Response of Grapes to Water-Deficit Stress in Particular Stages of Development

Severe water stress was induced in container-grown grapevines during five stages of fruit growth. Stress at each stage reduced fresh fruit yield. During the first three weeks after flowering, losses were greatest and were primarily attributable to reduced fruit set. Thereafter loss was associated with reduced berry size and, following stress after veraison, the failure of fruit to mature. Fruit which failed to mature also had a lower skin pigment content, whether assessed on a per-berry or per-unit-surfacearea basis. All fruit from stressed vines was late to mature, though the delay was greatest for fruit stressed during the lag phase.