SOMATIC HYBRIDIZATION BETWEEN SOLANUM-OCHRANTHUM AND LYCOPERSICON-ESCULENTUM

Incorporation of genes from wild species has been a major contributor to tomato improvement in recent years. Solanum ochranthum, a woody vin e-like tomato relative, is a potential source of resistance against to mato diseases and insect pests but is genetically isolated from tomato . Somatic hybridization methods were developed to facilitate the use o f S. ochranthum for tomato germplasm improvement. Leaf mesophyll proto plasts of S. ochranthum and selected Lycopersicon esculentum genotypes were chemically fused with polyethylene glycol. The protoplasts were initially cultured in Shepard's CL, a Murashige and Skoog-based medium , containing 1 mg l(-1) NAA, 0.5 mg l(-1) N-6-benzyladenine and 0.5 mg l(-1) 2,4-dichlorophenony - acetic acid. Tetraploid and hexaploid hyb rid regenerants and regenerants of an L. esculentum parent were recove red; S. ochranthum did not regenerate. Hybridity was established by mo rphological characters, peroxidase isozyme and RAPD markers.