S20 - Session O2 - Enhancing climate change resilience using intra-varietal diversity: Case of Chenin Blanc in the middle Loire Valley

Authors: Etienne Neethling *, Cécile Coulon-Leroy, Etienne Goulet, Virginie Grondain

Over the next century, the projected changes in regional climates are expected to have important consequences on wine production. They vary from short-term impacts on wine quality and style, to long-term issues such as varietal suitability and the economic sustainability of wine growing regions. In order to manage local wine identity in a global changing climate, a better understanding of past and future climate impacts is essential in framing adaptation strategies and policies. At the same time, the study of intra-varietal diversity is important to reflect the adaptive and evolutionary potential of current cultivated varieties to adapt to climate change. As case study, our research assessed the impacts of climate variations on grape composition of Chenin blanc in the Anjou-Saumur wine growing sub-region, France. A long-term assessment (1981-2020) was made on the influence and relation between climate trends and modifications in berry compounds (sugars and organic acids) and ripening speed. From here, data were collected for flowering and veraison growing stages for the various studied accessions and clones of Chenin blanc in the middle Loire Valley. For these phenological growing stages, heat requirements were established using nearby weather stations and phenological model performances were validated. Climate change projections were then integrated to predict the future behavior of the intra-varietal diversity. Study findings highlight the important trends in grape composition over time, providing an overview of climate change impacts on grape and wine quality. While model performances may still require improvements, this study is the first step towards quantifying heat requirements of different clones and how they can provide adaptation solutions for winegrowers to sustain wine identity in a changing climate. As genetic diversity is an ongoing process through point mutations and epigenetic adaptations, perspective work is to explore clonal data from a wide variety of geographic locations.