Regulation of fruit and wine quality parameters of 'Cabernet Sauvignon' grapevines (Vitis vinifera L.) by rootstocks in semiarid regions of India

Area under wine grape cultivation is increasing in semiarid tropical regions of India. There is lack of information on role of rootstocks influencing must composition and thereby wine quality under such climatic conditions. Majority of area under table grape cultivation is grafted on Dogridge rootstock, which is also been used for wine grapes. Grapes harvested from vines grafted on Dogridge were known to possess high potassium resulting in high pH which has adverse effect on wine quality. Hence, this study was initiated to understand fruit composition and wine quality of 'Cabernet Sauvignon' grapes grafted with each of the rootstocks 101-14Mgt, 1103P, 110R, 140Ru, Fercal, Gravesac and SO4. Rootstocks significantly influenced many of the must composition parameters such as sugars, organic acids, phenolic compounds, potassium and pH. Significant and positive correlation was observed between potassium content, juice pH and malic acid. Rootstocks 101-14 Mgt and Gravesac accumulated more potassium in fruits which also had higher malic acid and juice pH, while it was least on 110R, 1103P, Fercal and SO4 rootstocks. The potassium content in juice was directly related to wine pH, wherein wines made from 'Cabernet Sauvignon' grafted on 101-14 Mgt and Gravesac had highest pH. Content of most of the phenolic compounds in must and wine were significantly influenced by rootstocks. There was more than two fold increase in the total phenolic content from must to wines with highest phenols recorded in wines made from fruits harvested on 110R rootstock