Shades of shading: chemical and sensory evaluation of riesling grown under various shading techniques

Wine growing regions have recently faced intense and frequent droughts that have led to substantial economical losses, and the maintenance of grapevine productivity under warmer and drier climate will rely notably on planting drought-resistant cultivars. Given that plant growth and yield depend on water transport efficiency and maintenance of photosynthesis, thus on the preservation of the vascular system integrity during drought, a better understanding of drought-related hydraulic traits that have a significant impact on physiological processes is urgently needed. We have worked towards this end by assessing vulnerability to xylem embolism in 30 grapevine commercial varieties encompassing red and white Vitis vinifera varieties, hybrid varieties characterized by a polygenic resistance for powdery and downy mildew, and commonly used rootstocks. These analyses further allowed a global assessment of wine regions with respect to their varietal diversity and resulting vulnerability to stem embolism. Hybrid cultivars displayed the highest vulnerability to embolism, while rootstocks showed the greatest resistance. Significant variability also arose among Vitis vinifera varieties, with Ψ12 and Ψ50 values ranging from -0.4 to -2.7 MPa and from -1.8 to -3.4 MPa, respectively. Cabernet franc, Chardonnay and Ugni blanc featured among the most vulnerable varieties while Pinot noir, Merlot and Cabernet Sauvignon ranked among the most resistant. In consequence, wine regions bearing a significant proportion of vulnerable varieties, such as Poitou-Charentes, France and Marlborough, New Zealand, turned out to be at greater risk under drought. These results highlight that grapevine varieties may not respond equally to warmer and drier conditions, outlining the importance to consider hydraulic traits associated with plant drought tolerance into breeding programmes and modeling simulations of grapevine yield maintenance under severe drought. They finally represent a step forward to advise the wine industry about which varieties and regions would have the lowest risk of drought-induced mortality under climate change.

Knowledge of the reflectance spectrum of grape leaves is important to the identification of grape varieties in images of viticultural regions where several cultivars co-exist.

Grapevine (Vitis vinifera L.) is a challenging plant species to transform and regenerate due to its complex genome and biological characteristics. This limits the development of cisgenic and gene-edited varieties. One hurdle is selecting the best starting tissue for the transformation process, much like isolating suitable tissue for protoplasts. One promising method involves delivering crispr/cas components to protoplasts isolated from embryogenic calli, which are then induced to regenerate.

Una de las biotecnologías más potentes para disminuir el pH en vinos de zonas cálidas y en variedades de pH elevado es el uso de la levadura no-saccharomyces lachancea thermotolerans. Esta especie es capaz de formar ácido láctico a partir de azúcares, reduciendo al mismo tiempo ligeramente el grado alcohólico. Por lo tanto, mejora dos de los principales problemas de los vinos de regiones afectadas por el calentamiento global. El ácido láctico es un ácido orgánico con una buena integración sensorial en el sabor del vino, y también química y biológicamente estable durante el envejecimiento del vino.

En Anjou, une méthode de caractérisation des terroirs viticoles a été développée. Elle utilise un modèle de terrain basé sur la profondeur de sol et son degré d’argilisation. Le modèle concerne des terrains issus principalement de roches mères métamorphiques et éruptives du Massif Armoricain. Cet outil de caractérisation des terroirs viticoles nécessite d’être adapté lorsqu’il s’agit d’ensembles géologiques très différents, en particulier sur sols d’apport et de roches mères tendres et poreuses du Bassin Parisien. Une meilleure compréhension de la réserve hydrique des sols apparaît être un critère important de l’interaction entre le milieu et la plante.