Genetic divergence analysis in cluster bean [Cyamopsis tetragonoloba (L.) Taub.]
Thirty cluster bean genotypes collected from NBPGR Regional Station, Jodhpur was assessed to estimate the genetic divergence using Mahalanobis D2 analysis. The genotypes exhibited wide variability for all the characters studied. Thirty genotypes were grouped into V clusters. Cluster I consisted the maximum number of genotypes (12) followed by cluster II with 10 and cluster IV with 6 genotypes. Cluster III and V had only one genotype each. Intra cluster distance was maximum in cluster I with 12 genotypes indicating the high intra cluster diversity and inter cluster distance was highest between cluster V and cluster III (D2=174782.9) followed by cluster II and V (D2=115239.7), cluster III and IV (D2=78577.82), cluster I and V (D2 = 69202.2), cluster II and IV (D2 =41433.2). Mean number of branches, number of pod clusters/plant, number of pods/plant and pod yield/plant was highest for cluster V. Pod length, pod girth and pod weight were maximum in cluster III. Cluster IV and I was earliest to attain 50% flowering, days to first fruit set. Cluster III and II took minimum days for first harvest. Traits that contributed to divergence were pod yield/plant, days to 50% flowering and days to first fruit set. Hence while designing a crop improvement programme, parents for hybridization may be selected based on the inter cluster distance, mean performance of different traits and contribution of traits to divergence.