Jan. 1, 1925 
A Study of Variability in the Burt Oat 
13 
Wilds 14 studied the inheritance of 
basal hairs in crosses of Avena fatua 
with cultivated varieties of Avena sat- 
iva. He found that the length of the 
basal hairs was determined by a single 
pair of genes, shortness being domi¬ 
nant. These genes segregated inde¬ 
pendently of the other kernel charac¬ 
ters studied. 
In addition to basal hairs, the kernels 
of the wild oat parent of these crosses 
have dorsal hairs. The factor which 
determines the presence of hairs on 
both the lower and upper florets is 
linked with the black color factors. 
Love and Craig (70) crossed Avena 
fatua with Avena sativa variety Kher¬ 
son. Their results were similar in 
many ways to those of Nilsson-Ehle 
(91) and Surface (127). They ob¬ 
served the intermediate Fi type 
with basal hairs on either side but 
not on the back of the kernel. In F 2 
they found the sativalike base domi¬ 
nant, or at least partially so, to the 
type of base of the wild oat. They 
also found some linkage between the 
wild type of base of the wild oat and 
pubescence, and that the yellow form 
appeared to carry an inhibitor for 
pubescence. 
Wiggans 15 observed the behavior of 
the basal hairs in the cross Red 
Texas X Swedish Select. The Fi 
kernels had only a few basal hairs 
which were approximately the same 
length as the basal hairs of the Red 
Texas parent. The F 2 plants were 
grouped into two classes, hairy and 
glabrous, although within the first 
group there was a wide variation in 
the number of hairs. There was not a 
great amount of variation in the 
length of hairs, although a few indi¬ 
viduals appeared with much shorter 
hairs than the Red Texas parent. 
The results obtained in F 2 and F 3 
may be explained on a two-factor 
hypothesis. 
Fraser (87), in describing the Burt X 
Sixty-Day cross, states that a strong 
linkage exists between the fully awned 
condition and medium long hairs at 
the base of the grain. In 2,341 indi¬ 
viduals there was about 5 per cent 
of crossovers. He found short basal 
hairs or no basal hairs to be dominant 
to medium long basal hairs. In F 2 he 
obtained a ratio of three of the former 
to one of the latter. 
AWNS 
The awn is an extension of the 
midrib of the lemma and usually 
arises at a point slightly above the 
middle of the dorsal surface. In most 
wild species of oats the lemmas of 
all the florets are awned, the awns 
being stout and long with the lower 
portion twisted in a dextrorse or clock¬ 
wise direction and the upper portion 
bent over. In all cultivated varieties 
of Avena sativa the awn usually occurs 
only on the lower lemma, if at all, and 
usually is small in size. In some 
varieties derived from A. byzantina 
awns occur occasionally on both 
florets and sometimes they are twisted 
or geniculate. 
Raum (108) considered the presence 
of awns a very important character in 
oats, although influenced by climatic 
conditions and particularly by the 
rainfall. According to this investigator 
the weight of the floret and also of the 
lemma and of the caryopsis increased 
approximately 10 per cent with the 
presence of the awn. Completely 
awnless varieties of oats, however, were 
not found. 
Norton (99) found that awned and 
awnless oats when crossed gave a 
partially awned type in Fi, which in 
F 2 split up in a ratio of 1 awned to 2 
partially awned to 1 awnless. 
Fernekess (34) observed that the 
presence of awns was associated with 
heavier kernel weight in oats. 
Zade (153), on crossing a cultivated 
variety of Avena sativa with Avena 
fatua, found in Fi that the lower floret 
of the spikelet was awned, which 
showed presence of the strong awn to 
be dominant, to some extent at least, 
over its absence. In the F 2 he ob¬ 
served a ratio of 1 awned to 2 par¬ 
tially awned to 1 awnless. 
Nilsson-Ehle (95) observed in a cross 
between a black, strongly awned and a 
white awnless oat that the Fi showed 
the awn on the lower floret of the spike- 
let. In F 2 the ratio obtained was 1 
awned to 2 partially awned to 1 awn¬ 
less. He found awns to be produced 
more commonly by black and by white 
kernels than by yellow ones. He at¬ 
tributed the failure of yellow kernels to 
produce awns to an inhibitor carried by 
kernels of that color. He also observed 
that environmental conditions greatly 
influence the production of awns in cul¬ 
tivated varieties. He stated that 
plants having the gene for producing 
awns may fail to show the awns because 
of environmental conditions. 
Trabut (135) in tracing a series of 
forms between the wild Avena sterilis 
and its cultivated derivatives observed 
a gradual reduction in the number of 
awns per spikelet and in the strength of 
the awns. 
1 4 Wilds, G. J. op. cit. 
16 Wiggans, R. G. op. cit. 
