ancy.kuthokat@postgrad.curtin.edu.au

Wheat powdery mildew (WPM) is caused by the obligate biotrophic fungus, Blumeria graminis f. sp. tritici (Bgt). WPM is responsible for AU$18 million dollar in yield loss annum. Current strategies used to minimise the impact of WPM includes crop rotation, chemical control and genetic resistance.

Fungicide-resistant WPM have been reported across Australia therefore, genetic resistance is an effective and sustainable solution to control WPM. This requires information on current pathotypes, unfortunately, no proper studies have been reported on the pathotype and population structure of Australian Bgt. We collected 16 Bgt isolates from across Australia from 2020 to 2022.

We determined the level of virulence of these Bgt isolates using a diverse wheat panel consisting of varieties with defined WPM resistance (R) genes. As a result, we observed multiple R genes that can be deployed into Australian commercial varieties for effective resistance to WPM.

In addition, non-metric multidimensional scaling of virulence scores demonstrated evidence of distinct Bgt pathotypes present in Australia, revealing Western Australian isolates as significantly more aggressive than Eastern Australian isolates.

This data will be communicated to the cereal industry to enable effective deployment of the resources to improve profit through increased yield and grain quality. We also anticipate that the use of effective genetic resistance will reduce the demand for fungicides and thus increase the life span of a fungicide for future use. This will fill the voids between the researchers and the growers.