Rootstock Effect Influences the Phenolic and Sensory Characteristics of Syrah Grapes and Wines in a Mediterranean Climate

Wine quality depends on grape quality, which is affected by many factors such as edaphic, climatic and genetic, i.e., cultivar and rootstock. Rootstocks have been selected in worldwide viticulture to confer to vines some adaptation to several types of soil conditions in vineyards, but this adaptation may affect vine physiology and consequently may affect the chemical compounds of grapes, especially their phenolic compounds. Thus, this study compares the chemical composition of grapes and wines, and the sensory profile of wines from vines of the cv. Syrah grafted on two rootstocks, 5C and Gravesac, grown under a biodynamical management system. The results showed higher skin total phenols and skin total tannins in grapes from 5C rootstock. In the resulting wines, the same results were observed. The multivariate analysis demonstrated that the 5C wines presented a higher relationship with all the families of the low-molecular-weight phenolic compounds, while the Gravesac wines showed a strong relationship with acetylated and p-coumaroylated anthocyanins. The sensory analysis showed that the 5C wines presented more color intensity, more astringency and more meaty aromas compared with the Gravesac wines. The results proved that it was possible to obtain grapes and wines of different qualities depending on the rootstocks used under the same climatic and agronomical condition.