High-confidence genomic regions associated with leaf stripe and spot blotch resistance in barley

Barley is a key cereal grain utilized in malt production, animal feed and human food consumption. Epidemics require inputs to mitigate against a variety of destructive pathogens. However, the deployment of robust genetic resistance is known to be the most cost-effective method to reduce disease outbreaks. Two key diseases of barley include spot blotch and leaf stripe, and have been largely under-investigated in comparison to other barley diseases such as rust and net blotch. In addition, wild and landrace barley have been shown to harbour resistances that have been lost during the domestication process that could be recovered to ensure a larger catalogue of resistance genes is available for breeding elite germplasm. Association mapping of natural populations provides a rapid approach to identify resistance loci without the need for population development and can be achieved using low-density marker platforms for initial characterization. This study, utilizing landrace and wild barley and a low-density marker panel, identified three robust marker trait associations, one to spot blotch on chromosome 4H and two to leaf stripe on chromosomes 6H and 7H. The chromosome 6H leaf stripe locus is novel and may provide robust resistance not previously incorporated into breeding programs.