Mutagenic aspects of gamma irradiation: A generic approach for improvement in chickpea

The most viable approach to develop the climate smart varieties is the mutation breeding which creates the genetic variability by modifying a single gene without altering the entire genome. The experiment was undertaken to study the biological and mutagenic effects of different doses of gamma rays in chickpea (Cicerarietinum L). The two cultivars of chickpea viz., PG-114 (small seeded) and BG-256 (bold seeded) were irradiated with 5,10,15,20 & 25 KR of ⁶⁰Co at normal seed moisture content. The observation on germination, plant survival, seedling height, pollen fertility and meiotic chromosomal abnormalities were recorded for radio-sensitivity in M₁ generation. The genetic effects were determined on the basis of chlorophyll with viable mutation frequencies and spectra in M₂generation. The seed germination as percent of control was less affected by gamma rays except for 25 KR in small seeded chickpea variety PG-114. The reduction in germination was pronounced at higher dose of 20 & 25 KR of gamma rays in bold seeded chickpea variety BG-256.The variety PG-114 was less sensitive as compared to BG-256 for seed germination. The plant survival of both the chickpea variety showed similar trend as that of seed germination. The pollen fertility was considerably reduced at higher dose of 25 KR in PG-114, whereas 20 & 25 KR dose of gamma rays was effective for BG-256. Chlorophyll mutant were observed in higher dose 20 & 25 KR of gamma rays for PG-114, while 10,15,20 & 25 KR of gamma rays were effective except 5 KR in BG-256. Thus, the bold seeded chickpea variety BG-256 appeared more sensitive to gamma irradiation as compared to small seeded variety PG-114 suggesting the different role of genotype and seed size. The percent of meiotic chromosomal aberration increased with raise in dose of gamma rays for both the varieties.