Selection for Yield Improvement in Bambara Groundnut (Vigna subterranea L. Verdc.)

Abstract

Selection as the most practical and economical way of improving yield in an extreme autogamous crop was carried out in a Randomized Complete Block Design (RCBD) with three replications, with thirty three accessions of Bambara groundnut { Vigna subterranea (L.) Verdc}. Qualitative characters displayed a reasonable range of variation except for eye pattern, seed shape, pod texture and growth habit. The result on the analysis of variance (ANOVA) showed significant differences (p<0.05) for all traits except for plant height, number of leaves per plant and seed length that were statistically insignificant. The principal component analysis result revealed that eight components (Eigen values ≥ 1) accounted for 78.36 % of the phenotypic variance, and quantitative traits revealed more phenotypic variation among the accessions Pearson’s correlation coefficient showed that petiole length (r= 0.64), vigour index (r= 0.49), seed length (r=0.53), canopy width (r=0.38), and internode length (0.58). had a high positive correlation with seed yield. Ranking of the accessions based on significantly strong correlated traits with yield using the rank summation index (RSI) method, and the selection of the best top 5% of the entries identified accessions TVSU 1688 and 1638 with RSI scores of 31 and 43 respectively as the best high yielding Bambara groundnut lines. Correspondingly, accessions TVSU 1688 and 1638 had the highest mean seed yield per plant of 1150.5g and 720.8g respectively in the 3-year field evaluation; which further confirmed the precision of the ranking and selection result. Invariably these two accessions were inherently high yielding Bambara groundnut accessions.