This project will further develop the understanding of the role of rootstock choice and grafting in the regulation of water and nutrient uptake and abiotic stress response, based on a mechanistic understanding of root to shoot communication.
In addition to providing protection against nematodes and phylloxera, rootstocks are being selected for a range of other traits, including vigour and tolerance to abiotic stresses such as drought and salinity. Rootstock effects on scion vigour and fruit composition are driven by a variety of root-to-shoot signals, which vary further depending on the rootstock:scion combination. The scion response to soil water deficit is governed by root hormone signals, while rootstock conferred vigour is governed by a mechanism yet to be fully elucidated, but likely to involve hydraulics.
As the parent material of commonly utilised rootstocks originates in varied natural environments from wetlands to arid environments it is also likely that root signals of different genotypes vary in response to a given soil environment or stress. Better utilisation of these differences, based on an improved understanding of the processes and their regulation, provides an opportunity to improve rootstock choice for specific environments and develop management strategies for specific viticulture purposes.
Rootstock selector tools will be improved with information for specific viticultural situations based on a mechanistic understanding of root to shoot communication (e.g. vigour control, hormone signalling). 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.
Improved rootstock choice for planting or replanting, reducing post-establishment difficulties in crop management through greater surety of vine growth, production and response to the environment.