The term “hybrid” is often used to describe new disease-resistant grapevine varieties. However, this designation no longer reflects the genetic reality of the most advanced cultivars, particularly the varieties resulting from the work of Alain Bouquet. Following several generations of successive backcrosses with Vitis vinifera varieties, these cultivars now possess a significant share of the V. vinifera genome, exceeding 98%. It is therefore more accurate to speak of “resistant varieties” or “new varieties” rather than hybrids, as their genetic profile is intrinsically linked to the traditional cultivated grapevine.

Advances in Genetics and the Pursuit of Resistance

Genetics plays a crucial role in breeding disease-resistant grapevine varieties. As early as the beginning of the 20th century, crosses were made between the American grapevine Muscadinia rotundifolia, which is highly resistant to fungal diseases, and European Vitis vinifera. Alain Bouquet, a researcher based in Montpellier, pursued this path by launching a 35-year breeding programme. His method involved crossing the resistant variety NC6-15—itself derived from M. rotundifolia and V. vinifera—with traditional Vitis vinifera grape varieties such as Cabernet Sauvignon, Grenache, or Pinot. This process made it possible to incorporate resistance genes while enriching the genetic heritage with the oenological qualities of V. vinifera. The goal was clear: to develop varieties endowed with high natural resistance while retaining the organoleptic characteristics of wines crafted from classic grape varieties. To gain a clearer understanding of these different categories, explore our glossary of resistant, tolerant, hybrid, and PIWI grape varieties.

Advances in genomics substantiate this approach. The genome of the cultivated grapevine (Vitis vinifera) is diploid, with 38 chromosomes. Studying it has revealed that the grapevine is a palaeo-allohexaploid, confirming hypotheses put forward as early as 1951. Thanks to this in-depth knowledge, researchers can now pinpoint resistance genes with precision and guide crosses to achieve optimal results. The Bouquet varieties, for instance, are now considered the closest to V. vinifera in genetic, agronomic, and qualitative terms.

A Spectrum of Tolerance Within Vitis vinifera

While new resistant varieties are the outcome of extensive breeding work, varying degrees of disease tolerance also exist within classic Vitis vinifera varieties themselves. Genetic analysis of grape varieties has helped validate or rectify numerous parentages and trace the lineage of traditional cultivars. For instance, certain “forgotten” historical grape varieties, while not entirely resistant, showed lower susceptibility to specific diseases. Such is the case with Béquignol, which is “a grape variety somewhat less susceptible to downy mildew”. This understanding of genetic diversity is vital for adapting vineyards to climate change and reducing the use of plant protection products. Research continues to investigate these avenues, both in breeding new varieties and in harnessing the natural resilience of heritage grape varieties. To learn more about this topic, discover how mildew- and powdery mildew-tolerant grape varieties are transforming vineyards.

At Château Cazebonne, we are firmly committed to preserving and reviving Bordeaux's viticultural heritage, particularly by replanting heritage grape varieties and exploring resistant varieties. This research and experimentation is made possible thanks to the interest and support of wine lovers like you. To deepen your knowledge of these subjects, feel free to download our book on the history of Bordeaux grape varieties. You can also test your knowledge and discover new facets of wine with our wine quizzes. And to taste the fruits of our dedication, we invite you to discover our wines directly in our online boutique.