the phylogenetic relationships of species and cytotypes in the genus hordeum based on molecular karyotyping

1. Abstract Unravelling the relationships between the members of  Hordeum  is no easy task since many of its member taxa, including most of the tetra- and hexaploids, is of hybrid origin.  Hordeum  is one of the largest genera of the family Triticeae with more than 30 species dispersed all over the world. In order to analyze the phylogenetic relationships, intraspecific diversity and origin of polyploids, our group reported detailed ND- FISH, FISH and GISH based karyotypes of more than 50 accessions of different species and cytotypes of the four genomes ( H ,  Xa ,  Xu  and  I ) of the genus  Hordeum . This review will compile all this information with new accessions not reported previously. Each chromosome pair in all the accessions analyzed was identified and subgenomes distinguished in polyploids. The results allowed the assessment of the chromosomal diversity within species and the identification of possible homeologous relationships. A scheme of probable evolution shows the intricate pattern of relationships among species: 1) Genome  H :  H. vulgare  subsp.  vulgare  (2x) and subsp.  spontaneum  (2x) and  H. bulbosum  (2x and 4x). 2) Genome  Xa :  H. marinum  subsp.  marinum  (2x) and subsp.  gussoneanum  (2x and 4x). 3) Genome  Xu :  H. murinum  subsp.  glaucum  (2x and 4x), subsp.  murinum  (4x and 6x) and subsp.  leporinum  (4x and 6x). 4) Genome  I : The diploids  H. californicum ,  H. intercedens ,  H. cordobense ,  H. chilense ,  H. roshevitzii , and  H. bogdanii , and 4x  H. brachyantherum  and 5) Allopolyploids with  Xa  and  I  genomes:  H. secalinum  (4x),  H. capense  (4x) and 6x  H. brachyantherum . 2. Keywords :  Allopolyploids, Barley; Evolutionary History; FISH; GISH; Hordeum, ND-FISH; satDNA; SSRs