Origin of the H genome in StH-genomic Elymus species based on the single-copy nuclear gene DMC1

Previous studies have suggested that the H haplome in Elymus could originate from different diploid Hordeum species, however, which diploid species best represent the parental species remains unanswered. The focus of this study seeks to pinpoint the origin of the H genome in Elymus. Allopolyploid Elymus species that contain the StH genome were analyzed together with diploid Hordeum species and a broad sample of diploid genera in the tribe Triticeae using DMC1 sequences. Both parsimony and maximum likelihood analyses well separated the American Hordeum species, except Hordeum brachyantherum subsp. californicum, from the H genome of polyploid Elymus species. The Elymus H-genomic sequences were formed into different groups. Our data suggested that the American Horedeum species, except H. brachyantherum subsp. californicum, are not the H-genomic donor to the Elymus species. Hordeum brevisubulatum subsp. violaceum was the progenitor species to Elymus virescens, Elymus confusus, Elymus lanceolatus, Elymus wawawaiensis, and Elymus caninus. Furthermore, North American H. brachyantherum subsp. californicum was a progenitor of the H genome to Elymus hystrix and Elymus cordilleranus. The H genomes in Elymus canadensis, Elymus sibiricus, and Elymus multisetus were highly differentiated from the H genome in Hordeum and other Elymus species. The H genome in both North American and Eurasian Elymus species was contributed by different Hordeum species.

Characterization of fitness traits in thickspike wheatgrass

Poor seed production and stand establishment are limitations to the use of thickspike wheatgrass [Elymus lanceolatus (Scribn. & J.G. Sm.) Gould] in rangeland re-vegetation projects. This study assessed the heritability of seed production, rhizome proliferation, and biomass production and genotypic correlations among these traits in a population of half-sib thickspike wheatgrass families at a site near Nephi, UT, USA during 2005 and 2006. Heritability estimates were ~ 0.6 for seed production and rhizome spread, but non-significant for biomass production. Genotypic correlations among the traits were all low or non-significant. Key words: Biomass production, genotypic correlation, heritability, rhizome, seed production, thickspike wheatgrass

Mixtures of Buffalograss and Fine Fescue or Streambank Wheatgrass as a Low-maintenance Turf

We investigated mixtures of buffalograss [Buchloë dactyloides (Nutt.) Engelm. `Texoka' and `Cody'] and fine fescue species (Festuca rubra ssp. rubra L. `Vista', F. ovina var. glauca Lam. `Minotaur', F. rubra ssp. commutata Gaud. `Jamestown II') or stream-bank wheatgrass [Agropyron riparium Scribn. & Smith `Sodar'; syn. Elymus lanceolatus (Scribn. & Smith) Gould subsp. lanceolatus] as a low-maintenance turf with low irrigation requirements and season-long green color and growth. Buffalograss plots in Logan, Utah, were overseeded with fine fescue and streambank wheatgrass at two seeding rates. Plots of fine fescue, wheatgrass, or buffalograss alone were also established. At 50% evapotranspiration (ETo) replacement, fine fescues dominated the mixtures with no differences due to seeding rates. Wheatgrass mixture plots were unacceptable in quality. Buffalograss control plots and mixtures were similar for turfgrass quality in August, and fine fescue controls and mixtures were similar in spring and fall. The mixtures performed well in the low-maintenance turf situation, but dominance of fine fescue over the buffalograss limits the potential of these specific mixtures.

Ramet spacing of Elymus lanceolatus (thickspike wheatgrass) in response to neighbour density

Many plants exploit patchy resources through clonal foraging. Plants established in field plots were used to determine if Elymus lanceolatus ssp. lanceolatus (Scribner et J.G. Smith) Gould (thickspike wheatgrass) showed a clonal foraging response to neighbour densities, as it had previously shown to patchy soil nutrients. Neighbours consisted of the rhizomatous E. lanceolatus ssp. lanceolatus and the bunchgrass Elymus lanceolatus ssp. wawawaiensis (Scribner et Gould) J.R. Carlson et D.R. Dewey (proposed name), which are both native to the semiarid western U.S.A., and their ratios as well as total densities varied. Rather than an increase in spacing of exploratory ramets at high densities, as expected with clonal foraging, there was a decrease in spacing in both years of the experiment. Fewer target plants produced exploratory ramets at higher densities only in the second year. These reductions in exploratory clonal growth at higher neighbour densities, which were opposite to E. lanceolatus ssp. lanceolatus' response to low-resource patches, occurred perhaps because soil resource levels were too low overall to support rhizome production, and this condition was more pronounced in the second year. Physical resistance from neighbour roots perhaps also reduced rhizome production. However, rhizome growth may not be beneficial in such cases, and plants may be adapted to produce exploratory rhizomes only when some high-resource patches are encountered by the clone.Key words: clonal growth, competition, Elymus lanceolatus, plasticity, resource levels, rhizomes.

Perception of neighbouring plants by rhizomes and roots: morphological manifestations of a clonal plant

A previous study showed that clonal morphology of the rhizomatous grass Elymus lanceolatus ssp. lanceolatus (Scibner & J.G. Smith Gould) was influenced more by neighbouring root systems than by the local distribution of nutrients. In this study we determine whether individual rhizomes or roots of E. lanceolatus perceive neighbouring root systems and how this is manifested in morphological responses of E. lanceolatus clones. Elymus lanceolatus was grown in the same bin with Pseudoroegneria spicata (Pursh) A. Love or Agropyron desertorum (Fisch. ex Link) Schult. plants. Elymus lanceolatus was separated from its neighbours by different barriers. The barriers allowed either only E. lanceolatus roots; only a single E. lanceolatus primary rhizome; or both roots and rhizomes to contact the neighbour root system. When only a single E. lanceolatus primary rhizome with potentially developing branching rhizomes made contact with the neighbour, the clonal structure of E. lanceolatus was modified more with P. spicata as the neighbour than with A. desertorum. With root contact of E. lanceolatus alone there was a similar effect with the neighbouring plants, but there was a more marked inhibitory effect on E. lanceolatus clonal growth with P. spicata than with A. desertorum, compared with the treatment with only a single rhizome in contact with the neighbour. Root resource competition in the unconstrained treatment (roots and rhizomes) between neighbouring plant and E. lanceolatus was more apparent with A. desertorum than with P. spicata. This study is one of the first to document that rhizome and root contact of a clonal plant with its neighbours may induce different clonal responses depending on the species of neighbour. Key words: Agropyron desertorum, clonal morphology, Elymus lanceolatus ssp. lanceolatus, plant interference, plant contact, Pseudoroegneria spicata, rhizome structure, root systems.