Reactions of Winter Wheat, Spring Wheat, and Barley Cultivars to Mechanical Inoculation with Wheat Streak Mosaic Virus

Wheat streak mosaic virus (WSMV) causes sporadic epidemics in Montana, which can threaten profitability of the state's small grains production. One challenge for WSMV management in Montana is that most commercially available wheat and barley cultivars are susceptible to WSMV or their performance under WSMV pressure is unknown. In a 3-year field study from 2017 to 2019 winter wheat, spring wheat, and barley cultivars were evaluated for their susceptibility to WSMV and yield performance under WSMV pressure. Plants were mechanically inoculated, and WSMV incidence was assessed using double antibody sandwich ELISA. There was effective resistance to WSMV in breeding line CO12D922, which had consistently low WSMV incidence, highlighting promising efforts in the development of WSMV-resistant winter wheat cultivars. Moderate WSMV incidence and minor yield losses were observed from WSMV infection of commercial winter wheat 'Brawl CL Plus' and Montana State University breeding line MTV1681. Spring wheat cultivars in this study had high WSMV incidence of up to 100% in 'Duclair,' 'Egan,' and 'McNeal.' High WSMV incidence was associated with severe yield losses as high as 85% for Duclair and 'WB9879CLP' in 2019, demonstrating a high degree of susceptibility to WSMV inoculation. Barley cultivars had considerably lower WSMV incidence compared with spring and winter wheat. Grain yield response to WSMV inoculation was variable between barley cultivars. The study provided an experimental basis for cultivar recommendations for high WSMV pressure environments and identified breeding lines and cultivars with potential resistance traits of interest to breeding programs that aim to develop WSMV-resistant cultivars.