PLANTLET FORMATION OF SOMATIC HYBRIDS OF SWEET ORANGE (CITRUS-SINENSIS) AND ITS WILD RELATIVE, ORANGE JESSAMINE (MURRAYA-PANICULATA), BY ELECTRICALLY-INDUCED PROTOPLAST FUSION

Embryogenic callus protoplasts produced from a pollen embryoid of 'Trovita' orange (Citrus sinensiS OSBECK) were fused electrically with leaf-derived protoplasts of orange jessamine (Murraya Paniculata (L.) JACK), which is a remote wild relative of Citrus and has important agricultural characteristics, such as tolerance to alkaline soils and resistance to citrus nematode. The fusion efficiency (rates of binuclear heterokaryons) were around 15%. The fusion products were cultured using the method Of OHGAWARA et al. (1985) and embryoids were grown by our shuttle callus system (HIDAKA and OMURA 1989). Somatic hybrid identity was verified by rDNA analysis using rice-rDNA probes labeled with peroxidase complexes. The results confirm that this electrical fusion system is effective for producing somatic hybrids of citrus and its sexually incompatible remote wild relatives.