66 
BULLETIN 1403, U. S. DEPARTMENT OF AGRICULTURE 
Table 64. — Correlation between average yield -per plant and crude-protein content 
of F z strains of Marquis-Hard Federation wheat crosses grown at Bozeman, 
Mont., in 1924 
Crude-protein content 
Average yield of plant (grams) 
Total 
2.5 
3.5 
4.5 
5.5 
6.5 
7.5 
8.5 
10 per cent 
2 
5 
2 
5 
2 
10 
8 
2 
2 
11 per cent.. 
5 
12 per cent 
I 
1 
5 
7 
7 
29 
30 
3 
1 
4 
5 
26 
18 
2 
1 
1 
1 
16 
17 
10 
18 
14 per cent 
15 
15 per cent 
1 
1 
8 
2 
1 
91 
16 per cent 
76 
17 per cent 
7 
Total 
4 
36 
81 
56 
36 
10 
1 
224 
r=0.256±0.042. 
The other extreme condition, showing a large negative correlation, 
is illustrated by the Havre data and is given in Table 65. As pre- 
viously mentioned, the season at Havre was very dry, and under 
such unfavorable conditions the yields were low and the kernels 
light in weight but hard and vitreous. 
Table 65. — Correlation between average yield per plant and crude-protein content 
of Fz strains of Marquis-Hard Federation wheat crosses grown at Havre, Mont., 
in 1924 
Crude-protein con- 
Average yield per plant (grams) 
Total 
tent 
0.8 
1.3 
1.8 
2.3 
2.8 
3.3 
3.8 
4.3 
4.8 
12.5 per cent 
1 
1 
2 
1 
" r 
1 
13 per cent.. 
2 
3 
4 
6 
1 
1 
4 
1 
r 
7 
13.5 per cent 
i 
3 
5 
14 
12 
12 
6 
1 
r 
3 
5 
5 
7 
14 per cent.. 
1 
11 
17 
16 
27 
29 
14 
3 
11 
26 
3 
5 
10 
16 
21 
15 
8 
40 
15.5 per cent 
1 
40 
16 per cent 
49 
51 
17 per cent 
1 
2 
37 
17.5 per cent. 
20 
8 
Total 
3 
78 
118 
54 
14 ! 17 
6 
6 
i 
297 
-0.732±0.018. 
The distribution of the data in Table 65 strikingly illustrates the 
negative relationship which exists between yield and crude-protein 
content under dry-farming conditions and shows the importance of 
giving equal consideration to factors for quality and factors for yield 
in an improvement program in wheat breeding. 
CRUDE-PROTEIN CONTENT 
The coefficients of correlation obtained for crude-protein content 
one year with another at Bozeman and Bozeman one year with Havre 
the year following are given in Table 66. 
