Wheat researchers have discovered a combination of genes that provide resistance to the significant fungal disease Stagonospora nodorum blotch (SNB) in Western Australian varieties.

The discovery was made as part of a research project by the Department of Primary Industries and Regional Development and the State Agricultural Biotechnology Centre at Murdoch University, with funding from the Grains Research and Development Corporation (GRDC).

SNB costs Western Australian growers about $108 million per annum, due to leaf death and reduced grain fill – particularly in high rainfall areas and wet years.

Murdoch University’s Adjunct Professor Michael Francki and his team have been evaluating germplasm, including United States’ winter wheat, Australian lines and other international wheat lines sourced via the GRDC’s CAIGE project.

Professor Francki said field trials at the department’s Northam and Katanning Research Facilities helped researchers to identify resistant genes.

“We have found two or three genes from different wheat donors, when crossed with Australian lines and selected using DNA markers, expressed good levels of resistance to SNB at Northam and Katanning,” he said.

“As these are all minor genes, we expect a stronger resistance response to SNB when they are employed in combination as a group of two or three.”

Successful field trials

The department recently planted additional field trials in the new netted field plots at its Northam Grains Research Facilities, as well as its Manjimup Research Facility – where conditions are expected to be more conducive to the SNB pathogen.

“The resistant genes have been combined and selected using conventional breeding technology, in combinations of one, “two and three genes into several WA varieties,” Professor Francki said.

The plan now is to evaluate their performance in multiple environments and successive year trials.

“We expect the results to give us an insight into how the different gene combinations perform and the relative gains to be achieved in different WA production environments.”

The department has also provided the genetic markers and germplasm to commercial wheat breeding companies to accelerate their use in the development of new varieties.

“The transfer of technology and germplasm to breeding companies will help fast-track the delivery of new wheat varieties with enhanced SNB resistance expressed in WA production environments and ensure Australian wheat growers remain profitable under a disease conditions,” Professor Francki said.

“If all goes well, we could well see new varieties with improved SNB resistance included in National Variety Trials in four or five years’ time.”

Department researchers intend to continue evaluating germplasm from a range of sources, from as far away as Norway, for genes that are resistant to SNB.

The team is also using the draft wheat genome to identify causal genes for SNB resistance, which will be used as diagnostic DNA markers to further improve the selection efficiency of gene combinations in commercial wheat breeding.