Water Deficit Effects on Soybean Root Morphology and Early-Season Vigor

Abstract

This study was conducted to determine if root, shoot, and gas exchange traits of determinate and indeterminate soybean cultivars respond differently to soil water deficit. The effect of soil water deficit imposed 4 and 10 days after sowing on growth and development parameters of determinate and indeterminate soybeans was evaluated for 18 and 30 days in experiment I and II, respectively. At both 18 and 30 days after seeding, nearly all root, shoot, and physiological parameters were inversely correlated with the soil moisture level, and the adverse effects of drought stress were more evident in Progeny P5333RY than in Asgrow AG5332. For both cultivars, the effect of soil water deficit on net photosynthesis was mainly due to stomatal limitations. The developed algorithms for the plant processes based on the environmental productivity index were not different between the cultivars, suggesting that soybean plants respond in a similar way irrespective of their growth habits, probably due to the shorter period of water stress.