Variétés de vigne de demain : évolutions attendues, attentes professionnelles et sociétales, challenges

En 2015, le Catalogue Officiel Français comprend 377 variétés tous usages confondus. Chaque année, des variétés nouvelles viennent enrichir cette liste afin d'offrir à la viticulture des outils pour relever les défis qui se présentent à elle. En effet, la prise de conscience du changement climatique, la réduction recherchée des intrants phytosanitaires et la capacité à maintenir la compétitivité des entreprises font naître beaucoup d'attentes en matière de matériel végétal. Depuis les années 1960, la sélection clonale continue d'apporter des réponses (état sanitaire, performances) aux viticulteurs dans la mesure de la diversité naturelle que peuvent offrir les cépages traditionnels. Fertilité, vigueur, taille des grappes et des baies, arômes sont des critères que la sélection a pris en compte et continue d'étudier. Il en est de nouveaux que les conservatoires permettent d'appréhender : tardiveté, maturité polyphénolique, port,… Que faut-il en attendre ? Vis-à-vis du réchauffement climatique, des sélections accumulant moins de sucres tout en permettant une bonne maturation des polyphénols ? Des travaux sont en cours, mais les marges permises par la variabilité naturelle sont réduites et certaines questions devenues primordiales resteront sans doute sans réponses, concernant les grandes préoccupations sanitaires : maladies du bois, mildiou, oïdium, viroses… Dans ces domaines, la création variétale apparaît comme le seul levier de progrès significatif. Initiée au début des années 2000 par l'INRA et désormais en partenariat avec l'IFV, la création par hybridation de variétés de vigne résistantes au mildiou et à l'oïdium vise un double objectif : durabilité des résistances et qualités agronomiques, technologiques et gustatives. Les premières inscriptions au Catalogue sont prévues fin 2016. On assiste également depuis quelques années à un regain d'intérêt pour des variétés locales. Circuits courts, vins de niches à forte identité, sont autant d'arguments en faveur de la réintroduction de cépages délaissés, moyen idéal pour se démarquer d'une forme de standardisation. Le paysage composé de nos variétés classiques est donc inéluctablement appelé à évoluer. Sur quel pas de temps, dans quelles conditions ? Difficile à prédire mais il faut se rappeler que les hybrides représentaient la moitié du vignoble français dans les années 1950. Vivement demain 

Certified clone and powdery mildew impact rotundone in red wine from <i>Vitis vinifera L.</i> cv. Duras N

Aim: Few recent studies have been investigating the effect of clone on aroma compounds. The aim of this research work was to study the impact of certified clones from Vitis vinifera L. cv. Duras N on grape quality and rotundone, a sesquiterpene responsible for peppery aroma which has been reported recently in red wines made from this cultivar. Methods and results: The experimental site consisted of four consecutive rows, each row planted with one of the four certified clones of Duras N (554, 555, 627 and 654). For each clone, measurements were replicated on three experimental units per row. Each experimental unit consisted of twelve continuous vines. Rotundone concentration was measured in wines prepared by microvinification techniques (1-L Erlenmeyer flasks). For both vintages of study, rotundone concentrations were significantly higher in wines from clones 554 and 654 in comparison with clone 555, while clone 627 showed an intermediate level. In 2014, differences in powdery mildew (PM) severity on clusters were identified between the four clones and a positive logarithmic correlation (r2 = 0.58) was reported on the experimental site between rotundone in wines and PM severity on grapes. Conclusion: Our results found differences in rotundone concentrations in wines made from the four Duras N certified clones. The results also suggested that grapevine defence response to PM could enhance rotundone production in berries. Clonal differences in susceptibility to biotic stress, such as PM, might explain the differences observed in rotundone concentrations between the four studied clones. Significance and impact of the study: Our results may assist grape growers to produce high quality wines with a desired aroma attribute made from Duras N. One should consider planting clone 554 in order to promote high levels of rotundone in wines made from this cultivar

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A novel approach to discriminate the volatilome of Vitis vinifera berries by selected ion flow tube mass Spectrometry analysis and chemometrics

International audienceThis study investigated a quick way to discriminate grape varieties based on their composition in volatile compounds through a SIFT-MS scan coupled with simple chemometrics approaches such as analysis of variance (ANOVA), principal component analysis (PCA) and hierarchical ascendant classification (HAC).The 23 studied grape varieties were distinguishable using O2+, H3O+ and NO+ as reagent ions, and the combination of these three ions. For its ability to ionize most compounds, to efficiently fragment them to generate ions with distinct m/z ratio, and to enhance the differentiation of compounds of similar masses, O2+ reagent ion should be preferentially considered. The use of one single ion rather than three enables to limit the time of analysis and the number of variables to be treated. The technique allowed the distinction of high and low aroma compounds producers as confirmed by headspace solid-phase microextraction followed by gas chromatography-mass spectrometry (HS-SPME/GC-MS) analyses.SIFT-MS is a quick and interesting tool with potential application in various fields of viticulture such as phenotyping of grape varieties or non-targeted studies on the impact of environmental factors or viticultural practices on grape aroma composition

Agrobiodiversity dynamics in a French wine-growing region

International audienceAgrobiodiversity is a promising nature-based solution in the pursuit of sustainable agriculture. In wine-growing systems, commercial pressure and varietal regulations have narrowed agrobiodiversity in vineyards despite higher diversity being an important buffer against the effects of climate change. If drivers of grape diversity change are well-understood at national to global scales, little is known about the local, past or anticipated trajectories that drive agrobiodiversity dynamics depending on growers’ cultural values, practices and choices. We combined quantitative agricultural census data and qualitative ethnographic approaches to characterise changes in the diversity of grape varieties from 1960 to 2020 at the communal and vineyard levels in a French wine-growing region, and to decipher the drivers of change. We highlight that vineyards have drastically changed in 60 years, with a decline in planted area and in farm number. We outline that despite a loss of varietal richness across both vineyard and communal scales, varietal richness remains high and evenness have increased across geographic scales in 2020. Ethnographic field observations emphasize that growers account for external drivers (e.g., market changes, regulation and policy, technology, environmental), but also cultural values when they choose which grape varieties to plant. Grape diversity was maintained despite market integration as an insurance to spread production risk, mitigate market volatility and address environmental uncertainties. Securing livelihoods in the midst of market changes has been a major concern for growers over the last six decades and remains so. Despite a pessimistic future vision of the vineyard shared by most growers, the Gaillac region has a cultural heritage that values diversity and that thereby supports adaptation to climate change. We expect that environmental factors may play a more important role in grape selection and planting sites in the future under the influence of climate change and pesticide reduction policies. In order to expand individual initiatives resulting in diversified grape selection, growers need to be better connected with stakeholders at a variety of institutional levels

Expression différentielle des symptômes de la virose du court-noué chez Vitis vinifera : revue bibliographique, observations de terrain et notations en collection

La virose du court-noué, qui s’est étendue à la faveur de la reconstitution post-phylloxérique, constitue aujourd’hui une préoccupation majeure des vignobles mondiaux. La lutte directe s’avérant hors de portée à l‘heure actuelle, concernant une maladie incurable dont les vecteurs se maintiennent et restent infectieux dans le sol durant de très longues périodes, les efforts de la recherche se concentrent sur plusieurs pistes, parmi lesquelles la voie génétique semble la plus prometteuse et la plus avancée. Si la caractérisation de résistances et tolérances au sein du genre Vitis est exploitée en vue de l’obtention de porte-greffes retardant ou limitant la contamination, les différences d’expressions symptomatiques au sein des variétés de Vitis vinifera ont été très peu abordées jusqu’à présent. Dans cet article, basé sur des observations de terrain et des notations en collection, nous proposons une liste de cépages traditionnels de diverses origines peu ou très peu impactés par la maladie, dans le but de désigner du matériel d’étude pour de futurs travaux

Ozone Dissolved in Water: An Innovative Tool for the Production of Young Plants in Grapevine Nurseries?

International audienceGrapevine trunk diseases can infect nursery plants at different stages of propagation. Here, we evaluated the efficiency of aqueous ozone against two fungi associated with trunk diseases (Phaeoacremonium minimum and Phaeomoniella chlamydospora). The effect of ozone on the plant growth is also studied. Aqueous ozone completely suppressed spore germination in vitro. In planta fungal development was reduced six weeks post-inoculation. In the nursery, ozone treatment was comparable to the usual chemical treatment. Irrigation with aqueous ozone had no negative effects on plant growth. These anti-fungal properties and the absence of phytotoxicity make ozone a promising alternative for controlling microbial infection in nurseries