Genetic Diversity, Trait Associations and Selection Indices in Blackgram (Vigna mungo L. Hepper) Across Multi- Environment Trials

The present study was carried out across four Kharif (monsoon) environments to assess the genetic diversity and trait associations of 105 blackgram ( Vigna mungo L. Hepper) genotypes using multivariate statistical approaches. Significant variation among genotypes for 18 agro-morphogenic traits confirmed a broad genetic base. Traits such as thousand seed weight (TSW), single pod weight (SPW), number of seeds per pod (NSPP), biological yield per plant (BYPP), % of first harvest over total harvest, and greenness exhibited high heritability and selection accuracy indicating their potential for direct selection. Seed yield per plant (SYPP) showed moderate heritability but strong associations with highly heritable traits like BYPP, TSW, and SPW indicating value for indirect selection. BYPP was identified by path analysis as the most influential trait directly affecting SYPP while others influencing indirectly through it. Hierarchical clustering grouped the genotypes into five distinct clusters. Genotypes in cluster IV showed superior performance for yield related traits. Yield related traits such as SYPP, BYPP, and NCP were found to be the major contributors to the total genetic variation. In the PCA-biplot, phenological and vegetative traits aligned along distinct and opposing axes of diversity. Altogether, the findings reveal significant genetic diversity and identify key selection indices (TSW, SPW, NSPP, and BYPP). Hybridization between early-maturing and bold-seeded genotypes from cluster V and high-yielding genotypes from cluster IV is recommended to combine earliness, productivity, and broad adaptability for developing superior blackgram varieties suited to diverse environments.