Climate change focus in clonal trials

Dr Michael McCarthy’s latest research is testing his logistical skills as much as his scientific knowledge.

As lead investigator for a major AGWA-funded project assessing clonal variability in Chardonnay and Shiraz, he has to ensure that seven trial sites across three states are picked at similar maturities and that all small lot wines are prepared using similar protocols.

That means getting fruit from the Riverland and Barossa regions, as well as Armstrong, Drumborg and Mt Langi Ghiran in Victoria, to Adelaide’s Waite Campus for processing – often at short notice. WA fruit from Margaret River and Great Southern is sent to Bunbury, where after primary fermentation it also finds its way to Waite for finishing and bottling.

The Australian Wine Research Institute (AWRI) will then undertake sensory assessment of all wines of both varieties for three vintages (2014–16), as well as sequencing selected Shiraz clones to establish clonal relationships and evaluate genetic diversity across clones.

The project has two aims. The first is to improve our understanding of how clones can contribute to wine style and which clones are best suited to which regions. Dr McCarthy, Principal Scientist Viticulture with the South Australian Research and Development Institute (SARDI), believes a lack of such knowledge is a major reason why industry uptake of different clones has been slow.

‘With the Australian wine industry seeking more complexity and regional differences in wines, there is the opportunity to demonstrate that clones may bring another level of interest in wines’, he said.

Even more importantly, the research is investigating how knowledge of clonal variability can help the industry prepare for future climate change.

‘The Australian industry is fortunate in that, due to a number of factors, vineyards have greater longevity than in a number of other countries,’ Dr McCarthy said. ‘However, if climate change projections prove correct, vineyards planted now will experience warmer and probably drier conditions throughout their lifetime.

‘The challenge, therefore, is to know which clones should be planted now for this future. Can we use existing differences in the present climate between geographically separated sites as a surrogate for climate change and gain some insights about how clones may perform in this future climate?’

The four-year project, which began in June 2013, is evaluating clones from mature field plantings. A standard set of viticultural observations is made for all clones at each site and data loggers record canopy temperatures during the growing season. Nearby automatic weather station data is used to describe regional climate.

Dr McCarthy says progress to date has been ‘incredibly smooth’ due in no small part to the enthusiasm of everyone involved.

Drumborg suffered an unexpected cold snap in 2014, but all other sites were harvested and the wine processed. Sensory analysis of the Chardonnay was conducted late last year and the Shiraz early this year. The researchers are currently working through the AWRI’s reports.

All sites were harvested this year and the 2015 wine is now being made by Michael Coode at the Waite Campus and Richard Fennessy, from the WA Department of Agriculture and Food, in Bunbury.

The project’s other main collaborators are viticultural consultants Libby Tassie (SA), John Whiting (Victoria), and Dr Simon Schmidt from the AWRI.

In collaboration with the AWRI, two wine tastings will be available for Victoria in May. For more information about Clonal tasting and Shiraz benchmarking workshop to be held on May 12, 2015, click here. For information about next generation planting material workshop on May 14, 2015, click here. Tastings in other regions are planned for later in the year.