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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #350853

Research Project: Develop Improved Plant Genetic Resources to Enhance Pasture and Rangeland Productivity in the Semiarid Regions of the Western U.S.

Location: Forage and Range Research

Title: The relationship between seed mass and young-seedling growth and morphology among nine bluebunch wheatgrass populations

Author
item Jones, Thomas
item MUKHERJEE, JAYANTI - Azim Premji University
item Monaco, Thomas
item ADLER, PETER - Utah State University

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2018
Publication Date: 3/1/2019
Citation: Jones, T.A., Mukherjee, J., Monaco, T.A., Adler, P.B. 2019. The relationship between seed mass and young-seedling growth and morphology among nine bluebunch wheatgrass populations. Rangeland Ecology and Management. 72(2):283-291. https://doi.org/10.1016/j.rama.2018.11.006.
DOI: https://doi.org/10.1016/j.rama.2018.11.006

Interpretive Summary: Native plant materials that are more effective when seeded on harsh semi-arid rangelands are desirable for ecological restoration. However, it is less clear which seedling traits are conducive to establishment under various sets of environmental conditions. We found that diploid bluebunch wheatgrass plant materials displayed greater surface-to-biomass ratios in roots and leaves, while tetraploids produced shoots and roots with greater biomass. In addition, diploids, which tend to originate in driver sites, generally produced lighter seeds than tetraploids. This information may help to develop new plant materials that are more effective, as well as to match existing plant materials to appropriate sites.

Technical Abstract: Across-species relationships among seed mass, seedling morphological traits, and growth rates are well known in plant ecology, but within species, these classical relationships are not always sustained. We measured speed of germination, seedling root production, and seedling relative growth rate (RGR), as these traits are expected to impact establishment success of bluebunch wheatgrass (BBWG) (Pseudorogneria spicata) seedlings. We evaluated six diploid and three tetraploid populations of BBWG, a perennial Triticeae bunchgrass native to the Intermountain West, for seedling growth under two day/night temperature regimes (20/15 degrees C; 10/5 degrees C). Then we correlated seed mass with onset of germination, seedling morphological traits, absolute growth rate (AGR) and RGR. At the very-young seedling stage, we found differences among populations for AGR but not RGR. Lighter-seeded populations (all diploid) germinated and initiated shoots earlier and produced greater specific leaf area and specific root length (SRL). Heavier-seeded populations (mostly tetraploid) displayed greater shoot and root biomass, shoot length, and AGR. The light-seeded diploid, P-24, originated from the most arid site and exhibited the highest SRL at low temperature, while the heavy-seeded tetraploid, T-17t, originated from the most mesic site and exhibited moderate SRL. 'Whitmar', 'Goldar', and 'Anatone' Germplasm, all diploid populations valuable for rangeland revegetation, exhibited low seed mass and high SRL. Anatone displayed high root-to-shoot length at both high and low temperatures, perhaps explaining its wide and successful use in rangeland seedings.