Rust disease is a major threat to the crops that feed the world. Researchers at the University of Sydney are combining pathology, genetics and breeding techniques to tackle the problem in new ways.
To the untrained eye, rust disease looks like a crusty coating on the surface of crops. To anyone who knows anything about agriculture, it looks like a catastrophe.
The disease is caused by fungal pathogens that can destroy crops, including wheat, barley, oat and rye. An outbreak can cause yield losses of up to 100 percent. Given wheat provides approximately a fifth of humanity’s food, that makes rust a serious threat to global food security.
It’s bad news for the economy, too. In Australia, wheat is a $7 billion industry – one of the nation’s most valuable exports. The last severe outbreak in Australia happened in 1973, costing the industry as much as $300 million. These days, the cost of a serious, Australia-wide outbreak would likely exceed $1 billion.
The University of Sydney is at the forefront of the global fight against rust. Professor Robert Park leads the Australian Cereal Rust Control Program (ACRCP), which integrates pathology, genetics and plant breeding to protect important crops.
In the earliest days of agriculture, farmers used basic breeding techniques by selecting the crops that seemed most resistant to disease, and planting them again the following year.
“Over a period of time, they were actually modifying the genetics of wheat, just by selecting the ones they wanted to grow again,” says Professor Park. “What we do now is basically the same thing, but we understand the genetics. We can design the resistance we put in, to optimise the chance that the plant will survive challenges by the pathogen.”
Through cross-pollination, Professor Park and his team breed rust-resistant wheat lines, which they give to breeders who develop new, high-yielding, genetically resistant varieties to be grown on farms.
Researchers at the University of Sydney have been studying cereal rust for almost a century. Professor Park and his team are changing the way this type of research is typically undertaken by tackling the problem from multiple angles; the ACRCP is the only research program in the world that integrates pathology, genetics and breeding, working with breeders to send rust-resistant wheat to farmers’ fields.
The program also works directly with farmers, who send rust samples from infected crops to the researchers for testing, to analyse the level of risk to their crop.
A recent discovery – announced in the prestigious journal, Science – has created a new weapon in the battle to pre-empt the constantly evolving pathogen. The University’s researchers have developed and applied DNA-based markers to understand how rust pathogens change. In collaboration with international scientists, they have created a world-first DNA test that will show whether a rust sample can overcome a specific resistance gene. The test will allow suspect samples to be analysed within hours, rather than weeks, helping farmers act fast to protect threatened crops. “This will indicate whether or not a given wheat crop needs to be sprayed with expensive fungicide quickly to protect against rust – which would otherwise devastate the crop in a matter of weeks,” Professor Park says.
There are environmental as well as economic benefits from the program’s work. As global populations grow, so does the world’s need for wheat. Professor Park’s research helps maximise production without clearing land for more farms. It also reduces farmers’ reliance on pesticides.
Professor Park is passionate about ensuring his research makes a difference. “We’ve made a huge impact with the work we’ve done,” he says. “There’s a direct pipeline from our research into farmers’ paddocks.”
Professor Park's role as the Judith and David Coffey Chair of Sustainable Agriculture is funded by a $4 million gift to the University's INSPIRED campaign. Discover how philanthropy is transforming research and education.
Proportion of the world's food that comes from wheat
Likely cost of a national wheat rust outbreak