Effects of Water Stress on Yield Components and Yield of Soyabean Genotypes

Pot experiment was conducted at the Department of Agronomy Crop Pavilion of the University of Ilorin, Ilorin (80 29’ N, 40 35’ E) to evaluate the effects of water stress on yield components and yield of soybean genotypes. Six soybean genotypes (TGX 536-02D, TGX 1830-2DE, TGX 1019-2EN, TGX 1740-2F, TGX 1485-1D and TGX 1817-12E) were subjected to water stress at three growth stages (vegetative, flowering, post-flowering, and stages) with a well-watered control. The experiment was designed as a factorial trial and laid out in split-plot arrangements. Morphological growth characters such as number of leaves, leaf area, branch and dry matter production were measured during growth while yield components and grain yield were measured at harvest. Results show that yield components such as number of flowers, total number of pods, percentage aborted flowers, harvest index, biomass and grain yields were significantly reduced by water stress occurring at both vegetative and flowering stages, while post-flowering stress has no appreciable effects thereby suggesting that water stress occurring at post-flowering stage is not critical to grain yield in soybean. Amongst the investigated genotypes TGX 1817-12E was the most tolerant while 1485-1D was the least tolerant genotype.