Effect of water deficit at different stages of development on the yield components of cowpea (Vigna unguiculata L. Walp) genotypes

Abstract

Cowpea cultivation is widespread in West Africa where it is an important source of protein. This studyis aimed at determining the effects of water deficit applied at different stages of cowpea developmenton yield and its components (pod number, seed number, seed yield, aerial biomass yield, harvest indexand root biomass of the plant). The experiments were carried out in pots during the rainy season of2016 under natural conditions of illumination, temperature and relative humidity. Three water regimeswere applied to plants at different stages of cowpea development: total suspension of watering atflowering phase (43 days after sowing) (S1); suspension of watering at the beginning of pod formationon the 46th day after sowing (S2); and normal watering as control until harvest (S0). At the water regimelevel, yield components had higher values in S0 followed by S2. The lowest values were obtained at S1level. The root to aerial biomass ratios was higher under water deficit than in the control. In conditionsof water deficiency, Suvita2, IT96D-610, and ISV128 genotypes gave the highest seed yields and Tiligréthe lowest yield. The harvest index showed a genotypic variation according to the water regime. Suvita2and ISV128 gave the best harvest index in all water regimes. This study may have contributed to theselection of genotypes adapted to drought