Viticultural zoning applications at the detailed scale of a cooperative winery: terroirs in St­hilaire-d’Ozilhan (AOC Côtes-du-Rhône)

In order to study the impact of climate change on Bordeaux grape varieties and to assess the adaptation capacities of candidates to the grape varieties of this wine region to the new climatic conditions, an experimental block design composed of 52 grape varieties was set up in 2009 at the INRAE Bordeaux Aquitaine center. Among the many parameters studied, the three main phenological stages of the vine (budburst, flowering and veraison) have been closely monitored since 2012. Observations for each year, stage and variety were carried out on four independent replicates. Precocity indices have been calculated from the data obtained over the 2012-2021 period (Barbeau et al. 1998). This work allowed to group the phenological behaviour of the grapevine varieties, not only based on the timing of the subsequent developmental stages, but also on the overall precocity of the cycle and the total length of the cycle between budburst and veraison. Results regarding the variability observed among the different grape varieties for these phenological stages are presented as heat maps.

The wine industry, a key sector for the European Union’s economy, exhibits significant energy consumption, amounting to approximately 1,750 million kWh annually within this geographic context, with major contributions from Italy, France, Spain, and Portugal (Fuentes Pila et al., 2015).

Drought and heat waves deriving from climate change have been affecting grapevine plants and altering wine characteristics in the past years, and effects are expected to get worst. Innovative approaches to address this problem have been undertaken in several varieties, that consist in exploring intravarietal variability to identify genotypes that are tolerant to abiotic stress. Such is the case of the variety Arinto, where an experimental population of 165 clones installed according to a resolvable row-column design with 6 replicates, was scanned for several parameters, including surface leaf temperature (SLT). Linear mixed models were fitted to the data of the traits evaluated, and the empirical best linear unbiased predictors (EBLUPs) of genotypic effects for each trait were obtained as well as the coefficient of genotypic variation (CVG) and broad sense heritability.

The influence of climatic conditions on the development of the vine and on the quality of the wines no longer needs to be demonstrated at the scale of the vineyard, by the regional climatic characteristics, determining on this scale the viticultural potentialities (Huglin, 1978; Branas, 1946; Riou et al ., 1994); but also on a local scale, at the level of the basic terroir unit (Morlat, 1989), by the landscape differentiation of the natural environment inducing climatic variability within the same vineyard, and partly explaining differences in functioning of the vine, in connection with the processes of maturation and the quality of the wine (Becker, 1977 and 1984; Morlat, 1989 and Lebon, 1993a). According to these authors, the climatic diversity in a wine region constitutes in addition to the edaphic component, an important component of characterization of the Basic Terroir Units (UTB).

Wine aroma is influenced by several viticultural and oenological factors. In this study we used experimental wine making in a full factorial design to determine the impact of grapevine age, must turbidity, and yeast strain on the aroma of Vitis vinifera L. cv. Riesling wines. A recently developed, non-targeted SPME-GC-MS fingerprinting approach for wine volatiles was used. This approach includes the segmentation and mathematical transformation of chromatograms in combination with Parallel Factor Analysis (PARAFAC) and subsequent deconvolution of important chromatogram segments.