GENETIC VARIABILITY AND RELATIONSHIP AMONG YIELD, YIELD RELATED TRAITS AND SOME GRAIN NUTRIENT COMPOSITIONS IN SMALL SEEDED COMMON BEAN (Phaseolus vulgaris L.) GENOTYPES AT GORO AND GINNIR, SOUTHEAST ETHIOPIA

Abstract

Common bean (Phaseolus vulgaris L) is one of the crops produced by thousands of farmers in Bale. This study was conducted to assess the genetic variability and estimate the association of morpho-agronomic and seed quality traits among small seeded common bean genotypes. Sixty-four common bean genotypes were evaluated in 8 x 8 simple lattice designs at Goro and Ginnir in 2021. Results from analysis of variance for each location and over locations revealed the presence of significant differences among genotypes for 15 morpho-agronomic and seed quality traits. Number of pods per plant, number of seeds per plant, hundred seeds weight, grain yield, protein and grain mineral contents were significantly influenced by genotype x location interaction. The genotypes had average grain yield of 1675, 1479 and 1568 kg ha-1 at Goro, Ginnir and over locations, respectively. Moreover nine genotypes had significantly higher mean grain yield in the range between 10.42 and 21.8% than average yield of SER119 the best yielding check variety which is an indication of the higher chance to develop better varieties. The protein, Fe and Zn contents ranged from 14.45 to 27%, 4.5 to 13.3 and 2.38 to 18.48 mg 100g-1, respectively. Phenotypic (PCV) and genotypic (GCV) coefficient of variations ranged from 1.29 to 52.66% and 1.01 to 21.28%, respectively. Heritability (H2 ) in broad sense and genetic advance as percent of mean (GAM) ranged from 7.09 to 99.58% and 1.62 to 39.45%, respectively. Grain yield had positive and significant correlations with number of primary branches, number of secondary branches, number of pods per plant, number of seeds per pod and number of seeds per plant at genotypic and phenotypic levels at two locations. These traits except number of seeds per plant had positive direct effects on yield at genotypic level. Days to flowering had negative and significant genotypic and phenotypic correlations with grain yield and the trait also exerted negative direct effect on grain yield at genotypic and phenotypic levels at both locations. The first six principal component axes (PCA) with Eigen values >1 accounted for 83.67% variation of genotypes. The genetic distance of genotypes estimated using Euclidean distance ranged from 1.48 to 11.96 with 5.57, 1.73 and 31.0%, of mean genetic distance, standard deviation and coefficient of variation, respectively. The genotypes were grouped into eight distinct clusters of which Cluster I, III and three clusters (IV, VII and VIII) consisted of 40(62.5%), 15(23.4) and 2(3.1%) genotypes, respectively, while cluster II, V and VI consisted of 1(1.6%) genotypes. Generally, the result of this research showed the presence of variations among common bean genotypes for yield, seed qualities and other agronomic traits that could be potentially exploited in future breeding programs.