Agro-Morphological Evaluation of Gamma-Induced Bambara Groundnut [Vigna subterranea (L.) Verdc.] Mutants in North-Central Namibia

Abstract

Bambara groundnut [Vigna subterranea (L.) Verdc.] is an important legume for subsistence farming in Africa, valued for its ability to withstand adverse environmental factors. The experiment was conducted at the University of Namibia-Ogongo campus experimental field during the 2024/2025 cropping season. The study assessed the phenotypic variability of Bambara groundnuts induced by gamma(γ) irradiation. The four Bambara groundnut genotypes, namely Namblack, Nambrown, Namcream, and Namred seeds, were exposed to gamma irradiation doses at 100 Gy, 200 Gy, 300 Gy, 400 Gy, and 500 Gy, and 0 Gy as a control. The growth and yield phenotypic traits were evaluated in this study. The result from the analysis of variance on growth traits such as first emergence, 50% emergence, and plant leaves were significant at P < 0.05, and yield traits such as days to maturity, number of pods, and pod length were significant at P < 0.05 and yield per plot, pods weight, pod width, and biomass were significant at P < 0.05. The association between growth and yield-related traits was analyzed using Pearson's correlation, which revealed a strong association. The phenotypic variability observed in this study will be used as a basis for mutation breeding in Bambara groundnut. The study also encourages future research in other Bambara groundnut genotypes using gamma irradiation.