Mutations in rice induced by X-rays.

Abstract

1. With the aim of inducing reciprocal translocations of chromosomes in rice, soaked seeds of four varieties were x-rayed with the dose of about 20, 000 r. The plants from the treated seeds (X₁) and their progenies (X₂) were investigated. 2. The fertility of X₁ plants was remarkably reduced. 80% of main heads showed less than 50% fertility and those with the fcrtility under 20% were the commonest. No difference was found among the varieties in the degree and the mode of sterility. The reduction was aiso found in the number of tillers. 3. The sterility of tillers from iower nodes somewhat differed from that of main culm in X₁ generatiori. The secondary tillers had generally the same degree of sterility with primary ones from which they grow.