Evaluation de différents clones du Chardonnay pendant la maturation dans un terroir viticole du Friuli-Venezia Glulia (Nord-Est de l’Italie)

– Several practices can be applied to vineyards in order to ensure good healthy for grapevines, adequate yield and fruit quality. Among them, the use of cover crops is a relevant option for soil management. It increases the organic matter, improves water infiltration, reduces risks of soil erosion and greenhouse gas emissions, in addition improving biodiversity in the vineyard.

Wine growing regions have recently faced intense and frequent droughts that have led to substantial economical losses, and the maintenance of grapevine productivity under warmer and drier climate will rely notably on planting drought-resistant cultivars. Given that plant growth and yield depend on water transport efficiency and maintenance of photosynthesis, thus on the preservation of the vascular system integrity during drought, a better understanding of drought-related hydraulic traits that have a significant impact on physiological processes is urgently needed. We have worked towards this end by assessing vulnerability to xylem embolism in 30 grapevine commercial varieties encompassing red and white Vitis vinifera varieties, hybrid varieties characterized by a polygenic resistance for powdery and downy mildew, and commonly used rootstocks. These analyses further allowed a global assessment of wine regions with respect to their varietal diversity and resulting vulnerability to stem embolism. Hybrid cultivars displayed the highest vulnerability to embolism, while rootstocks showed the greatest resistance. Significant variability also arose among Vitis vinifera varieties, with Ψ12 and Ψ50 values ranging from -0.4 to -2.7 MPa and from -1.8 to -3.4 MPa, respectively. Cabernet franc, Chardonnay and Ugni blanc featured among the most vulnerable varieties while Pinot noir, Merlot and Cabernet Sauvignon ranked among the most resistant. In consequence, wine regions bearing a significant proportion of vulnerable varieties, such as Poitou-Charentes, France and Marlborough, New Zealand, turned out to be at greater risk under drought. These results highlight that grapevine varieties may not respond equally to warmer and drier conditions, outlining the importance to consider hydraulic traits associated with plant drought tolerance into breeding programmes and modeling simulations of grapevine yield maintenance under severe drought. They finally represent a step forward to advise the wine industry about which varieties and regions would have the lowest risk of drought-induced mortality under climate change.

Regarding the food quality, authenticity is one of the most important issues in the context of ensuring the safety and security of consumers, but is also more important when it comes to wine (one of the most counterfeited foods in the world).

Over the past two decades, climate change has contributed to an increase in sugar content in grape must, and consequently, in the ethanol levels of wines.

L’étude des relations Terroir – Vigne – Raisin est complexe. La recherche et le développement des facteurs qualitatifs qui influencent le caractère des vins sont multiples. Divers travaux mettent en évidence la relation entre l’alimentation en eau de la plante, son développement végétatif et les caractéristiques de ses raisins.