Abstract
When the seeds of 27 soybean varieties were exposed to gamma-rays, distinct varietal differences in the frequency of chromosome aberrations were found at the first root tip mitosis. The varieties tested could be divided into resistant and sensitive groups. F2 seeds from crosses between resistant and sensitive varieties were irradiated and from the frequency distribution of chromosome aberrations it was concluded that the intervarietal differences were controlled mainly by a single recessive gene rs1 which had been detected by Takaki and Yamashita to control the degree of seedling growth inhibition in both seed and growing plant irradiations.
