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ARS Home » Pacific West Area » Pullman, Washington » Plant Germplasm Introduction and Testing Research » Research » Publications at this Location » Publication #307870
Title: Relating adaptive genetic traits to climate for Sandberg bluegrass from the intermountain western United States

Author
item Johnson, Richard
item HORNING, MATTHEW - Us Forest Service (FS)
item Espeland, Erin
item VANCE-BORLAND, KEN - The Conservation Planning Institute, Inc

Submitted to: Evolutionary Applications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2014
Publication Date: 1/28/2015
Citation: Johnson, R.C., Horning, M.E., Espeland, E.K., Vance-Borland, K. 2015. Relating adaptive genetic traits to climate for Sandberg bluegrass from the intermountain western United States. Evolutionary Applications. 8:172-184. doi:10.1111/eva.12240.

Interpretive Summary: A cycle of increasingly frequent fires and the spread of invasive weeds--aggravated by changing climate--is eroding the stability and functionality of rangeland plant communities in the inter-mountain Western U.S. Among the important rangeland species in the inter-mountain West is Sandberg bluegrass. It is grazed by livestock and wildlife, the seeds are consumed by birds and small mammals, and it is competitive with invasive weeds. Yet there are no studies of its genetic variation in relation to source climates, or guidelines for seed transfer of Sandberg bluegrass to ensure adaptation and genetic diversity during restoration. Research in common gardens revealed extensive genetic diversity in Sandberg bluegrass for plant adaptive traits among 130 populations collected across the inter-mountain West. In common gardens, accessions from warmer, dryer locations generally had earlier development, lower dry weight, and smaller, narrower leaves than those from cooler, wetter locations. Statistical models were developed that related genetic variation and source climates. These were mapped using a geographic information system resulting in 12 seed zones to guide the choice of germplasm in restoration in the inter-mountain west. Of the 700981 km2 mapped, four seed zones represented 92% of the area in typically semi-arid and arid regions. The link between genetic variability and source climates suggested climate driven natural selection and evolution. We recommend the use of seed transfer zones to enhance Sandberg bluegrass adaptation and diversity for large scale restoration projects.

Technical Abstract: Genetic variation for potentially adaptive traits of the key restoration species Sandberg bluegrass (Poa secunda J. Presl) was assessed over the intermountain western United States in relation to source climate. Common gardens were established at two intermountain west sites with progeny from two maternal parents from each of 130 wild populations. Data was collected over two years at each site on fifteen plant traits associated with production, phenology, and morphology. Analyses of variance revealed strong population differences for all plant traits (P<0.0001), indicating genetic variation. Both the canonical correlation and linear correlation established associations between source populations and climate variability. Populations from warmer, more arid climates had generally lower dry weight, earlier phenology, and smaller, narrower leaves than those from cooler, moister climates. The first three canonical variates were regressed with climate variables resulting in significant models (P<0.0001) used to map 12 seed zones. Of the 700981 km2 mapped, four seed zones represented 92% of the area in typically semi-arid and arid regions. The association of genetic variation with source climates in the intermountain west suggested climate driven natural selection and evolution. We recommend seed transfer zones and population movement guidelines to enhance adaptation and diversity for large scale restoration projects.