An innovative research project underway in Western Australia hopes to provide the first real evidence as to whether viral infection has any beneficial impact on the final wine produced, particularly with the Gingin Chardonnay clone.
At the very least, this Incubator Initiative project will start an important conversation around disease management practices, particularly if viral infection is found to be favourable to the wine quality from the Gingin Chardonnay clone.
Introduced in 1957, the Gingin clone is generally acknowledged to be a contributing factor to the high quality of Western Australian Chardonnay, particularly Chardonnay from Margaret River.
The attributes associated with the clone – poor fruit set, millerandage, low yields and unique wine style – are widely believed to be due to an interaction with one or more grapevine viruses.
Dr Monica Kehoe is investigating whether viral infections in the Gingin Chardonnay clone have a beneficial impact on the final wine produced.
Dr Kehoe’s project, funded by Wine Australia and developed in collaboration with the Western Australia Regional Program cluster, is specifically investigating whether viral infections in the Gingin clone influence vine phenotype, performance and subsequent wine quality.
‘We know that grapevine leafroll viruses GLRV1 and GLRV3 cause reduced fruit quality and yields and that these viruses are common in vineyards around Australia. However, the effects of the viral infection on overall wine quality are less well understood and the very little research in the area focuses mainly on red varieties, not white’, Dr Kehoe, a researcher with the Western Australia Department of Primary Industries and Regional Development, said.
So far Dr Kehoe and her team have completed the initial survey for the project, and have selected a number of vines to monitor between now and harvest.
‘The vines will be tested once more at harvest to be sure that we are picking with or without virus, and then we will make small batch wines for sensory evaluation’, she said.
Dr Kehoe said the results of her research wouldn’t be available until the end of 2019 but they would be worth waiting for.
‘Viral infection is not usually thought to be a good thing, but in this instance, it may be possible that it is contributing to the sought-after unique nature of high quality wines, such as those produced from the Western Australian Gingin Chardonnay clone,’ she said.
Dr Kehoe said understanding the impact of viral load and its influence on vine performance will provide producers with a greater understanding of this valuable Chardonnay clone.
‘Purposely maintaining a level of viral infection in a vineyard would require a modified disease management strategy for the vines and vectors – including scale and mealy bugs – to make sure that infection doesn’t spread into nearby blocks where it isn’t wanted.’
‘This research is important because if viral infection is not found to be beneficial in this instance, then an interesting discussion around producing virus-free vines would no doubt occur. It may be that virus-free vines would produce a greater yield, and winemakers would be able to produce more high quality/value wines from the same number of vines.’
She said results from the project would also verify existing plantings of the Gingin clone in Western Australia and provide vital information on how viral infection can influence grape and wine quality.