Russian wildrye [Psathyrostachys juncea (Fischer) Nevski] accessions
in the U.S. National Plant Germplasm System have not been
adequately characterized for agronomic and morphological traits.
Such characterization would be helpful in development of improved
cultivars. Objectives of this study were to (i) measure consistency of
dry-matter and seed yields as well as plant height and vigor of 65
Russian wildrye accessions and four cultivars at three diverse test
sites, (ii) characterize phenotypic diversity among these accessions
using duster analysis, and (iii) define needs for future evaluation and
collection of Russian wildrye germplasm. Field tests were conducted at
Logan, UT; Mandan, ND; and Swift Current, Saskatchewan, Canada.
Dry-matter and seed yields were not consistent among accessions
and cultivars at the three locations, and testing at each location was
necessary to identify accessions that were best suited to a specific
location. Variance component estimates were small and of little consequence
for accession x year interaction effects. The 69 entries were
grouped into 10 clusters based on multivariate analysis of 17 classification
variables. Accessions in Cluster 3 averaged 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 America. Only four
accessions had high levels of resistance to Septoria spraguei Uecker &
J.M. Krupinsky, an important foliar disease. Accessions from a defined
geographic area tended to cluster, but some accessions from a particular
area were spread among several clusters. This emphasizes the value
of sampling diverse collection sites within a defined geographic area