Temperature variability inside a wine production area and its effect on vine phenology and grape ripening. An example from the Saint-Emilion-Pomerol

The spine grapes (Vitis davidii Foëx.) are wild grape species that grow in southern China, and can be used for table grapes, juicing and winemaking. To systematically investigate the flavor profiles of spine grapes, flavonoids and volatile compounds were detected in five spine grape varieties (Seputao, Ziqiu, Miputao, Tianputao and Baiputao) using HPLC-QqQ-MS/MS and GC-MS. The content of these compounds highly depended on the variety, such as the total concentrations of anthocyanins (91.43-328.85 mg/kg FW) and free norisprenoids (2.60 to 11.46 μg/kg FW).

Knowledge of vine reaction to plant spacing under high potential soil conditions is restricted. This study was done to determine effects of vine spacing

ln the Mid-Loire Valley, in France, for the fast twenty years a network of experimental plots has been used to analyse the terroir effect on the behaviour of the Cabernet franc variety of grape. The study of the primary leaf area (SFI) for several vintages shows that it differs greatly from one terroir to another.

Rotundone is the main aroma compound responsible for peppery notes in wines whose biosynthesis is negatively affected by heat and drought. Through the alteration of precipitation regime and the increase in temperature during maturation, climate change is expected to affect wine peppery typicality. In this context there is a demand for developing sustainable viticultural strategies to enhance rotundone accumulation or limit its degradation. It was recently proposed that ultraviolet (UV) radiations could stimulate rotundone production. The aim of this study was to investigate under field trial conditions the impact of grape exposure and UV treatments on rotundone in Vitis vinifera L. Tardif, an almost extinct grape variety from south-west France that can express particularly high rotundone levels. Four different treatments were compared in 2021 to a control treatment using a randomised complete block design with three replications per treatment. Grape exposure was manipulated through early or late defoliation. Leaf and laterals shoots were removed at Eichorn Lorenz growth stages 32 or 34 on the morning-sun side of the canopy. During grape maturation, UV radiations were either reduced by 99% by installing UV radiation-shielding sheets, or applied four times using the Boxilumix™ non thermal device (Asclepios Tech, Tournefeuille) with the aim of activating plant signalling pathway. Loggers displayed in solar radiation shields were used to assess the effect of such shielding sheets on air temperature within the bunch zone. The composition of grapes subjected to these treatments will be soon analysed for their rotundone content and basic classical laboratory analyses. Grapes will be harvested to elaborate wines under standardized small-scale vinification conditions (60kg) that will be assessed by a trained sensory panel.

Vineyard water management in Australia is often associated with irrigation in warm and hot climates, but in cooler regions the larger share of the seasonal water demand is met by rainfall.