Unravelling relationships within Hordeum, one of the largest genera of the tribe Triticeae (Hordeae), is difficult, as many taxa, including most of the polyploids, are of hybrid origin. Mapping phylogenetic relationships, Cuadrado et al. investigate origins and interspecific affinities of the allotetraploids Hordeum secalinum and H. capense using molecular karyotyping.
Genomic in situ hybridization distinguishes the subgenomes Xa and I while FISH/ND-FISH determines the distribution of ten repetitive DNA sequences. Identification of each chromosome pair in the six analysed accessions reveals an intricate pattern of homologous and putative homeologous relationships among barley species carrying the Xa genome.
This paper is part of the Annals of Botany Special Issue on Polyploidy in Ecology and Evolution. It will be free access until October 2017, then available only to subscribers until August 2018 when it will be free access again.