The effect of water stress on yield was most severe when drought occurred during panicle
development. Anthesis was delayed, the number of spikelets per panicle was reduced to 60% of the irrigated control and the
percentage of filled grains decreased in one crop to zero. This decrease in grain yield to less than 20% of the control was
associated with low dry matter production during the drought period as well as during the recovery period following the
drought. When drought occurred during grain filling, the percentage of filled grains decreased to 40% and individual grain
mass decreased by 20%. The effect of stress was also related to its severity during grain filling.