Western Canadian wheat farmers are helping scientists find solutions for a major new disease threat to global wheat production.

"Ug99" is a new strain of stem rust first identified in Uganda and now spreading in east Africa and toward the Indian subcontinent. Canadian wheat researchers are part of an international effort to combat the disease by identifying and developing wheat varieties that are genetically resistant to the disease. In Western Canada, this effort is supported in part by farmers through the Wheat Check-off Fund, administered by Western Grains Research Foundation (WGRF).

"We've had excellent resistance to stem rust in all of our spring wheat varieties for 50 years, so the emergence of a new strain is something we want to monitor closely and make sure we're prepared for," says Dr. Tom Fetch, pathologist at Agriculture and Agri-Food Canada's (AAFC) Cereal Research Centre in Winnipeg. "This strain may be a threat to Canadian wheat production, but it appears we have good genetic material to work with if stronger resistance is needed in our varieties. This is certainly a wake-up call on the need to be prepared."

Western Canadian researchers want to ensure the region's efforts to maintain rust resistance remain strong, he says. "At the same time, we want to lend support to the international effort to combat this new strain in threatened wheat production areas."

As its name implies, Ug99 was first reported in Uganda in 1999, but its potential as a threat to wheat production is only now becoming understood. It is now also known as "black rust" and has spread to both Kenya and Ethiopia, possibly beyond.

The world's leading international wheat research organization, the Mexico-based International Maize and Wheat Improvement Centre (CIMMYT), has sounded the alarm, calling the new strain of wheat stem rust "a major, strategic threat to global wheat production."

Of greatest immediate concern is the threat of black rust to the countries now grappling with the disease in east Africa and the potential threat to other developing countries, says Fetch, who has participated directly in the CIMMYT-led Global Rust Initiative, set up to combat Ug99. The primary rust-resistance gene deployed to protect wheat against the disease in these countries, Sr31, has shown ineffectiveness against the new strain.

Canadian wheat varieties feature different genetic sources of stem rust resistance, says Fetch. While the specific gene or genes behind those sources of resistance have not been pinpointed, testing so far shows at least some Canadian wheat material appears to have a level of resistance to Ug99.

"We took samples of our material over to Kenya for testing and did identify some lines that showed good resistance to the strain," says Fetch. "But more research on this race and on the genes for resistance is needed. It's unknown if Ug99 is from a single mutation or if it represents more than one strain. There also is a lot to learn about the specific genes that confer resistance."

More information on Ug99 and Canada's role in the new initiative is featured in the February edition of Western Grains Research Magazine, now available at www.westerngrains.com. Western Canadian wheat and barley growers are major investors in breeding research through the Wheat and Barley Check-off Funds, administered by WGRF. The Research Magazine offers "Ideas and issues for farmer research investors."