INTERGENERIC SOMATIC HYBRIDIZATION OF SEXUALLY INCOMPATIBLE PARENTS -CITRUS-SINENSIS AND ATALANTIA-CEYLANICA

Protoplast fusion using polyethylene glycol (PEG) was conducted to com bine Citrus sinensis (L.) Osbeck cv. 'Hamlin' sweet orange protoplasts , isolated from nucellus-derived embryogenic callus with Atalantia cey lanica (Arn.) Oliv. leaf protoplasts. Five plants regenerated from ind ependent fusion events following protoplast culture were identified as intergeneric allotetraploid somatic hybrids of 'Hamlin' sweet orange and A. ceylanica, and confirmed by isozyme analysis and chromosome num ber determination in root tip cells (2n=4x=36). Two different types of leaf morphology were observed among the hybrids (normal and narrow), although no differences in chromosome number nor isozyme banding patte rns were observed. This is the first report of the production of hybri d plants between these sexually incompatible genera.