As a new stem rust pathogen spreads across Africa, world wheat production is threatened
In the mid ‘50s, 40 per cent of western Canada’s wheat crop was wiped out by stem rust, then known as the polio of agriculture. Thanks to Norman Borlaug and the Green Revolution wheat breeders have developed varieties with genes that are resistant to the stem rust with no incidence reported in almost 50 years.
However, a new strain of stem rust – P. graminis – was discovered in Uganda in 1999. Ug99 is able to attack approximately 80 per cent of wheat varieties world-wide, is spread by the wind so it travels very easily.
The pathogen has been found in Ethiopia, Iran, Zimbabwe and South Africa, soon to be knocking on India and China’s doors, the world’s biggest wheat consumers. That’s more than a billion people threatened. Just a single spore – as tiny as red blood cell – could easily makes it way to North America, latched on to the shirt of an unsuspecting tourist.
Unless stopped, the pathogen could wreak havoc on the world’s wheat supply which provides a third of our calories. According to an article in the March 2010 issue of Wired, “a single hectare of infected wheat releases upwards of 10 billion spores, any one of which can cause the epidemic to spread. The circumstances have to be just right, though – the prevailing winds must blow toward an area of wheat cultivation, and the P.graminis spores must survive the airborne journey.”
The race is on to build varieties with resistant genes but it could take as long as 10 years to develop a breeding line. Leading the charge is Cornell University, which recently received a five-year grant of $40 million from the United Kingdom’s Department of International Development (DFID) and the Bill & Melinda Gates Foundation to combat the disease.
The grant was made to the Durable Rust Resistance in Wheat (DRRW) project at Cornell which is working to identify new stem rust resistant genes in wheat, improve surveillance, and multiply and distribute wheat seed that is rust resistant to farmers.
Thanks to the concerted efforts of the DRRW researchers have distributed new resistant wheat varieties for testing and evaluation in 40 countries. According to Cornell University, they have “have strengthened nurseries in Kenya and Ethiopia for screening wheat for vulnerability to rusts and distributed nearly five tons of Ug99-resistant seed for planting in the at-risk nations of Ethiopia, Kenya, Egypt, Pakistan, Afghanistan, Bangladesh and Nepal.”
Interested in learning more about what’s being done to combat rust? The best place to go is the Borlaug Global Rust Initiative.
Founded by the late Dr. Borlaug in 2005, the initiative is a resource for international research and policy makers about the rusts in wheat.
Ron Wall is constantly on the quest for insights to fuel his relentless creativity. He can be contacted directly at Ron.Wall@adfarmonline.com