Behaviour of two training systems for mechanical pruning combined with different nitrogen fertilizations on cv. Colombard

AIM: Bonarda, the second red grape variety in Argentina, produces high yields per hectare generating, in several cases, wines with low levels of quality compounds.

Dehydrodicatechins have recently received attention as oxidation markers especially in grapes and wine. Their analysis mainly uses LC-MS/MS which is able to differentiate them from their natural isomers (dimeric procyanidins), based on specific fragments

Previous work from our laboratory has shown that both a purified toasted oak powder and extracts made from unoaked and oaked red wines influenced physiological parameters, metabolism and hepatic gene expression in high-fat fed C57/BL6J male mice (Luo et al., 2020).  Impacted pathways included glucose metabolism, liver fat accumulation, markers of chronic inflammation, and expression of the Gsta1 mRNA.  

Pinot noir is an interesting vat variety for the high quality products it provides in the most suitable areas. In France, the most important Pinot Noir growing areas are Burgundy, Champagne, Alsace and the Loire. In Italy, Pinot Noir is grown almost exclusively in the northern regions of Trentino-Alto Adige, Lombardy and Friuli-Venezia Giulia.

As elsewhere, southwestern France vineyards face more recurrent summer heat waves these last years. Among the possibilities of adaptation to this climate changing parameter, the use of net shading is a technique that allow for limiting canopy exposure to radiations. In this trial, we tested net shading installed on one face of the canopy, on a north-south row-oriented plot of cv. Gros Manseng trained on VSP system in the PDO Pacherenc-du-Vic-Bilh. The purpose was to characterize the effects on the ambient canopy temperatures and radiations during the season and to observe the consequences on the composition of grapes and wines. Two sorts of net were used with two levels of obstruction (50% and 75%) of the photosynthesis active radiation (PAR). They have been installed on the west side of the canopy and compared to a netless control. Temperature and PAR sensors registered hourly data during the season. On specific summer day (hot and sunny) manual measurements took also place on bunches (temperature) and in different spots of the canopy (PAR). The results showed that, on clear days, the radiation is lowered by the shade nets respecting the supplier criteria. The effects on the ambient canopy temperature were inconstant on this plot when we observed the data from the global period of shading between fruit set and harvest. However, during hot days (>30°C), the temperature in the canopy was reduced during afternoon and the temperature of the bunch surface was reduced as well comparing to the control. A decrease of the maturity parameters of the berries, sugar and acidity, was also observed. Concerning the wine aromatic potential, no differences clearly appeared.