Techniques for delaying berry ripening adapting red grape and wine composition to global warming

Abstract

Climate change is affecting viticulture particularly because in wine production most of the value is provided by the desired tipicity. High air temperatures decouple grape sugars and anthocyanins accumulation impacting negatively wine composition. In this trial, carried out under the temperature-warm and semi-arid conditions of eastern Spain, we assessed two field strategies in cv. Bobal and Tempranillo aiming to delay ripening to cooler periods; 1) late leaf removal (LLR) and 2) late pruning (LP). During two consecutive seasons, LP was applied after the apical shoot budburst took place and the LLR approximately ten days prior to veraison. Both techniques were effective in delaying berry ripening and thus the harvest date compared to the traditional (Control) winter pruning and canopy management. Notwithstanding, slight yield constrains were observed in LP and LLR treatments compared to that of Control vines in both cultivars. Furthermore, both techniques reduced significantly grape sugar to acidity ratio. The effect of the treatments on polyphenolic composition was different since LP increased grape phenolic potential but the opposite was obtained by LLR. The wine composition analysis confirmed these results, highlighting the usefulness of these techniques to modulate grape ripening period. Therefore, particularly the LP field practices, may be interesting for viticulture adaptation to the warmer future scenarios predicted by most of the more recent climate change models.