RPB2 sequences reveal a close phylogenetic relationship between tetraploid Hordelymus and diploid Hordeum species in Triticeae (Poaceae)

► A 24 bp indel in rpb2 gene was found between two sequences from H. europaeus. ► One genome in tetraploid H. europaeus closely related to the genome in Hordeum species. ► No obvious relationship was found between Hordelymus and either the Ta genome or the Ns genome. ► Our data further confirms that Hordelymus europaeus is allopolyploid.