THE INFLUENCE OF SOIL MOISTURE STATUS ON REPRODUCTIVE GROWTH AND DEVELOPMENT OF BAMBARA GROUNDNUT (Vigna subterranea (L.) Verdc) LANDRACES IN GHANA

The increasing threat of water deficits for crop production requires evaluating potential drought tolerant crops for cultivars that can withstand and efficiently produce under moderate to low soil moisture conditions. Bambara groundnut is one such drought tolerant crop, but this trait varies among landraces with respect to its reproductive development. Experiments were therefore carried out on bambara groundnut in Ghana, to evaluate the reproductive response of two contrasting landraces; Cream-seeded and Mottled-seeded, under three soil moisture regimes, viz. 30-40%, 50-60% and ≥70%. In both landraces, days to 50% flowering, pod and seed numbers, dry matter, pod and seed yield and harvest indices were significantly higher at 50-60% soil moisture than at 30-40% and ≥70% soil moisture regimes. The 30-40% soil moisture greatly promoted early flowering and pod-filling with enhanced harvest indices of the landraces than ≥70% soil moisture. There was higher biomass production at ≥70% soil moisture, but this did not translate into higher harvest indices as compared to 30-40% soil moisture. In all three soil moisture regimes, the pod, seed and dry matter yields, and harvest indices, were higher in Cream-seeded landrace than in Mottle-seeded landrace. Cream-seeded landrace was the most soil moisture efficient cultivar, and demonstrated superiority and better adaptation to low soil moisture condition than Mottledseeded landrace, and could be chosen in areas of inadequate rainfall. The differences in reproductive response patterns of the landraces under varying soil moisture conditions might provide basis for developing strategies towards stabilizing bambara groundnut yields in areas of low rainfall.