Frost is putting pressure on wheat yields as climate variability continues to play a larger role in farm decision making. Photo: Dr Felicity Harris
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Australian wheat growers are facing mounting pressure as climate variability stretches and intensifies the risk window for frost damage, with new research suggesting current best-practice management may not be enough.
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A CSIRO study, supported by the Grains Research and Development Corporation, has found that late spring frosts and earlier heat events are continuing to challenge producers, costing the industry as much as $360 million in yield losses yearly.
Wheat is Australia’s major winter crop, sown in autumn and harvested through spring and summer.
Growers manage frost risk largely through cultivar selection and timing, aiming to bring crops into flower during an optimal window that balances frost, heat and water stress.
The study assessed how well are those strategies actually hold up.
Researchers ran long-term simulations across 83 locations in the Australian wheatbelt, drawing on climate data stretching back to 1970 and a wide range of wheat varieties.
The results were sobering.
Even when crops flowered within the optimal window under best management conditions, frost remained a significant constraint on yield.
Dr Dreccer and her team are researching how best to build frost tolerance in wheat.
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CSIRO lead researcher Dr Fernanda Dreccer said growers were increasingly caught between competing climate risks, with no easy way out.
“As seasonal conditions vary, attempts to avoid heat and drought can increase exposure to frost during sensitive stages,” Dr Dreccer said.
“The biggest impacts occur when frost and heat stresses co-occur.”
The study also found that while managing flowering periods remains a critical tool, it is no longer sufficient on its own.
Advances in agronomy and cultivar selection have helped, but yields are still being constrained in adverse seasons.
Dr Dreccer said reducing the sensitivity of crops to frost offered one of the more promising pathways forward.
Over the past two years, her team has been evaluating genetically diverse wheat lines across trial sites in NSW, South Australia and Western Australia, working to better understand what drives frost damage and when.
The research is also improving understanding of environmental conditions around frost events, particularly the role of humidity and dew formation.
“While progress in managing frost has been slow, this improved understanding is helping to better assess risk and guide both agronomic strategies and the development of crops with reduced sensitivity during critical growth stages,” Dr Dreccer said.
