Researchers at the Centre for Crop and Disease Management (CCDM) in Australia have identified three new resistance genes (RBgh1-3) in exotic barley varieties with a novel mechanism for resistance in mature plants to the powdery mildew pathogen. Powdery mildew is reportedly a common challenge for Australian barley growers, especially in high-rainfall and humid weather, and can result in substantial losses in quality and yield. The pathogen readily mutates to overcome conventional resistance genes and agrochemicals such as the triazole class of fungicides, which is now widespread in areas in southwest Australia. The novel genes reportedly provide durable resistance to the pathogen and can be bred into elite barley lines. The research was funded by the Grains Research and Development Corporation (GRDC) and Curtin University.

During the study, researchers searched for resistance in more than 1000 exotic lines and wild relatives of barley from regions of the crop’s diversity in the horn of Africa, the Near East and Asia, accessed through the Australian Grains Genebank. The researchers leveraged genetic mapping and multi-pathogen disease screening to discover that not only were the exotic barley lines themselves diverse, so were their types of resistance.