28 
BULLETIN 1403, U. S. DEPARTMENT OF AGRICULTURE 
in presenting the results. The F 2 hybrids again show greater vari- 
ability than either of the parents, but the extreme dates oi earliness 
or lateness of the parents were not exceeded by F 2 plants of the 
hybrids. Variability constants computed for the growing period, or 
days from emergence to ripening, are given in Table 28. 
Table 28. — Mean, standard deviation, and coefficient of variation for the growing 
period or days from emergence to ripening of F 2 wheat hybrids and for the Hard 
Federation and Marquis parents grown at Bozeman, Mont., in 1923 
Material compared 
Mean 
Standard 
deviation 
Coefficient of 
variation 
F 2 hvbrid 
91. 09±0. 09 
89.63-s- .21 
3. 298±0. 065 
3. 136+ .150 
3. 621-J-0. 072 
Hard Federation 
3. 499± . 168 
Marquis. . 
10S.90-I- .12 1.725-4- .082 
1.584zh .076 
The data show a slight but not a significantly greater variability 
for the hybrids than for the early and most variable Hard Federation 
parent, although the hybrids are significantly later. Because of the 
lateness of Marquis, variability for this variety was probably much 
less than normal. 
Table 29. — Dates when fully ripe in the F 3 generation of 672 Marquis-Hard 
Federation wheat hybrids, in comparison with 79 parent checks, grown at Bozeman, 
Moccasin, and Havre, Mont., in 1924 
Dates when fully ripe 
Number of rows 
Bozeman 
hybrid 
Hard 
Feder- 
tion 
Mar- 
quis 
Moccasin 
Havre 
v ; Hard 
Mar- 
quis 
-r, I Hard 
Mar- 
quis- 
August 12 
August 13 
August 14 
August 15 
August 16 
August 17 
August 18 
August 19.... 
August 20 
August 21 
August 22 
August 23.... 
August 24 
August 25 
August 26 
August 27 
August 28 
August 29.... 
August 30 
August 31 
September 1. 
September 2. 
September 3_ 
September 4. 
September 5. 
Total 
Average time of ripen- 
ing: 
August 
September 
14 
15 
17 
29 
26 
17 
21 
10 
1 
?, 
9 
11 
26 
6 
66 
7 
89 
1 
1 
38 
2 
8 
21 
3 
17 
1 
3 
17 
1 
2 
2 
224 
13 
29.5 
150 
19.5 
2.5 
17. 3 22. ! 
298 j 18 
17. I 16. 4 
17 
18.8 
