High-resolution aerial thermography for water stress estimation in grapevines

The amino acids in grape juice are an important nitrogen source for yeast during alcoholic fermentation. Additionally, certain AAs are precursors to some of the volatile compounds found in wine and overall

AIM: Vitamins are essential compounds to numerous organisms, including yeasts, and appear highly significant during winemaking processes.

Italy is a rich hub of viticultural biodiversity harboring hundreds of indigenous grape varieties that have adapted over centuries to the diverse climatic and geographic conditions of its regions. Preserving this biodiversity is essential for maintaining a diversified genetic pool, crucial for addressing future challenges such as climate change and emerging plant diseases. Rising temperatures, precipitation pattern variations, and extreme weather events can affect grape ripening, crop quality, and contribute to disease development. Integrated disease management necessitates exploration of novel strategies. Biotechnologies emerge as a significant player in tackling modern viticulture challenges.

Grapes composition is a factor well known to affect wines composition and sensory expression. The goal of this study was to evaluate how grapes composition modifications linked to maturity level could affect wines aromatic expression and esters composition.

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.