GENETIC VARIABILITY AND CHARACTER ASSOCIATION ANALYSIS OF F 3 , BC 1 F 2 AND BC 2 F 1 POPULATIONS IN INDIAN MUSTARD (Brassica juncea L.)

Abstract

The investigation was carried out to estimate the variability and correlation among the yield attributing traits of twenty-one F 3 , seventeen BC 1 F 2 and seven BC 2 populations of Indian mustard. The experimental set up was organized at Sher-e-Bangla Agricultural University, Dhaka during the Rabi season 2022/23 for evaluation of these populations which was preceded by a generation advancement and a backcross program performed in previous Rabi 2021/22 through which the seeds for these populations were developed. In the study twelve yield attributing traits were observed and they had shown significant variation among all the populations. Considering the mean performance G1 (26.44 gm) of BC 1 F 2 population showed the highest yield per plant among all the populations, whereas G10 (19.89 gm) of F 3 F 1 and G6 (23.33 gm) of BC 2

represented the top position within F 3 and BC 2 F 1 populations for yield per plant respectively. For earliness G20 (93 DAS) of F 3 population required the minimum duration for crop maturity among all the populations followed by G1 (94.67) of BC 1

For short plant G2 (131.67 cm) of F 3 population showed the most promising result. A lower environmental variance was found to be associated with all of these traits. Majority of the traits had also shown a higher phenotypic coefficient of variation and genotypic coefficient of variation. Higher heritability as well as higher genetic advance was also found to be associated with all of the traits and among them the maximum heritability coupled with a higher genetic advance as percentage of mean was observed with yield per plant (98% and 63.26%) and number of primary branches per plant (98% and 62.70%). Finally, the correlation study revealed that plant height (0.52), number of primary branches (0.66), number of secondary branches (0.66), siliquae length (0.30), thousand seed weight (0.60) and harvest index (0.30) had a highly significant correlation with yield in a positive manner. Furthermore, the path coefficient study unveiled that, majority of the traits had a positive direct effect on the yield among which the number of primary branches (0.578) had the maximum direct effect along with a highly significant positive correlation with the yield. Considering altogether, G1 and G5 of BC 1 F 2 and G10 and G20 of F 3 populations could be taken into account for further evaluation to develop high yielding and early maturating population, as well as G2 of F 3 population might be considered for developing population with short plant stature.