Title:

Evaluation of Diverse Kentucky Bluegrass Germplasm for Seed Production in Alternative Residue Management Systems

Objectives:

1. Evaluate phenotypic and genetic diversity in Kentucky bluegrass germplasm with a wide genetic base.
2. Determine seed production capacity of diverse germplasm in burn and alternative residue management systems while evaluating for turf potential.

Principal Investigator:

Dr. William J. Johnston, Assistant Agronomist,
Department of Crop and Soil Sciences, WSU, Pullman, WA

Cooperators:

Dr. Richard C. Johnson, Research Agronomist,
USDA/ARS Western Regional Plant Introduction Station, Pullman, WA

Dr. Robert L. Warner, Plant Physiologist,
Department of Crop and Soil Sciences, WSU, Pullman, WA

Dr. Jerrry Sitton, Plant Pathologst, WSU, Pullman, WA
Department of Crop and Soil Sciences, WSU, Pullman, WA

Mr. Matthew C. Nelson, Graduate Student, WSU, Pullman, WA
Department of Crop and Soil Sciences, WSU, Pullman, WA

Abstract:

Field studies were begun in 1994 to estimate diversity within the USDA/ARS plant introduction collection of 228 Kentucky bluegrass (Poa pratensis L.) accessions and 17 commercially available cultivars. These studies were continued in 1996 in randomized complete blocks with three replications at Pullman, WA. Experimental units consisted of 1.0-m planting strips with 0.31 m spacing between units. Significant variability was observed for all 17 phenotypic and agronomic traits evaluated for turfgrass and forage characteristics. Wide variation existed in disease resistance, seed yield, and dwarf growth habit. Although highly significant, heading, flowering, and harvest dates had less relative variability. The collection has been characterized by a representative core utilizing cluster analysis (Ward method). Clusters were identified that exhibited high seed yield, dwarf growth, fine texture, and good turfgrass and forage characteristics. The presence of given traits did overlap among clusters, however. The core collection, nine cultivar checks from diverse morphological groups, and 17 selections based on turfgrass potential and seed yield were chosen for studies of seed yield and turfgrass performance in separate plots. Field plots were established in September 1995; however, due to extreme precipitation in the fall, washing of the plots occurred and plots had to be reestablished in 1996. Scoring of RAPD markers for DNA fingerprinting of 228 Kentucky bluegrass accessions and 17 commercial cultivars was completed. A total of 86 reproducible markers were identified and will be used to calculate the genetic distance among cultivars and accessions.

Justification:

Traditionally, Kentucky bluegrass seed production management practices have included open-field burning after harvest to remove residue and stimulate seed production the following year. Field burning, however, produces smoke and particulate pollution of increasing public concern. Increased regulation, restriction, and a complete ban on burning is expected in the years to come. It is uncertain that bluegrass cultivars that maximize seed production under field burning systems will maximize production under alternative residue management systems. As these new management systems are developed, it is critical that new germplasm be identified and developed that maximizes seed production while maintaining turfgrass quality.