PRODUCTION AND CHARACTERIZATION OF INTERGENERIC SOMATIC HYBRIDS THROUGH PROTOPLAST ELECTROFUSION BETWEEN POTATO (SOLANUM-TUBEROSUM) AND LYCOPERSICON PENNELLII

Mesophyll protoplasts of Lycopersicon pennelli Corr., a wild relative of tomato, were electrofused with those from a dihaploid potato clone, cv Nicola, with the objectives of transferring saline tolerance from L. pennellii to cultivated potato. 150 calli were selected from the fu sion experiments, finally giving 2 hybrid shoots. Their hybrid nature was verified by examining isoenzyme patterns for esterases (EST), pero xidase (PRX), phosphogluconate dehydrogenase (6-PGD), and glutamate ox aloacetate transaminase (GOT). The hybrid plants had an intermediate m orphology, and grew vigorously in vitro. When transplanted to soil, th ey were less vigorous, due to difficulties in rooting, but were still capable of flowering, and forming short stolons and mishaped tubers, p robably resulting from the effects of gene dosage due to the novel ass ociation of two genomes from a tuberizing (potato) and a non tuberizin g species (L. pennellii). The characteristics of such mishaped tubers provided strong evidence of a hybrid nature for the selected plants. T he hybrid plants were highly sterile, producing only 3-7% viable polle n. Tests for salt tolerance showed that the growth of the somatic hybr id plants was reduced by 50% as for L. pennellii, whilst potato did no t grow at all under saline conditions.