Abstract
In cross experiment, the deviation of genotypic class numbers from those expected was found in F2 and backcross segregation of only B blood group system, due to the fact that the number of heterozygous genotypes was larger than that expected.
The B blood group genotypes of zygotes associated themselves with marked differences in embryonic mortality over the whole incubation periods, especially at periods of 16-21 days of incubation.
The hatchability of each homozygote was lower than the mean hatchability in F2 and backcross. The maintenance of stable polymorphism could be explained by differences in mortality among genotypes.
