MORPHOLOGICAL CHARACTERIZATION AND GENETIC DIVERGENCE IN OLEIFEROUS BRASSICA SPECIES

Abstract

A field experiment was conducted in the experimental field of Genetics and Plant Breeding Field Laboratory of Sher-e Bangla Agricultural University, Dhaka. Bangladesh to study on the morphological characteristics and genetic divergence in oleiferous Brassica species. They showed wide variation and thus were categorized under three cultivated species - B. rcipa. B. napus and B. juncea based on the morphological characteristics. The genotypes of three different species showed Qreater diversity. 41 genotypes were grouped in 6 different groups. Many of the groups comprise of the genotypes of the three different species. There is diversity among the genotypes of each species. Cluster 111 and V was the largest cluster comprising of 10 genotypes and cluster I and 11 with 3 genotypes each. Cluster H had the highest intra-cluster distance (0.813) Cluster I'V had the lowest intra cluster distance (0.378). Inter cluster distance was maximum (0.902) between clusters II and Vi. The results revealed that genotypes chosen for hybridization from clusters with highest distances would give high heterotic F1 and broad spectrum of variability in segregating generations. The phenotypic variance of each of characters was higher than respective genotvpic variance showing the minimum role of environment on these characters. High heritability with low genetic advance was observed for the characters days to 50% flowering. days to maturity, primary branches/plant, 1000-seed weight and vieldlplant. Yield/plant confirmed highly siiif1cant positive association with plant height (0.503). length of siliquae (0.277), siliquae/plant (0.658) and seedlsiliquae (0.303) but insignificant negative azsociation with days to 50% flowering (4058) days to maturity (-0.092).Path analysis showed that siliquaWplant had positive direct effect (0.628) on yield/plant. Path analysis revealed that days to 50% flowering had negative direct effect (41 R4) on vieldiplant.