The Australian Cereal Rust Control Program has confirmed that a sample of stripe rust collected from a wheat crop in north-east Victoria is the first Australian pathotype with virulence for the Yr27 resistance gene.
The program is based at the University of Sydney’s Plant Breeding Institute (PBI).
NSW Department of Primary Industries' Dr Colin Wellings, on secondment to the PBI, said greenhouse experiments revealed the pathotype had features identical to the 'Jackie' pathotype, but that a differential test wheat variety carrying the Yr27 gene had shown a susceptible reaction.
Current varieties carrying Yr27 include GBA Combat, GBA Ruby, Merinda and Mira, and these must be considered "at risk" until further information becomes available.
Dr Wellings said the newly-named 'Jackie Yr27' pathotype was avirulent for the Yr17 resistance gene, so this gene should provide protection against the new strain.
However a stripe rust pathotype virulent for Yr17 is also widespread in eastern Australia, so Yr17 varieties are "at risk" to this pathotype.
The Grains Research and Development Corporation has advised growers that their best defence is to grow resistant varieties.
* More information about managing rust is at the GRDC website.
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