Genetic assortment of Indian mustard (Brassica juncea) germplasm for rainfed conditions

Abstract

Indian mustard (Brassica juncea L) grown under rainfed conditions is usually affected by drought stress at different
stages resulting in negative effect on yield. The assessment and quantification of morphological diversity for the traits
contributing towards drought tolerance studied on 442 germplasm linesin an alpha lattice design for 10 morphological
characters during Rabi 2018-19. Significant differences were observed among the genotypes for most of the characters
studied under rainfed conditions. The hierarchical cluster analysis using R-software grouped all the genotypes into 4
clusters comprising of 127, 134, 100 and 81 germplasm lines; respectively. The highest distance was observed between
cluster I and II (1290.51) followed by cluster I and III (1112.21). However minimum intra-cluster distance was observed
among cluster II indicating similarity of germplasm lines in the cluster. Maximum intra-cluster distance was observed
among the genotypes of cluster III indicating diversity among the genotypes. Dendrogram demonstrated sufficient
diversity among the germplasm lines for various traits and association between different clusters. The results concluded
that morphological diversity in the studied material structured by germplasm lines could be utilized in breeding program
to develop transgressivesegregants with a wide range of adaptability to drought conditions in semi-arid regions.