Electrofusion of protoplasts from Solanum tuberosum, S. nigrum and S-bulbocastanum

Leaf protoplasts of two wild species, Solanum nigrum var. gigantea (S. ngr. gig) and S. bulbocastanum Dun. IS. bib), were electrofused with leaf proto plasts of two diploid potato clones, H-8105 and ZEL-1136, respectively, in order to confer the late blight-resistance from the wild species to the cul tivated potato. The: S. ngr gig mesophyll (+) H-8105 mesophyll combination resulted in regenerants of mostly normal ngr phenotype. Two regenerants fro m this combination were proved to be true hybrids by RAPD analysis but they routed poorely in vitro and did not survive the transfer to soil. The: S. ngr gig (+) H-8105 fusion combination was also performed with H-8105 call s uspension derived protoplasts enabling an easy identification of interspeci fic fusants on basis of their intermediate morphology. From the S. ngr gig mesophyll (+) H-8105 cultured call combination, many abnormal shoots were r egenerated. The two lines which survived had normal ngr phenotype but the p resence of tuberosum (tbr) genome in those regenerants was not confirmed by RAPD analysis. No plants with tbr phenotype were obtained from both of S. ngr gig (+) H-8105 combinations. On the contrary, when S. bib mesophyll pro toplasts were electrofused with ZEL-1136 mesophyll protoplasts, all regener ated plants had tbr phenotype, indicating much lower morphogenetic potentia l of S. bulbocastanum in comparison with that of S. nigrum var, gigantea. H owever, the hybridity of those regenerants has not been confirmed by RAPD a nalysis with two different primers. The efficiency of the applied fusion pr ocedure and analysis of the regenerants is discussed.