264 '-^^ INHERITANCE OF HIE FL ONVERING TIME IN PEAS AND RICE 
from the zygotic series'^ in F._,, various variation types in F3 and and 
compare those types with the actual variation types in Fg and F^ raisings, one 
will readily see that the two-factor hyjiothcsis is more probable than the 
three-factor hypothesis. 
As a natural outcome of the foregoing discussion, we are convinced that 
our proposed hypothesis of the presence of two alleromorphic pairs and of the 
occurrence of gametic contamination is the most reasonable interpretation 
of the inheritance of the flowering time in peas. To explain the nature and 
cause of contamination is difficult in such experiments as those on the inheri- 
tance of flowering time. But it is certain that the contamination in our case 
at least is not "inconstancy" in the sense of Castle (19 12). In each of the 
F.J raisings which showed the variation types of monohybrid segregation, all 
earlier constant families had almost the same variation means and ranges and 
also all later constant families had uniform variation types. This indicates 
gametic constancy in the F2 grand-parents. The hypothesis of the presence 
of a secondary determiner or determiners might be maintained to some ex- 
tent. If we assume that the gametes from an early parent carry with pri- 
mary fcictors (ab) some secondary determiner or determiners which act on 
the factors from a late parent as an agent or agents having the power to has- 
ten flowering time to a slight extent, and that those from the late parent carry 
a secondary determiner or determiners, acting on the primary fcictors from 
the early parent as a retarding agent or agents, we can explain the occurrence 
of both pseudo-early and pseudo-late constant families. The variation types 
in J and L in Table 14 can be interpreted if we assume that their F^ grand- 
were homozygous in the 
primary factors (aaBB) but heterozygous in 
Constant 
Monohyljiid 
Dibylirid Trihybrid 
I aabbcc 
2 Aabbcc 
4 AaBbcc 8 AaBbCc 
I AAbbcc 
2 aaBbcc 
4 aaBbCc 
I aaBBcc 
2 aabbCc 
4 AabbCc 
I aabbCC 
2 AaBBcc 
4 AaBbCC 
I AABEcc 
2 AabbCC 
4 AaBBCc 
I AAbbCC 
2 AABbcc 
4 AABbCc 
I aaBSCC 
2 AAbbCc 
I AABBCC 
2 aaBbCC 
2 aaBBCc 
2 AABBCc 
2 AABbCC 
2 AaBBCC 
