US scientists close to producing super-wheat resistant to deadly-rust variants

Thursday, June 16th 2011 - 23:08 UTC

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The new super-wheat is expected to have 15% higher yields

United States scientists say they are close to producing super varieties of wheat that will resist from variants of Ug99, a new and deadly form of wheat rust and at the same time boost yields by as much as 15%.

Scientists released in Minnesota a report with new data that showed key Ug99 variants have now been identified across all of eastern and southern Africa and that it may only be a matter of time before the spores travel to India or Pakistan, and even Australia and the Americas.

Ronnie Coffman, head of the Durable Rust Resistance in Wheat project at Cornell University, and his colleagues note that significant obstacles will have to be overcome before the new varieties of wheat can replace susceptible varieties that cover most of an estimated 225 million hectares of wheat fields throughout the breadbaskets of South Asia, the Middle East, China, Europe, Australia and North America.

The Boarlaug Global Rust Initiative was created after confirming that a new stem rust strain called Ug99 could overcome a crucial resistance gene, Sr31 that had been widely used in the world’s wheat breeding programs to protect the world’s wheat crop from the disease.

Coffman states, “Declining support for public agricultural research got us into this problem with Ug99. Unless that changes, the problem is likely to arise again in a few years. We are dealing with a constantly-evolving pathogen, and we need to stay at least one step ahead of it at all times.”

The plan to protect the world from Ug99 is focused not on creating a single variety of Ug99 resistant wheat, but on conferring genetic resistance in wheat and transferring these traits to local varieties.

The Ug99 is a new variant of the black rust which attacks wheat’s stem impeding the plant to feed and in the fifties and sixties in some years finished with 40% of crops in the United States and Canada.

Another disease, yellow rust, appears to be adapting to warmer conditions and moving into areas where the disease has not previously caused economic losses. Scientists see the growing demand for yellow rust-resistant wheat as an opportunity to disseminate new high-yield varieties resistant to multiple pathogens, including yellow rust and stem rust.