The benefits of a Wine Australia project that aims to ensure the sector has an ongoing supply of healthy and true-to-type planting material have been demonstrated in an offshoot project to provide virus-free planting material of Chardonnay P58 — a widely recognised and favoured selection among Australia’s premium Chardonnay producers.
Oakridge Wines, a part of Pinnacle Drinks, has co-invested in the three-year project which will see the resulting planting material used to establish source blocks for both Pinnacle Drinks and the broader grape and wine sector through the nation’s vine improvement groups and nurseries. The background of P58, also known as Penfolds 58 or simply ‘Penfolds’, is also being established as part of the project.
The ‘P58 Project’, as it has come to be known, came to life when Steve Faulkner, viticulturist for Oakridge Wines, became frustrated with the inability to consistently access grafted P58 due to virus and related propagation issues.
‘We are reliant on using grafted vines in the Yarra Valley and see P58 as an important selection for the region,” Steve explained. “When I realised that virus removal could be performed, I first spoke to [Oakridge chief winemaker] Dave Bicknell and then, with his support, approached Nick Dry from Foundation Viticulture about the potential for collaborating through the National Grapevine Collection program.”
Funded by Wine Australia since 2021, the National Grapevine Collection (NGC) program supports national, centrally-coordinated grapevine collections. These grapevine collections give the sector access to planting material with verified identity and health status, while supporting their long-term security.
Before going down the path of making virus-free selections of P58, the project first needed to confirm whether the vines believed to be P58 in Australia are indeed the selection in question. Nick Dry, coordinator of the National Grapevine Collection, said this has been no easy feat.
“For whatever reason, P58 isn’t in any of Australia’s vine improvement blocks and doesn't exist in any public grapevine collections. So, we had to look to grower vineyards, but a lack of traceability data is often inherent with these vineyards which leaves a degree of uncertainty about whether it is what we think it is,” Nick said.
“If this had come up five or 10 years ago, we would have had to take a bit of a punt. But with the development of the world’s-first grapevine clonal genetic testing by the AWRI, we have the opportunity to apply this technology to help confirm the genetic identify of P58,” he said.
The next step was to identify vineyards containing P58 which had good historical data to give a degree of certainty around the clone’s origin. The vineyards also had to be in Phylloxera Exclusion Zones so the vine material could be readily accessed for sampling.
Eventually, samples were taken from three vineyards in the Mornington Peninsula, two in the Hunter Valley and one in Bendigo in the spring of 2023.
Interestingly, the results from the genomic sequencing showed that there was diversity amongst the population of P58 which suggested that it was imported as a mass selection. Further investigations of the literature confirmed that the original P58 cuttings were imported into Australia by Penfolds from Montrachet in Burgundy, France, as a mass selection. This was supported by further investigations and interviews with the likes of Brian McGuigan whose father, Perc McGuigan, managed Penfolds’ experimental vineyard in Dalwood, in New South Wales, which was planted during the mid-‘60s. Brian recalls being involved with planting a range of varieties, including Chardonnay, from imported selections.
Nick Dry presented his findings from the P58 project to the Chardonnay Symposium at Levantine Hill Estate in Victoria’s Yarra Valley in November last year. There was keen interest in the project among attendees, resulting in a further three premium commercial P58 vineyards being added to the project for sampling.
And Nick is keen for more owners of P58 vineyards, particularly in Victoria, to come forward and offer their vines for the project, especially if the provenance of those vines can be traced not just to a nursery, but to a source block.
“We know P58 came to Dalwood, we know it went to Griffith, and we know that material was being supplied to growers, but we seem to be missing the source blocks for the vineyards we’ve sampled so far in Victoria.
“Despite reaching out to lots of people about where that original source vineyard in Victoria might be, I'm still struggling to find it. I want to get to the bottom of it.
“The good thing is we've identified two distinct genetic groups of P58, known as clades, in the samples we've taken so far. We’re confident that Clade 1 is P58 given the number of samples. We don’t have as many samples of Clade 2, but because of where those samples have come from, there's good provenance around them,” Nick said.
Once the best representation of P58 is identified, virus elimination will be performed. This clean material will then be made available to the grape and wine sector through the National Grapevine Collection. Although cuttings won’t be available until around 2030, the project serves as a valuable test case for providing virus-free, genetically-verified planting material of industry-critical grapevine clones through the NGC.