Effects of water stress on the sugar accumulation and organic acid changes in Cabernet Sauvignon grape berries

The eastern foot of Helan Mountains in Ningxia belongs to the semiarid area and has been identified as the best wine grape producing area in China. In order to solve the problems of a high sugar content, organic acid falling too fast and severe shortage of acidity in the berries during ripening, which lead to lack of wine harmony, this study took Vitis. vinifera L. cv. ‘Cabernet Sauvignon’ as the experimental material and expanded nine treatments from setting to harvest. Nine rows were selected and divided into three groups, treated with mild (–0.20 MPa ≥ Ψb ≥ –0.40 MPa), moderate (–0.40 MPa ≥ Ψb ≥ –0.60 MPa), severe (Ψb ≥ –0.60 MPa) water stress from setting to veraison separately. From veraison to harvest, within each group, the mild, moderate, severe water stress were set, forming light-light (CK), light-medium (T1), light-heavy (T2), medium-light (T3), medium-medium (T4), medium-heavy (T5), heavy-light (T6), heavy-medium (T7), heavy-heavy (T8) treatments. The results showed that when the medium treatment was used from setting to veraison and the medium or severe treatment was used during post-veraison to harvest, it would facilitate the transportation and accumulation of sugar and improve the fruit quality.