Dr. Smith has completed his PhD in genetics and acquired substantial research experience in cellular, molecular, and plant developmental biology in the United States. In 2012, he relocated to Adelaide to spearhead the Rootstock Breeding Team at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), focusing on the creation of climate-resilient rootstocks that offer long-term resistance to grape phylloxera and root knot nematode, specifically designed for Australian environments. He remarked, ‘We’re at a point where innovation in rootstock breeding isn’t just a luxury – it’s essential for the future of viticulture in an evolving climate.’
Currently, the majority of rootstocks utilized in vineyards were developed over a hundred years ago in Europe, and they lack the genetic diversity necessary to sustain immunity against soil pests for extended periods due to their reliance on a single resistance trait.
For instance, in California, vineyards that were planted with rootstocks like Freedom and Harmony, which possess a single resistance gene against root knot nematodes, initially offered protection from this soil pest. However, over time, certain local populations of root knot nematodes in the soil evolved and overcame the resistance provided by this singular trait.
‘The challenge lies in the fact that pests like root knot nematodes and phylloxera can evolve and adapt to feeding on plants with a single resistance gene, making it crucial for us to develop rootstocks that can sustain resistance over prolonged periods,’ Dr. Smith said, stressing the pressing nature of his research.
Furthermore, climate change is introducing additional challenges for managing vineyards. During drought conditions, water scarcity affects vineyards significantly. When water supplies dwindle, the quality often declines due to increased salinity. Elevated soil temperatures can also compromise the resistance to root knot nematodes and diminish salinity tolerance in certain rootstocks. “Climate change represents not just a set of immediate and future challenges; it is a dynamic force that continually affects vineyard performance every day,” noted Dr. Smith.
To protect vineyards from pests, Harley’s team is employing a breeding method aimed at combining phylloxera and root knot nematode resistance traits into a range of genetically varied rootstocks. They have pinpointed various traits related to these pests from diverse parental breeding lines and are utilizing DNA markers associated with these traits to integrate them into future rootstocks. “Our objective is to create genetically diverse rootstocks that offer long-term resistance to phylloxera and root knot nematodes, ensuring the sustainability of Australian vineyard production,” Dr. Smith elaborated.
To mitigate the effects of climate events on vineyard productivity caused by inferior water quality, Harley’s team has also discovered salinity-tolerant genes and is using DNA markers to combine these genes with resistance traits. Moreover, they have set up in-vitro and greenhouse testing systems to select rootstocks that maintain resistance to root knot nematodes and salinity tolerance even at elevated soil temperatures. Additionally, water deficit field trials will be used to identify rootstocks that thrive with reduced irrigation.
Interestingly, the choice of rootstocks can also impact the quality of the grapes and wine produced. “Different rootstocks can modify flavour profiles and significantly affect the color of red wines, which adds further complexity to the selection of new rootstocks,” explained Dr. Smith. This highlights the necessity of conducting field trials to evaluate rootstocks, not only for their yield-related characteristics but also for their influence on grape and wine quality aspects.
Following the assessment and selection of these rootstocks, Harley’s team is optimistic that they will be ready for availability by the year 2032. Supported by funding from Wine Australia and CSIRO, Harley and his team are collaborating with various sectors to create pathways for adoption, ensuring that Australian wine grape producers can access the new rootstock options once they are launched.
The research led by Dr. Smith and his colleagues at CSIRO marks a pivotal advancement in the future of viticulture, especially in response to climate change and changing pest challenges. Their cutting-edge method of breeding rootstocks, which emphasizes the combination of multiple resistance traits and the tackling of climate-induced issues, presents a sustainable approach aimed at preserving wine grape production in Australia.
These new rootstocks, designed to enhance pest resistance along with improving the quality of grapes and wine, will provide farmers with the tools necessary to adjust grape cultivation practices in a changing climate. As the industry eagerly looks forward to the rollout of these rootstocks by 2032, it is evident that Dr. Smith’s initiatives are set to foster a more robust and sustainable future for wine production.