Growth Rate of Grains and Grain Yield of Wheat in Relation to Drought

A spring sown wheat (cv. “Sappo”) was grown on a loamy sand in lysimeters and affected by drought during the flowering and grain filling stage, respectively. Drought during the flowering stage reduced the grain yield by reducing the number of ears per unit of ground area, and the numbers of grains per ear. During the grain filling stage the grains continued to grow at the same rate in spite of increasing water stress until the soil water content reached the permanent wilting capacity. Then the growth stopped. Irrigation four weeks after terminated flowering, just before the permanent wilting capacity had been reached, had no effect on the further growth.