Ug99 - Gene Resistance

Gene Resistance

Ug99 and its variants differ from other strains of the Black Stem Rust (BSR) pathogen due to their ability to overcome resistance genes in wheat that have been durable against the BSR pathogen for decades. These resistant Sr genes, of which 50 are known, confer different resistance to stem rust. The virulence in Uganda was associated with Sr31 and is specific to Ug99. The massive losses of wheat that have occurred have been devastating, but in recent years the wheat rust epidemic has been effectively controlled through selection and breeding for these Sr genes. The United States Department of Agriculture (USDA) researchers are testing genes to substantiate their Ug99 resistance, which will ultimately aid in developments of wheat varieties that will be able to fight off the rust. USDA researchers have stated that resistance has been identified in spring wheat land races and that they are now studying winter wheat land races where resistance is more probable. Due to the fact that the screening of the winter races is more challenging, results from the studies are not expected for another five to seven years. In addition to the research being conducted by the USDA, The United Kingdom’s Department for International Development (DFID), along with The Bill & Melinda Gates Foundation, announced in February 2011 that they will by granting $40 million dollars to a global project led by Cornell University to combat deadly strains of Ug99. The five-year grant to the Durable Rust Resistance in Wheat (DRRW) project will support attempts to identify new resistance genes as well as reproduce and distribute rust resistant wheat seeds to farmers.