Borlaug Global Rust Initiative provides momentum for wheat rust research

Abstract

The discovery in 1999 in Uganda (Pretorius et al. 2000) of stem rust on wheat varieties with the 1BL.1RS translocation carrying the gene known as Sr31 came as re-awakening, even when it should not have been unexpected. The worldwide deployment of wheat varieties with the translocation probably had an effect of reducing inoculum, resulting in low incidence of the disease over an extended period. Stem rust resistance was only one of a number of advantageous features of the translocation. With acquisition of virulence for Sr31, race Ug99 as it became known, was subsequently found in epidemic proportions in Kenya and Ethiopia. Stem rust had not been a significant problem in Kenya for many years prior to 2000 although the region was a historic hotspot for the disease. In Ethiopia, with about 40% of the area growing durum the situation was different; stem rust continued to be a recurrent problem on durum whereas bread wheat was generally resistant. Subsequent events of rapid mutational changes in Ug99 to attack varieties with Sr24 and Sr36, and its further migration to Yemen and Iran, caused major concern and a prediction of the likelihood of further movement to the important grain production areas of the Indian subcontinent and beyond. Previously races of the stripe rust pathogen virulent for Yr9, also in the same 1BL.1RS translocation, were observed sequentially from equatorial Africa to India suggesting the entire wheat area in Asia may comprise a single epidemiologic zone (Singh et al. 2004, 2008). Preliminary laboratory and field tests with Ug99 confirmed that it not only had virulence for Sr31, but it also possessed virulence to other genes deployed in contemporary wheat varieties along with obvious fitness attributes. Most importantly it could cause disease on the widely used variety (mega-variety) Attila and sibs that were being widely grown from Kenya to India and Afghanistan under several different names. International concern regarding the threat to world wheat production caused by Ug99 led to the durable rust resistance in wheat project at Cornell University funded by the Bill and Melinda Gates Foundation and establishment of a Global Rust Initiative (later Borlaug Global Rust Initiative, BGRI). The BGRI led by Cornell University, CIMMYT, ICARDA and FAO is supported by many national governments and research centres. Clearly, stem rust is only one of the three rusts that threaten wheat, and currently there is a group of rapidly spreading races of the stripe rust pathogen that is a major threat to production at least as great as Ug99. One of the objectives of BGRI is to conduct an annual meeting. The first meeting was held at Ciudad R. A. McIntosh (&) The University of Sydney Plant Breeding Institute Cobbitty, Private Bag 4011, Narellan, NSW 2567, Australia e-mail: robert.mcintosh@sydney.edu.au