Precipitation variability in a temperate coastal region and its impacts on Tannat and Albariño cultivars

Faculty of Agronomy, Universidad de la República Oriental del Uruguay, Av. Garzón 780, CP 12900 Montevideo, Uruguay

Abstract

Climate is one of the main components that define the development and behaviour of the plant, conditioning the health status and the final quality of the grapes. The objective was to describe the precipitation (PP) variability during the last 32 years and how Tannat and Albariño responded in three growing seasons (GS). We analyzed PP data from two agro-meteorological stations and calculated descriptive indexes. In addition, we measured vine water potential, plant physiological parameters, grapes’ final composition and health status at harvest in 2019, 2020 and 2021. In the last 32 years, PP during GS ranged from 133-1154 mm and 10-599 mm during the grape ripening period. An average of 51 days had PP, which means one event every four days. However, when analyzing the dry periods (moving average of 15 days with PP<6 mm), 24 events per GS were recorded with a variability from 0-101, which shows the alternation between excess and deficit of water in the terroir. Regarding plant response, both cultivars showed differences in soluble solids, pH and berry weight between GS. In particular, Albariño showed differences in bunch weight. In contrast, Tannat showed differences in total acidity, anthocyanins, leaf area, yield with the incidence of Botrytis cinerea sp., pruning weight and bunch weight between GS. Therefore, the inter-annual variability had an impact on Tannat performance. Still, Albariño was more stable than Tannat between rainy and dry GS, an interesting option for winegrowers searching for durable and sustainable products.