GENETIC VARIABILITY, CORRELATION AND PATH ANALYSIS IN F4 GENERATION OF Brassica napus L.

Abstract

A huge part of Bangladeshi economy is spent on importing edible oil every year to meet its own requirements. The need is to enhance and improve the production of the local cultivars and for that purpose the genetic diversity of the local cultivars must be fully explored. Sixty two F4 genotypes of Brassica napus L. were evaluated based on randomized complete block design with three replications at the experimental field of Sher-e-Bangla Agricultural University, Dhaka, to study the variability, correlation, path analysis and genetic diversity during November 2015 to February 2016 growing seasons. The genotypes were found significantly variable for most of the characters. Comparatively phenotypic variances were higher than the genotypic variances for most of the character studied. The high GCV value was observed for number of secondary branches per plant (42.31). Number of secondary branches (98.70) exhibited the highest value of heritability followed by seed yield per plant (98.03) while days to maturity (88.02) exhibited the lowest value of heritability. The significant positive correlation with seed yield per plant were found with all most all the characters except days to 50% flowering (0.033) and days to maturity (-0.096). Path co-efficient analysis revealed that days to 50% flowering, number of secondary branch, number of siliqua per plant, number of seed per siliqua, and thousand seed weight had the positive direct effect on yield per plant whereas days to 80% maturity, plant height, number of primary branch and siliqua length had the negative direct effect on yield per plant. On the basis of cluster analysis, all the genotypes were classified in five clusters. The highest inter cluster distance was observed between cluster I and IV (10.309). The lowest inter-cluster distance (3.513) was observed between the cluster III and IV. Considering group distance and other agronomic performance genotypes G3, G4, G24, G35, G51 and G55 might be suggested for future breeding program.