Phylogenetic analysis of Hordeum marinum Huds. based on nucleotide sequences linked to the vrs1 locus

More than 100 accessions of Hordeum marinum ssp. marinum, ssp. gussoneanum 2x and ssp. gussoneanum 4x were studied by analyzing the nuclear DNA homologous to the chloroplast translation elongation factor. PCR amplification using the locus-specific primers generated a 932 bp fragment from ssp. marinum, a 915 bp fragment from ssp. gussoneanum 2x, and 915 bp and 931 bp fragments from ssp. gussoneanum 4x. Sequencing of the entire DNAs showed that the 915-bp fragments of diploids and tetraploids are identical, indicating that the diploid probably is the immediate donor of the 915-bp fragment of tetraploids. Although the donor of the 931-bp fragment was not determined, phylogenetic analysis of the data showed that the clade of the 931-bp fragment was included in the H. marinum complex. A MspI site was diagnostic to distinguish ssp. marinum into two clades with disjunct distributions, the Iberian Peninsula (type 2) and other regions (type 1). Nucleotide variation was revealed in the type 2 accessions but all the other clades were highly uniform.