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.

Based on double pseudo-testcross theory, a population of 76 F1 clones, which were derived from a cross of China type tea plants (Camellia sinensis var. sinensis) with a Korean tea cultivar, ‘Kemsull’ for female parent and a Japanese tea cultivar, ‘Houshun’ for male parent, was used to construct a genetic linkage map with AFLP markers. Totally, 2,360 markers were detected by 26 pairs of primers and 90.8 markers for each pair on average. Among these, 481 markers (20.3%) were polymorphic, 392 markers (81.5%) of which showed Mendelian segregation ratio (p=0.01). Of these Mendelian segregated markers, 139 (35.5%) were segregated in 3:1 ratio and 253 (65.5%) were segregated in 1:1 ratio. The construction of AFLP molecular marker based linkage map were carried out by Joinmap 4.0 version. The linkage map of ‘Kemsull’ contained 227 markers which distributed into 18 linkage groups. The linkage map of ‘Kemsull’ covered 1,382.2 cM with the average distance between two markers of 6.0 cM. The linkage map of ‘Houshun’ contained 154 markers which were distributed into 17 linkage groups and were spanned with the total map length of 1,540.9 cM and the average distance between two markers of 10 cM. However, these AFLP markers were not distributed evenly and further even saturation is additionally required.