Jan. 1, 1925 
A Study of Variability in the Burt Oat 
basal articulation of outer grain very marked; 
glumes, long, coarse, long pointed, nerves 9-10, fine; 
length of glumes 26 mm.; husk, pale yellow, gla¬ 
brous, nerves not prominent; awns, numerous, not 
long, fine, neither twisted nor geniculate; basal hairs 
numerous, short, fine, white; rachilla, glabrous, 
long, fine, persistent to upper grain; grain with husk 
(outer grain) length 17-18 mm., long pointed, nar¬ 
row, practically no shoulder; grain without husk 
(outer grain) length 8-9 mm., brush long; straw, 
fine to medium fine, non-hairy. First node of 
rachis normal, straight, inclined to lodge; foliage, 
medium in width, medium to sparse, early growth, 
medium erect to medium spreading; stooling, 
sparse; season, very early. 
Marquand (75), of the Welsh Plant 
Breeding Station, considers the Burt 
oat a variety of Avena sterilis, sub¬ 
species culta, and gives the following 
description of the variety, which is in 
close agreement with that of Etheridge 
(33): 
Young plant sub-erect. Lower leaves with mar¬ 
ginal hairs towards the base of the lamina. Stems 
slender. Average height of the plant 80cm. Panicle 
small, sub-equilateral, branches sub-patent. Spike- 
lets 2-3 grained. Glumes 26-30mm. long, 7-8.5 mm. 
wide. Grains dull yellow, attenuate; usually both 
upper and lower grains provided with long slightly 
twisted but rarely geniculate awns. Lower grain 
17-20mm. long, 2.5-2.8mm. wide, 1.9-2.1mm. thick; 
basal articulation only partly solidified. Outer 
palea glabrous, long pointed, with the apex not 
upturned. Rachilla also glabrous. Basal hairs 
numerous but very short (0.5-2 mm. in length), 
forming compact tufts. Early in ripening. 
Marquand (75) also called attention 
to the fact; apparently not recognized 
by many agronomic workers, but em¬ 
phasized in the present paper, that the 
majority of the older varieties of oats 
and some of the more recent ones are 
not pure lines but consist of a number 
of strains, sometimes amounting to 
hundreds, differing in their properties 
in a greater or less degree. 
In a conversation with the writers in 
September, 1921, Prof. N. I. Vavilov, 
director of the Bureau of Applied 
Botany and Plant Breeding, of Petro- 
grad, stated that possibly the Burt oat 
is similar to the European type classi¬ 
fied as Avena sterilis byzantina. 
Different authors do not agree on 
the amount of natural crossing wdiich 
occurs in oats. It is generally be¬ 
lieved, however, that while some cross¬ 
ing occurs, the extent is not great. 
Reports by Rimpau (111, 113), Jamie¬ 
son (54), Norton (98), Peacock (103), 
Livermore, 9 Heribert-Nilsson (50), 
Hayes and Garber (47), and others, 
indicate that natural crosses occur to 
some extent. Several other authors, 
namely, Hunt (53), Pope (105), Bab¬ 
cock and Clausen (7), Love and Craig 
(72), and Fraser (37) indicate that 
natural crosses in oats are of extremely 
rare occurrence. 
From the results obtained in these 
experiments the authors believe that 
natural crossing in the Burt oat occurs 
to a greater extent than has been gen¬ 
erally believed, although not so freely 
as believed by Jamieson (5J). How¬ 
ever, it probably is true that sufficient 
natural crossing does occur to account 
for some of the aberrant forms which 
appear and possibly for some of the 
recurring heterozygosity of the Burt 
oat. 
Variability in oat varieties has long 
been recognized. More than 15 years 
ago Webber (147) stated that few pure 
strains of oats existed, and that varieties 
frequently were mixtures of different 
types. Warburton (14$) pointed out 
the urgent need for definite experi¬ 
ments and scientific methods for oat 
improvement. Welton and Gearhart 
(148) have stated that great variability 
exists in the physiological and other 
characters of the plants of oat varie¬ 
ties. The extent and nature of the 
variability existing in Burt has only 
recently been fully realized, but the 
same condition may exist, to some 
extent at least, in other oat varieties. 
AVENA BYZANTINA KOCH AND ITS 
RELATIONSHIPS 
The following are brief reviews of 
the available literature on the classifi¬ 
cation of oats, with especial reference 
to the taxonomic position of the culti¬ 
vated varieties supposed to have been 
derived from the wild Avena sterilis. 
Koch (63, p. 392) published the 
original description of Avena byzantina, 
as follows: 
Glaberrima; Spiculae magnae, biflorae; basis 
flosculi inferioris pilis quartam ejusdem flosculi 
partem attingentibus obsita, superioris nuda; Flo¬ 
sculi aristati, glabri, laeviusculi; Palea inferior 
bifida; Aristae pars inferior tortilis, glabra, laevis. 
He states that it is similar in appear¬ 
ance to A. sativa but differs in having 
both florets awned and the lower 
hairy. He states further that Peter- 
mann’s A. hybrida, according to its de¬ 
scription, has a hairy rachilla and floret 
base. Koch based his description on 
plants from the vicinity of Constanti¬ 
nople and stated that he had received 
similar plants from the collection of 
Thirke made near Brusa and had 
previously determined these errone¬ 
ously as A. sativa. 
Cosson (22) published a paper on 
the classification of the species of 
Avena, in which Avena byzantina C. 
Koch is listed with A. hybrida Peterm. 
as being synonymous with Avena 
fatua var. glabrescens. 
9 Livermore, K. C. natural cross fertilization in oats. 1912. [Unpublished thesis, Cornell 
Univ., Dept. Plant Breeding.} 
