ASYMMETRIC SOMATIC HYBRID PLANTS BETWEEN AN INTERSPECIFIC LYCOPERSICON HYBRID AND SOLANUM-MELONGENA

Asymmetric somatic hybrid plants were obtained by a modified PEG/DMSO fusion procedure between protoplasts derived from suspension cells of an interspecific tomato hybrid, Lycopersicon esculentum x L. pennellii , and mesophyll protoplasts of Solanum melongena, eggplant. The tomato hybrid was previously transformed with Agrobacterium tumefaciens and contained the kanamycin-resistance marker gene. Prior to fusion, the d onor protoplasts of the tomato hybrid were gamma irradiated at 9.0 kra d. Thus, non-division of irradiated tomato hybrid protoplasts coupled with kanamycin sensitivity of eggplant enabled selection of somatic ce ll hybrids. Forty-nine calli selected post-fusion regenerated leaf-lik e structures in the presence of 50 mg/l kanamycin. However, only four of the 49 calli regenerated intact shoots which rooted in the presence of 50 mg/l kanamycin and were later transferred to the greenhouse. An alysis of phosphoglucoisomerase and peroxidase isozymes, and Southern hybridization with a nuclear-specific pea 45 S ribosomal RNA gene conf irmed somatic hybrid status. Cytology revealed that the four hybrid pl ants had chromosome numbers of 45, 60, 42 and 57, respectively; they w ere all sterile.