[Production of intergeneric somatic hybrid plants via protoplast electrofusion in citrus]

Leaf derived protoplasts of Sour orange (Citrus aurantium L.) were fused electrically with embryogenic protoplasts of Microcitrus papuana Swingle. Plants were regenerated from the fusion products, which were characteristic with three types of leaf morphology. Most of the plants were identical to Sour orange (namely, Leaf-parent-type plant) and two plants had large and thick leaves whereas one plant had bifoliate and trifoliate leaves. Chromosome examination showed that these plants were diploid with 18 chromosomes (2n = 2x = 18). RAPD analysis was employed to verify the hybrid characteristics of the plants in the first two types. Four 10-mer arbitrary primers with polymorphism were chosen. Band pattern of the plants was similar with the leaf parent (Sour orange) for the primer OPAA-17. Band pattern of the plants was similar with either Sour orange or M. papuana for OPA-08. As for OPA-07 and OPA-04 three kinds of band profiles were detected. Results of RAPD marker, together with chromosome determination, indicated that all of the analyzed plants were intergeneric diploid somatic hybrids between Sour orange and M. papuana.