Analysis by PCR-based markers using designed primers to study relationships between species of Hordeum (Poaceae)

An investigation was made into the relationships between six species or sub species of the genus Hordeum that grow in the Iberian Peninsula and Baleari c Islands. Plant material included samples of 19 populations of the annual species H. marinum subsp. marinum, H. marinum subsp. gussoneanum, H. murinu m subsp. murinum, and H. murinum subsp. leporinum, and the perennial specie s H. bulbosum and H. secalinum. Relationships were analysed using PCR-based molecular markers. Thirteen sets of primers were designed and synthesized based on sequences of mapped RFLPs from genomic libraries and conserved reg ions of structural genes of known function in cultivated species. Primers w ere used to amplify genomic DNA from all populations. The number of amplifi ed products ranged from 1 to 18 per primer and a total of 168 markers were scored. The markers revealed different degrees of relationships. Hordeum bu lbosum was clearly separated from the rest. The populations of both subspec ies of H. murinum were closely related. H. marinum subsp. gussoneanum appea red to be closely related to H. secalinum, yet relatively separated from it s conspecific subspecies marinum. The use of a large number of DNA markers in this kind of analysis is discussed.