Sensitivity and mutability of gamma ray-treated cotton

Dry cotton seeds were irradiated by 5, 10, 15 and 25 krad doses. The six cotton cultivars (cvs) studied which differ in genotype proved significantly different in their radiosensitivity. Cv 38 had highest resistence to high doses of gamma-radiation, while cv 4521 was most sensitive. The mutating ability of the individual cotton cvs was closely related to their genetic constitution. Cvs 433, 10-I and Pavlikeni 73 showed highest mutability. Original mutant forms such as ultra early, with falling leaves, and of an utmost branching type, etc., were produced in these cvs. No correlation was observed between the radiosensitivity of the cvs and their mutability. The least mutable were those that were the most sensitive and the most resistent to gamma-radiation, namely, cvs 4521 and 38. Most effective for the induction of useful mutations in almost all cvs (433, 10-I, Pavlikeni 73) proved the irradiation dose of 15 krad. A high effect was produced by 5 krad irradiation of cv Tashkent-1