Bluegrass Seed Production without 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 restricted in Oregon and Idaho.  The objective of the study was to develop cultivars that have sustainable seed yield without post-harvest field burning and still maintain 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 unit area^-1, and highest seed yield.  These, plus remnant seed from the original population, were planted in a seed increase nursery that was harvested in June 2006 and 2007.  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 2010.  Selection for seed yield components had a variable response and yield was more dependent on accession.  Accession PI 368241 showed promise of being able to provide excellent seed yield under both irrigated and non-irrigated non-burn management over multiple years while maintaining good turfgrass quality.  Under non-irrigated seed production, selection within Kenblue for seeds panicle^-1 had good seed yield and turfgrass quality.  These studies will be followed for one to two additional harvests to determine if a non-burn Kentucky bluegrass can be developed for sustainable grass seed production for the Pacific Northwest.