Soil or geology? And what’s the difference? Some observations from the New World

Understanding grapevine responses to increasing atmospheric CO2 (aCO2) concentrations is crucial for assessing the impact of climate change on viticulture. Previously, at the VineyardFACE (Free Air Carbon dioxide Enrichment) experiment in Geisenheim, leaf gas exchange measurements were made as Vitis vinifera cv. Cabernet Sauvignon established from planting (2014 to 2016) under aCO2 or elevated CO2 (eCO2, aCO2 + 20%) concentrations. Contrary to many preceding observations with grapevines and other perennial plant species the young vines showed an increased intrinsic water use efficiency (WUEi) that was mainly associated with an increase in net assimilation (A) rather than a decrease in stomatal conductance (gs) under eCO2.

Germicidal ultraviolet-C (UV-C) light has shown promising results for suppression of several plant-pathogenic microorganims, including Erysiphe necator, which attacks grapevine. In Washington State the majority of winegrape production is in a semi-arid steppe environment, with historically low powdery mildew disease pressure, making it a promising area to deploy UV-C as a disease management tool. Trials focusing on UVC application timing and frequency will assist in developing regionally-appropriate application recommendations for eastern Washington State.

Disease resistant hybrid grape cultivars are now allowed in a number of EU wine PDOs, and are also accepted in a number of countries outside the EU. There is increasing interest in diseases resistant hybrid grape cultivars (RHGCs) because they allow for the production of healthy, high quality grapes with limited use of pesticides and the associated environmental and public health

Production of volatile compounds by yeast is known to be modulated by must nitrogen. Nevertheless, various parameter of must quality have an impact on yeast fermentation. In this study we propose to evaluate the impact of nitrogen / lipids balance on a Sauvignon Blanc grape juice (Val de Loire).
Must was prepared from the same grapes at pilot scale. Three modalities were carried out: direct pressing, direct pressing with a pre-fermentation cold stabulation and pellicular maceration before pressing.

Un grand nombre de travaux ont été consacrés à la mise en éyidence et à la quantification de l’effet du climat sur la qualité de la production viticole. IIs ont permis de caractériser les grands types de production à une large échelle géographique, et d’en évaluer les variations interannuelles au niveau des millésimes.