Four new mutations of Ug99, a strain of a deadly wheat pathogen known as stem rust, have overcome existing sources of genetic resistance developed to safeguard the world’s wheat crop, the Borlaug Global Rust Initiative (BGRI) reported in May 2010. Leading wheat experts said the evolving pathogen may pose an even greater threat to global wheat production than the original Ug99. The new “races” have acquired the ability to defeat two of the most important stem rust-resistant genes, which are widely used in most of the world’s wheat breeding programmes.

(BGRI/ib)