706 
Journal of Agricultural Research 
Vol. XXVIII, No- 7 
diffusa var. montana Al. was graded 3. The rest were uniformly 4. These two 
are low, slender-strawed varieties of small value. Vavilov pointed out that 
black rust of oats is a weakly specialized fungus which lives freely on several 
genera besides Avena, and states that “we come to a simple statistical conclusion 
as to the very slight probability of plant breeders finding oats resistant to black 
rust.” 
Parker (14) tested 120 strains of oats with both crown and stem rusts. Only 
White Tartarian and Ruakura Rustproof showed pronounced resistance to stem 
rust. Later, Durrell and Parker ( 1 ) published the results of a five-year test of 
about 200 lots of oats. The following were found resistant to stem rust: White 
Russian (White Tartar), Ruakura, Green Russian, A. sativa grisea , A. orientalis 
mutica , and A. barbata . 
A beginning has been made in the breeding of oats for resistance to stem rust. 
Garber ( 4 , 5) made crosses between White Russian (White Tartar), a rust- 
resistant oat with side panicle, and Minota and Victory, susceptible forms with 
open panicle. He found that “rust resistance is inherited as a dominant char¬ 
acter depending on a single factor difference for its expression,” and that rust 
reaction and panicle type are independent in their inheritance. Griffee (6’) 
reports the rust test of the F 8 generation of these crosses. Of the resistant F 2 
families, one-third bred true for resistance in the F 8 and two-thirds segregated. 
Table I .—Result of inoculation of oat varieties with stem rust at Berkeley, Calif,, 
in the summer of 1920, as measured on a scale of 0 to 4, in which 0 represents 
immunity and 4 represents complete susceptibility ° 
Host 
Lot No. 
C. I. 
No. 
Greenhouse tests 
Field tests 
First 
Second 
First 
Second 
Avena brevis Roth. 
var_ 
R 134d 
4 
3+ 
2+ 
3— 
Do. 
R 142a 
4- 
3+ 
3— 
4— 
Do. 
R 280a 
1783 
3 
3 
3+ 
3+ 
Avena fatua L. 
var. 
R 290a 
1779 
4 
4 
3+ 
4- 
var. California Wild Oat. (Lemmas 
slightly 2-toothed)_ 
C 1024 
4— 
3+ 
3+ 
4 
Avena nuda L. 
var. chinensis ... 
R 301 
4- 
4— 
3 
4— 
var. Chinese Hull-less... 
W 686 
298 
4- 
3 
var. inermis . 
R 294a 
1768 
3+ 
4 
3 
3+ 
var. Liberty. 
R 292a 
845 
4- 
3+ 
3 
4- 
Do. 
R 293a 
1769 
3 
4- 
3+ 
Do. (Differs in having geniculate 
awns)___ 
C 1000 
3 
4 
Avena sativa L. 
var. Abundance.... 
R 269a 
731 
4- 
4— 
3 
var. Abyssinian. 
R 303a 
1747 
4 
4 
4— 
3 
var. Albion. 
R 270a 
729 
4- 
3 
3 
3 
Do. 
R 304a 
729 
4- 
4 
3 
4- 
Do. (Iowa 103).. 
161 
729 
4— 
3— 
var. aristata _ 
R 35g 
3 
3+ 
3— 
4— 
var. aurea _ 
R 7s 
4- 
3+ 
4— 
Do. 
R 328a 
1772 
4- 
4 
3 
4- 
var. Awnless Probsteier. 
R 114d 
1888 
4- 
3 
3+ 
4 
var. Banner. 
R 271a 
160 
4- 
3+ 
4 
4 
Do... 
C 1031 
3+ 
3- 
3+ 
4— 
Do.. 
W 764 
1191 
4 
3+ 
4 
4— 
var. Belyak. 
R 115e 
1899 
4- 
3 
3+ 
3+ 
Do. 
R 306a 
1726 
4 
4 
4- 
4 
<* In the tables, the lot numbers indicating the different selections are preceded by various capital letters, 
which indicate the sources from which the seed was received. The lot numbers following the letter “C” 
are accession numbers of the California Agricultural Experiment Station. The lots designated by the 
letter ‘*1” were received from the Iowa Agricultural Experiment Station and the numbers are nursery 
row numbers or selection numbers of the Department of Botany and Plant Pathology. The one lot 
bearing the letter “ K” was received from the Kansas Agricultural Experiment Station. The numerous 
lots bearing the letter “R” were received from Dr. O. M. Reed, then pathologist in charge of smut investi¬ 
gations, Office of Cereal Investigations, Bureau of Plant Industry, United States Department of Agri¬ 
culture, and the numbers are those used by him in the oat-smut nursery. The lots following the letter 
“ W” were received from the Washington Agricultural Experiment Station, and the numbers are accession 
numbers of that station. 
