Isolation of yellow vein mosaic virus (YVMV)-resistant mutants of okra (Abelmoschus esculentus L.) through applied mutagenesis

Okra, Abelmoschus esculentus (L.) Moench, being highly susceptible to yellow vein mosaic virus (YVMV) disease warrants its genetic improvement for resistance. Applied mutagenesis programme using two optimum doses of gamma radiation, namely, 350 Gy and 450 Gy radiation, was administered for the variety Pusa Sawani rated as excellent for fruit quality but highly susceptible to YVMV disease. Two selected putative mutant families, namely, 350//10///3-9////28 and 450//66///2-4////39, isolated in the M-5 generation with slightly different plant morphology as compared to the parental genotype, Pusa Sawani, showed consistent resistance against YVMV disease. Upon evaluation in the M-6 generation, eight morphological characteristics and five quantitative characteristics differed significantly among the mutants and Pusa Sawani. Proximate compositions and enzyme activity in leaf were significantly higher in the two YVMV-resistant mutants. Disease screening under artificial inoculation in the insect proof cages confirmed YVMV resistance in these mutants. DNA fingerprinting further validated the alterations occurred in these two isolated mutants compared to the parental genotype. These mutants deserve due attention towards the development of YVMV-resistant variety.