Submitted to: International Turfgrass Society Research Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/1/2004
Publication Date: 5/15/2005
Citation: Poole, G.J., Johnson, W.J., Johnson, R.C. 2005. Regional climatic characterization of pacific northwest, usa, green-type poa annua. International Turfgrass Society Reseach Journal. 10:565-571 Interpretive Summary: Annual bluegrass (Poa annua) appears to be a wild species with a high environmental plasticity. Presently, there are an unknown number of biotypes flourishing in the turf grass ecosystem. This research has illustrated that there are well-adapted populations of P. annua with acceptable putting green quality on Pacific Northwest golf courses. The climatic region variability identified in this study can be used in future P. annua collection and breeding programs to develop greens type P. annua with superior turf quality and acceptable commercial seed production characteristics. The northwestern coastal region of Oregon and southwestern Washington offers the most promise for germplasm collection of greens type P. annua in the Pacific Northwest.
Technical Abstract: Poa annua L. (annual bluegrass) has become one of the most dominant naturally invading turfgrass species of older, highly maintained golf courses. The most intensively-managed areas of the golf course are the greens, where many unique, high-density biotypes of P. annua thrive. The objective of this study was to relate agronomic and collection site parameters of P. annua f. reptans (Hausskn.) T. Koyama accessions (biotypes) to their climatic region of origin in the Pacific Northwest, USA. Accessions of P. annua f. reptans distinguished in morphology were collected from 78 golf courses throughout Washington, Oregon, and Idaho. For each accession, three cores were transplanted into a field plot on 0.6 m spacing at Pullman, W A arranged in a randomized complete block with three replications. In addition to six collection site parameters, accessions were evaluated for 10 agronomic parameters in field trials from September 1999 to August 2000. The 78 golf course sites were placed into six climatic regions by unweighted pair-group method using arithmetic averages (UPGMA) cluster analysis based on long-term data for temperature, rainfall, snowfall, and growing degree days from 26 weather stations in close proximity to the golf course collection sites. Analysis of variance and principle components analysis differentiated climatic regions based on accession parameters. Accessions from the cool-moist, primarily, coastal region of northwestern Oregon and southwestern Washington were the most unique. In particular, these accessions were characterized by good turfgrass quality and produced few seedheads, which would make a superior greens-type turfgrass but could place limitations on seed production.