Genotypic variation of bambara groundnut (Vigna subterranea L.Verdc) for phosphorus efficiency

Abstract

Low phosphorus (P) in agricultural ecosystems limits growth of bambara. Field trials were carried out at 2 P levels (0 and 35 kg/ha) to determine the variation of 12 bambara genotypes in phosphorus efficiency, identify P-efficient and responsive genotypes for cultivation in sub optimal P environments. Genotypes differed significantly (P ≤ .05) in plant biomass, grain and biological yields due to P levels and seasonal effects. BAM002, BAM010 and BAM011 recorded high grain yields in both seasons. Phosphorus accumulation (PA) in biomass, grain and biological yields was influenced by genotype, P levels and genotype * P levels interaction. High yielding P-efficient and responsive genotypes including BAM002, BAM010 and BAM011 also had high values of phosphorus physiological efficiency index and phosphorus harvest index at low P indicating that they are P-efficient. Genotypes were classified into four and three groups based on the relationship between total PA and grain yield at low and adequate P, respectively. Moreover, genotypes were categorised into in-efficient, medium and efficient based on total index score. Principal component analysis grouped together the genotypes BAM002, BAM010 and BAM011 at both P levels. These genotypes are adapted to P-deficient soils and utilise acquired P efficiently for optimum grain production