Skip to main content
ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #327167

Research Project: Develop Improved Plant Genetic Resources to Enhance Pasture and Rangeland Productivity in the Semiarid Regions of the Western U.S.

Location: Forage and Range Research

Title: Progress on the determination of genetic variation for orchardgrass' resistance to the choke disease

item Bushman, Shaun

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/16/2016
Publication Date: 3/2/2016
Citation: Bushman, B.S. 2016. Progress on the determination of genetic variation for orchardgrass' resistance to the choke disease. Meeting Abstract.

Interpretive Summary:

Technical Abstract: Choke is a disease caused by a sexual form of the fungus Epichloe typhina. Choke specifically occurs in some pasture and turf grasses while not in others. In orchardgrass, the sexual forms of Epichloe typhina rapidly mass around the seed head of orchardgrass at the time of flowering, and thus choke off the production of seed. Choke infestations have caused up to 50% loss of seed production in some stands. Because of this dilemma, we initiated a project to assess if there is variation among orchardgrass sources in the ability of choke to occur. We established two replicated field trials of 48 orchardgrass varieties and accessions near Albany, Oregon. Each year at heading, we counted the number of plants in each plot that have choke and have tracked the progression of the disease for two years. We found that certain varieties quickly became infested with choke, while most varieties showed a slower incidence and progression. Some varieties still do not show any choke in their replicated plots. These data indicate differences among orchardgrass sources in their ability to be affected by Epichloe typhina.