which he worked but 
probably several additional color fac¬ 
tors. The strain of Burt used by 
Fraser doubtless was a light-colored 
form. Most of the strains of Burt 
oat observed by the writers have had 
at least a few dark-colored kernels, 
including blacks or dark browns, light 
browns, and grays, which produced 
dark-colored kernels in their progenies. 
ASSOCIATION OF SPIKELET 
CHARACTERS 
An attempt was made to determine 
what correlation, if any, existed be¬ 
tween the kernel characters studied. 
These studies were made from the 
original descriptions of the 1920 crop 
grown at Manhattan. No correlation 
data are presented on the material 
grown at Akron in 1920 nor on the 
material grown at either station in 
1921. Studies of correlation or associ¬ 
ation were made of the following pairs 
of characters: (1) Floret disjunction 
and spikelet disarticulation, (2) spike- 
let disarticulation and basal hairs, (3) 
spikelet disarticulation and awns, (4) 
lemma color and spikelet disarticu¬ 
lation, (5) lemma color and awns. 
These studies indicate very clearly 
that certain spikelet and floret char¬ 
acters “tend to go together in hered¬ 
ity/ * and that genetic coupling or 
linkage probably is involved. It has 
been thought best, however, to use 
the terms association and correlation 
in the discussion of these data, for 
