July 1, 1924 
Inheritance in Kota-Hard Federation Crosses 
41 
DATE OF HEADING AND STEM-RUST 
INFECTION 
The effect of earliness on infection of 
stem rust is a problem of considerable 
•economic importance. Correlations 
between date of heading and stem-rust 
YIELD AND DATE OF HEADING 
Productiveness or yield is the desired 
result of wheat breeding. Other char¬ 
acters are important in so far as they 
affect yield. Quality is important with 
high yield. The principal characters 
Table XXXIV.— Correlation between date of heading and percentage of stem-rust 
infection in F% material of crosses of Kota and Hard Federation wheats grown at 
Mandan, N. Dak., in 1922 
Date of heading 
Stem-rust infection (per cent) 
June j 
i 
July 
Total 
26 
28 
30 ! 
i 
2 
4 
6 1 
8 
10 
12 ! 
14 
.5. _ __ 
1 4 ' 
7i 
1 
j i 
! 1 1 
7 
15_ _ _ 
42 
31 ! 
9 
I 12 ! 
2 
1 
|_ 
97 
25 . _ _ 
1 
30 ! 
30 1 
16 
! 13 1 
16 
2 
1 
_ , . 
109 
35 
1 
1 27 i 
53 ! 
24 
j 28 ! 
23 
6 
5 
1 
! 
168 
45 ..._ 
I 45 ! 
60 ! 
45 
i 46 
36 
11 
5 
1 
| 1 
250 
55 
1 
27 ! 
33 i 
21 i 
1 30 
22 
12 
5 
_ ,i 
' 151 
65 _ 
1 
26 | 
36 | 
28 
! 48 
36 
23 
7 
3 i 
i 2 
210 
75 . _ _ .. 
4 
5 ! 
8 
16 
12 
7 
2 
2 
56 
85 
4 
2 
2 
6 
2 
1 
17 
“95_ 
1 
1 
2 
Total_ 
4 
205 
253 
| 154 
j 197 
153 
65 
24 
7 
5 
1,067 
r=0.311±0.019 
infection have been studied in F 2 
material of the Kota-Hard Federation 
crosses at St. Paul, Minn., and Mandan, 
N. Dak., in 1922, and F 3 material at 
Mandan in 1923. The Mandan F 2 
data are given in Table XXXIV. 
The coefficients obtained are sum¬ 
marized as follows: 
F 2? 1922: 
At St. Paul, Minn_ 0. 093 ±0. 029 
At Mandan, N. Dak_ . 311 ± . 019 
F 3 , 1923: 
At Mandan, N. Dak_ . 156 ± . 025 
A significant positive correlation was 
found between date of heading and stem- 
rust infection in three instances. The 
coefficient was not large at St. Paul, 
but a fairly high degree of correlation 
w T as indicated at Mandan in both years. 
The wheat in 1922 was later in matur¬ 
ing at Mandan than at St. Paul, due 
to later seeding and being farther 
north, and rust may have had as good 
a chance to infect the early plants as 
the late ones. On the other hand, 
there probably was more rust inoculum 
present in the latter part of the ripen¬ 
ing period, so that some of the early 
plants may have partly escaped. 
Selections of rust-resistant plants, there¬ 
fore, must be thoroughly tested to be 
certain that they are resistant rather 
than escaping. A few fairly late plants 
in both F 2 and F 3 appeared resistant at 
Mandan. 
previously discussed which could affect 
production are now studied for correla¬ 
tion with yield. 
The effect of time of maturity on 
yield usually is important in the 
northern spring-wheat area. The aim 
of the breeder is to produce just as 
early a wheat as can be grown without 
sacrificing productiveness. Data on 
correlations between date of heading 
and yield of plant were obtained in F 2 
from St. Paul, Minn., and Mandan, 
N. Dak., in 1922, and in F 3 at Mandan 
in 1923. The results from Mandan in 
F 3 are given in Table XXXV. 
The coefficients obtained are as fol¬ 
lows: 
F 2 , 1922: 
At St. Paul, Minn__ —0. 321 ±. 026 
At Mandan, N. Dak. —0. 176±. 020 
F 3 , 1923: 
At Mandan, N. Dak. -0. 193±. 024 
A significant negative correlation was 
found between yield and date of head¬ 
ing under the three conditions. The 
correlation was most important at St. 
Paul. At Mandan in both 19^2 and 
1923 the amount of correlation is not 
sufficient to be considered very impor¬ 
tant from a selection standpoint. 
Early heading selections, however, offer 
the greater possibilities for high yield. 
It seemed desirable to determine the 
inheritance of date of heading in F 3 in 
relation to that of F 2 . The correlation 
of 0.758 ±0.024, obtained from 148 
plants and shown in Table XXXVI is 
very important. 
