Improved wheat to counter climate extremes

In some parts of the world, wheat has adapted to grow under scorching climates. What makes certain wheat lines more resilient to harsh temperatures than others is written in their genes, and Professor Richard Trethowan, director of the Plant Breeding Institute, has spent 10 years unlocking the conundrum at the University of Sydney.

Over the past decade, he and his team compared the yield performance of thousands of wheat lines under different sowing times, heat shock conditions and within temperature-controlled glasshouses. 

He has identified lines that perform especially well when sown in optimal conditions yet maintain yield when temperatures rise, advancing the understanding of the genetic control of heat resistance in wheat. The team used a genomic selection approach to introduce enhanced tolerance into agronomically adapted wheat. These enhanced materials and the molecular tools needed to track the new diversity in the wheat breeding process have already been adopted by Australian commercial wheat breeders.

“The progress we have made with our research supports the wheat industry including grain growers and commercial breeders.”

These extraordinary results have led Professor Trethowan to win one of the eight 2021 Royal Society of NSW awards, which recognise excellence in science and are among the oldest and most prestigious awards in Australia.

Professor Trethowan was awarded the Poggendorff Lectureship for his plant breeding and genetics research. “Receiving the prize means recognising the value of plant breeding to our wheat industry, our economy and the global food security,” he says.

Although Australian wheat varieties possess heat tolerance because of years of breeding and selection in a torrid environment, periods of extremely high temperature can severely compromise yield and grain quality. Professor Trethowan has identified genetic material that, recombined with local lines, offers increased heat tolerance, which could mitigate the effects of a warming climate.

“Every line arrives at heat tolerance in different ways, and each of those traits that confer that tolerance have a genetic control,” says Professor Trethowan. 

He began collecting thousands of wheat lines from the hottest places on earth and sowed them at different times of the seeding season at the Narrabri breeding facility in North New South Wales. 

The team used heat chambers to induce thermal shocks at various stages of the plant's development and aerial images to measure the reflectance and temperature of the canopy. “If the canopy of a line is cooler than the adjacent one, it means it is managing the heat a lot better,” Professor Trethowan says. 

Combining this information with genetic sequencing and yield data, such as seed size and shape, allowed him to identify lines that tolerated heat shocks best. “It's an exercise in collecting a lot of information in the field and combining it all into a single value or weighted index that tells us about the potential of the line.”

Thanks to his close collaboration with the grain industry, Professor Trethowan had narrowed the selection to a handful of lines that showed remarkably consistent results across the country. “We can test lines in one or two environments, but our commercial partners can test them in tens of different environments,” he says.

Testing in multiple locations is crucial, and something that Professor Trethowan has been able to do thanks to his close relationship with industry. Over the years, he has worked closely with Australian Grain Technology, LongReach Plant Breeders, InterGrain, Austgrains, Rebel Seeds, BASF and KWS among others. 

“They sit on our project teams, provide valuable intel, suggest commercial backgrounds and road test our research outputs- they are part of the process.” And that, he says, shortens the lag period between the research and farmers accessing the best products. Industry partners can integrate the genetic material into commercial breeding pipelines early in the research and represent a direct pathway to the market once the best products are identified.

“This way, we can ensure that the farmers get to see this valuable new diversity in cultivars five to six, even 10 years earlier.”

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The University of Sydney is commited to research in agriculture, and sustainability across all fields. We have a series of ongoing research projects and partnerships across a wide range of industries. Explore our website to uncover more of our work, and partnerships we are engaged in.