Induction of mutations for heat tolerance in potato by using in vitro culture and radiation

Heat tolerant mutants were obtained in two commercial potato cultivars, 'Kufri Jyoti' and 'Kufri Chandramukhi' through in vitro mutagenesis of in vitro propagated plantlets. Gamma-irradiated (20 and 40 Gy) shoots were micropropagated for three cycles (M(1)V(3)). A large number of the micropropagated shoots produced microtubers at 28 degrees C. Microtubers induced at high temperature had distorted shape but showed normal germination in field. Under stress conditions of high temperature, the frequency of chlorophyll variants increased in the gamma irradiation-derived material, however, nearly 40% of the plants had normal leaf tissue, whereas control plants showed completely damaged leaves.