Comparison of space-plant versus sward plot selection in thickspike wheatgrass (Elymus lanceolatus)

Authors: Robins, Joseph; Jensen, Kevin

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2018
Publication Date: 11/22/2018
Citation: Robins, J.G., Jensen, K.B. 2018. Comparison of space-plant versus sward plot selection in thickspike wheatgrass (Elymus lanceolatus). Plant Breeding. 138(1):114-120. https://doi.org/10.1111/pbr.12662.
DOI: https://doi.org/10.1111/pbr.12662

Interpretive Summary: We evaluate the perfomrance of 50 thickspike wheatgrass families and five cultivars under space-plant and sward plot conditions at a Box Elder County, Utah field site. We measured stand percentage, flag leaf height, and herbage dry mass across three growing seasons. The results were low to moderate heritability of the measured traits. Correlations between the two evaluation systems were also low to moderate. Thus, there was little evidence that selection in space-plant conditions served as an appropriated replacement for selection in sward conditions.

Technical Abstract: Thickspike wheatgrass (Elymus lanceolatus [Scribn. & J.G. Sm.] Gould) is an important native perennial grass species used for rangeland revegetation in North America. Plant breeding efforts relying on space-plant evaluations have resulted in limited improvement in this species. The purpose of this study was to characterize the performance of thickspike wheatgrass half-sib families under space-plant and sward plot evaluations, estimate the correlation between measured phenotypes in both evaluation settings, and determine the validity of selecting thickspike wheatgrass for rangeland revegetation in the non-target environnment space-plant plots. The study included 50 thickspike wheatgrass half-sib families and five commercial cultivars and experimental populations which were evaluated over three years in space-plant and sward plot evaluations at a field site in Box Elder County, Utah, USA. Collected data included stand percentage, flag leaf height, and herbage dry mass. Narrow-sense heritability estimates were low to moderate (h2<0.60) and Spearman and genetic correlation estimates among phenotypes were also generally low to moderate. Overall, there was little evidence to suggest the use space-plant evaluations in thickspike wheatgrass improvement programs.