Variation in agronomic and morphological traits among Russian wildrye accessions

Russian wildrye [Psathyrostachys juncea (Fischer) Nevski] accessions in the U.S. National Plant Germplasm System have not been adequately characterize d for agronomic and morphological traits. Such characterization would be he lpful in development of improved cultivars. Objectives of this study were t o (i) measure consistency of dry-matter and seed yields as well as plant he ight and vigor of 65 Russian wildrye accessions and four cultivars at three diverse test sites, (ii) characterize phenotypic diversity among these acc essions using cluster analysis, and (iii) define needs for future evaluatio n and collection of Russian wildrye germplasm, Field tests were conducted a t Logan, UT; Mandan, ND; and Swift Current, Saskatchewan, Canada, Dry-matte r and seed yields were not consistent among accessions and cultivars at the three locations, and testing at each location was necessary to identify ac cessions that were best suited to a specific location. Variance component e stimates were small and of little consequence for accession x year interact ion effects. The 69 entries were grouped into 10 clusters based on multivar iate analysis of 17 classification variables. Accessions in Cluster 3 avera ged well above the overall test mean for dry-matter yield, seed yield, and plant vigor and have high utility in plant breeding programs in North Ameri ca. Only four accessions had high levels of resistance to Seproria spraguei Uecker & J.M. Krupinsky, an important foliar disease. Accessions from a de fined geographic area tended to cluster, but some accessions from a particu lar area were spread among several clusters, This emphasizes the value of s ampling diverse collection sites within a defined geographic area.