Comparison of physiological response to growth stage-based supplemental and conventional irrigation management of wheat

Abstract

AbstractA field experiment was carried out to evaluate the effect of different conventional and supplemental irrigation strategies on leaf stomatal conductance (gs) and chlorophyll content (SPAD) yield and irrigation water productivity (IWP) of wheat using sprinkler line source in 2014 and 2015 in the Mediterranean region. The irrigation strategies were, supplemental irrigation (SI) during flowering and grain filling (SIFG), SI during grain filling (SIG), SI during flowering (SIF) and conventional irrigation (CI). These strategies were conducted under four irrigation levels 25, 50, 75, 100% and a rain-fed as control. The results indicated that CI100 and CI75 produced the greater grain yield and IWP, respectively. CI100 resulted in the increased chlorophyll content by 8.8% over rain-fed. The results confirmed that the SPAD and stomatal conductance values were not equally sensitive to water stress during growth stages. The wheat crop suffered a greater SPAD and gs reductions when the water stress occurred during the grain filling stage (SIF strategy) compared to other strategies, which means that the grain filling stage is more sensitive and effective to decrease the yield of winter wheat. The higher grain yields were achieved when the seasonal mean gs reached 207.4 mmol/m2s in CI and 169.2 mmol/m2s in SI, and the stomatal closure responded well to low, moderate and severe drought treatments. The leaf stomatal conductance (gs) was correlated linearly with grain yield. These relations could be used as a physiological indicator to evaluate water stress effect on the growth and productivity of wheat.