Barley is a widely grown cereal crop that is used chiefly for livestock feed, food, and malting to produce alcoholic beverages such as beer and whiskey. Unfortunately, both the yield and quality of the crop can be lowered by various fungal diseases. In a recent article in the journal Plant Disease , researchers at the University of Minnesota reported that foxtail barley (Hordeum jubatum), a wild relative of the cultivated crop, can harbor several fungal pathogens and may play a role in the disease epidemiology of barley.
Foxtail barley is a common native grass species found across agricultural areas, native prairies, and disturbed sites in North America—from Alaska to central Mexico. This perennial wild grass can often be found growing next to cultivated fields of barley. To assess the compatibility of H. jubatum to pathogens of barley and its possible role in disease epidemiology, the researchers collected 100 diverse accessions of the species from Minnesota, Wisconsin, and North Dakota in the United States and from Manitoba in Canada and tested them for their reactions to seven fungal pathogens causing diseases of barley.
None of the foxtail barley accessions showed any visual signs of infection when challenged with the powdery mildew and leaf rust pathogens. In contrast, 97% to 100% of the evaluated accessions were infected by the pathogens that cause net blotch, spot blotch, stem rust, stripe rust, and crown rust. The relative degree of compatibility of H. jubatum to these latter five pathogens ranged from low (similar to resistant barley) to high (similar to susceptible barley). These results demonstrate that H. jubatum can be infected by isolates of important barley pathogens but typically not with the same degree of compatibility as susceptible barleys. Still, when infected plants of H. jubatum are growing near barley fields, they could serve as reservoirs of inoculum to initiate some diseases.
"These findings highlight the important role alternative hosts can play in the survival and spread of crop diseases," the researchers said. "Understanding these relationships is critical for developing effective disease management strategies."
