June 9, 2010

US research develops new gene to resist rust disease in beans

The USDA's Agricultural Research Service (ARS) and university scientists has developed new cultivars of a common bean might defend the legume against the fungal disease common bean rust.

Talo Pastor-Corrales, an ARS plant pathologist in Beltsville, Maryland, said the new cultivars possess two or more genes for resistance to the rust fungi. Most of the cultivars also harbour Ur-11, which is considered the most effective rust-resistance gene in the world.

Researchers at the University of Nebraska and Colorado State University said they used the multi-gene strategy in response to the high diversity of strains of the bean rust pathogen.

The researchers said virulent new races of rust have recently overcome the Ur-3 resistance gene in Michigan and North Dakota.

Until that occurred, the Ur-3 gene had been very effective in controlling rust in the US. Now scientists fear Ur-3-protected varieties are succumbing to the disease and there's concern the new races will spread to other Northern Plains states where common beans are grown, such as Colorado and Nebraska.