CMA banding patterns of chromosomes of eleven Jeju citrus landraces were characterized and compared by means of sequential staining using fluorochromes of chromomycin A3 (CMA) and 4’,6-diamidino-2-phenylindole (DAPI). The somatic metaphase chromosomes examined in this study were all diploids (2n = 18). Chromosomes were classified into five types based on the number and distribution of CMA positive bands; A: two telomeric and one proximal bands, B: one telomeric and one proximal bands, C: two telomeric bands, D: one telomeric band, E: no band. Four to five types of chromosomes and unique chromosome compositions were observed from each accession. The CMA banding patterns of Jeju citrus landraces were 1A+1B+1C+9D+6E in jinkyul, 1A+1B+1C+8D+7E in cheongkyul, 1B+1C+10D+6E in hongkyul, 2A+1B+3C+6D+6E in sadoogam, 1A+2B+1C+8D+6E in dangyooza, 1A+1B+3C+7D+6E in dong-geongkyul, 2B+2C+7D+7E in pyunkyul, 2A+2B+2C+6D+6E in gamza, 1A+2B+1C+7D+7E in byungkyul, 1A+1B+1C+9D+6E in jigak, 1A+1C+10D+6E in binkyul. Type D and E chromosomes were predominant in all Jeju citrus landraces. The chromosome composition with an even number distribution in gamza was observed, hence it could be recognized as a non-hybrid species. The results indicated all Jeju citrus landraces except gamza seemed to be hybrids, but might be diverged from species originated or cultivated in Jeju, Korea and other countries.

• Kyunguk Yi(Faculty of Bioscience and Industry, Jeju National University)
• Chi‐Won Chae(Jeju Provincial Office, Korea Seed & Variety Service)
• Young‐Chul Park(Citrus Breeding Center, Jeju Special Self-Coverning Province Agricultural Research and Extension Service)
• Ho‐Bang Kim(Life Sciences Research Institute, Biomedic Co., Ltd.)
• Kwan‐Jeong Song(Faculty of Bioscience and Industry, Jeju National University) Corresponding Author