Variability of Tempranillo grape composition in the Rioja DOCa (Spain) related to soil and climatic characteristics

Soil and climate are terroir elements that condition vine response. This research was intended to evaluate the variability of grape composition of the Vitis vinifera L. cv. Tempranillo in the Qualified Designation of Origin Rioja (DOCa) (Spain) in La Rioja (Spain), and its relationships with soil and climate characteristics.

The relationships between grape composition (sugar content, acidity, phenolic compounds, and berry weight) and climate characteristics were analyzed for the period 2008-2017 in 20 plots scattered throughout Rioja Alta and Rioja Baja, using multiple-regression analysis. The spatial variability of grape composition and the effect of soil properties were evaluated using cluster analysis. Despite the high variability in climate characteristics from year to year, it was possible to define the soil and plot characteristics that affect grape composition at ripening.

Acidity and anthocyanin concentrations were affected by temperature and by precipitation recorded in different time periods throughout the growing cycle. The increase in temperature in earlier stages reduced the total acidity and increased the total polyphenols, while an increase in temperature during the ripening period produced a decrease in total acidity, malic acid, and anthocyanin concentration, and a lower ratio between anthocyanins and sugars. The plots located in soils with higher soil water availability presented higher acidity and lower anthocyanin concentrations. © 2018 Society of Chemical Industry.