Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 13, 2011
Publication Date: January 3, 2012
Citation: Jensen, K.B., Mott, I.W., Robins, J.G., Waldron, B.L., Nelson, M. 2012. Genetic improvement and diversity in Snake River wheatgrass (Elymus wawawaiensis) (Poaceae: Triticeae). Rangel Ecol Manage. 65:76-84. Interpretive Summary: Vast areas of semiarid rangelands in the western U.S. are severely disturbed, frequently burned, increasingly eroded, and subsequently infested with troublesome weeds. Reseeding these disturbed rangelands with improved plant materials that are competitive enough to replace existing undesirable vegetation is often the most plausible and economically feasible way to reclaim such sites. This study describes the agronomic and genetic relationships of Snake River wheatgrass and its wildland collections. At least within Snake River wheatgrass, it seems possible to increase through selection traits that will enhance Snake River wheatgrasses ability to establish on semi-arid rangelands and successfully compete with invasive annuals such as cheatgrass and medusahead without affecting the overall genetic makeup of the native populations.
Technical Abstract: With the increased emphasis to use native plant materials in range revegetation programs in the western US, it is critical to develop native grasses that are competitive with invasive weeds, easy to establish, persistent, and produce high seed yield. One such native grass species with appreciable drought tolerance is Snake River wheatgrass (Elymus wawawaiensis J. Carson & Barkworth). Thus, the seed and forage traits and underlying genetic components of National Plant Germplasm System collections of Snake River wheatgrass, 28 half-sib Snake River wheatgrass families, and the cultivar Secar were characterized in 2005 and 2006 at the Nephi Research Field Sataion. Mean total seed yield was significantly (P<0.05) greater in the half-sib families (HSF) (32 g plot-1) than either the PI's (19 g plot-1) or cultivar Secar (22 g plot-1). After several cycles of recurrent selection for individual seed weight (g 100-seeds-1), the HSF possessed significantly (P<0.05) heavier seeds than did the PI's and Secar. The HSF of Snake River wheatgrass possessed significantly (P<0.05) higher rates of seedling emergence than Secar, but were similar to the PI's examined. Likewise the mean dry matter yield (DMY) was significantly (P<0.01) greater in the HSF (314 g plot-1) and Secar (291 g plot-1) than in the PI's (229 g plot-1). Secar had significantly (P<0.05) lower digestibility than did the PI's and the HSF. Given the observed variation and heritability estimates, it seems reasonable that Snake River wheatgrass can be improved for seed yield, 100-seed weight, DMY, IVTD, and decreased NDF.