EVALUATION OF GENOTYPES AND LIMING ON COMMON BEAN (Phaseolus vulgaris L.) TOLERANCE TO SOIL ACIDITY AT BAKO, WESTERN ETHIOPIA

Abstract

The study was conducted to investigate the response of common bean genotypes on limed and unlimed acid soils at Bako Agricultural Research Center (BARC) during-2015 main cropping season. The objectives were to evaluate common bean genotypes for tolerance to soil acidity, to determine the effect of liming on yield, yield components and on root phenotypes of common bean genotypes on acidic soil. Sixteen common bean genotypes were tested by using split plot design with three replications. Data on phenological, growth, yield, yield components and root traits were collected and subjected to various data analyses. Analyses of variance; phenotypic, genotypic, and environmental analysis have been performed based on their expected mean squares (EMS). The broad sense heritability (H2) values were more than 60% for most of the traits. Highest heritability in broad sense values exhibited greater than 90%. The result of the study indicated highly significant (p<0.01) differences among genotypes for plant height, number of pods per plant, seeds per plant, seeds per pod, number of root whorls, tap root branches, number of adventitious roots, adventitious root branches, nodule number, grain yield, average grain yield and hundred seeds weight under limed and unlimed soils. Genotypes such as ALB-204, ALB-179 and ALB-209 were high yielder as well as they showed selectable root traits for soil acidity tolerance and equal performance under limed and unlimed soil. In addition, this study has revealed that multivariate analysis can be used as an indirect tool for selecting superior genotypes with the most important desirable traits that contribute to soil acidity tolerance. The first three principal components contributed 76 and 75% of the total variation among the sixteen common bean genotypes grown under unlimed and limed soils, respectively. Among the measured traits, first root whorl angle, yield per plant, primary branches, second root whorl angle, grain yield, number of seeds per plant, stem diameter, plant height, biomass yield, hundred seeds weight, basal root branching, basal root diameter, tap root branching and tap root width showed significant differences among genotypes. Genotype by trait (GT) bi-plot indicated that the largest variation came from 1stroot whorl angle, yield per plant, primary branches, second root whorl angle, grain yield, seeds per plant, stem diameter, plant height, biomass yield, hundred seeds weight, basal root branching, basal root diameter, tap root branching and tap root width.. GT bi plot classified the genotypes into four groups. The first group (cluster), which contained the genotypes ALB-204, ALB-212, ALB-209, and ALB-179 outperformed genotypes in the other group (clusters) when grown under limed acid soil.