REGENERATION AND ANALYSIS OF INTERSPECIFIC ASYMMETRIC POTATO - SOLANUM SSP HYBRID PLANTS SELECTED BY MICROMANIPULATION OR FLUORESCENCE-ACTIVATED CELL SORTING (FACS)

Recipient protoplasts from three Solanum tuberosum genotypes, cv 'Folv a' (2n = 4x = 48), cv 'Matilda' (4n) and '161:14' (2n), were electrofu sed with X-ray-irradiated donor protoplasts from two wild species S. s pegazzinii (2n) or S. microdontum x S. vernei (2n). Prior to fusion, p rotoplasts were fluorescence-labelled with either fluorescein diacetat e or scopoletin. Fusion products were identified by dual fluorescence and selected by micromanipulation or fluorescence-activated cell sorti ng (FAGS). All putative hybrid plants were analysed by the random ampl ified polymorphic DNA (RAPD) technique. Our analysis demonstrates that each asymmetric hybrid plant has an individual and stable profile of donor-specific RAPD bands. The irradiation of donor protoplasts hamper ed the growth of selected heterofusion products in a dose-dependent wa y. Irradiation resulted in donor chromosome elimination, but not in a dose dependent way, in the tested interval. In asymmetric hybrids with the S. spegazzinii donor 33-68% of the donor-specific RAPD bands were missing, indicating a similar-level of chromosome elimination. In asy mmetric hybrid plants with the S. microdontum x S. vernei donor 74-95% of the donor RAPD bands were missing. Chromosome countings revealed t hat these hybrids had chromosome numbers equal to or below the chromos ome numbers found in the tetraploid recipients. This is the first time that highly asymmetric hybrid plants between two tetraploid potato re cipients and the donor S. microdontum x S. vernei have been obtained.