RESUMEN
Mutation breeding in crop plants is an effective approach in improvement of crop having narrow genetic base such as groundnuts (Arachis hypogaea L.). Determination of effective irradiation dose is prerequisite for mutation breeding and development of genetic variability by induced mutation. Three groundnuts (Arachis hypogaea L.) genotypes (JL12, JL24 and Kimpese) were irradiated to the absorbed doses of 100, 200, 400 and 600 Gy for effective dose determination and to compare their sensitivity to different doses of gamma irradiation in a completely random design. It was found that, irradiation reduced significantly germination and survival percentages of seedlings in higher doses and this reduction was more pronounced in JL 24 cultivar. This sensitivity expresses himself distinctly to the rank of stem lengths and roots. Results show a negative interrelationship indeed between doses of irradiation applied and lengths of stems and roots. With attention to LD50 data, our results indicated that optimum doses were 200 Gy for JL12 and Kimpese, and 100 Gy for JL24. We concluded that JL24 are more sensitive to gamma irradiation than JL12 and Kimpese.