Development, growth and dry matter partitioning in bambara groundnut (Vigna subterranea) as influenced by photoperiod and shading

A semi-controlled environment study was conducted from May to September 199 6 in Wageningen, The Netherlands, to investigate the interaction between gr owth and development in bambara groundnut (Vigna subterranea) and the influ ence of photoperiod on dry matter partitioning. The experimental design was a split-plot with four photoperiods (10.5, 11.8, 13.2 and 14.5 h/d) and tw o light treatments: unshaded and shaded (42 % light reduction). The selecti on used was 'DipC94' from Botswana. The dates of 50 % flowering and 50 % po dding were determined, and samples of plants were harvested at 22, 36, 50, 64, 78, 92, 106 and 120 days after sowing. Total dry matter production was 41 % lower in the shaded treatment than in the unshaded treatment, but the rates of progress from sowing to flowering and flowering to podding decreas ed by only 3 and 12 % respectively. This suggests that growth and developme nt in bambara groundnut are largely independent. Photoperiod influenced dry matter partitioning indirectly, through its influence on the onset of podd ing. There were, however, no strong direct photoperiod effects on dry matte r partitioning, either before or after the onset of podding.