Assessment of Genetic Variability and Diversity in Indian Mustard (Brassica juncea L.) under Timely and Late Sown Conditions

The present investigation was carried out at Research farm of Genetics and Plant Breeding, Birsa Agricultural University, Kanke, Ranchi, Jharkhand, India during Rabi 2022-2023. In this study two sets of field experiments were conducted with 43 genotypes of Indian mustard consisting 30 F1 hybrids and 13 parents to assess the genetic variability, heritability and genetic advance under timely (TS) and late sown (LS) conditions. The genotypes were evaluated for twelve quantitative characters. The analysis of variance showed highly significant differences among the genotypes for all the characters. The maximum GCV and PCV were recorded for the characters, number of secondary branches / plant and seed yield / plant in both timely sown and late sown condition. High heritability coupled with high genetic advance was observed for 1000 seed weight and seed yield /plant 1 in both TS and LS conditions which suggested that these characters can be considered as favourable for improvement through selection. D2 analysis grouped the 43 genotypes into 9 clusters in TS and 7 clusters in LS conditions. The distribution of genotypes in both the environments was different. Maximum genotypes (28) were present in TS while maximum genotypes (27) were present in cluster I. The maximum inter cluster distance was observed between clusters VI and IX in TS while in LS the clusters IV and VI showed maximum inter cluster distance. Therefore, it can be concluded that the genotypes in these clusters exhibit the highest degree of genetic diversification. This diversity makes them valuable for incorporation into a successful breeding program for development of new varieties.