Rootstock effects on grapevine scion vigour and fruit composition are driven by a variety of root-to-shoot signals, which vary further depending on the rootstock:scion combination. This project will use a mechanistic understanding of root to shoot communication (e.g. vigour control, hormone signalling) to develop comprehension of the role of rootstock choice and grafting in the regulation of water and nutrient uptake and abiotic stress response. Rootstock selector tools will be improved with information for specific viticultural situations based on this mechanistic understanding. Existing rootstock:scion combinations will be evaluated and key traits such as vigour and specific root to shoot signalling will be identified for future breeding targets. The use of existing deficit irrigation strategies for vigour control and water use efficiency will be examined as well as the potential to develop 'precision planting' utilising multiple rootstocks within a single vineyard block based on soil type.