Characterization of Bambara Groundnut Landraces and Their Evaluation by Farmers in the Upper West Region of Ghana

Abstract

The Bambara groundnut (Vigna subterranea [L.] Verdc.) has a large number of landraces throughout Africa, where small-scale farmers have preserved its genetic diversity on their farms. In 2004, we surveyed farmers in the Upper West Region of Ghana to determine their strategies for managing crops and for maintaining varieties of neglected Bambara groundnut landraces. We collected 22 landraces from the region, and conducted field experiments in 2005 and 2006 to evaluate their phenotypic variability with respect to agronomic and morphological traits. Important characters correlated with grain yield that could be used for selection and improvement of Bambara groundnut varieties were the 100-seed weight (the most important character influencing grain yield; r=0.95) and shelling percentage (r=0.86). There were negative correlations between grain yield and canopy spread (r=-0.62) and between grain yield and days to maturity (r=-0.37), providing evidence that spreading landraces have a longer vegetative phase, take longer to mature, and therefore suffer declines in yield due to the low soil moisture levels in the savannah zone. Late flowering also has a detrimental effect on seed yield of the Bambara groundnut in the savannah zone (r=-0.39). Landraces have local names based on their maturity period, growth habit, and seed coat colour or on their use. Some of the neglected landraces are common to more than one ethnic group. Local farmers largely prefer fast-cooking, early varieties of Bambara groundnut with large, cream-coloured seeds. Further improvement of Bambara groundnut must take these selection criteria and farmer preferences into account.