Effect of Water Deficit Stress on Grain Yield of Rice

Abstract

We tested whether exposing rice plants to water stress during reproductive growth affects the rice grain yield, yield components and grain growth, which is one of the most important traits for rice growing in a rainfed condition. A field experiment was conducted in the rainout shelter at the farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur, Bangladesh, during wet season. One locally popular high yielding rice variety BRRI dhan49 grown at three levels of moisture regime- irrigation stop at 1^st heading to maturity (WS1), irrigation stop at 15 days after heading to maturity (WS2) and optimum irrigation or well watered (WW) condition. Water stress during the reproductive stage reduced grain yield but the magnitude was greater when water stress imposed at 1^st heading. Grain yield reduced 44% and 9% by WS1 and WS2 respectively compared to well watered condition. The increased spikelet sterility caused by water stress was closely related to the reduction of the total spikelet number per panicle.