Abstract
1. With certain varieties of apples, a number of cross pollinations were conducted in 1961 for the purpose of breeding. Among the many F1 seedlings in 1962, albino seedlings were found, which ceased their growth soon after the sprouting and died away. The relation of the frequency of albino to the cross combination was investigated.
2. Of 29 cross combinations, 14 crosses segregated the normal seedling and albino at the rate of 3:1, while the other 15 crosses produced no albino seedlings. Thus, it suggests that such varieties as Golden Delicious, Jonathan, Megumi, J. G-93, etc. had a recessive lethal gene in the heterozygous type respectively, and albino seedlings had recessive lethal genes in the homozygous type. On the other hand, those varieties as Yellow Transparent, Red Gold, Starking, Winesap and G. Y-172, seemed to have no lethal gene and never produced albino seedlings.
