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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #351477

Title: Productivity and morphological traits of thickspike wheatgrass, Snake River wheatgrass, and their interspecific hybrids

item BELL, B - Utah State University
item Jones, Thomas
item Monaco, Thomas

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2018
Publication Date: 1/1/2019
Citation: Bell, B.P., Jones, T.A., Monaco, T.A. 2019. Productivity and morphological traits of thickspike wheatgrass, Snake River wheatgrass, and their interspecific hybrids. Rangeland Ecology and Management. 72(1):73-81.

Interpretive Summary: Rangeland environments in the Intermountain Region are increasingly in need of restoration due to abiotic and biotic stresses. In turn, improved plant materials are needed that may tolerate these stresses and return productivity to the land. Thickspike wheatgrass (TSWG) displayed desirable traits, e.g., low specific leaf area (SLA) and high specific root length (SRL), that may confer stress tolerance relative to TSWG's closest relative, Snake River wheatgrass (SRWG). Hybrids of these species produced more aboveground biomass than SRWG. However, SLA and SRL were similar between hybrids and SRWG, while root biomass of hybrids was lower. Hybrid materials may have a place in rangeland seedings, but because of these findings more documentation of their performance under drought conditions is warranted prior to widespread use.

Technical Abstract: We measured shoot and root dry-matter (DM), seed yield, specific leaf area (SLA), C:N ratio, and specific root length (SRL) of 9 Elymus populations ('Bannock' thickspike wheatgrass [TSWG] (E. lanceolatus); 'Secar', 'Discovery' and 3 experimental Snake River wheatgrass [SRWG] (E. wawawaiensis) populations; and 3 interspecific hybrid TSWG x SRWG populations) in two replicate field experiments at Millville, UT. Seedlings were transplanted from a greenhouse into high-density (25 plants/m2) and low-density plots (7.8 plants/m2) in spring 2005 (Exp. 1) and again in spring 2006 (Exp. 2). Shoot DM was quantified in Nov. 2005 and July 2006 (Exp. 1) and in Oct. 2006 and July 2007 (Exp. 2). Bannock TSWG and the hybrids displayed 38.6-158.2% and 10.4-33.7% greater shoot DM per plant (P<0.0001) than SRWG, respectively, in six comparisons each across the two experiments. In Exp. 2, where a density x population interaction (P<0.0001) for shoot DM was present in both years, Bannock TSWG also displayed a greater increase in shoot DM per plant at high density relative to low density (183.7% and 202.0% in year 1 [establishment year] and year 2, respectively) than hybrid (85.7-119.2% and 117.4-135.1%) or SRWG (61.9-130.2% and 123.2-140.6) populations. Bannock TSWG also displayed 22.4% lower SLA (P<0.01), 11.1% higher C:N ratio (P<0.05), and 61.9% greater SRL (P<0.0001 than SRWG, while the hybrids were similar (P>0.05) to SRWG for these traits. Bannock TSWG consistently displayed greater shoot DM than SRWG and TSWG x SRWG hybrid plant materials, and its morphological traits (rhizomes, low SLA, high SRL) may have allowed it to tolerate or avoid moisture and nutrient stress. Current work emphasizes recurrent selection for fertility and seed yield in the E-38X hybrid population with the goal of developing plant material suitable for rangeland seedings.