Genetic Divergence Analysis Using Mahalanobis D² Statistics in Black Gram [Vigna mungo (L.) Hepper]

Black gram (Vigna mungo (L.) Hepper), popularly referred to as urdbean or mash, is a grain legume domesticated from Vigna mungo var. silvestris. Esteemed for its exceptional nutritional profile, it is notably abundant in phosphoric acid and calcium. The aim of the study is to diversity analysis in Black gram. The present investigation was conducted at the Field Experimentation Centre, Department of Genetics and Plant Breeding, Naini Agricultural Institute, SHUATS, Prayagraj, Uttar Pradesh during the Zaid season of 2019. Fifty diverse genotypes of black gram were evaluated under field conditions to assess character association and contribution of yield-attributing traits through correlation and path coefficient analyses. The experimental site, benefited from institutional support for resources and management, ensuring successful trial execution. Results revealed highly significant genotypic differences (p ≤ 0.05) across all 17 studied traits, indicating substantial genetic variability with potential for crop improvement. Based on Mahalanobis’ D2 statistics, fifty genotypes of black gram were stratified into seven well-defined clusters, reflecting considerable genetic diversity. Cluster I encompassed the largest number of genotypes (30), followed by Cluster III with 12 genotypes. Cluster II housed four genotypes, while Clusters IV, V, VI, and VII were monotypic, each comprising a single genotype. Intra-cluster D2 distances ranged from 0.00 to 24.11, with Cluster III exhibiting the highest intra-cluster divergence (24.11), indicative of significant genetic heterogeneity within this group. The inter-cluster D² values among genotypes spanned from 33.17 to 168.17, underscoring marked genetic variability across clusters. The most substantial genetic divergence was recorded between Clusters IV and VI (168.17), followed by Clusters II and VI (137.92), and Clusters IV and VII (115.80), suggesting these combinations may be particularly promising for hybridisation to exploit heterosis and broaden the genetic base. It was also reported that plant height, number of branches per plant, number of clusters per plant, number of pods per plant, number of seeds per pod, biological yield per plant, 100-seed weight, harvest index and seed yield per plant—together accounted for approximately 86.90% of the total genetic divergence.