Setting up a climate adaptation strategy for vines begins with the choices for planting vines. The choice of the variety is already fundamental, as it will have an impact on the vine for decades. In a context of greater climatic variability, in particular with increasingly long periods of drought, the wine grower should favor drought-resistant varieties whenever possible.

In the genetic selection of these varieties, 3 mechanisms come into play:

• Drought tolerance: limited production and quality losses when faced with water stress
• Water use efficiency: ability to use less water for equivalent grape yield and quality
• Drought resistance: chance of survival in case of extreme drought

These 3 characters interact permanently to define the vine's response to drought.

In the field, depending on pruning techniques, a drought-tolerant variety will have discontinuous canopy (limiting perspiration while preserving shade) and efficient stomatal control (in particular to limit night sweating).

The most drought resistant varieties belong to different categories:

• Varieties that are currently planted but may be expanded in the future (for example, favoring Grenache and Mourvèdre over Syrah in some Mediterranean denominations)
• Ancient grape varieties, which in the past have been abandoned due to the difficulty of reaching an ideal ripeness of the grapes. These varieties have now gained interest due to their greater resistance to drought.
• Varieties that are grown in regions that already face more intense water stress conditions. In the Mediterranean, for example, Greek grape varieties such as Assyrtico or Portuguese varieties such as Touriga Nacional can be of great value to French winemakers (provided that consumers adapt to the new flavor). Aglianico, Airen, Bobal, Calabrese, Trepat, Torrontes riojano, Malvasia di Sardegna, Zinfandel and others are added to this list of grape varieties used in very dry conditions.
• Creation of new varieties. Some hybrid varieties are created to resist mildew and mildew. They may be more drought resistant, but varieties specifically resistant to drought are currently designed.

The choice of the variety must also be complementary to the choice of a rootstock that provides a deeper rooting, for example. This choice of variety is critical; however, the resistance of a vineyard to drought is also determined by other technical choices (pruning strategy, production goals, business organization, sun exposure of the leaves ...), the quality and soil management, the sun exposure or the planting density of the vineyard.

References:

(1) http://www.aredvi.asso.fr/AREDVI_public/MA/26-02-08_chato9/contrainte_hydrique.pdf
(2) https://techniloire.com/sites/default/files/fiche_choisir_son_porte_greffe.pdf
(3) https://www.reussir.fr/vigne/ramsey-un-porte-greffe-tolerant-la-secheresse
(4) https://www6.bordeauxaquitaine.inra.fr/egfv/content/download/3468/36302/version/1/file/Article+E+Marguerit+et+al+CIVB+2011.pdf