Cytogenetic and molecular characterization of somatic hybrids between Solanumcultivars and Solanum bulbocastanum

Somatic hybrids between five different cultivars of potato Agave, Baltica, Delilcat, Quarta and Rasant and the wild species Solanum bulbocastanum characterized for high resistance to late blight have bee.n produced by mesophyll protoplast electrornsion. Eightepn putative somatic hybrid plants have been analyzed by flow cytometry. microsatellites (SSR) using seven primers for expressed sequences, cnrornosomes- numbers using DAPI stain1ng and GrSH using staining with FITC and counterstaining with DAPI and hybridization with S. bulbocastanum DNA. All the plants analyzed proved to be somatic hybrids. Moreover, the results obtained so far show regenetation of both symmetric and asymmetric hybrids, and the integration of a limited number of chroroosome.c; from tl~ wild species into potato genome. Out of 7 EST-SSR primers 4 gave polymorphism and allow good characterjzation of the somatic hybrids. One somatic hybdd between potato cv. Delikat and S. bulbocastanum was shown as tetraploia by uowcytometric analysis; some amplification bands are missing in SSR electrophoreograms indicating loss of potato genetic material; the integration of S. bulbocastanum DNA was revealed by GISH. Although electrofusion of mesophyll protoplast was conducted in order to gain symmetric somatic hybrids. many of the combinations ended up with asymmetric hybrids, some with intermediary morphology in in virro cultnre and very slow atypical growth suggesting some kind of somatic incompatibility between potato and the wild species genomes.