July i, 1924 
inheritance in Kota-Hard Federation Grosses 
45 
Table XLI.— Correlation between percentage of stem-rust infection in F 2 and F 3 
material of reciprocal crosses of Kota and Hard Federation wheats grown at St. 
Paul, Minn., and Mandan, N. Dak., in 1922, and at Mandan, N. Dak., in 1923 
SUMMARY 
1. This genetic study was made for 
the purpose of obtaining resistance to 
drought and rust in a high-yielding 
hard red spring wheat of superior 
milling and bread-making quality. 
2. The Kota and Hard Federation 
varieties w^ere selected as parents for 
the crosses because they appeared to 
be the best available material for com¬ 
bining in one study the problems of 
obtaining resistance to drought and 
rust, combined with high yield and 
quality. 
3. The material was grown at three 
points, i. e., Davis, Calif., under ideal 
conditions, St. Paul, Minn., under con¬ 
ditions of rust prevalence, and Mandan, 
N. Dak., under droughty conditions. 
4. Reciprocal crosses were studied. 
No important maternal or paternal 
influence was found although a slight 
and consistent influence was noted for 
certain characters. With these, only 
when the variety with the dominant 
character was used as the female parent 
was a fit significantly close to the ex¬ 
pected ratio usually obtained. 
5. The inheritance of awns was par¬ 
tially explained on a dihybrid Mende- 
lian ratio, in which five classes were 
studied and the short-awned and awned 
classes were shown to be recessive to 
the awnless, apically-awnletted and 
awnletted classes. Neither the awned 
nor awnless classes bred true in F 3 , and 
complete homozygosity for these classes 
could be interpreted only on a multiple- 
factor hypothesis. 
6 . Glume color did not appear to 
be inherited in a monohybrid ratio in 
F 2 , but those data corrected on the basis 
of F 3 , when a part of the recessive 
white-glumed class segregated, proved 
that only one genetic factor was 
involved. 
7. The color of the kernel segregated 
in F 2 in numbers close to the 15:1 ratio. 
In F 3 the white strains bred true and 
the red strains bred true or segregated 
in a 3:1 or 15:1 ratio. 
8 . Early maturity as determined by 
date of heading was found to be domi¬ 
nant to late maturity. 
9. Tallness of plant appeared to be 
partially dominant but due principally 
to heterosis and was easily affected by 
environmental conditions. 
10. Resistance to stem rust proved 
recessive and in F 2 appeared to occur 
close to a 1:15 ratio. In F 3 , however, 
not one of nearly 300 resistant F 2 fami¬ 
lies bred true for resistance, although at 
St. Paul, Minn., 8.1 per cent of 2,068 
F 3 plants were resistant and at Man¬ 
dan, N. Dak., 23.4 per cent of 6,387 
were classed as resistant. Evidence 
was shown that strains homozygous for 
resistance could be obtained in F 4 . 
11. Yield appeared to be due to 
multiple factors. F 2 hybrids exceeded 
the parents in variability, but F 3 selec¬ 
tions were less variable in comparison 
with the parents than the F 2 selection. 
12. Segregation for quality and quan¬ 
tity of the gluten was shown, by the 
use of viscosity and crude-protein de¬ 
terminations, to have occurred prior 
to the F4. 
