|ELIAS, SABRY - Oregon State University|
|HULTING, ANDREW - Oregon State University|
Submitted to: Seed Technology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2011
Publication Date: 7/31/2011
Citation: Alderman, S.C., Elias, S.G., Hulting, A.G. 2011. Occurrence and trends in weed seed contaminants in fine fescue seed lots in Oregon. Seed Technology Journal. 33:7-21.
Interpretive Summary: Nearly all of the seeds for fine fescues, which are highly valued turfgrass species, are produced in Oregon. A study was initiated to determined the frequency of occurrence and trends in weed seed contamination in commercial fine fescue seed lots. Results from this study provide the first comprehensive analysis of weed seed contamination in fine fescue seed lots, including a list of over 125 weed seed contaminants, their frequency of occurrence and trends from 1986-2006. The information from this study will be of interest to seed marketers, seed testing labs, seed growers, and agricultural specialists such as extension agents, weed scientists and plant pathologists.
Technical Abstract: Fine fescues are highly valued cool-season turf species. Nearly all of the U.S. fine fescue seed is produced in Oregon, although little is known about the occurrence of weed seed contaminants in fine fescue seed lots. This study was conducted to assess the diversity and frequency of occurrence of weed seed in chewings [Festuca rubra L. subsp. commutata Gaudin], red [Festuca rubra L. subsp. rubra], and hard fescue [Festuca trachyphylla (Hack.) Krajina] samples submitted to the Oregon State University Seed Laboratory. The samples represent seed lots from seed production fields. Weed seed data from 1986-1995 and 2002-2006 were collected from the purity analysis reports of certified seed samples of chewings, creeping red and hard fescue. Ninety-five weed seed contaminants were identified to species, with an additional 30 identified to genus. No weed seeds contaminants were found in 30-50% of the seed lots, depending on the year. Typically, fewer than three different weed species were detected within a sample. The most common contaminates, occurring annually, were rattail fescue [Vulpia myuros L.], annual bluegrass [Poa annua L.], and downy brome [Bromus tectorum L.]. Among these, rattail fescue was the most common, occurring in 30-61% of seed samples, depending on the year. The number of weed species varied among years and increased as the number of seed lots tested per year increased. During the past decade, the number of new weed species contaminants detected increased at a rate of approximately three per year.