GENETIC VARIABILITY, INTERRELATIONSHIP, PATH COEFFICIENT AND GENETIC DIVERSITY ANALYSIS IN Brassica napus L.

Abstract

A field experiment was conducted with 22 Brassica napus L. advanced lines at the experimental farm of Sher-e-Bangla Agricultural University, Dhaka to study the genetic variability, interrelationship, path coefficient and genetic diversity in Brassica napus L. during November 2008 to March 2009. The genotypes were found to differ significantly for all the characters studied except days to 80% maturity. The characters days to 80% maturity, plant height, number of primary branches per plant, number of seeds per siliqua, number of siliqua per plant and seed yield per plant showed higher influence of environment whereas, siliqua length and 1000-seed weight showed least. Moreover, the number of primary branches per plant, number of secondary branches per plant, siliqua length, number of seeds per siliqua, number of siliqua per plant, 1000-seed weight and seed yield per plant showed moderate broad base heritability while plant height exhibits the highest heritability. The significant positive correlation with seed yield per plant was found in plant height, number of primary branches per plant and number of siliqua per plant. However, the highest significant positive correlation was found between days to 50% flowering and plant height. Path coefficient analysis showed that the plant height had maximum positive direct effect on seed yield followed by number of siliqua per plant and siliqua length. Plant height, number of primary branches per plant and number of siliqua per plant were the most important contributors to seed yield per plant which could be taken in consideration for future hybridization program. Different multivariate analysis techniques were used to classify 22 Brassica napus genotypes. The genotypes were grouped into four clusters. The highest inter-cluster distance was observed between clusters II and IV whereas the maximum intra-cluster distance was found in cluster II. Therefore, the genotypes belonging to cluster I and cluster II, cluster II and cluster Ill and cluster Ill and cluster IV have been selected for future hybridization program. The role of number of secondary branches per plant and number of siliqua per plant in both the vectors were important components for genetic divergence in these materials. Considering group distance and other agronomic performance the inter-genotypic crosses between 01 and 02, 02 and G6; G6 and 07; 06 and G8 and G7 and 08 might be suggested for future hybridization program.