Genetic diversity analysis using agro-morphological traits of Brassica juncea subspecies rugosa (Pahari rai) from North-Eastern Himalayan region

Twenty genotypes of Brassica juncea subspecies rugosa were grown in a randomized block design (RBD) for assessment of diversity using Mahalanobis D² and Principal component statistics. Genetic diversity plays an important role in plant breeding because hybrids between parents of diverse origin generally displayed greater heterosis than those between closely related. Geographical diversity may not be the only factor responsible for causing diversification, thus focus should be laid on selecting the parents based on genetic diversity rather than geographical diversity. The Eigenvalue of the first principal component was accounted for 7.46 of variation. The first six principal components axes explained 88.79 per cent of the variation, suggesting considerable diversity among the genotypes for all the characters on the basis of D² analysis the genotypes were grouped into four clusters. Based on cluster analysis the results revealed maximum inter-cluster distance (41.68) between cluster II and IV followed by cluster I and IV, thereby paving the chance for them to be used in hybridization breeding programs. As per the biplot, the most stable genotypes are IC-399826, IC-338751, IC-338535, and IC-399839. The outcome of the study indicated that the genotypes having greater genetic diversity will be useful for developing segregants by utilizing in crossing programmes.