Phenotypic and Genotypic Variability of Bambara Groundnut (Vigna subterranean L) Accessions at Tepi Southwest, Ethiopia

Abstract

Bambara groundnut (Vigna subterranea (L) Verdc. is a grain-legume and neglected crop in Africa. The knowledge of genetic variability and breeding techniques is crucial in crop improvement programs. This information is important in underutilized crops such as Bambara groundnut, which have limited breeding systems and genetic diversity. Hence the objectives of this study were to estimate the phenotypic and genotypic variability of different quantitative traits of Bambara groundnut accessions and to identify potential accessions for future breeding work. A field trial was conducted in the 2020/21 cropping session at Tepi, southwest Ethiopia. Alpha lattice design with two replications was applied to 276 Bambara groundnut accessions. Data were collected on 19 agro-morphological traits, and statistical analysis was conducted using Sas 9.3 and R-package. The analysis of variance results showed significant differences among accessions. Phenotypic coefficient of variation ranged from 6.53% for days to flowering to 81.49 % for grain yield and genotypic coefficient of variation ranged from 6.55 % for days to flowering to 53.64% for shell weight. Low heritability 6.969 % for pod width to high heritability 99.816 % for leaf length was recorded. Genetic advance as present of mean ranged from 4.74 % for Pod width to 93.14 % for shell weight. Grain yield was positively and significantly correlated with plant height, number of branch per plant, leaf width, number of pods per plant, seed weight, and 100swt at genotypic level. Cluster analysis showed the existence of wide variability among accessions and grouped them into five clusters. The maximum intra-cluster distance was recorded in cluster-V followed by cluster III. Maximum inter-cluster distances were recorded between cluster-II and cluster-IV followed by cluster-I and cluster-V, but the minimum inter-cluster distance was found between cluster-I and cluster-II. The first six principal components have Eigenvalues greater than 1 explained about 73.35 % of the total variations among two hundred seventy-six accessions evaluated for nineteen quantitative traits. The first component accounts for 29.89% of the total variation. The accessions TVSu-1307, TVSu-252, TVSu-1340, TVSu-1363 and TVSu-1101 had gave maximum value of grain yield and yield related traits, therefore they can be used for further breeding work. However, further studies on these accessions in two or more locations may be required to verify the consistency of the observed variation.