Fertile asymmetric somatic hybrids between Lycopersicon esculentum Mill. and Lycopersicon peruvianum var. dentatum Dun.

Summary Thirteen nuclear asymmetric hybrids were regenerated under selective conditions following fusion of chlorophyll-deficient protoplasts from cultivated tomato (Lycopersicon esculentum Mill.) and -(-irradiated protoplasts from the wild species Lycopersicon peruvianum var. dentatum Dun. All hybrid plants were classified as being asymmetric based on morphological traits, chromosome numbers and isozyme patterns. The majority of the hybrids inherited Lycopersicon peruvianum var. dentatum chloroplasts. Mitochondrial DNA analysis revealed mixed mitochondria populations deriving from both parents in some of the hybrids and rearranged mitochondrial DNA in others. The asymmetric hybrids express some morphological traits that are not found in either of the parental species. Fertile F₁ plants were obtained after self-pollination of the asymmetric hybrids in four cases. The results obtained confirm the potential of asymmetric hybridization as a new source of genetic variation, and as a method for transferring of a part of genetic material from donor to recipient, and demonstrate that it is possible to produce fertile somatic hybrids by this technique.