Effect of water stress and rootstock genotype on Pinot Noir berry composition

Abstract

Background and Aims Grape berry growth and composition depend on complex interactions between the genotypes of the rootstock and the scion, vineyard management and environmental factors. The present work aimed to characterise the effect of rootstock genotype and water deficit on the primary and secondary metabolism of the grape berry. Methods and Results Vitis vinifera cv. Pinot Noir grafted on either rootstock 110R (drought tolerant, mid to high vigour) or 125AA (drought sensitive, high vigour) was studied during three growing seasons in the field under normal rainfall or water shortage conditions. Water status, yield and berry composition (sugars, organic acids, free amino acids and anthocyanins) were measured throughout berry development during the three growing seasons. Water stress did not significantly affect berry mass, yield, sugar and organic acids concentration, but increased anthocyanin concentration of the berries regardless of the rootstock. Furthermore, the data showed that the berry amino acid concentration at harvest depended on interactions between water supply and rootstocks. Conclusions Scion berry composition differed only slightly between the two rootstocks tested. Rootstocks and water stress, however, affected the concentration of amino acids, and plants grafted onto 125AA were more sensitive to drought stress. Significance of the Study This work provides novel insights into the response of grape berry metabolites to rootstock and to drought in a changing environment.