A Consideration of Variegation.

The segregation of albino or chlorophyll deficient seedlings in a pedigree propagated by self-fertilization is due either to a definite genetic factor or factors according to DEMEREC (1923) in maize, HALLQVIST (1926) in barley, etc., or to the abnormality of the plastids themselves according to CORRENS (1909) in Mirabilis, BAUR (1909) in Pelargonium, ANDERSON (1923) in maize, CLAUSEN (1927) in Viola, etc. In the former cases, the albino segregates occur in one-fourth, seven-sixteenths, onesixteenth and so on, according to the number and behavior of the factors by which the deficiency of chlorophyll is manifested, while in the latter their segregating proportion is quite irregular, varying according to the degree of variegation on the parental plants from which the seeds were collected, or, in other words, the abnormal plastids conduct themselves independently of the genetic factors, their transmission therefore being non-Mendelian. Professor S6 (1921) studying the genetics of variegated barley made its peculiar behavior clear. His conclusions published in the Japanese language induced me to write this paper, in which I will give a critical discussion of the complicated heredity of some variegated plants in the light of Professor S6’s work and of analogous cases from observations made by myself.