Production of triploid somatic hybrids in citrus

To produce citrus triploids through somatic hybridization, protoplasts isolated from nucellar calli of 'Juman' satsuma mandarin, 'Ohmishima' navel orange or 'Trovita' sweet orange were fused electrically with protoplasts from mesophyll cells of haploid strains of Clementine (No. 1 and No. 2); three combinations (satsuma mandarin + haploid No. 1, navel oranges + haploid No. 2, and sweet orange + haploid No. 1) were practically tried. Chromosome observations of root tip cells showed that the regenerated plants were diploid (2 n=18) or triploid (2 n=27). In each combination, triploid giants were observed. Hybridity of the plants was checked by RAPD-PCR method. Triploid plants produced in this study contained both parent-specific bands, indicating that the triploid plants are somatic hybrids.