Jim White from Cloudy Bay recently presented at the 2025 Australian Wine Industry Technical Conference, focusing on the promising future of disease-resistant grape varieties (DRVs), often referred to as PIWIs. This topic is gaining traction in Europe and gaining attention in Australia and New Zealand. White emphasized the environmental benefits, stating that this could signal a significant shift in the wine industry.
Historically, the introduction of powdery and downy mildew to Europe in the 19th century led to a reliance on pesticides for Vitis vinifera varieties. Unlike other Vitis species that have developed resistance over time, Vitis vinifera lacks the necessary resistance genes. In contrast, DRVs incorporate these resistance genes to block disease progression upon recognizing pathogens.
White outlined four potential methods for improving plant disease resistance:
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Cross-Breeding: This traditional method involves hybridizing Vitis vinifera with disease-resistant species from America or Asia, taking approximately 25 years to produce new varieties.
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Mutation Breeding: This method involves stressing plant meristems to induce mutations. While many resulting mutants may not be viable, some can exhibit desirable traits. For instance, the Bragato Institute in Marlborough, New Zealand, is experimenting with this method by planting 6,000 clones for evaluation over about eight years.
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Transgenics: Genetic modification to incorporate resistance genes from American and Asian varieties is another approach. Although this technology has seen success in Australia, it has not yet been implemented in vineyards due to societal readiness concerns.
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Genome Editing: This modern approach employs CRISPR-Cas9 technology to target and remove susceptibility genes, potentially halting infection processes. Just five to seven years may be needed to realize this method, although progress is complicated by public sentiment and regulatory frameworks.
Focusing on hybrid breeding, current programs aim to combine preferred Vitis vinifera varieties with disease-resistant variants. This involves checking for the presence of resistance genes during generations of back-crossing to enhance Vitis vinifera parentage while ensuring resistance.
The ultimate objectives include stacking multiple resistance genes to combat evolving pathogens and ensuring good agronomic performance, such as appropriate yield, growth conditions, and organoleptic properties of the resulting wine. Effective management in vineyard settings is still necessary to prevent pathogen resistance.
Historically, the hybridization between Vitis vinifera and American/Asian species started in response to phylloxera, resulting in the first generation of hybrids that, while disease-resistant, did not produce the highest quality wines. Despite that, their ease of cultivation led to significant plantings in France before their eventual ban.
Later generations of DRVs released in Germany and success stories from Italy and France have renewed interest, with Italy currently having 8,000 to 10,000 hectares of DRVs planted. White’s experiences with the world’s largest vine nursery in Italy show the potential scale of DRV production, with significant numbers of grafted vines being produced.
Australia has also started to follow suit, with CSIRO focusing on DRVs since the early 2000s, now aiming to stack resistance genes for improved outcomes. Collaborations with nurseries in Australia and New Zealand are bringing established European DRVs into the region.
A key consideration remains labelling. While Italy often uses familiar varietal names for resistant varieties, France enforces stricter labeling regulations to prevent consumer confusion. If successful, a Cloudy Bay Sauvignon crafted from a disease-resistant variety may hit the market in a few years, promoting a more environmentally sustainable production approach.