Effects of soil water content and environmental conditions on vine water status and gas exchange of Vitis vinifera L. cv. chardonnay

It is well known that free varietal thiols, in particular 3-mercaptohexanol (3MH) and 3-mercaptohexyl ace-tate (3MHA), are important constituents to the aroma of New Zealand Sauvignon blanc wines.

The nitrogen composition of the grapes directly affects the developments of alcoholic fermentation and influences the final aromatic composition of the wines. The aim of this study was to determine the effect and efficiency of foliar applications of urea on the nitrogen composition of grapes. This study was carried out during 2023 vintage and in the Chenin vineyard located in Estacion Experimental Mendoza (Argentina). Three urea concentrations 3, 6 and 9 Kg N/ha (C1, C2, and C3, respectively) and control (T) were applied in this vineyard at veraison. In all solutions were added 1ml/l of Tween 80 ® surfactant.

The plant surface typically comprises of various epidermal cell types which synthesise and deposit a protective waxy layer known as the cuticle. The cuticle is a significant contributor to important crop traits related to drought tolerance, biotic stress, postharvest fruit quality as well as providing structural support. In this work we have investigated grape berry cuticle formation in the context of the accumulation of anti-fungal specialised metabolites and the ability of the cuticle to structurally cope with the rapid expansion of ripening berries. Metabolic QTL analysis was performed in a grapevine cross population, using chemical profiling data collected via GC-MS analysis for cuticular waxes.

Les effets de l’état hydrique et de l’alimentation en azote sur le potentiel aromatique des raisins de Sauvignon blanc ont été mesurés sur des vignobles du Bordelais. Les déficits hydriques ont été caractérisés par le potentiel tige déterminé en milieu de journée ΨTmin)­. L’alimentation en azote a été étudiée à partir d’une zone carencée en azote. Une part de cette zone a été supplémentée avec de l’azote minéral.

The quality of wine is assessed, among other things, by its color, which is mainly due to its anthocyanin content. These pigments are polyphenols that give red, purple and blue hues depending on the relative proportion of anthocyanins produced by the action of flavonoid 3’5′ hydroxylase (delphinidin-3-glucoside, petunidin-3-glucoside, malvidin-3-glucoside) or flavonoid 3′ hydroxylase (cyanidin-3-glucoside, peonidin-3-glucoside). To study the genes involved in this biosynthetic pathway, we focused on Vitis vinifera cv. Tannat, known for producing wines with higher anthocyanin content and darker purple color compared to most red grape varieties. In this work, we have performed RNA-Seq analysis of skins during berry development, taking green and red berries at 50% veraison as separate samples, as an experimental strategy to focus on the differential expression of genes of interest.