Drought stress affects starch in rice grains. Key enzymes control starch production. Drought increases starch movement from leaves to grains. Starch in grains increases with higher enzyme activity under drought. Starch, amylopectin, and sucrose increase, while amylose decreases in grains under drought. Starch decreases in mature grains due to shorter filling time from drought. Yield loss is higher in susceptible rice compared to tolerant rice under drought.