Agronomy and Horticulture Department


Date of this Version



Genetics 19 (1934), pp 137-156.


Copyright 1934 R. A. Emerson


The Ga, or “gamete” gene of maize can be studied only or principally by its disturbance of normal Mendelian ratios of contrasted characters differentiated by genes linked with it. The amount of this disturbance can be used as a measure of the intensity of linkage between Ga and other genes of the su-Tu group.

Disturbance of the 3:1 ratio of starchy, Su, to sugary, su, endosperm has been most studied. In one of the early papers on Mendelian inheritance, Correns (1902) reported that, although crosses between most starchy and sugary varieties gave an F2 ratio of 3:1 for starchy and sugary kernels, a popcorn with pointed kernels, when crossed with sugary races, gave only 16 percent of sugary kernels in F2. That Su and su segregated normally was shown by reciprocal crosses of F1 with the sugary parent, which gave approximately 50 percent sugary kernels. From this Correns concluded that the deficiency of sugary kernels in F2 is due to selective fertilization.