Efficient hybridization between Lycopersicon esculentum and L. peruvianum via embryo callus.

Embryo callus was produced in up to 12% of the undeveloped seeds of the interspecific cross L. esculentum cv. VFNT cherry x L. peruvianum LA1283-4, a cross which does not produce viable seeds. Plants were produced from 90% of those callus clones by regeneration and rooting. Evidence that these plants were hybrid includes morphology, isoenzyme patterns and fertility relations. Both diploid and tetraploid plants were produced, 40% of the regenerated callus clones producing at least one diploid plant. Thus, up to 4% of the undeveloped seeds plated for callus production eventually yielded diploid hybrid plants. In contrast, among 401 undeveloped seeds dissected, no embryos suitable for embryo culture were found. A backcross of the embryo callus hybrids to the L. esculentum parent has succeeded - producing, as expected, only undeveloped seeds; these undeveloped seeds have produced callus.