Cytological and molecular approach to analyse Patagonian Bromus species

A. M. GARCÍA, G. E. SCHRAUF, G. GONZÁLEZ, L. POGGIO, C. A. NARANJO, M. P. DUPAL, J. W. FORSTER, G. SPANGENBERG;

Vienna, Austria

Congreso; XVII International Botanical Congress; 2005

UNI-CAMPUS Hörsaalzentrum Vienna

Bromus pictus, B.setifolius and B.brevifolius are taxa of the section Pnigma, native from the Patagonia. It is believed that they constitute a specific complex whose morphological trait variation did not permit a clear delineation between the taxa. Variation within this group was detected using AFLP´s and RAPD´s. B.brevifolius has a close affinity with B. pictus and both taxa are relatively more distantly related to B.setifolius. Cytogenetic analysis revealed that B. setifolius is: 2n=28; B. pictus: 2n=70; and B.brevifolius: 2n=70. The genomic in situ hybridization (GISH) of labelled DNA of B.setifolius over the 70 mitotic chromosomes of B.pictus reveals that the probe hybridized 28 chromosomes, morphologically similar to those of B. setifolius. This result confirms that B pictus must be separated from B.setifolius and given full specific status. Moreover, GISH confirms the allopolyploid origin of B pictus and the relationship with its putative progenitor B.setifolius.