The strategy to adapt the vineyard to climate change needs to be implemented from the planting stage. The choice of grape variety is crucial, as it engages the winemaker over several decades. The rise of the average temperature induces an earlier bud break of the vine (milder winters) and a shortening of the vegetative period which leads to earlier veraison and maturity (direct effect of temperature on the growth and physiology of the vine). Since 2010, the harvest in Europe has started two to three weeks earlier than before the 1980s. The maturity period is therefore close to the core of summer, with higher temperature conditions that amplify the effects of climate change. The sugar content of the grapes and therefore the alcohol content of the wine increases; the flavours change; the risk of a greater decrease in acidity increases… In these circumstances, it may be interesting to opt for a later variety.

A late variety is a variety that needs more heat to reach maturity. It will therefore be better adapted to warmer climates, and possibly less affected by heat waves (depending on when this heat wave occurs). The Pulliat Classification defines a late variety as having reached maturity 36 days after an early reference variety: the Chasselas. The grape varieties Carignan, Mourvèdre, Piquepoul, Clairette, Manseng, Cabernet-Franc, Morrastel, Rivairenc, Sciaccarello, Terret, Tourbat are late varieties. (1) (5). The Vitadapt (ISVV Bordeaux) experiment has thus made it possible to characterize well the late or early character of 52 grape varieties (2).

Planting a late grape variety helps to maintain maturation outside periods of high temperatures. The late type of vines can be so-called old type of vines, abandoned precisely because of the difficulties in reaching a sufficient level of maturity in the previous climate. It may also be less sensitive to frost, due to later bud break (3). These later grape varieties may also be indigenous grape varieties from warmer regions of the world. These include the Caucasian grape varieties Saperavi and Rkatsiteli, the Mavrud of Eastern Europe, the Portuguese Touriga Nacional, the Greek Assyrtiko (4) (5).

Of course, the choice of grape variety is not only based on this later criterion for maturity. It must also take into account the adaptation to the “Terroir” (sunshine, water constraints, soil, etc.) and to the winegrower’s production objectives (yield and quality). It must also be selected based on its resistance to diseases and pests (new varieties resistant to downy and powdery mildew). But the criterion of late maturity is an important point to take into account in the face of climate change.

References:

1. https://www.le-vin-pas-a-pas.com/comment-classer-facilement-les-cepages-selon-leur-maturite/
2. https://www6.bordeaux-aquitaine.inra.fr/egfv/Ressources/Dispositifs-experimentaux/Parcelle-VITADAPT
3. https://www.bastamag.net/Rechauffement-climatique-ces-cepages-anciens-qui-pourraient-sauver-les
4. https://www.vitisphere.com/images/magazine/Encepagement.pdf
5. http://lesclosdemiege.fr/2017/11/la-vigne-a-la-croisee-des-chemins-quels-cepages-demain-en-occitanie/
6. https://www.supagro.fr/fondation/wa_files/Livret_cepages_prometteurs_HMahe.pdf
7. https://www6.bordeaux-aquitaine.inra.fr/egfv/Ressources/Dispositifs-experimentaux/Parcelle-VITADAPT