Zonage vitivinicole: recherches et considérations initiales sur une proposition de “nouvelle” méthodologie d'”évaluation de la qualité” du produit tel qu’élément base pour le zonage aussi

Since the arrival of Phyloxera (Daktulosphaira vitifolia) in Europe at the end of the 19th century, grafting has become essential to cultivate Vitis vinifera. Today, grafting provides not only resistance to this aphid, but it used to adapt the cultivars according to the type of soil, environment, or grape production requirements by using a panel of rootstocks. As part of vineyard decline, it is often mentioned the importance of producing quality grafted grapevine to improve vineyard longevity, but, to our knowledge, no study has been able to demonstrate that grafting has a role in this context. However, some scion/rootstock combinations are considered as incompatible due to poor graft union formation and subsequently high plant mortality soon after grafting. In a context of climate change where the creation of new cultivars and rootstocks is at the centre of research, the ability of new cultivars to be grafted is therefore essential. The early identification of graft incompatibility could allow the selection of non-viable plants before planting and would have a beneficial impact on research and development in the nursery sector. For this reason, our studies have focused on the identification of metabolic and transcriptomic markers of poor grafting success during the first days/week after grafting; we have identified some correlations between some specialized metabolites, especially stilbenes, and grafting success, as well as an accumulation of some amino acids in the incompatible combination. The study of the metabolome and the transcriptome allowed us to understand and characterise the processes involved during graft union formation.

The French “Coteaux du Layon” Appellation of Origin has built its Jarne on the production of sweet white wines. A network of experimental plots, based on the “terroir” concept, was established in 1990; it allows for the follow-up of the overripening behaviour of the grapes in relation with the agroviticultural parameters.

Wines with tropical fruit aromas have become increasingly more available1,2. With increased availability of different wine styles, it has become important to understand the compounds that cause the fruity aromas in wine. Previous work using micro fermentations showed that fermentation temperature gradients and time on skins resulted in an increase in thiol and ester compounds post fermentation and these compounds are known to cause tropical fruit aroma in wines³. This work aimed to scale up these fermentations/operations to determine if the desired aromas could still be achieved and if there is a perceivable difference in tropical fruit aromas, liking, and emotional response in the wines at the consumer level.

Grapevine breeding focuses on high wine quality and climate-adapted grapevine varieties with fungal disease resistances to be cultivated in a pesticide-reduced and sustainable viticulture.

In the face of climate change, new grapevine varieties will have to show an adaptive phenotypic plasticity to maintain production with erratic water resources, and still ensure the quality of the final product. Their selection requires a better knowledge of the genetic basis of those traits and of the elementary processes involved in their variability. ‘PlastiVigne’, an emblematic project of the Vinid’Occ key challenge, funded by the Occitanie Region (France), tackles this issue with innovative genomic and physiological tools implemented on a unique panel of grape genetic resources representing the genetic diversity of Vitis vinifera. A graph-pangenome is developed from a representative set of high-quality genomes to study the extent and impact of structural genome variations and chromosomal rearrangements in the rapid adaptation capacity of grapevine.