Abstract: AFLP(Amplified Fragment Length Polymorphism)analysis system was established on Ponc／rusaccessions．Seven p1inler pairs th hish polymorphism have been screened from 40 pemer pairs．The screenedsubset of primer paiIs produced 539 bands， 146 of which were polymorphic． Genetic similarity among 36accessions ranged from 0．23 to 0．78． A儿the 36 accessions could be clearly diferentiated based on the bands obtained from three of the seven primer pairs．1his provided a first example to distinguish all tested Ponc／nts
accessions．The genetic distance was calculated and a dendrogram was constructed based on AFLP data of 7 primerliirs．Th e separation of Poncirus accessions did not correspond to their geographical distribution，which may result from the frequent exchan ge of seeds of Poncirus plan ts among diferent regions recently．

Key words: Trifoliate orange, AFLP, DNA fingerprinting, Silver staining