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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #353622
Title: Variation among orchardgrass (Dactylis glomerata L.) germplasm for choke prevalence caused by Epichloe typhina

Author
item Bushman, Shaun
item SINGH, DEVESH - Barenbrug West Coast Research Station
item LAMP, ROBIN - Barenbrug West Coast Research Station
item YOUNG, CAROLYN - Noble Research Institute
item CHARLTON, NIKKI - Noble Research Institute
item Robins, Joseph
item ANDERSON, NICOLE - Oregon State University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2018
Publication Date: 12/4/2018
Citation: Bushman, B.S., Singh, D., Lamp, R., Young, C.A., Charlton, N.D., Robins, J.G., Anderson, N. 2018. Variation among orchardgrass (Dactylis glomerata L.) germplasm for choke prevalence caused by Epichloe typhina. Plant Disease. 103(2):324-330. https://doi.org/10.1094/PDIS-05-18-0867-RE.
DOI: https://doi.org/10.1094/PDIS-05-18-0867-RE

Interpretive Summary: Orchardgrass, or cocksfoot (Dactylis glomerata L.) is a cool-season forage grass susceptible to the choke disease caused by sexual Epichloe typhina. Choke has been reported in orchardgrass seed production fields across the temperate regions of the world, but fungicides have not been efficacious in reducing choke incidence or prevalence. In order to assess the potential for genetic resistance or tolerance of orchardgrass to choke, we evaluated the variation in orchardgrass cultivars and accessions for choke prevalence and characterized infected plants for endophyte secondary metabolite and mating type gene presence. Significant variation was detected across years and locations. Choke prevalence did not always increase with the age of the stand, nor did choke prevalence correlate with flowering time or swathing time of the entries. Both mating types of E. typhina were detected in approximately equal proportions, and no evidence for loline, ergot alkaloid, or indolediterpene biosynthesis was found. Plants with multiple tillers often showed more than one mating type present in the plant, indicating multiple infections. Both accessions and cultivars with significant choke, and no choke, were detected; which preesent sources of germplasm for further testing and breeding.

Technical Abstract: Orchardgrass or cocksfoot (Dactylis glomerata L.), is a cool-season forage grass susceptible to the choke disease caused by sexual Epichloe typhina. Choke has been reported in orchardgrass seed production fields across the temperate regions of the world, but fungicides have not been efficacious in reducing choke incidence or prevalence. In order to assess the potential for genetic resistance or tolerance of orchardgrass to choke, we evaluated the variation in orchardgrass cultivars and accessions for choke prevalence and characterized infected plants for endophyte secondary metabolite and mating type gene presence. Significant variation was detected across years and locations. Choke prevalence did not always increase with the age of the stand, nor did choke prevalence correlate with flowering time or swathing time of the entries. Both mating types of E. typhina were detected in approximately equal proportions, and no evidence for loline, ergot alkaloid, or indolediterpene biosynthesis was found. Plants with multiple tillers often showed more than one mating type present in the plant, indicating multiple infections. Both accessions and cultivars with significant choke, and no choke, were detected; which present sources of germplasm for further testing and breeding.