Drought affects vineyard soil microbiome: approach to select micro-organisms adapted to drought

Phenolic compounds are fundamental to wine quality, influencing its colour, mouthfeel, stability, and ageing
potential [1]. Their extraction and evolution during fermentation plays a crucial role in determining the final sensory
attributes and requires careful monitoring to guide winemaking decisions.

High quality wines start in the vineyard however little is known about the role vineyard management practices play in this quality outcome. Gold medals and well-known regionality increase consumer preference for purchasing a wine. An increase in the former will certainly also drive an increase in the latter and therefore practices in production that consistently lead to gold medal winning wines will improve both the marketability of the region and its products. It is argued that vinification is the main driver of wine quality and in fact, the presence of some oak compounds is a well-known consumer and expert mark of quality. However, only select wines are vinified in oak and therefore the original grape quality at the winery door must in fact drive all further downstream vinification decisions.

Water use efficiency is one of the most valued objectives in vine growing in mediterranean climates (de la fuente et al., 2015). Due to this, the grape growers provide different adaptation strategies according to their efficient consumption against the presumable water deficit generated under these environmental conditions. The use of non-positioned shoot systems (like sprawl, bush, etc.) Can help to achieve this objective.

Climate change represents a major challenge for the French wine industry. Climatic conditions in French vineyards have already changed and will continue to evolve. One of the notable effects on grapevine is the advancing growing season. The aim of this study is to characterise the evolution of agroclimatic indicators (Huglin index, number of hot days, mean temperature, cumulative rainfall and number of rainy days during the growing season) at French wine-growing regions scale between 1980 and 2019 using gridded data (8 km resolution, SAFRAN) and for the middle of the 21th century (2046-2065) with 21 GCMs statistically debiased and downscaled at 8 km. A set of three phenological models were used to simulate the budburst (BRIN, Smoothed-Utah), flowering, veraison and theoretical maturity (GFV and GSR) stages for two grape varieties (Chardonnay and Cabernet-Sauvignon) over the whole period studied. All the French wine-growing regions show an increase in both temperatures during the growing season and Huglin index. This increase is accompanied by an advance in the simulated flowering (+3 to +9 days), veraison (+6 to +13 days) and theoretical maturity (+6 to +16 days) stages, which are more noticeable in the north-eastern part of France. The climate projections unanimously show, for all the GCMs considered, a clear increase in the Huglin index (+662 to 771 °C.days compared to the 1980-1999 period) and in the number of hot days (+5.6 to 22.6 days) in all the wine regions studied. Regarding rainfall, the expected evolution remains very uncertain due to the heterogeneity of the climates simulated by the 21 models. Only 4 regions out of 21 have a significant decrease in the number of rainy days during the growing season. The two budburst models show a strong divergence in the evolution of this stage with an average difference of 18 days between the two models on all grapevine regions. The theoretical maturity is the most impacted stage with a potential advance between 40 and 23 days according to wine-growing regions.

Deir El Ahmar, Bekaa Valley, Lebanon (1000 – 1100 m a.s.l.), is a semi-arid viticultural region characterized by harsh agroclimatic conditions.