Kentucky Bluegrass Germplasm Evaluation for Non-Burn Seed Production.

Removal of post-harvest residue with open-field burning, which maintains grass seed yield and stand longevity, has been eliminated in Washington and is restricted in Oregon and Idaho.  Our objective is to develop Kentucky bluegrass (Poa pratensis L.) cultivars that have sustainable seed yield without field burning and still maintain acceptable turfgrass quality.  The study consists of eight PI accessions and two checks (‘Kenblue’ and ‘Midnight’).  Accessions were previously selected for seed yield without burning and turf quality.  In a space-plant nursery at Pullman, WA, several agronomic yield parameters were evaluated over a 2-yr period and individual plants were selected within each accession or check with the highest seed weight, highest seeds per panicle, highest panicle number per unit area, and highest seed yield.  These, plus seed from the original population, were planted in a seed increase nursery at Central Ferry, WA.  The nursery was harvested in June 2006 and 2007 and seed was planted in turfgrass plots in 2006 and seed production plots in 2007 at Pullman, WA.

The turfgrass trial was evaluated monthly during 2007 and 2008 according to National Turfgrass Evaluation Program protocol for establishment, turf quality, color, texture, chlorophyll index, and spring green-up.  In 2008, seed production plots were evaluated for seed yield, seed weight, seed yield per plant, seed per panicle, and panicle number per unit area.  Selection for seed yield components had a variable response and appeared to be dependent on accession.  Two accessions, PI 371775 and PI 368241, show promise of being able to provide good turfgrass quality and seed yield under non-burn management.  These studies will be followed for several harvests to determine if a turf-type Kentucky bluegrass can be developed for sustainable seed production without field burning in the Pacific Northwest.