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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #299759

Title: Occurrence and trends of weed seed and ergot contaminants in Oregon grown Poa pratensis and Poa trivialis seed lots

item Alderman, Stephen
item ELIAS, SABRY - Oregon State University
item HULTING, ANDREW - Oregon State University

Submitted to: Seed Technology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2014
Publication Date: 11/30/2014
Citation: Alderman, S.C., Elias, S.G., Hulting, A.G. 2014. Occurrence and trends of weed seed and ergot contaminants in Oregon grown Poa pratensis and Poa trivialis seed lots. Seed Technology Journal. 35(2):237-250.

Interpretive Summary: Oregon is a major producer of Kentucky bluegrass and rough bluegrass seed, although little is know about the occurrence of weed seed and ergot contaminants in bluegrass seed lots. Oregon State University Seed Lab records from 1986-1995 and 2002-2010 were used to determine weed seed and ergot contaminant frequency of occurrence and trends within each of three major production areas . This study revealed a wide and increasing diversity of weed seed contaminants in bluegrass seed lots and provides comprehensive summary of contaminants that will be of interest to seed growers, seed testing labs, seed cleaners, pathologists, and weed scientists.

Technical Abstract: This study was conducted to assess the diversity and frequency of occurrence of weed seeds and sclerotia of the fungus Claviceps purpurea (ergot) in certified seed lots of P. pratensis (Kentucky bluegrass) and P. trivialis (rough bluegrass) based on purity analysis at the Oregon State University Seed Laboratory during 1986-1995 and 2002-2012. Oregon is well known for grass seed production; although little is known about weed seed and ergot contamination of certified Oregon Poa seed. For P. pratensis, 155 different weed seed contaminants were detected, with 113 identified to species, 39 to genus, and 3 to family. For P. trivialis, 26 contaminants were identified to species and 14 to genus. Between 2002 and 2012, the percentage of seed lots per year with no weed contaminants ranged from 48% to 75% and 43% to 68% for P. pratensis and P. trivialis, respectively, depending on year, indicating consistent high quality standards for Oregon certified seed. Between 1985 and 2012 the number of new contaminants in P. pratensis increased at the rate of three new contaminates per year. In P. trivialis only one new contaminant species was detected after 2007. The percentage of P. pratensis or P. trivialis seed lots with ergot ranged from 22% to 61%, and 0% to 10% respectively, depending on year with no trend of increasing or decreasing level of ergot. This study documented a wide and increasing diversity of weed seed contaminants, especially in P. pratensis and revealed that although the level of ergot from year to year is variable, ergot remains a persistent problem in P. pratensis seed production and as a seed contaminant.