Kentucky Bluegrass Germplasm Evaluation for Seed Production without Open-Field Burning.

Open-field burning of Kentucky bluegrass (Poa pratensis L.) post-harvest residue, which maintains grass seed yield and stand longevity, has been eliminated in Washington and is severely restricted in Idaho and Oregon.  The objective of the study was to develop bluegrass cultivars that have sustainable seed yield without post-harvest field burning while maintaining acceptable turfgrass quality.  The study consisted of eight PI accessions and two check cultivars (‘Kenblue’ and ‘Midnight’).  Accessions were previously selected for both seed yield without field burning and turfgrass quality.  In a space-plant nursery at Pullman, WA, several agronomic yield parameters were evaluated over a 2-year period and individual plants were re-selected within each accession, or check, with the highest seed weight, highest seeds panicle^-1, highest panicle number area^-1, and highest seed yield.  Remnant seed from the original populations were also included.  At Pullman, WA, turfgrass plots were established in 2006 and irrigated and non-irrigated seed production plots were established in 2007.  The turfgrass trial was evaluated monthly from 2007 to 2010 according to National Turfgrass Evaluation Program protocol for turfgrass quality.  Seed production plots were harvested 2008 to 2011.  Selection for seed yield components had a variable response and yield was more dependent on accession.  Accession PI 368241 and Kenblue selection for seeds panicle^-1 showed promise of being able to provide excellent seed yield under both irrigated and non-irrigated non-burn management over multiple years (four harvests) while maintaining good turfgrass quality.  These studies will be followed at least through 2012 (5^th harvest) to determine if a non-burn turf-type Kentucky bluegrass can be developed for sustainable grass seed production for the Pacific Northwest.