VARIABILITY STUDIES IN F4 PROGENIES OF Brassica rapa OBTAINED THROUGH INTERVARITAL CROSSES

Abstract

A research was conducted by using twenty six (26) F.1 populations of some inter-varietal crosses of Brassica rapa and grown in the experimental farm of Sher-e-Bangla Agricultural University. Dhaka, during November 2009 - March 2010 to study the magnitude of variations in characters, heritability, genetic advance, character associations, direct and indirect effect of different characters on seed yield. There were significant variations in number of primary branches per plant, number of secondary branches per plant, number of silliqua per plant, days to 50% flowering, length of siliqua, number of seeds per siliqua, 1000 seed weight and yield per plant showed least difference between genotypic and phenotypic variances. Plant height, length of siliqua, number of silliqua per plant, days to 50% flowering showed low genotypic and phenotypic coefficient of variation. Plant height, number of primary branches per plant, number of secondary branches per plant and number of silliqua per plant showed high heritability coupled with high genetic advance and very high genetic advance in percentage of mean. However, length of siliqua showed low heritability. Correlation study revealed that yield per plant had significant positive association with plant height. number of primary branches per plant, number of siliqua per plant, seeds per siliqua. and siliqua length (genotypic or phenotypic level). Path co-efficient analysis revealed that plant height, number of primary branches per plant, number of siliqua per plant, seeds per siliqua, and siliqua length had the positive direct effect on yield per plant and days to 50% flowering, number of secondary branches per plant, and thousand seed weight had the negative direct effect on yield per plant. Based on the variability study, some F4 plants showing high heritability for short duration and yield contributing characters were selected from some of cross combinations of the intervarital crosses of Brassica rapa for further selection.