Assessment of Radiosensitivity and Chemosensitivity in Green gram [Vigna radiata (L.) Wilczek] Varieties under Different Mutagenic Treatments

Abstract

Green gram (Vigna radiata (L.) Wilczek) is an important pulse crop, and induced mutagenesis can generate genetic variability for crop improvement. This study assessed the radiosensitivity and chemosensitivity of two green gram (Vigna radiata (L.) Wilczek) varieties, RMG 975 and RMG 1166, following exposure to gamma rays, sodium azide, and their combinations under laboratory conditions. Gamma-ray treatments comprised 200, 400, and 600 Gy, while sodium azide concentrations were 0.01, 0.02, and 0.03%. A total of 16 treatments, including the untreated control, were evaluated. Germination percentage, root length, shoot length, seedling fresh weight, seedling dry weight, seed vigour index-I, and seed vigour index-II were recorded. Analysis of variance showed highly significant treatment effects for all evaluated traits in both varieties. Increasing gamma-ray doses and sodium azide concentrations generally reduced germination, seedling growth, biomass accumulation, and seed vigour. Combined treatments generally caused stronger inhibitory effects than individual mutagens. The greatest reductions in most traits occurred under 600 Gy + 0.03% sodium azide. Germination declined to 40.33% in RMG 975 and 43.33% in RMG 1166 under this treatment, compared with 85.66% and 93.33% in their respective controls. Root and shoot lengths, fresh and dry weights, and both vigour indices also decreased with increasing mutagenic intensity. The two varieties differed in their responses across treatments, indicating genotype-dependent sensitivity. These findings provide preliminary evidence for selecting mutagenic treatments for subsequent mutation-breeding work in green gram.