Yield, yield components and nitrogen partitioning in bambara groundnut (Vigna subterranea), common bean (Phaseolus vulgaris), and cowpea (Vigna unguiculata) grown under stress and non-stress soil moisture conditions

Globally, moisture stress is a major constraint in agricultural production resulting in millions of dollars in economic losses. A study was conducted in the rainshelter at the Kellogg Biological Research Station, Hickory Corners, Michigan, in 1995 and 1996 to evaluate the effect of moisture stress on yield, yield components and N partitioning in Bambara groundnut (Vigna subterranea) genotypes ZVS530 and ZVS564; common bean (Phaseolus vulgaris) genotypes Carioca, Natal Sugar and T3147-2; and cowpea (Vigna unguiculata) genotypes IT82D-889 and 475/89. The experiment was a split-plot in a randomized complete block design with moisture status as the main effect and species as the sub-plot. Moisture stress reduced yield by as much as 79% in common bean and 46% in cowpea. Cowpea genotypes aborted more seeds per pod than the other species. Significant species differences were observed in seed weight, number of seeds per pod, number of pods per plant, and in N concentration of the different plant parts. Moisture stress did not significantly affect N concentration in any structures.