Quantifying the effect of temperature on decoupling anthocyanins and sugars of the grape (Vitis vinifera L. 'Maturana Tinta de Navarrete')

Abstract

The objective of this work consists of the quantification of decoupling anthocyanin:sugar ratio produced by higher temperature on Vitis vinifera L. 'Maturana Tinta de Navarrete'. Two vineyards were studied in two different climatic areas during a 3-year period (2010-2012). The average Winkler index during the three years in the two studied areas was 1364 °C and 1619 °C, respectively. This implies a difference of 1.3 °C for the mean temperature between both areas from April to October. Both total anthocyanins and the anthocyanins:sugars ratio decreased, significantly, in the warmer area during the three years. The highest anthocyanin sugars decoupling occurred in the warmest year (2012) and the lowest in the coolest year (2010). Given that the grape ripening begins in August, it could be concluded that the above decoupling is higher as higher is the temperature in August. For further research, it would be very interesting to study the anthocyanins : sugar ratio at different times from veraison onwards.