The introduction of pathogen-resistant varieties in organic viticulture: frontiers and challenges

Viticulture is one of the agricultural sectors with the highest reliance on plant protection products. Downy mildew and powdery mildew, in particular, require multiple applications in spring to protect developing grape clusters. Various disadvantages of the limited copper-based products, to which organic viticulture is restricted, make the challenge even greater. Pathogen-resistant varieties are intra-specific hybrids that inherit genetic tolerance to these fungal diseases from non-vinifera Vitis parental lines. Historically, they have been bred across Europe to reduce pesticide use, enhance vineyard sustainability, and maintain good wine quality. Currently, 45 resistant varieties are authorized in France, 35 in Italy, and about 40 in Germany. Although some recently bred Italian varieties closely resemble traditional cultivars, the enological characteristics of wines produced from these hybrids often differ from those of their parental lines. The adoption of pathogen-resistant varieties is increasing in Europe, yet two new frontiers are emerging: (i) the need for varieties resistant to phytoplasmas such as Flavescence dorée, which threaten vineyard viability; and (ii) the potential introduction of new breeding techniques based on CRISPR-Cas technology. These techniques could produce resistant V. vinifera varieties genetically identical to standard clones (e.g., Chardonnay, Sauvignon, Riesling), potentially transforming pathogen management in viticulture. Organic farming associations will then face a critical decision: either accept these innovations or continue relying on extensive copper-based treatments.