Jan. 1,1925 
A Study of Variability in the Burt Oat 
41 
The awns described as nontwisted 
long apparently are unstable in breed¬ 
ing behavior, segregating into all classes 
ranging from twisted to absent. Pa¬ 
rental kernels having nontwisted long 
awns produced about 74 per cent of such 
kernels in their progenies. The long 
and short subclasses grade into one 
another, making classification ex¬ 
tremely difficult in many cases. 
Parental kernels with nontwisted 
short awns produced 28.9 per cent of 
short-awned kernels and only 6.1 per 
cent of the twisted-awned kernels in 
their progenies, while parental kernels 
with the nontwisted long awns pro¬ 
duced 7;2 and 14.9 per cent, respec¬ 
tively. From this it appears that these 
two subclasses, that is, the long and 
short awned, are somewhat different 
genetically. Kernels with awns absent 
reproduced that character in 59.3 per 
cent of the progenies, while 4.4 and 20.9 
per cent, respectively, were nontwisted 
short and nontwisted long and 15.4 per 
cent were twisted. 
In general the results on the inherit¬ 
ance of awns obtained by the writers 
correspond with those of previous inves¬ 
tigators, except that previous workers 
have not differentiated between non¬ 
twisted long and short awns. In the 
Burt oat the absent or awnless condi¬ 
tion seems partially dominant, while 
the twisted awn seems recessive. The 
influence of physiological and other fac¬ 
tors may account for the fact that some 
kernels which apparently carry the gene 
for producing awns failed to produce 
them. The possible influence of en¬ 
vironmental factors on the development 
of awns in oats has been recognized by 
several other investigators. 
Awns are readily observable and have 
been studied by more investigators than 
have some of the other characters of the 
oat spikelet. Nilsson-Ehle (95) states 
that certain yellow oats carry an inhibi¬ 
tor for awns. Fraser (37) in studying 
the cross Burt X Sixty-Day found no 
evidence of the existence of such an in¬ 
hibiting factor in the Burt variety, 
but his ideas were in agreement with 
those of Nilsson-Ehle with respect 
to the presence of an awn-inhibiting 
factor in yellow oat kernels in the 
Sixty-Day variety. In the crossing ex¬ 
periments of Zade (153), Nilsson-Ehle 
(91, 93), Surface (127), Love and Craig 
(70), Love and Fraser (69), and Fraser 
(37), it was found as a rule that in crosses 
of awned X awnless oats the Fi was in¬ 
termediate and in F 2 the fully awned type 
behaved as a recessive. Fraser (37) re¬ 
ports that in the cross of Burt, which he 
states was usually awned, and Sixty-Day 
awnless, he found nearly complete 
dominance of the awnless type in Fi. 
13949—25f*-4 
LEMMA COLOR 
The color of the oat lemma probably 
is the most complex of all of the char¬ 
acters considered. This is due in part 
to its being much more easity affected 
by physiological and climatic condi¬ 
tions than most of the other charac¬ 
ters, which are morphological. In its 
genetic basis also lemma color in the 
Burt oat is certainly very complex, per¬ 
haps more so than any of the other 
spikelet characters studied. The color 
of the lemma is not fully developed 
until the kernel approaches maturity. 
Hence any condition which interferes 
with normal ripening has a marked 
effect on the color and makes it one 
of the most difficult oat characters to 
classify accurately. For these reasons 
it may be considered less important 
from the genetic and taxonomic stand¬ 
point, although it is perhaps the char¬ 
acter with which agronomists, grain in¬ 
spectors, seedsmen, and farmers are 
most familiar. 
The lemma color in the progenies 
grown was described as black, dark 
brown, light brown, red, yellow, and 
white. An incomplete series of kernel 
colors is shown in Plates 4 to 6, inclusive. 
The names of the color classes used in the 
text and in the tables are those com¬ 
monly recognized by agronomists. The 
colors graded into one another, and often 
it was extremely difficult to deter¬ 
mine the correct color classification. 
This was especially true of the lighter 
colored kernels. 
STUDY IN 1920 
In the classification of the parental 
material at Akron in 1920 a class termed 
“variegated” was created for those 
kernels showing a more or less mottled 
color. Very few variegated kernels 
were found in the progenies harvested 
in 1920, apparently proving that varie¬ 
gation resulted from climatic conditions 
or physiological causes. For this reason 
the variegated class was no longer used. 
Data were obtained in only two of the 
eight strains on the 1920 progeny ker¬ 
nels from parental kernels described as 
variegated. In describing the original 
material no distinction was made at 
either station between the dark and 
light shades of brown. In describing 
the 1920 progenies from the Manhat¬ 
tan station and one strain, Kansas No. 
5220, from the Akron station, no dis¬ 
tinction was made between the two 
shades of brown. This differentiation 
was made in the other seven strains 
grown at Akron in 1920. 
A few grayish-brown kernels were 
observed in the course of the experi¬ 
ments, but as they were not of frequent 
