50 
BULLETIN 1403, U. S. DEPARTMENT OF AGRICULTURE 
Table 46. — Segregation in the F% generation into frequency classes for crude-protien 
content of the grain of 567 F 2 plants of Marquis-Hard Federation and reciprocal 
wheat crosses, in comparison with 189 plants of the parent varieties, grown at 
Bozeman, Mont., in 1923 
F2 hybrids 
Crude-protein content (NX5.7 
cent moisture) 
13.5 per 
Hard Fed- 
eration X 
Marquis 
Marquis X 
Hard Fed- 
eration 
Total 
Hard 
Federation 
Marquis 
12 per cent.. 
12.5 per cent. 
13 per cent._ 
13.5 per cent. 
14 per cent-. 
14.5 per cent. 
15 per cent.. 
15.5 per cent. 
16 per cent.. 
16.5 per cent. 
17 per cent.. 
17.5 per cent. 
18 per cent.. 
1 
8 
27 
74 
121 
168 
US 
38 
8 
2 
1 
Total 282 
Mean per cent and probable error...; 14. 43±.03 
285 
14.31±.03 
567 93 
14.37±.02 J 13.99±.05 
14. 94±. 06 
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The data show that 
in theF 2 generation the 
hybrids were inter- 
mediate to the parents 
in crude-protein con- 
tent. The average of 
Marquis exceeded the 
average of Hard Feder- 
ation by 0.95 ±0.08 
per cent. This differ- 
ence is significant. The 
difference between the 
average of all the hy- 
brids and that of Hard 
Federation, 0.38 ±0.05 
per cent, proves that 
the hybrids are sig- 
nificantly higher in 
crude-protein content 
than the Hard Feder- 
ation parent. The 
difference between the 
average of the hybrids 
and that of Marquis, 
0.57 ±0.06 per cent, 
likewise proves that 
the hybrids are sig- 
nificantly lower in 
crude-protein content 
than the Marquis par- 
ent. The results from the reciprocal crosses differ by 0.12 ±0.04 per 
cent in favor of the Hard Federation-Marquis crosses. This 
difference is statistically significant, although the difference of the 
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Fig. 11.— Frequency distribution of F2 and F3 hybrid wheat 
plants and the range of variation of the Marquis and Hard 
Federation parents, together with their average crude-protein 
content at Bozeman, Mont., in 1923 and 1924 
