ARS | Publication request: Cheatgrass germination at three seed maturity stages from five plant communities in northwestern Nevada

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 17, 2009
Publication Date: February 8, 2010
Citation: Harmon, D.N., Clements, C.D., Clark, M.D. 2010. Cheatgrass Germination at Three Seed Maturity Stages From Five Plant Communities in Northwestern Nevada [abstract]. Society for Range Management. 63:30.

Technical Abstract: The invasive exotic plant cheatgrass (Bromus tectorum), has invaded numerous plant communities throughout the Intermountain West. Our goal was to test whether cheatgrass seed in different phenotypic stages and site characteristics differ in germination. Cheatgrass seed from sites dominated by Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), Nevada dalea (Psorothamnus polydenius), black greasewood (Sarcobatus vermiculatus), Jeffrey Pine (Pinus jeffreyi) and cheatgrass was collected every 2 weeks from May through July 2009. Seed was put into three categories: 1) immature (green), mature (red) and fully mature seed (tan). Seeds were germinated 1 week after collection under six temperature regimes (2, 5, 15, 20, 25ºC, and 2/15ºC alternating 8/16 hours) as well as three pre-treatments (four weeks dry 40ºC, dry 2ºC, and moist 2ºC). Immature seeds have not previously been reported to germinate, however we did observe germination even though it was at much lower percents than mature seed (Jeffery pine site at 15ºC=13% immature, 49% fully mature). Fully mature seed from the Jeffery Pine and the spotted dahlia collections had the highest germination percent prior to pre-treatments (2/15ºC = 59% and 57%, respectively) and had the largest tiller length of all the sites. The cheatgrass dominated site had the lowest germination (2/15ºC = 4%) and smallest plants. Moist 2ºC pre-chill treatment had the most reliably effect on increasing germination. At the coldest and warmest temperatures 2ºC and 25ºC, very little germination occurred without any pre-treatment. The ability of cheatgrass to germinate at the various phenotypic stages is significant when conducting cheatgrass control efforts as well as the site specific differences that were observed.