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Couhins experimental winegrowing domain, Bordeaux.  INRA, MAITRE ChristopheCouhins experimental winegrowing domain, Bordeaux. INRA, MAITRE Christophe

At a global scale, just 12 grape varieties (or 1% of cultivated varieties) occupy up to 80% of vineyards in some countries. Scientists from INRA and Harvard University in the USA have suggested that one of the levers that could be operated to adapt wine-growing to climate change is to exploit the diversity of other cultivated varieties by planting those that are less well known, and thus encouraging winegrowers and consumers to adopt new practices. Their study is published on 2 January 2018.

Earlier harvest dates, vines suffering from more severe water deficits, or wines with higher alcohol contents, less acidity and new aromatic profiles all indicate that winemaking has already been affected by climate change, and scientists are studying different strategies to enable the adaptation of this industry. Scientists from INRA and Harvard University have focused on the possibility of exploiting the diversity of grape varieties that are cultivated but little used by wine-growers in order to adapt to new climatic conditions in winegrowing regions.

To achieve this, the scientists first of all utilised knowledge of the genetic diversity of vines found in the scientific literature. They notably analysed data from the INRA Biological Resource Centre for Grapevines in Vassal-Montpellier, an ampelographic* collection that is unique in the world. This international research repository contains grapevines from 54 winemaking countries (2700 varieties, 350 wild-type vines, 1100 interspecific hybrids, 400 rootstocks and 60 vine species).

The research team then crossed this knowledge with a database published by Australian scientists that describes the global distribution of the grape varieties actually planted in all vineyards. Overall analysis of these data enabled the observation that at present, winegrowers only use a very small proportion of the genetic diversity that exists at a global level (which is also the case for numerous other species such as banana, cocoa, coffee and kiwi). Indeed, just 1% of varieties (12 out of the 1100 grape varieties cultivated) occupy around 45% of vineyards throughout the world, and in some countries such as China, Australia or New Zealand, this percentage may concern more than 80% of vineyards. Even more extreme is the fact that in China, 75% of vineyards grow just one variety, Cabernet-Sauvignon.

Among these 1100 cultivated varieties, some are better adapted to hotter climates and are more drought-resistant than the twelve best known and most widely cultivated. It is therefore important to better understand and experiment with varieties from elsewhere in different production regions so as to evaluate their potential to deal with future change. This is notably what has already been initiated by the experimental facility of the VitAdapt plot managed by the Institute of Vine and Wine Science (ISVV) which is describing the long-term behaviour and adaptation of some fifty varieties to the climate in the Bordeaux region.

This study suggests the need for a greater involvement of winegrowers in testing and evaluating new grape varieties. It is also necessary to encourage them to share their data with scientists (for example, in the context of participatory research) so that strategies can be developed together to adapt to future climatic conditions and attenuate the negative effects of climate on their production. In some regions - particularly in Europe - a certain number of barriers need to be broken down and notably those of a regulatory type (e.g. regulations on Protected Designation of Origin, or PDO, in France). But it is also up to consumers to adapt their habits and be ready to taste new wines made using less well known grape varieties.

*Ampelography is the branch of taxonomy that applies to grapevines and has three complementary aspects: the description and identification of grape varieties; study of the evolution of varieties and the relationships between them, and the appreciation of their agronomic, technological and genetic aptitudes and potential.