Submitted to: Proceeding of International Seed Testing World Conference
Publication Type: Proceedings
Publication Acceptance Date: 9/1/2000
Publication Date: N/A
Interpretive Summary: Kentucky bluegrass is used extensively for golf courses, parks, athletic fields, lawns, and grazing pastures. It is the most widely used cool-season turfgrass in North America. Kentucky bluegrass is hardy, persistent, and best adapted to sunny sites in temperate to subarctic climates around the world. There is tremendous diversity within Kentucky bluegrass owing to a long period of natural selection over a wide geographic range with extensive climatic variation. The USDA-ARS maintains a collection of Kentucky bluegrass represented by more than 250 accessions from 27 countries, which is available to researchers at no charge. In a cooperative program between Washington State University and the USDA-ARS, Pullman WA, this collection was extensively evaluated for basic agronomic traits. This information was used to develop a core subset of accessions that represented most of diversity found in the larger collection. This core was used in advanced evaluation work for factors such as yield and turf quality that would have been too expensive to complete on the entire collection. Through this effort, a number of accessions were found that have potential for utilization in breeding programs to develop improved Kentucky bluegrass.
Technical Abstract: To support the expanding turfgrass industry, it is critical that new germplasm be identified and developed that maximizes seed production while maintaining turfgrass quality. Field studies were conducted to estimate the diversity within the USDA-ARS germplasm collection of Kentucky bluegrass (Poa pratensis L.). Ward's cluster analysis was completed on evaluation data based on 17 agronomic factors from 245 accessions resulting in a dendrogram from which 22 clusters were identified. From each cluster an accession was taken at random to develop a core collection representing a large part of the diversity in the total collection. In addition, an analysis using RAPD makers was completed on the same set of material as the agronomic evaluations. There was as significant correlation between the agronomic and molecular distance matrices which showed a degree of correspondence between both data types. The Ward's core and 17 additional selections with high turf potential and seed production potential were grown in separate seed production and field plots. Several accessions had seed yield and turf quality characteristics greater than or equal to the commercial cultivar checks. The core collection enabled a detailed study of seed yield and turf quality in the entire Kentucky bluegrass collection to an extent that would have been prohibitively expensive on the entire collection.