Induced Mutagenesis Expands Genetic Base and Drives Cultivar Development in Black Gram

Abstract— Black gram is a nutritionally rich grain legume constrained by a narrow genetic base. Induced mutagenesis is a valuable technique for creating novel variability. This study investigated the potential of gamma rays and electron beam irradiation to induce mutations in the black gram variety TU94-2 and characterized the biochemical basis of Urdbean Leaf Crinkle Virus (ULCV) resistance. Seeds were treated with 200, 300, 400, and 500 Gy of each mutagen. The M₁ generation was assessed for biological damage, while chlorophyll and morphological mutants were screened in the M₂ generation. Mutagenic effectiveness and efficiency were calculated. Selected mutants and control cultivars were evaluated for ULCV resistance and seed sugar composition. The results indicated that 400 Gy gamma rays and 300 Gy electron beams were optimal, causing low plant damage while inducing high genetic effects. Biochemical profiling revealed that the resistant cultivar VBN (Bg) 6 maintained chlorophyll and protein homeostasis under infection, unlike the susceptible CO 5. The study demonstrates that induced mutagenesis is a potent tool for generating valuable genetic diversity for black gram improvement.