Effect of Sowing Seasons on Growth and Development of Bambara Groundnut (Vigna subterranea L.)

Bambara groundnut (Vigna subterranea (L.) Verdc.), an indigenous African legume valued for its drought tolerance, is popular in most parts of Africa. The study used six landraces of Bambara groundnut (Nam 1759/3, Uniswa Red, S-19/3, KFBN 9709, KFBN0105 and KFBN 0116). The effects of different sowing dates and watering regimes on the growth and development of the landraces were studied. There were three sowing dates: one earlier in the year when it is hot and dry, one during the rainy season, and one late in the winter season. There were two watering regimes: one where watering was done twice a week until harvesting and a drought treatment with no irrigation from 60 days after sowing until final harvest. Parameters recorded for growth and development measures were number of leaves, pods and flowers; leaf, pods and root dry mass at 20, 45, 60, 105 and 120 days after sowing (DAS). No significant difference was observed among the different landraces between the two watering regimes at any particular DAS as far as growth and development variables were concerned. Seed sown in the field earlier in the year gave a larger harvest (204.396-336.535 kg/ha) than the ones sown mid-season (57.469-133.697 kg/ha), with those sown during the winter season doing extremely poorly (11.778-65.125 kg/ha). All landraces showed significant differences among the different sowing dates as far as harvest yield was concerned (chi(2)=9.269, chi(2)=9.846, chi(2)=8.000, chi(2)=9.269, chi(2)=9.269, chi(2)=9.302). Looking at their yield at harvest, the landraces were classified based on the BAMnut Model - Crop Biomass and Pods Model - and they ranged from unsuitable (Uniswa Red) to moderately suitable (KBFN 0105).