Radiosensitivity and Frequency of Chlorophyll Mutations in Pigeon Pea

The seeds of early (Prabhat), medium (R 60 and BS 1) and late (NP(WR) 15, T 7, L 1 and I 2) pigeon pea strains were irradiated with 5, 10, 20, 30 and 40 kr ⁶⁰Co gamma-rays. Gamma-irradiation reduced germination, seedling height, pollen fertility and survival at maturity; the reduction was greatly pronounced at 5 kr indicating a threshold physiological effect of gamma-rays in this species. The three maturity groups were similar in their response to gamma-rays. R 60 was the least whereas (NP(WR) 15 was the most radiosensitive. Three types of chlorophyll mutations (Viridis, Chlorina and Xantha) were recovered in M₂. The most radiosensitive strain (NP(WR) 15 gave the highest frequency of chlorophyll mutations. Among chlorophyll mutations Xantha was the most frequent and Chlorina the least.