Like most experts working in sustainable agriculture today, The UWA Institute of Agriculture Senior Research Fellow Dr Sheng Chen knows he’s in a race against time.

The crop to which he’s dedicated much of his career – canola – is particularly sensitive to heat stress, and the evidence is now clear that the Earth is warming at an unprecedented rate. Dr Chen’s own research has shown that temperatures of more than 30 degrees during canola’s Australian flowering season (September) can significantly reduce seed yield and quality.

“Climate change has brought the heat waves earlier and earlier in the year, and the intensity of the heat is greater,” Dr Chen says.

“This year in Australia (at Penrith Lakes in NSW), there were a record six continuous days of temperatures greater than 32 degrees during September, with the highest reaching 36.5 degrees – that’s a big challenge for canola.

"If a heat wave like that comes when the canola flower has just opened, the yellow petals become white and the male and female organs lose viability so they can’t produce seed.”

Canola is Australia’s third-most valuable crop behind wheat and barley, with more than half the nation’s production – four million tonnes annually – coming out of WA. Most of the state’s crop is exported, generating about $1.2 billion each year.

Image: UWA Institute of Agriculture Senior Research Fellow Dr Sheng Chen.

But with the canola success story now under threat from climate change, growers are looking to researchers like Dr Chen to come up with solutions. In 2019, the Australia’s Grains Research & Development Corporation announced funding for a five-year national research project, led by Dr Chen, to produce heat-tolerant germplasm for canola breeders.

“Canola breeders may then incorporate this germplasm into new commercial cultivars and ultimately help the industry maintain productivity as mean temperatures rise,” Dr Chen says.

The current project is unique in that it isolates the impact of heat stress from other factors such as drought and disease. “The genes that influence a plant’s ability to withstand water stress are different to those that make them heat-tolerant,” Dr Chen explains.

In 2019 he designed a purpose-specific heat screening facility, housed at UWA’s Shenton Park Field Station, to control temperature conditions at flowering stage for various canola lines and then compare their yields.

“In the last four years we’ve screened more than 300 canola lines, with about 10 per cent showing good results in terms of heat resilience,” Dr Chen says.

The heat-tolerant canola lines are taken from Shenton Park and sent to Wagga Wagga, where UWA’s research partner, the NSW Department of Primary Industries, has set up 16 portable heat chambers to monitor the varieties in field conditions. From there, lines are tested again in natural field conditions but with controlled heat stress at flowering stage. This year 48 strong canola lines are under further validation at five sites across WA, Victoria and NSW.

With less than a year left before the project’s completion, Dr Chen is confident of delivering tangible benefits to the industry.

“We will be able to deliver to breeders useful information and seeds of heat-tolerant potential parental genotypes to use for their specific environment and planting schedules,” Dr Chen says.

“Commercial canola cultivars can currently lose up to 25-to-50 per cent of their seed yield when impacted by heatwaves, but the lines we will recommend may lose only five-to-10 per cent or none at all. We should therefore see better crops and yield stability in the coming years.”

While the current project has studied existing canola lines, Dr Chen says the next research challenge will be to successfully cross lines to produce even more heat-tolerant cultivars.

“As heat waves increase in frequency, intensity and duration in Australia, we will have to produce cultivars with higher tolerance and that will need to happen through pyramiding multiple heat-tolerant genes,” Dr Chen explains.

“We are in competition with climate change – this is a race – and we will try our best to beat it.”