34 
BULLETIN 1403, U. S. DEPARTMENT OF AGRICULTURE 
period of individual F 2 plants from reciprocal crosses was studied, 
however, and these data in comparison with those of the Hard Feder- 
ation parent are presented in Table 33 and graphically in Figure 5. 
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Fig. 5.— 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 fruiting periods at 
Bozeman, Mont., in 1923 and 1924 
Table 33. — Segregation in the F 2 generation into 2 -day frequency classes for fruiting 
period of 583 plants of Marquis-Hard Federation wheats and reciprocal crosses, 
in comparison with the Hard Federation parent, grown at Bozeman, Mont., in 1928 
Number of plants 
Fruiting period (time from heading to ripening) 
F2 hybrids 
Hard Fed- 
eration X 
Marquis 
Marquis X 
Hard Total 
Federation 
Hard 
Federation 
35.5 days _. 
1 
7 
14 
51 
45 
74 
57 
1 
9 
32 
92 
88 
124 
128 
37.5 days 
2 
18 
41 
43 
50 
71 
52 
12 
39.5 days 
4 
41.5 days 
11 
43.5 days 
10 
45.5 days 
26 
47.5 days 
21 
49.5 days 
34 86 
10 22 
1 1 1 
18 
51.5 days 
8 
53.5 days 
1 
Total - 
289 
45. 67±. 13 
294 583 
99 
Mean period in days and probable error 
45. 07±. 13 
45. 37±. 09 
46. 33±. 22 
The data show that in the F 2 generation the fruiting period of the 
hybrids averaged 0.96 ±0.24 days shorter than that of Hard Federa- 
tion. This difference, which is 4.0 times its probable error, is signifi- 
