Abstract: Leaf-derived protoplasts of Rough lemon ( Citrus jambhiri Lush, 2n = 2x = 18) were electrofused with embryogenic suspension protoplasts of its relative, Microcitrus papuana 5wingle (2n = 2x = 18), with an intention of creating novel germplasm. Six plants were regenerated following protoplasts fusion. Cytological examination demonstrated that they were diploids with 18 chromosomes (2n = 2x = 18). RAPD (random amplified polymorphic DNA) analyses with six arbitrary 10-mer primers showed that the regenerated plants had identical band pattems to those of Rough lemon for primers OPA-07, OPAN-07, OPE-05 and OPA-08, whereas for the other two primers, OPA-04 and OPS-13, bands specific to M. papuana could be detected in the regenerated plants. Cytological and RAPD analysis revealed that the regenerated plants were diploid somatic hybrids between M. papuana and Rough lemon. The putative hybrids were morphologically similar to Rough lemon. This is the first report on production of diploid somatic hybrid plants between citrus with its related genus via symmetric fusion.

Key words: Citrus, Microcitrus pap uana, Electrofusion, Somatic hybrid, RAPD