Wheat foliar diseases

Rusts and yellow spot

Foliar diseases, such as rust and yellow spot, are common and geographically widespread across the Australian wheat belt and worldwide. To accelerate the discovery of new sources of genetic resistance, the HickeyLab has developed innovative phenotyping methods that are adapted to speed breeding conditions. This enables rapid disease screening all year round. Methods have been developed for yellow spot (Dinglasan et al. 2016), stripe rust (Hickey et al. 2012), leaf rust (Riaz et al. 2016), and stem rust (Riaz et al. 2017). To identify new sources of resistance to rust and yellow spot, the HickeyLab team is screening the Vavilov Wheat Collection, which includes diverse wheat accessions from around the world – collected by renowned Russian botanist Nikolai Vavilov and his colleagues prior to modern plant breeding.

Solution to wheat foliar diseases

By collaborating with leading pathologists and geneticists from the Department of Agriculture and Fisheries and CSIRO, the team has discovered novel genomic regions for leaf rust (Riaz et al. 2018), yellow spot (Dinglasan et al. 2019), and stripe rust (Jambuthenne et al. 2022). In partnership with Curtin University, genomic regions conferring resistance to septoria nodorum blotch have also been uncovered in the Vavilov wheats (Phan et al. 2018). Based on these findings, ongoing work is aiming to functionally validate candidate genes within the novel genomic regions and determine the value in terms of protecting grain yield under disease conditions.

Fusarium crown rot

Reduces yield and grain quality in a wide range of winter cereals in Australia and worldwide

Fusarium pseudograminearum causes crown rot on a wide range of winter cereals reducing yield and grain quality in Australia and worldwide. The broad range of host species presents a major challenge for cropping systems, affecting the productivity of the barley, wheat, oats, and durum wheat industries. The frequency of disease severity and prevalence in Australia has notably increased with the introduction of minimum tillage cropping practices, less frequent precipitation events during the growing season and more frequent heat waves due to climate change. This has resulted in the exacerbation of CR symptoms. For more than 30 years CR has been considered the most significant fungal disease of temperate cereal crops in Queensland and northern New South Wales.

Solution to fusarium crown rot

Our research explores the opportunity to investigate physiological traits for improved water-use efficiency, such as deep root systems or stay-green, which could minimise yield and grain quality losses due to crown rot. By studying wheat populations in field trials, our team has discovered that key genes for above- and belowground physiological traits can be combined to enhance yield potential under crown rot conditions (Alahmad et al. 2020). We anticipate that these insights will assist breeders to design improved varieties that mitigate production losses due to drought and crown rot.

Barley foliar diseases

Barley leaf rust caused by Puccinia hordei

Barley leaf rust, caused by Puccinia hordei, is arguably the most common and widely distributed disease of barley crops. The deployment of genetic resistance is the most economical, effective, and ecologically sustainable approach to control foliar cereal diseases. In a project funded by the GRDC (2013-2017) conducted in partnership with the University of Sydney, the HickeyLab applied innovative approaches to accelerate the utilisation and deployment of durable adult plant resistance to leaf rust in barley. The major outcomes of this project was the discovery of genomic regions conferring stable resistance to leaf rust in elite breeding populations, as well as the characterisation of a new adult plant resistance gene called Rph24 (Ziems et al. 2017). The research team demonstrated that pairing Rh20 (Hickey et al. 2011) with Rph24 provided a pathway for barley breeders to develop new cultivars with high levels of leaf rust resistance.

Solution to barley foliar diseases

In a new project funded by the GRDC, the HickeyLab team is collaborating with Prof Ben Hayes and pathologists around Australia to minimise the impact of barley foliar diseases on yield and profit including spot form net blotch, net form net blotch, and scald. The pathogens are diverse and they’re able to reproduce sexually and have the ability to rapidly develop new virulences and overcome genetic resistance, hence it is important to identify novel sources of resistance. The objective of this program is to increase diversity for resistance genes and determine the optimal combinations of resistance genes to enable greater durability of resistance in deployed cultivars, and ultimately more sustainable barley cropping systems for Australian growers. The project uses ‘FastStack’ technology developed at UQ, which integrates artificial intelligence genetic algorithms to identify parents that carry desirable resistance genes, genetic simulations to optimize crossing strategies, and speed breeding to accelerate crossing and line development.