Screening for Drought Tolerance Among Cowpea (Vigna unguiculata L. Walp) Genotypes.

Cowpea (Vigna unguiculata L. Walp) is a crop that many people around the world rely on to meet their basic nutritional needs. Both humans and livestock can consume the protein and fiber rich grain and vegetative matter of the cowpea plant. Water stress affects this crop like many other crops; by reducing total biomass and grain yields. Cowpea has evolved differing physiological mechanisms that may confer tolerance to water deficit. Mechanisms vary among genotypes, and may be classified as conferring avoidance or escape responses.  The goal of this project was to evaluate cowpea genotypes for differential tolerance to water stress using two screening methodologies. Five genotypes of cowpea were grown in a randomized complete block design in pots and large plastic containers in the greenhouse. Water was withheld from half of the plants upon the expansion of the trifoliate leaves. Transpiration, chlorophyll flouresence and biomass measurements were recorded. Significant differences among genotypes for were observed for the data recorded. Pot and box screening methodologies also resulted in significant differences.