High chromosomal variability of mandarins (Citrus spp.) revealed by CMA banding

Fluorochrome staining with chromomycin A₃(CMA) was used to characterize and compare the CMA banding patterns of chromosomes in 17 accessions of mandarins (Citrus spp.). All accessions had 2n = 18 chromosomes. These chromosomes were classified into six types based on the number and position of CMA positive bands; A: two telomeric and one proximal band, B: one telomeric and one proximal band, C: two telomeric bands, D: one telomeric band, E: without bands, F: one proximal band. Each accession possessed two to five types of chromosomes, and showed unique CMA banding patterns. Type D and E chromosomes were predominant in all accessions. Their numbers were generally higher in Chinese and Indian mandarins. Type F chromosome was present only in some mandarins originating in Japan, which could thus be distinguished from mandarins originating in other areas. This study is the first report of type F chromosome in citrus. The Vietnamese mandarins we studied were the only one shaving type A, B, C, D and E chromosomes. This revised version was published online in July 2006 with corrections to the Cover Date.