Variation of the climate of a Terroir and its consequence on the vine's response

Abstract

Viticultural climate, a major component of Terroir, in Uruguay southern region was classified as moderately dry, temperate-warm, with temperate nights and influenced by sea breeze. During the 1994-2016 period, thermal and water regimes and their influence on grapevine yield, sanitary status and berry composition was analyzed for Tannat cultivar grown in commercial vineyards. Principal component analysis (PCA) separated years in three groups: Group 1 (wet), rainfall over the growing season higher than the average, sanitary status is limiting, acidity and yield higher than the average, whereas sugar content is lower, late harvest. Group 2 (warm and dry), thermal conditions greater and water component lower than the average, better sanitary status, sugar contents and acidity lower than the average, early harvest. Group 3 (fresh, wet in spring and dry during ripening), thermal conditions lower than the average, rainfall higher during budbreak-fruitset and lower than the average in the month previous to harvest, berry size and sugar contents greater than the average, late ripening. Correlations among climate, yield and berry quality variables were established. In the studied years, climate variability within the region was high and the response of the Tannat cultivar was in accordance to this variability.