[en] The results are reported of study of radiosensitivity and mutability of different sorts of the cotton plant in different periods of ontogenesis and also the character of changes of the biological, morphological and industrial signs under the influence of irradiation of seeds and vegetating plants. Techniques of using radiation for distant hybridization are elucidated and the scheme of selection process in experimental mutagenesis is given. Scientists are looking for a more rational method of using induced mutagenesis as a source of new initial material for selection. It has been found that in the determination of the character of plant reaction to irradiation biological features of the cotton plant play a definite part. Cotton changes radiosensitivity during the vegetation period: in the first half of vegetation plants can not bear high radiation doses. Different sorst and types have different radiosensitivity. Irradiation technique and the stage of the material irradiated influence heredity. Use of irradiated pollen in cross-mating can enhance the frequency of forms with a better combination of morphobiological signs and stability