Bambara groundnut (Vigna subterranea) seed quality in response to water stress on maternal plants

Farmers who still cultivate bambara groundnut (Vigna subterranea) rely on landraces and seed retained from previous harvests. Given that the crop is typically cultivated in semi-arid regions, seed quality of farmers' retained seed might be compromised due to water stress experienced by maternal plants during production. The aim of this study was to determine the effect of water stress on maternal plants on subsequent seed quality of bambara groundnut. A single bambara groundnut landrace was characterised into four distinct selections based on seed coat and speckling colour. Initial seed quality (viability and vigour) was evaluated prior to planting seed in a field trial under irrigated and rainfed conditions. Final yield and yield components were determined at harvest. Thereafter, seed quality (viability and vigour) of progeny of different landrace selections was evaluated. Yield was lower under rainfed than irrigated conditions. Overall, subsequent seed quality showed improvement from initial seed quality of the original seedlot. Seed viability was higher in seeds produced under irrigated than rainfed conditions. Seed quality of bambara groundnut may be reduced underwater-limited production conditions. Seed enhancement practices such as priming may assist farmers to achieve better emergence. In the long term, seed production should be done under optimum conditions in order to achieve high-seed quality.