EFFECT OF SOWING DENSITY AND SEEDBED TYPE ON YIELD AND YIELD COMPONENTS IN BAMBARA GROUNDNUT (VIGNA SUBTERRANEA) IN WOODLAND SAVANNAS OF COTE D'IVOIRE

SUMMARYBambara groundnut (Vigna subterranea) is one of the most promising food legumes in Africa, due to its agronomic and nutritional potential. To take advantage of these attributes, several research programmes gathering agronomic and genetic data are being implemented throughout Africa. In this context, the response of yield and yield components to sowing density and seedbed type were tested in a three-year (2005, 2006 and 2007) field experiment using a bambara groundnut landrace with a semi-bunch growth habit. Three plant population densities: 13 900 plants ha−1, 62 500 plants ha−1 and 250 000 plants ha−1 were coupled with two seedbed types – raised and flat. A factorial trial using a split-plot design with three replicates was set up to analyse seed yield and plant biomass, as well as nine yield components. Sowing density influenced significantly (p < 0.05) seed yield (direct relationship) and most of the yield components (inverse relationship). The highest seed yields were observed on high-density plots (4.11 ± 1.05 ha−1). In contrast, seedbed type and year of experiment did not influence significantly the marketable yield and plant biomass (p > 0.05). This result has been attributed to the suitability of the amount and distribution of rainfall and temperature for the production of bambara groundnut at the target site. Based on the trend of yield response, cultivation of landraces of bambara groundnut characterized by a semi-bunch growth habit at high density on flat seedbeds was suggested in woodland savannas of Côte d'Ivoire to enhance seeds yield and reduce labour.