Mutagenic efficiency of gamma rays in sesamum

Seeds of sesamum Cv. Kayamkulam-1 were irradiated with gamma rays at doses 5 to 30 krad. The effects of irradiation in the M1 and M2 generations were studied. The doses employed had no effect on germination, seedling emergence and plant height in the M1 generation. With increase in the dose there was a steady decrease in survival and pollen fertility. The frequency of chlorophyll mutation estimated on M1 plant basis was higher than the estimate on M2 plant basis. The mutation spectrum included xantha(yellow) and chlorina (yellow green). Segregation ratio was maximum at 10 krad and minimum at 25 krad. Mutagenic effectiveness and efficiency were high at the lower doses and decreased with increasing doses. These observations indicate that gamma rays at low to medium doses can be successfully, employed for inducing mutations in sesamum. (author)