Improving Wheat Grain Yield under Water Stress by Stem Hydrocarbon Reserve Utilization

Abstract

Current assimilation and remobilization of dry matter during grain filling in wheat subjected to different levels of water deficit during phenological growth stage. The experiment was conducted as split plot. Time of water stress and levels considered as main and sub plots, respectively. water stress treatments exposed at jointing, anthesis and seed filling stage and levels of water stress include, Full Irrigation (FI), Low Water Stress (LWS), Moderate Water Stress (MWS) and High Water Stress (HWS). Grain yield and dry matter accumulation and remobilization were negatively affected by water stress. The lowest grain yield was obtained from HWS and when water stress occurred at anthesis. Dry matter accumulation at LWS was 4.87%, at MWS was 14.86% and at HWS was 26.55% lower than FI, respectively. Spike density and the number of kernel per spike were affected similarly and decreased with water deficit increased. The decrease in the number of spikes per unit area due to LWS, MWS and HWS was 13, 23 and 30% compared to FI, respectively. As the water stress was imposed at jointing stage, the lowest number of spikes per unit area and when imposed at anthesis, the lowest number of kernel per spike was obtained. With increase in water stress intensity, the contribution of mobilized DM (DMRC) to grain yield increased. The highest DMRC value obtained from HWS with 25.37%.