GROWTH, DEVELOPMENT AND YIELD OF BAMBARA GROUNDNUT (VIGNA-SUBTERRANEA) IN RESPONSE TO SOIL-MOISTURE

Stands of bambara groundnut (Vigna subterranea (L.) Verdc.) were grown in five controlled-environment glasshouses at the Tropical Crops Rese arch Unit, University of Nottingham, Sutton Bonington Campus, in 1990. Five soil moisture regimes were imposed (one per house), from fully i rrigated each week (treatment A), to no irrigation after crop establis hment at 35 days after sowing (DAS) (treatment E). Decreasing the amou nt of water applied resulted in a decline in total dry matter producti on and harvest index, and a reduction in pod yield from 4.12 (treatmen t B) to 0.04 t ha(-1) (treatment E) at 125 DAS. A maximum leaf area in dex of 5.4 was achieved by treatments B and C at 90 DAS, resulting in a fractional interception of c. 0.8 of incoming radiation. Total accum ulated radiation interception values were 749, 693, 688, 618 and 554 M J m(-2) for treatments A, B, C, D and E, respectively. The efficiency of conversion of the radiation intercepted into dry matter was reduced from 1.41 to 0.50 g MJ(-1) by drought.