Identification of thickspike wheatgrass accessions with superior rhizome spread, seed production, and seed quality

Thickspike wheatgrass (Elymus lanceolatus (Scribn. & J.G. Sm.) Gould [Poaceae]) accessions evaluated for performance in the Intermountain/Great Basin region of the US differed significantly (P = 0.05) for several agronomic and seed quality traits. In this study, 50 accessions of thickspike wheatgrass, including all accessions in the USDA National Plant Germplasm System collection and 5 cultivars were characterized for rhizome spread and seed production at a site near Eureka, Utah, during 2007 and 2008. The resulting seeds from both production years were then further evaluated in laboratory and greenhouse experiments for germination percentage, seed weight, emergence rate, and total emergence after deep seeding. Significant interaction between the accessions and the year of production necessitated characterization of results within each year of production, rather than across years. The Utah Experimental population was among the highest performing accessions for 4 of the traits in at least one of the years of the study. None of the accessions, however, were among the high performers for all 6 evaluated traits. Based on summation of accession standard normalized mean variables for each trait, several accessions including 552794 from Colorado and 562039 from Wyoming showed promise for combining good performance for most of the traits for production in the Intermountain/Great Basin region. Accessions from outside this area were poorly adapted. Thus, untapped potential exists to cultivate thickspike wheat-grass seed sources with higher seed production and seed quality than are now commercially available.