Grain Growth and Yield Performance of Wheat under Subtropical Conditions: II. Effect of Water Stress at Reproductive Stage

Abstract

Wheat is predominantly grown under rainfed conditions in the subtropics where the crop growth mostly depends on stored soil moisture content. As the evaporative loss of soil moisture exceeds rainfall for several months, wheat crop suffers from moisture stress at reproductive stage. The objective of this study was to analyze the effect of water stress at reproductive stage on grain growth pattern and yield responses of wheat. Variety Kanchan was grown under well-watered conditions in two large plots (4m × 5m). At heading, one plot was subjected to water stress (1/3rd moisture at field capacity), and the other one received regular irrigation. Water stress affected most of the plant characters. Only 79% of tillers of stressed plants produced ears, compared to 94% of the irrigated plants. Water stress did not affect grain setting, however, affected greatly the individual grain weight. The grain yield was reduced to 65% in the stressed plants compared to that of irrigated plants. The grain growth period was shortened from 39 days after anthesis (DAA) to 33 DAA due to the stress. The linear growth phase of grain growth was primarily affected by the stress. Water stress treatment did not influence the dynamics of grain moisture content. The smaller grain in water stressed plants was presumably due to shortened linear grain growth phase as well as slower grain growth.