GENETIC VARIABILITY AND ASSOCIATION OF TRAITS IN COMMON BEAN (Phaseolus vulgarisL.)GENOTYPES IN SEKOTA, NORTH WESTERN ETHIOPIA

Abstract

Common bean (Phaseolus vulgaris L.) is one of the most important pulse crops in Ethiopia, contributing to income generation and food security. Information on the genetic variability and trait associations of common bean in the Sekota district of north Western Ethiopia is inadequate. This study was initiated with the objective to assess variability, heritability and trait association among 64 common bean genotypes for quantitative traits using 8x8 simple lattice design at Aybra main research site 2023 under rain fed conditions. Analysis of variance was performed using SAS software and the ANOVA revealed highly significant variations among genotypes for all the traits considered in the study. The yield ranged from 1633.1 to 3702.10 kg ha-1with a mean of 2542.53 kg ha-1. There was a yield advantage of 24.56 to 55.89% over the checks. A moderate genotypic coefficient of variation coupled with high heritability and high genetic advance as a percentage of the mean was obtained for plant height, branches per plant, hundred seed weight, seed yield, and harvest index. Branches per plant, aboveground biomass and harvest index had significant positive correlations and direct effects on seed yield at the genotypic and phenotypic levels while days to maturity had a significant negative correlation and indirect effect with seed yield at the genotypic. The maximum inter cluster distance was found between clusters VII and 8 (D2=351.39), followed by clusters V and VIII (D2=331.23). The first five principal component axes accounted for 74.3% of the total variation, with eigenvalues greater than unity. The number of days to maturity, plant height, number of pods per plant, number seeds per pod, seed yield, and harvest index were the traits that contributed most of the variation in the first PCs. Generally, the presence of variability, and strong positive association of traits among the genotypes were observed in the traits under study. Therefore, selection based on agronomic performance and hybridization based on cluster distance could be possible for the improvement of common bean in the study area.