Université de Bordeaux
LabEx COTECluster of Excellence
Cluster of excellence

VitisDroughtAdapatation (EGFV / ISPA)

Understanding grapevine varietal differences in response to soit water and vapor pressure deficit (VPD) under drought.

Climate change will impose increasingly challenging environmental conditions to natural plant species and cultivated crops. Temperatures will încrease worldwide by up to 4°C towards the end of the century. Rainfall patterns will be modified with marked regional differences. However, even in regions with unchanged rainfall, plants wiJl be subjected to increased drought because of a general increase in potential evapotranspiration (ET0) , as a direct consequence of increased temperatures. Eco- and agro-systems will have to adapt to these new conditions. For agriculture, growers will need to develop new strategies in order to secure yields and crop quality. In the long tenn, irrigation is not a sustainable option, because of increasingly limited water resources. Instead, the choice of drought resistant plant material is a sustainable and environmentaHy friendly way to adapt crops to increased drought occurrences. In winegrowing, conventional wisdom recognizes important differences among cultivars in tenns of drought resistance. These are most likely related to differences in vine water transport capacîty (hydraulic conductance) and the abîlity of varieties to maintain their leaf water status (water potential) over the course of the day through stomatal control of transpiration. To date, no classification based on physiological measurable parameters exists to help growers in comparing performances of varieties in tenns of yield, grape quality, and resistance to mortality witb regard to drought. This project focusses on unravelling varietal differences in stomatal responses to soil water availability and atmospheric demand for water (vapour pressure deficit). The objective is to utilize a common garden to classify 50 widely planted varieties for tbeir stomatal control in both well-watered and drought conditions. This classification will belp growers select appropriate plant materials and design and manage their vineyards better in the face of changing climate.

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