Effect of a deficit irrigation regime on the quality of wines made from white grapes (Vitis vinifera L.) grown in semiarid areas

The dependence of wine quality on the irrigation management strategies in Vitis vinifera L. was tested from 1999 to 2002. A drip-irrigation experiment was performed on white grapes of the cultivars Baladí, Airén, Montepila, Muscat Blanc à Petits Grains and Pedro Ximénez, grafted and vineyard-planted in 1995 in Cabra (Cordoba, Spain). Treatments consisted of a nonirrigated control and an experimental deficit irrigation, in which water was applied from fruit set until near harvest. A total of 19 analytical parameters were measured, including alcohols, total phenol content and optical density as well as ethanol, pH, total acidity and dry extract. Wines were evaluated for their visual characteristics, aroma, taste and finish. The irrigation treatment contributed to a higher dry extract, and an increase in malic acid and potassium in wines. There was a decrease in pH, isobutanol and isoamyl alcohols with increasing water application. Sensory evaluation ranked irrigated over nonirrigated wines with the only exception of the wines of Muscat Blanc à Petits Grains. The main defects of nonirrigated wines were attributed to visual characteristics and poorer taste quality. Proper irrigation management, i.e., optimizing both the timing and the amount of water supplied, plays a significant role in wine quality and is especially important in arid and semiarid areas. The aim of this study was to ascertain the effect of irrigation in wine quality. In this study, irrigation was applied only during periods in which water stress might affect production and harvest quality. The chemical results ranked irrigated over nonirrigated wines and Muscat Blanc à Petits Grains over other cultivars, regarding their quality. Sensory evaluation ranked irrigated over nonirrigated wines with the only exception of the wines of Muscat Blanc à Petits Grains. Therefore, deficit irrigation during berry development and ripening appears to be a promising technique for the production of quality young wines in semiarid achieving a compromise between aroma and taste quality.