EFFICIENT SELECTION OF POTATO HETEROKARYONS BY FLOW CYTOMETRIC SORTING AND THE REGENERATION OF HYBRID PLANTS

A method for the selection of potato heterokaryons after the electrofu sion of dihaploid lines of potato (Solanum tuberosum L,.) or dihaploid potato lines and Solanum commersonii has been developed. The selectio n of heterokaryons was based on the staining of mesophyll protoplasts with fluorescein diacetate or scopoletin. In several experiments, up t o 100 000 objects were sorted in a dual laser equipped FACStar Plus, u sing a 160 mu m nozzle and culture medium as sheath fluid. A large num ber of plants was regenerated from 1 intraspecific and 5 interspecific fusion combinations. RAPD analysis of 244 tetraploid plants from 5 di fferent fusion combinations showed that 240 of these were hybrids. The potential of this selection method for the efficient integration of p rotoplast fusion technology into potato breeding is discussed.