FACTORS FOB YIELD AND QUALITY OF SPRING WHEAT 
13 
The breeding behavior of the F 2 classes in the F 3 generation by 
percentages in comparison with the calculated was as shown in 
Table 10. 
Table 10. — Comparison of the breeding behavior of the two classes with that calculated 
Comparative items 
F 2 fam- 
ilies 
F3 plants 
Classes ! 
1 and 2 
Class 
Obtained. 
Calculated. 
26.8 i 100.0 
50.3 ! 65.2 34.8 
22.9 100.0 
25.0 I 100.0 \ 
50.0 75.0 J 25.0 
25.0 L. — 100.0 
A fairly close fit to the expected 1:2:1 ratio was obtained for the 
F 2 families involved. There resulted, however, an excess of class 3 
plants in the F 3 generation. 
On the basis of the F 3 distribution, assuming that 22.9 per cent 
of the Bozeman F 2 families would have proved homozygous for class 
3 if tested, it appears that 4.51 per cent should be added to the 18.34 
per cent, as originally classified. Correcting the Bozeman F 2 data 
on the F 3 results, the figures obtained agree closely with the original 
Moccasin data. (Table 11.) 
Table 11. — Comparison of the corrected Bozeman and original Moccasin data 
Station 
1 
Classes 
1 and 2 
Class 3 
Devia- 
tion from 
3 : 1 ratio 
Probable 
error 
Bozeman (corrected) ... 
454 
338 
135 
193 
12 
8 
7.09 
6.27 
Moccasin (original) _ .. ..... . 
Total (both stations) .. ... 
792 
258 s 
9.47 
These deviations are less than three times their probable errors 
and show a fit which is not significantly different from the one factor 
or 3:1 ratio. It seems reasonably certain, therefore, that there is a 
primary factor for the degree of awn development of Marquis (class 
3) which is recessive to a factor determining less awn development. 
On the hypothesis that a second factor is responsible for the dif- 
ferences between the awnless and apically awnletted classes, it will be 
necessary to find 6.25 per cent of recessives of F 2 strains at the other 
extreme breeding true. 
Table 12. — Percentage totals of F 2 results obtained by combining classes 2 and 3 in 
comparison with class 1 
Localities 
Class 1 
Classes 
2 and 3 
Bozeman. 
6.5 
6.1 
93 5 
Moccasin 
93.9 
Percentage of total 
6.3 
93 7 
