Exploring grapevine genetic diversity to feed breeding programs to sustain wine viticulture facing warming issues

Abstract

Genotype x Environment x Practices interactions exert a tight tuning on wine profile. To maintain the typicality of wine produced in traditional regions becomes a critical challenge in the context of rapid climate changes. While some practices may reduce adverse effects of abiotic stresses on the vine (e.g. the use of watering to maintain photosynthesis), the impacts of high temperature stresses on berry development are more difficult to manage. Main effects of temperature rise on berry composition are related to both primary, with a deterioration of the sugars/acidity balance, and secondary metabolism. In the long term, genetic breeding appears as one of the most promising strategies to support wine production facing temperature regime fluctuations. Unfortunately, knowledge is lacking about the phenotypic and genetic diversity for berry traits impacted by temperature.

The goal of this study was to characterise the phenotypic diversity that could be used in breeding programs. For that, we have selected 12 V. vinifera varieties within the French repository of Domaine de Vassal and 21 offsprings from a microvine progeny. Based on expert advices and preliminary phenotyping data, these genotypes were selected as displaying different developmental features for berry growth and primary metabolites. The accumulation of organic acids and sugars was followed during berry growth and ripening. We observed a huge phenotypic diversity for malic and tartaric acid contents as well as for sugars and berry size before and at ripe stages, indicating that genetic diversity existing within V. vinifera could support breeding for varieties better coping with climate change.