Chapters authored
Convenience of Applying of Viticulture Technique as a Function of the Water Status of the Vine-Stock
This study determined the effect that the irrigation dosage and cluster thinning showed over the antioxidant activities and total phenols in grapes, and phenolic profile and chromatic characteristics of cv. Tempranillo wines. The experiment was carried out over two consecutive seasons at an experimental vineyard in Extremadura (Spain). The plants were subjected to two post-véraison irrigation treatments, one at 100% (R100) and the other at 25% (R25) of crop evapotranspiration (ETc). Two crop loads (C and T) were additionally established for each irrigation treatment by cluster thinning at véraison. The winemaking process involved separate use of the grapes from each of the four resulting treatment groups (R100C, R100T, R25C and R25T) and followed a common protocol. In grapes, the effect of thinning enhanced when combined with water deficit, resulting in increases phenylpropanoids and flavonoids at the harvest, while leaving the polyphenol oxidase´s activity unaffected. In wines, the higher post-véraison water stress of the R25 treatments resulted in higher values of dimeric flavonol and flavanol concentrations. The wine hue was affected by water status. The cluster thinning caused additional increases in the concentrations of monomeric flavanols and anthocyanins, as well as resulting in stronger wine colour intensity.
Part of the book: Grapes and Wines
Effects of Vine Water Status on Yield Components, Vegetative Response and Must and Wine Composition
Despite Vitis vinifera L. is a drought-tolerant species—rainfed traditionally grown in a very diversity of climates—irrigation has more and more become a usual practice aimed to obtain regular yields along seasons and to control must composition. Results on vineyard irrigation are dependent on the timing, length and intensity of the water deficit. From budbreak to flowering, shoot growth is very sensitive to water stress, while reproductive growth is almost unaffected. Severe water deficit during fruit set can reduce yield by affecting ovary cell multiplication and expansion. During maturation water stress induces yield reduction by limiting berry growth; along this phase must composition is also affected. There is a positive, linear relationship between must sugar content and available water; however, no relationship has been found to either total acidity or pH. Biosynthesis of anthocyanins and fruity aromas is enhanced by water deficit. Usually, wines from moderate irrigation treatments scored the highest. There is a general agreement that severe, long water deficits diminish must quality, leaf area, fertility and yield, and it has a negative carryover effect on the next seasons by limiting wood reserves to be used the following seasons.
Part of the book: Advances in Grape and Wine Biotechnology