32 
S. DEPARTMENT OE AGRICULTURE 
on account of greater variation of the parents. The data for all of 
the F 3 plants studied for date of ripening at Bozeman and Havre are 
compared in Table 31 with similar data from parent plants grown 
in duplicate check rows. The Bozeman data are illustrated in Figure 3. 
At Bozeman the mean date of ripening of the hybrids is nearer that 
of Hard Federation; at Havre the mean of the hybrids is nearer that 
of Marquis, this latter fact being due probably to forced ripening of 
Marquis by drought. All F 3 data for date of ripening tend more 
toward an intermediate position in respect to the parents than 
toward a dominance of earliness, as was found for date of heading. 
Both F 2 and F 3 plant data for date of ripening in Figure 3 showbimodal 
curves, but no genetic importance can be given to this, as the parent 
varieties show the same types of curves, and the hybrids in F 2 at 
Moccasin and F 3 at Havre do not produce similar curves. Both 
date of heading and date of ripening data produce more or less skew 
curves with the mode for date of heading toward the early side and 
the mode for date of ripening toward the late side. As the same 
relationship holds true for the parents as well as the hybrids, it must 
be considered as due to environmental rather than genetic factors. 
Homozygosity for date of ripening, like that for date of heading, 
is best expressed in terms of variability. The number of days re- 
quired for all rows at Bozeman, Moccasin, and Havre to pass from 
first to fully ripe is shown in Table 32. 
Table 32. — Ripening period 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. 
Number of rows 
Ripening period (time from 
first to fully ripe) 
Bozeman 
Moccasin 
Havre 
F 3 
hybrids 
Hard 
Feder- 
ation 
Mar- 
quis 
F 3 
hybrids 
Hard 
Feder- 
ation 
Mar- 
quis 
F 3 
hybrids 
Hard 
Feder- 
ation 
Mar- 
quis 
1 day 
1 
2 days.. _ 
26 
64 
89 
75 
33 
5 
4 
1 
_. 
6 
6 
3 

3 
3 days. _ . . . . 
4 
4 davs . 
5 
5 days. 
4 
6 days... . .. .. . 
1 
7 days. 
8 days.. _ 
9 days. .. . . ... 
18 
41 
27 
41 
18 
2 
1 
2 
_- 
2 
4 
1 
10 days.. . 
11 days 
2 
2 
4 
12 days 
13 davs.- 
4 
23 
38 
38 
51 
32 
24 
12 
1 
1 
1 
1 
6 
1 
1 
2 
1 
4 
3 
3 
16 days.-- - 
17 days 
18 days.. 
19 days... 
i 
20 days.. 
2 
j 
21 days.- 
22 days 
, .! 1 
23 days 
1 
! | 
Total . 
224 
17.7 
13 
16.8 
13 
17.2 
150 
11.1 
9 
11.1 
9 
11.9 
298 18 ! 17 
Average period in days. 
4.2 
4.9 
,s 
The data show very contrasting differences in the ripening period 
at the three stations and that there are numerous hybrid strains 
