A new study from CSIRO showed changing climate conditions were extending and intensifying the window of time for risk of frost damage.
The study, conducted by Australia’s national science agency in partnership with the Grains Research and Development Corporation (GRDC), showed late spring frost and earlier heat continued to challenge producers, with frost able to cause up to $360 million annually in wheat production losses.
CSIRO lead author Dr Fernanda Dreccer said the study examined how well current best-practice management was performing.
“Growers have access to a range of strategies including cultivar selection and sowing time so crops flower within the optimal flowering period,” she said.
“That is the window where yield is maximised by balancing frost, heat and water stress, with adequate nitrogen fertilisation.
“But our study asked the question: what are the limits of these best management strategies under increasing climate variability?”
To answer this, the research team ran long-term simulations across the Australian wheatbelt at 83 locations using climate data dating back to 1970 and a wide range of wheat cultivars.
The results showed even under these best management conditions, frost remained a major constraint on yield even when flowering occurred within the optimal window.
Dr Dreccer said the study highlighted how management decisions for growers could involve unavoidable trade-offs between competing climate risks.
“As seasonal conditions vary, attempts to avoid heat and drought can increase exposure of frost during sensitive stages, with impacts compounded by late spring frost and the biggest impacts occurring when frost and heat stresses co-occur,” she said.
Dr Dreccer said the findings showed while phenology (the study of recurring biological events in plant life cycles) remains a critical tool, it was no longer sufficient on its own, with yields still constrained despite advances in agronomy and cultivar selection.
“The results show that reducing crop sensitivity to frost can deliver meaningful gains, particularly in adverse seasons,” she said.
Over the past two years Dr Dreccer and her team have been researching how best to build frost tolerance in wheat, with a focus on evaluating genetically diverse wheat lines across multiple environments, including sites in New South Wales, South Australia and Western Australia, to better understand frost damage and the conditions that drive it.
“As part of this work, we are also improving understanding of the environmental conditions associated with frost events, particularly the role of humidity and dew formation, which are key drivers of frost type and damage,” she said.
“This highlights an important gap in current approaches, which often rely on air temperature alone and do not fully capture canopy-level conditions that influence whether damage occurs.
“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.”
