Determining the Genetic Divergence for Biometrical Attributes in Cluster Bean (Cyamopsis tetragonoloba (L.) Taub. Accessions through Mahanalobis D2 Statistics

Abstract

Aims: Genetic divergence plays a crucial part in determining the selection of genotypes for any breeding programme in order to generate superior segregants. Assessing the local or related genotypes for divergence, imposses a necessity to conduct experiments on specific agro-ecological situations to breed specific varieties suitable for vegetable and gum purpose. Study Design:  Randomized Block Design Place and Duration of Study: An elaborate study was performed in January to April 2022 at the field in Poothurai village of Villupuram District, Tamil Nadu to evaluate and screen the cluster bean germplasms. Methodology: A total of 102 genotypes (including Pusa Navbahar - a check variety) procured from various regions of the country were utilized. Observations were recorded for growth attributes (plant height; number of branches per plant; days to maturity), flowering and pod characters (days to 50 % flowering; number of clusters per plant; number of pods per cluster; pod length; pod girth), yield parameters (pod weight; number of pods per plant; total pod yield per plant), seed characters (number of seeds per pod; hundred seed weight; total seed yield per plant) and physiological components (guar gum; protein and fibre) on five randomly selected plants. Results: It divulged a paramount of diversity with the genotypes being grouped into 14 clusters based on 17 parameters. Seven clusters had more than 2 genotypes, and the remaining were solitary. Yield parameters such as total per plant yield (22.20%), pods per cluster (15.30%), and clusters per plant (14.80%) contributed to the highest percentage diversity. The distance between intra clusters ranges from 0.00 to 2031.87. The maximum distance between clusters observed is between cluster V and cluster IX (15980.81).  Conclusion: Of the 102 genotypes, Cluster XIV having the sole member Pusa Navbahar performed better for six out of seventeen parameters observed for the mean of clusters. With respect to the above results obtained and per se performance of the landraces, selection can be made to obtain superior cluster bean recombinants.