GENETIC DiVERSITY, CORRELATION AND PATH ANALYSIS OF BC,F2 POPULATION IN Brasska napus L.

Abstract

A field experiment was conducted at the experimental field of Genetics and Plant Breeding Department, Sher-e-Bangla Agricultural University. Dhaka. Bangladesh to study genetic diversity, correlation and path analysis of BC I F2 lines obtained through first back cross of iirassica napus L. during November 2011 to March 2012. Significant variation was observed among all the genotypes for all the characters studied. Considering genetic parameters high genotypic co-efficient of variation (GCV) was observed for seed yield per plant (14.67) followed by number of secondary branches per plant (11.49), number of primary branches per plant (11.41). number of siliqua per plant (9.12) and number of siliqua per plant (9.00). Iligh heritability with low genetic advance in percent mean was observed for days to 50% flowering. days to maturity, plant height, number of secondary branches per plant, length of siliqua and 1000 seed weight which indicated that non-additive gene effects were involved for the expression of this character and selection for such trait might not be rewarding. High heritability with moderate genetic advance in percent mean was observed lbr number of primary branches per plant, number of siliqua per plant, number of seeds per siliqua and seed yield per plant indicating that this trait was under additive gene control and selection for genetic improvement for this trait would be effective. Different multivariate analyses were performed to c1assil 31 genotypes. All the genotypes were grouped into live clusters. Principal Component Analysis, Principal Coordinate Analysis, Cluster Analysis, Canonical Variate Analysis gave similar results. Cluster IV was the largest cluster comprising of S genotypes and cluster I was the smallest cluster with 2 genotypes. Cluster I had the highest intra-cluster distance and cluster V had the lowest intra cluster distance. Inter cluster distance was maximum (15.405) between cluster I and 111. The results revealed that genotypes chosen for hybridization from clusters with highest distance would give high heterotic and broad spectrum of variability in future segregating generations. The characters between days to 50% flowering and days to maturity, plant height and days to maturity, plant height and number of siliqua per plant, plant height and number of seeds per siliqua. number of primary branches per plant and number of secondary branches per plant. number of secondary branches per plant and number of siliqua per plant, number of siliqua per plant and yield per plant were highly positively correlated. Path coefficient analysis showed that days to maturity, plant height, number of secondary branches per plant, number of siliqua per plant. length of siliqua and number of seed per siliqua had positive indirect effect on seed yield per plant. Considering cluster distance, inter genotypic distance and other agronomic performance 06 and 08 from cluster I: 01 from cluster If; 021 and 024 from cluster 11!and 016 from cluster V might be considered to be better parents for future uses in hybridization program to develop high yielding varieties with early maturity.