title: Molecular phylogeny of the genus Hordeum using three chloroplast DNA sequences.
abstract: The genus Hordeum consists of three cytotypes (2x, 4x, and 6x). Its reproductive isolation has been incomplete between closely related species and hence the genetic relationship is reticulate and complex. We used 32 taxa of Hordeum and three chloroplast DNA sequences, matK, atpB-rbcL, and trnL-trnF in the current study. Molecular phylogenetic analysis based on sequence data of the three chloroplast DNA regions clearly demonstrated genetic relationships among taxa and origin of polypoids. The formation of H. secalinum likely involved hybridization between Hordeum marinum subsp. marinum and a Eurasian diploid possessing the H genome. The formation of hexaploid Hordeum brachyantherum involved hybridization between tetraploid H. brachyantherum and diploid H. marinum subsp. gussoneanum. The formation of three tetraploids, H. brachyantherum, Hordeum jubatum, and Hordeum guatemalense, probably involved hybridization between H. brachyantherum subsp. californicum and an altered H genome diploid. The formation of Hordeum arizonicum involved the two taxa Hordeum pusillum and H. jubatum.
authors.affiliation: Genetic Diversity Department, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602, Japan. tomotaro@affrc.go.jp
authors.forename: Tomotaro
authors.initials: T
authors.lastname: Nishikawa
authors.forename: Björn
authors.initials: B
authors.lastname: Salomon
authors.forename: Takao
authors.initials: T
authors.lastname: Komatsuda
authors.forename: Roland
authors.initials: R
authors.lastname: von Bothmer
authors.forename: Koh-ichi
authors.initials: K
authors.lastname: Kadowaki
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D018742:DNA, Chloroplast / Q000235:genetics*; D018745:Genome, Plant; D001467:Hordeum / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D018742:DNA, Chloroplast