Dr Peter May Award – Dr Marcos Bonada, PIRSA-SARDI

The Dr Peter May Award was introduced in 2018 by the ASVO to honour the late Dr Peter May who was the foundational editor of the Australian Journal of Grape and Wine Research (AJGWR). The award is presented to the author(s) of the most cited original research paper published in the Australian Journal of Grape and Wine Research in the previous five years.

Dr Marcos Bonada, from the Department of Primary Industries and Regions, South Australian Research and Development Institute (PIRSA-SARDI), and co-authors were honoured to receive this award in 2020 for the paper published in the AJGWR in 2015.

Bonada, M., Jeffery, D., Petrie, P., Moran, M. and Sadras, V. (2015), Temperature and water effects on grapes and wines. Australian Journal of Grape and Wine Research, 21: 240-253. https://doi.org/10.1111/ajgw.12142

The paper reports the results of an investigation into warming and drought that can disrupt berry traits and wine style. Against the background of climate change, many studies focused on either elevated temperature or drought, mostly under unrealistic experimental conditions (potted vines, controlled environments). Dr Bonada’s work pioneered the investigation of the combined effects of warming and water stress in realistic vineyard conditions with a focus on Barossa Shiraz. To capture the interactions between stresses, Dr Bonada combined factorially two thermal regimes (untreated controls and vines heated with open-top chambers) and two water regimes (irrigated and water deficit).
Dr Bonada’s study opened a window into hotter and drier futures for the industry; it revealed previously unknown interactions between temperature and water stress on fruit traits and wine composition. The effect of water deficit during ripening typical with current temperatures – increasing the concentration of fruit phenolic compounds returning colourful and flavoursome wines – did not hold under warmer conditions. Wines from both water stressed, and heated vines were rated lower on tannin structure, berry flavours and colour saturation. Dr Bonada’s study provides the industry with indications of the shift in wine style that may be expected in a changing climate in the absence of technological innovations to preserve the identity of Barossa Shiraz.