Evolutionary history of wild barley (Hordeum vulgare subsp. spontaneum) analyzed using multilocus sequence data and paleodistribution modeling.

Studies of Hordeum vulgare subsp. spontaneum, the wild progenitor of cultivated barley, have mostly relied on materials collected decades ago and maintained since then ex situ in germplasm repositories. We analyzed spatial genetic variation in wild barley populations collected rather recently, exploring sequence variations at seven single-copy nuclear loci, and inferred the relationships among these populations and toward the genepool of the crop.

Progenitor-derivative relationships of Hordeum polyploids (Poaceae, Triticeae) inferred from sequences of TOPO6, a nuclear low-copy gene region.

Polyploidization is a major mechanism of speciation in plants. Within the barley genus Hordeum, approximately half of the taxa are polyploids. While for diploid species a good hypothesis of phylogenetic relationships exists, there is little information available for the polyploids (4×, 6×) of Hordeum.

Population demography influences climatic niche evolution: evidence from diploid American Hordeum species (Poaceae).

In this study, we explore the interplay of population demography with the evolution of ecological niches during or after speciation in Hordeum. While large populations maintain a high level of standing genetic diversity, gene flow and recombination buffers against fast alterations in ecological adaptation. Small populations harbour lower allele diversity but can more easily shift to new niches if they initially survive under changed conditions.

Two extinct diploid progenitors were involved in allopolyploid formation in the Hordeum murinum (Poaceae: Triticeae) taxon complex.

Wall barley (Hordeum murinum) occurs with three subspecies, naturally distributed from southern Central Asia through the Mediterranean region to northwestern Europe, but now is an invasive weed in many parts of the world. Subspecies glaucum is diploid, while subspp. murinum and leporinum are tetraploids, the latter also occurring with a hexaploid cytotype.

Phylogeographic analyses and paleodistribution modeling indicate pleistocene in situ survival of Hordeum species (Poaceae) in southern Patagonia without genetic or spatial restriction.

Although many phylogeographic studies have been conducted to analyze the impact of the ice age on species history of Northern Hemisphere mountain plants, such studies are nearly absent for plants of the Southern Hemisphere, particularly for lowland vegetation units. These species should have been primarily influenced by climate cooling and changes in precipitation regime instead of glaciers covering their distribution areas. It is thought that New World lowland species generally evaded climate changes by equatorial migration during Pleistocene cold cycles and recolonized their habitats at higher latitudes when climate warmed up again.

Combined ecological niche modelling and molecular phylogeography revealed the evolutionary history of Hordeum marinum (Poaceae)--niche differentiation, loss of genetic diversity, and speciation in Mediterranean Quaternary refugia.

The Hordeum marinum species group consists of two annual grasses of western Eurasian saline meadows or marshes. The two grasses split in the Quaternary about two million years ago. Hordeum marinum and the diploid of Hordeum gussoneanum (2x) co-occur throughout the Mediterranean basin, while the autotetraploid cytotype of H.

A chloroplast genealogy of hordeum (poaceae): Long-term persisting haplotypes, incomplete lineage sorting, regional extinction, and the consequences for phylogenetic inference.

To analyze reasons for inconclusive results of earlier chloroplast phylogenies in the grass genus Hordeum, we established a genealogy of chloroplast haplotypes by sequencing the trnL-trnF region in 875 individuals, covering all 31 species of the genus. Although the outcomes of phenetic and parsimony analyses of 88 haplotypes were ambiguous, a network approach showed that in Hordeum ancient chloroplast types co-occur with their descendants. Moreover, we found up to 18 different chloroplast haplotypes within a single species and up to 6 species sharing single haplotypes.

The considerable genome size variation of Hordeum species (poaceae) is linked to phylogeny, life form, ecology, and speciation rates.

Genome size variation in plants is thought to be correlated with cytological, physiological, or ecological characters. However, conclusions drawn in several studies were often contradictory. To analyze nuclear genome size evolution in a phylogenetic framework, DNA contents of 134 accessions, representing all but one species of the barley genus Hordeum L.