FACTORS FOE YIELD AND QUALITY OF SPRING WHEAT 
35 
cant. Reciprocal crosses show what might be interpreted as slight 
maternal influence, the Hard Federation X Marquis crosses averaging 
0.60 ±0.18 days longer in fruiting period than crosses of Marquis X 
Hard Federation. This difference is 3.3 times its probable error. 
The variability of the hybrids appears slightly greater than that of 
Hard Federation, and their coefficients of variability are as follows: 
Coefficient of variation 
F 2 hybrids 7. 295±0. 144 
Hard Federation 6. 915± .331 
Difference. 
380± .361 
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Fig. 6.— Frequency distribution of F3 hybrid wheat strains and the range of variation of the Mar- 
quis and Hard Federation parent checks, together with their average fruiting periods at Havre, 
Moccasin, and Bozeman, Mont., in 1924 
As the difference is only about once the error, the variability of the 
hybrids can not be said to be significantly different from that of 
Hard Federation. 
The fruiting periods of F 3 strains and parent checks grown in rod 
rows in 1924 at Bozeman, Moccasin, and Havre were computed from 
the date of first heading to the date when fully ripe. The frequency 
data obtained are shown for the three stations in Table 34 and 
graphically in Figure 6. 
