Genetic ivdersity of African bambara groundnut [Vigna subterranean (L) Verdc] landraces for yield traits in southwestern agro-environments of Nigeria

Abstract

Assessment of genetic diversity is crucial in crop improvement programs. This study aimed at assessing
genetic diversity in nineteen Bambara groundnut landraces for identification of promising genotypes for yield improvement. Experiment was carried out on the field in 2019 and 2020 cropping seasons at two locations in southwestern agro-environments of Nigeria. Data were collected on seed yield/ha (SY), days to first and 50% flowering (DFF, D50F), pods/plant (POPP), pod length (PODL), maturity (MAT), seeds/pod (SPPO), pod yield/plant (PYPP), seed yield/plant (SYPP), 100-seed weight. The data were subjected to analysis of variance, principal component (PC) and cluster analyses. Genotype (G) was significant for all of the traits at p≤ 0.01. Also, location (L), year (Y) and their interactions (GxL, YxG, YxL, YxGxL) were significant for most of the traits. Accessions evaluated in Kishi had a higher seed yield/ha than those in Ile-Ife by 14.59% with seed yield of 1443.78 kg/ha across locations. The first four PCs accounted for75.82%, where PC1 and PC 2 responsible for 55.38% of the total variation. The PC1 was associated with SY, PYPP, SYPP. PC 2 was mainly associated with DFF, D50F, MAT. Phenotypic distance estimates ranged from 0.001 to 0.99 with a mean of 0.32, based on Euclidean-distance. This indicates low level of genetic diversity among bamabara groundnut evaluated, which could be improved through mutation breeding, recombination or hybridization, and introduction. Nineteen accessions were delineated into five clusters. However, nine accessions (47.36%) were homogenous and found in Cluster IV. The members in this cluster had the lowest seed yield and also in other yield contributing traits. Therefore, accessions in clusters II and III had the best yield attributes, which could be selected for release to farmers after further trials.