Responses of "Chardonnay" to deficit irrigation applied at different phenological stages: vine growth, must composition, and wine quality

Adoption of water-saving irrigation strategies is necessary especially for grapevine that has the highest acreage of any fruit crop in the world. We applied deficit irrigation to Chardonnay wine grape at the following phenological stages: anthesis to fruit set, fruit set to veraison, and veraison to harvest. Four irrigation levels (0, 25, 50, and 100 % of crop evapotranspiration, ETc) were applied in 2009. Vines grown in large containers were used to enable imposition of water stress early in the growing season. The following parameters were measured: midday leaf water potential, vine growth, yield, and quality of must and wine. The same parameters were measured in 2010 although all vines were fully irrigated. The 0 and 25 % treatments caused defoliation and had negative impacts on yield and wine quality in both 2009 and 2010. Chardonnay was most sensitive to water stress in post-veraison in terms of productivity and wine quality.