Fluorescent chromosome banding in the cultivated species of Capsicum (Solanaceae)

Fluorochrome chromosome banding is applied for the first time to 15 samples of five cultivated Capsicum species, all with 2n = 24, and allows a detailed analysis of the karyotypes (Tables 2-3, Fig. 8). Banding patterns differ between cytotypes, species and groups, reflecting the dynamics of chromosomal differentiation and evolutionary divergence. Taxa have from 1 to 4 NOR-bearing satellited chromosome pairs and exhibit increasing numbers of terminal (rarely intercalary and indistinct centromeric) heterochromatic fluorescent bands. Amounts of heterochromatin (expressed in % of karyotype length) increase from the group with C. annuum (1.80-2.88), C. chinense (3.91-5.52), and C. frutescens (5.55) to C. baccatum (7.30-7.56), and finally to C. pubescens (18.95). In all taxa CMA+ DAPI- (GC-rich) constitutive heterochromatin dominates, only C. pubescens has an additional CMAo DAPI+ (AT-rich) band. The fluorochrome bands generally (but not completely) correspond to the Giemsa C-bands. Structural heterozygosity can be demonstrated but is not prominent. The independent origin of at least three evolutionary lines leading to the cultivated taxa of Capsicum is supported.