Genetic Variability and Yellow Vein Mosaic Virus (YVMV) Resistance in Mutant Lines of Blackgram (Vigna mungo L. Hepper) under Field Condition

Background: The creation of genetic variability in a gene pool is the prerequisite of a breeding program. To introduce a higher degree of variability and to identify favourable recombinants, a combination of hybridization and mutation methods is employed. Among various diseases infecting and reducing yield of blackgram, yellow mosaic disease caused by Mungbean Yellow Mosaic Virus (MYMV) is the crucial one. Due to non-availability of resistant cultivars, cultivation of blackgram crop land is diverted to other cereal crop cultivation and for MYMV management in urdbean production, breeding with the resistant cultivars is effective which is also ecofriendly Methods: A field experiment was carried out during Kharif 2022 by using 90 F4 M3 laid out in an augmented design at AHRS, Bavikere. Based on seed yield, disease index and incidence, 30 F5 M4 were selected for summer 2023 from the first season and laid out in RCBD design. These lines obtained through the hybridization of PU31 and Rashmi, followed by the treatment of F2 seeds with gamma irradiation (20kr) at IIHR in Bangalore. Results: The research we conducted exhibited significant variations for the majority of traits. For the first season, high PCV, GCV, broad sense heritability and genetic advance as per cent of mean observed for the number of clusters per plant, number of pods per cluster, pod length, number of seeds per pod and seed yield. For the second season, moderate PCV, GCV and high broad sense heritability with genetic advance as per cent mean observed for the number of branches per plant, number of clusters per plant, number of pods per cluster, number of pods per plant and number of seeds per pod. Estimated high values of PCV indicates more variability for the trait seed yield per plant in the population and the narrow range between GCV and PCV which implies lesser influence of the environmental effects on the expression of traits. BLM 9, BLM 20, BLM 29, BLM 44, BLM 51 and BLM 58 in the first season and BLM 30 and BLM 51 in the second season showed resistant reaction to YVMV with the least per cent disease index. Hence, these mutant lines can be used for further crop improvement.