Every year, as soon as the vine develops its foliage and flowers, any onset of downy or powdery mildew is monitored... because once established, these diseases are difficult to contain and require frequent treatments, using copper and sulphur, or synthetic pesticides. These treatments – on average 16 per year – represent 80% of plant health measures on grapevine. To overcome this, INRAE researchers have created resistant grape varieties from natural crosses. These innovations were developed through high-level research in partnership with the Institut Français de la Vigne et du Vin (IFV – French Wine and Vine Institute) and interprofessional unions, a prerequisite to the success and accelerated uptake of the innovation. Indeed, the choice of planting a new grape variety is a serious commitment for a winegrower: a vine is generally planted for 30 to 40 years, and the restructuring of a vineyard a carefully thought-out choice...
Innovation that plants the future of winegrowing
The success of this long-standing adventure is linked to the close partnership between research, the IFV and the wine industry
The creation of disease-resistant grape varieties that are now becoming available is the successful culmination of 40 years of research, from prospecting to identify sources of resistance in genetic resource collections, to crossing and selection to integrate and assemble them into grape varieties that suit our growing conditions and consumer tastes, their introduction to ensure that they deliver durable resistance over time, and adapting to regional specificities.
Four grape varieties with natural resistance to downy and powdery mildew are now available which produce wine as good as that made with traditional grape varieties. It took 14,000 seedlings from natural crosses, which allowed 700 plants to be selected for their resistance and other characteristics of interest before these four varieties were registered in 2018. As of 2021, these varieties are now grown on 800 ha – a record speed for an uptake of innovation in the sector! The success of this long-standing adventure is linked to the close partnership between research, the IFV and the wine industry, which has made it possible to explain, present and taste the products of this innovation to professionals before they adopt it.
In 2019, on the 43 sites, the resistant varieties enabled a 96% reduction in the use of fungicides!
Another objective was met in terms of disease resistance, as measured by OsCaR. OsCaR is a participatory research tool used in all the wine-growing regions of France to enable participating winegrowers to test resistant varieties in real growing conditions and fully take part in the research process. This system, which is unique in Europe, is used to determine the durability of resistance by monitoring downy and powdery mildew populations and the possible appearance of secondary diseases. It is now possible to quantify how these complex genetic resistances reduce the fungicide treatment frequency index: in 2019, on the 43 sites, it was possible to reduce the use of fungicides by 96%! OsCaR is also used to determine optimal conditions for the introduction of a variety, via a modelling approach implemented on the basis of the data collected, as well as to analyse the production and quality of the wines made from the resistant grape varieties.
In the 1990s, the Entav-Inra brand (the result of a joint IFV–INRAE collaboration) was launched for the marketing of certified grapevine plants. Today, this brand represents 95% of the material sold in France and is also distributed abroad. The two organisations continue to work together for the joint management of genetic resources. This exceptional resource collection is among the most extensive in the world: https://www.youtube.com/watch?v=S5bSFCqUA14 In the current context of climate change and the emergence of diseases and pests, grapevine genetic resources are a source of resilience for viticulture... Maintaining and preserving them is our responsibility for future generations.
Reducing plant protection treatments, adapting to climate change and meeting consumer expectations are just some of the challenges French vineyards face for this century. Organic farming is one solution being explored. Since 2019, winegrowers, whether they are certified organic or not, can count on the four “INRAE-ResDur” varieties resistant to the two main fungal diseases downy and powdery mildew: Floreal and Voltis for white wines, Artaban and Vidoc for reds.
Looking to the future
France is home to an array of wine-producing regions, each of which has marked regional characteristics associated with well-identified grape varieties: Pinot, Cabernet, Syrah, Grenache, Ugni Blanc, etc. A tailored selection is currently being rolled out via 12 four-part programmes (INRAE, IFV, interprofessional unions), financed by the industry. The aim is to create resistant grape varieties that are as close as possible to the typical varieties currently used in vintages and regional production. Within this framework, more than 70,000 seedlings have been created and 2,000 resistant plants selected for testing in vineyards.
The creation of grapevine varieties, both for scions and rootstocks*, must also take into account new challenges that research is tackling: adaptation to environmental constraints, resistance to new diseases such as grapevine fanleaf virus, or ‘court-noué’, which affects most vineyards (by combining resistance to the virus that causes the disease and the nematode that carries it), black rot, which is progressing with the reduction in fungicide treatments, and emerging diseases such as Pierce's disease, caused by the bacterium Xyllela fastidiosa. The next challenge is to reduce breeding time: it took 18 years from the initial cross to the creation of the downy- and powdery mildew-resistant Floréal variety, registered in 2018. To shorten this time frame, scientists are mobilising genomic selection and phenotyping, which are already used on annual plants. Characterising promising genotypes as quickly as possible necessarily includes the wine-making process: a mini-cellar device – used to test organoleptic quality with just one kilogram of grapes – is currently in development.
* A scion is the harvested variety and aerial part of the plant. The rootstock on which the scion is grafted confers resistance to phylloxera (aphid pest) and is essentially the root part.