Assessment of genetic variation in soybean (Glycine max (L.) Merrill) using Mahalanobis D² analysis

Abstract

The study aimed to investigate the genetic divergence and variability of yield and its contributing traits in soybean (Glycine max (L.) Merrill). A total of 27 soybean genotypes were evaluated in a randomized complete block design (RCBD) for important agronomic traits, including plant height, pod number per plant, seed number per pod, seed weight, and overall yield. Genetic divergence was assessed using Mahalanobis’D² statistics, which enabled the classification of genotypes into distinct groups based on their phenotypic traits. The analysis revealed significant genetic variability among the genotypes studied, with notable divergence identified for yield- related traits. High heritability in broad sense was observed in number of seeds per plant (93.89), seed yield per plant (g) (90.56), number of pods per plant (90.40), number of primary branches per plant (83.32), pod bearing length (cm) (82.44) and plant height (cm) (81.70). Multivariate analysis indicated that genotypes displayed a broad range of variability for traits, which is crucial for breeding programs focused on improving soybean yield. Genetic diversity analysis was done based on D2 values, 27 genotypes were grouped into five clusters. Cluster-I had the largest group of genotypes which were 23 genotypes and Cluster-II, Cluster-III, Cluster-IV and V consisting only one genotype each. The highest inter-cluster distance was showed between cluster II and III, followed by between cluster II and V, cluster II and IV, cluster I and III , cluster I and V, cluster I and IV, cluster I and II, cluster III and V and cluster IV and V.