Cumulative effects of repeated drought stress on berry composition, and phenolic profile: Field experiment insights

L’étude du comportement physiologique et agronomique de la vigne (cv. Chasselas) a été réalisée en 2001 par la Station fédérale de recherches en production végétale de Changins sur divers terroirs viticoles vaudois (Suisse), dans le cadre d’un projet d’étude des terroirs viticoles vaudois en collaboration avec le bureau I LETESSIER (SIGALES) à Grenoble et l’École polytechnique fédérale de Lausanne (EPFL).

To improve its sustainability, viticulture should increase the provision of ecosystem services to decrease its use of inputs and the resulting environmental impact while maintaining high socio-economic performance. Soil functions in relation with their physical, chemical and biological properties can be regulated by proper soil surface management.

The study was carried out in 2006 with Merlot grapes from vines grown using the trellis system, where four treatments were compared with different levels of water stress.

In a previous work1, it was suggested that the different contents in delphinidin and catechin of the grapes were determinant on the O2 consumption and Strecker aldehyde (SAs) accumulation rates. Higher delphinidin seemed to be related to a faster O2 consumption and a smaller SAs accumulation rate, and the opposite was observed regarding catechin.
In the present paper, these observations were fully corroborated by adding synthetic delphinidin to a wine model containing polyphenolic fractions (PFs) extracted from garnacha and synthetic catechin to a wine model containing PF extracted from tempranillo: The delphinin-containing garnacha model consumed O₂ significantly faster and accumulated significantly smaller amounts of SAs than the original garnacha model, and the catechin-containing tempranillo model, consumed O2 significantly slower and accumulated significantly higher amounts of SAs than the original tempranillo model.

The application of sensors in viticulture is a fast and efficient method to monitor grapevine vegetative, yield and quality parameters and determine their spatial intra-vineyard variability. Molecular analysis at the gene expression level can further contribute to the understanding of the observed variability by elucidating how pathways responsible for different grape quality traits behave in zones diverging for one or the other parameter. The intra-vineyard variability of a Cabernet Sauvignon vineyard was evaluated by a standard Normalized Difference Vegetation Index (NDVI) mapping approach, employing UAV platform, accompanied by detailed ground-truthing (e.g. vegetative, yield, and berry ripening compositional parameters) that was applied in 14 spots in the vineyard. Berries from different spots were additionally investigated by microarray gene expression analysis, performed at five time points from fruit set to full ripening.