Exploring the factors affecting spatio‐temporal variation in grapevine powdery mildew

Climate change has become a reality that is becoming more and more apparent every day, with changes in the physico-chemical composition of grapes and an increase in the alcohol content of finished wines. These higher alcoholic degrees are not without consequences for the success of alcoholic and malolactic fermentation. Correcting the alcohol content (-20% of the initial alcoholic strength) is also part of an approach designed to meet consumer expectations for healthier, lighter or lower-alcohol wines (9 to 13% vol.). Correcting the alcohol content of wines also rebalances the mouthfeel by reducing the alcohol’s burn.

Global grape production amounts to approximately 70 million tons per year, with Europe contributing 61% of the world’s wine output, primarily from Italy, France, and Spain.

AIM Verdicchio and Lugana are two Italian white wines produced in the Marche and Garda lake regions respectively. They are however obtained using grape varieties sharing the same genetic background, locally known as Verdicchio in Marche and Trebbiano di Soave in Garda. Anecdotal evidence suggests that these two wine types exhibit distinctive aroma features. The aim of this work was to explore the existence of a recognizable odour profile for Lugana and Verdicchio, and whether specific aroma chemical markers could be identified. METHODS 13 commercial wines, 6 Lugana and 7 Verdicchio were used. Sensory analysis was done using sorting task methodology, assessing only odor similarities. A total of 53 volatile compounds were identified and quantified GC-MS analysis. Aging behaviors were also evaluated after an accelerated aging at 40 ° C for 3 months. RESULTS HCA analysis of sorting task data identified indeed two groups: one characterized by floral and minty notes and mostly associated with Lugana wines, the other characterized by spicy and toasted aromas and mostly associated with Verdicchio. From a chemical point of view, major differences between the two wines types were observed for cis-3-hexenol, methionol, phenylethyl alcohol, and geraniol.

This synthetic presentation deals with :
• A description of the variability and the main models of grapevine canopy architecture in the world.
• A precision on the model « potential exposed leaf area SFEp », which estimates the potential of net carbon balance of the plant, and shows a regulating effect of high SFEp levels on production decrease.

Les fromages d’Appellation d’Origine Contrôlée (AOC) représentent un enjeu économique important pour la filière laitière (11 % des fromages produits en France sont des fromages d’AOC, et dans certaines régions de montagne, cette proportion dépasse 50 %). Les spécificités de ces fromages et leurs liaisons avec les caractéristiques du terroir constituent un système complexe où interagissent en particulier la technologie fromagère et les caractéristiques des laits (composition chimique en particulier). Ces dernières dépendent elles-mêmes des caractéristiques des animaux (origine génétique, facteurs physiologiques, état sanitaire) et de leur mode de conduite (alimentation, hygiène, traite…) (fig. 1). L’influence de ces facteurs de production (alimentation et type d’animal en particulier) sur les caractéristiques des fromages est fréquemment mise en avant par les fromagers, sur la base d’observations empiriques. Il existe cependant très peu de travaux expérimentaux sur le sujet, en raison, entre autres, de la difficulté de séparer correctement les effets propres de ces facteurs d’amont de ceux liés à la technologie fromagère.