Scientists are close to developing resistant wheat strains, but getting them to farmers may be a challenge
Scientists are close to producing new wheat varieties resistant to a deadly wind-borne disease that threatens to destroy crops around the world, fuel food price hikes and potentially lead to worsening hunger, they said.
Ug99, a virulent strain of wheat stem rust discovered over a decade ago, could potentially damage up to 90 percent of the world’s wheat crop, particularly as changing climatic patterns carry it to new regions, the scientists warned. That is a serious problem as world demand for food is surging, particularly as incomes and appetites grow in emerging giants like China and India.
But new varieties should help defuse the threat, say the scientists, who have been working to stay one step ahead of the pest.
“Stem rust is devastating - it’s the source of the great biblical plagues,” said Ronnie Coffman, principal investigator of the Durable Rust Resistance in Wheat Project, an effort aiming to combat wheat crop diseases, and director of International Programs of the College of Agriculture and Life Sciences at Cornell University.
POTENTIAL LOSSES
Since it was discovered in East Africa in 1998, Ug99 has been detected in nearly a dozen nations in Africa and the Middle East. It is a dangerous epidemic; in the early 1950s, a major outbreak of stem rust destroyed 40 percent of North America’s spring wheat crop.
Now, scientists aim to create and distribute resistant strains before the disease makes its way to the world’s breadbaskets located throughout Africa, North and South America, the Indian subcontinent and Australia.
With progress on new varieties well advanced, Coffman said, the main challenge will be getting farmers in areas yet to be affected by stem rust to plant the resistant varieties.
The new varieties offer some side benefits: an increase in crop yields of 15 percent and resistance to yellow rust, a less damaging pest that is currently hurting crop yields in Africa and the Middle East.
Coffman hopes these added factors will help win over governments and farmers. If not, a reduction in the production of wheat - the world’s most widely grown crop and the number one staple for a third of the world’s population - could wreak havoc on the already tight global food supply.
The threat from Ug99 comes at a time when food security issues already loom large. With the world’s population expected to reach 9.1 billion by 2050, food production must increase by 70 percent to sustain it, according to the UN Food and Agriculture Organization. And with changes in the climate affecting levels of rain fall and temperature, growing crops has become unpredictable or simply difficult for a growing number of farmers.
“Climate change up till now has been fairly moderate, but it’s already changing and impacting quite heavily (on farmers),” said Andrew Jarvis, a leader on climate change, agriculture and food security for the Consultative Group on International Agricultural Research Program (CGIAR), which conducts research on global warming and food security.
As climate impacts become stronger, Jarvis’ research models suggest world wheat production could drop by a minimum of 15 percent.
CLIMATE RISK
While some crops, such as rice and maize, are likely to see initial increases in productivity as climatic conditions change, more crops come out losers than winners, with wheat – a heat sensitive crop - suffering the most.
Besides altering temperature and rainfall levels, climate change can directly impact the severity and spread of crop pests and diseases like Ug99, according to Karen Garrett, a professor of plant pathology at Kansas State University.
“People have known for a long time that plant pathogens and the probability that they’ll effect disease is really strongly influenced by weather,” Garrett said.
For instance, if a pathogen needs a certain temperature or moisture level to attack, changes in climate could allow pests to become established in areas where they previously could not survive.
Coffman said that although there is not enough information to discern a clear connection between climate change and the spread of Ug99, unpredictable environmental conditions linked to large-scale weather shifts make dealing with Ug99 more challenging.
Stem rust, for instance, has never been recorded in northern India. Scientists speculate that the region’s extreme heat kept it at bay. But with greater wheat cultivation in the region and changing climate conditions – including alterations to India’s monsoon – it is now unclear whether the area will remain immune to the disease.
“The kind of unsettling thing is that we can’t rely on history to tell us where the devastation from stem rust will occur,” Coffman said.
Soumya Karlamangla is an AlertNet Climate intern.
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