Farmers beside a crop of Digalu wheat in Ethiopia, Africa, about 40,000 hectares of which was affected by a strain of rust unrelated to the Ug99 rust family in 2014 and 2015.
PHOTO: Robert Park
The 2015 Borlaug Global Rust Initiative (BGRI) technical workshop hosted by the University of Sydney’s Plant Breeding Institute attracted some 350 international scientists to Sydney in September to assess the rust threats to global wheat cropping.
The focus of this seventh annual technical event were the rust challenges posed, and progress made in genetic approaches to the pathogens’ control.
Providing the impetus for the inaugural workshop in Mexico in 2009, and the workshops since, was the discovery of a wheat stem rust race Ug99 about 10 years earlier.
BGRI advocacy, including efforts by Nobel Laureate Dr Norman Borlaug, subsequently led to a Durable Rust Resistance in Wheat (DRRW) project, co-funded by the Bill and Melinda Gates Foundation and the UK Department for International Development and managed by Cornell University in the US.
As its name suggests, the Ug99 stem rust race was originally found in Uganda in 1999. Since that time, however, DRRW surveillance efforts have found at least 12 more races (strains or pathotypes) that are part of the Ug99 ‘family’, each of which has a different ability to overcome rust-resistance genes in wheat.
DRRW researchers have also established that one or more of the Ug99 group of races are now present in countries stretching from South Africa to Iran, including Egypt where two Ug99 races were detected for the first time in 2014.
While races within the Ug99 family have caused localised stem rust epidemics in east Africa, a race unrelated to Ug99 caused more serious rust outbreaks in Ethiopia in 2014 and 2015. Last year, this outbreak affected about 40,000 hectares of the Digalu wheat cultivar, with complete crop losses in many areas.
The DRRW project has fast-tracked discovery of resistance genes and the development of wheat germplasm with resistance to these stem rust threats.
Importantly, the DRRW has also helped raise awareness of gene stewardship, which involves careful use of new resistance genes to minimise the chance of them being rendered ineffective by new rust races.
The Australian Cereal Rust Program’s efforts in gene stewardship were recognised with a BGRI Gene Stewardship Award in 2013. In 2015, the award recognised three Kenyan scientists who have spent the past eight years building a collaborative platform for rust research, which has allowed tens of thousands of wheat lines from around the world to be field tested for their response to the Ug99 rust races.
Professor Robert Park,
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Dr Will Cuddy,
02 9351 8871
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