Cytogenetic studies in Herbertia Sw. (Iridaceae).

Conventional Feulgen staining, CMA/DAPI banding and FISH with 18-5.8-26S rDNA probe were used to determine chromosome numbers, karyotypes and physical position of GC or AT rich heterochromatin and rDNA sites in three South American species 4 Herbertia: H. lahue subsp. amoena, H. quareimana, and H. darwinii. The basic number of the genus is x=7, but the analyzed taxa have different ploidy levels. The chromosome number was 2n=14 for H. darwinii and 2n=28 for H. quareimana. The two populations studied of H. lahue subsp. amoena did result in: 2n=42 (Gualeguaychu) and 56 (Palma de Castillo). Chromosome size varied between 1.60 and 5 mu m. The karyotypes did give with a total of 8 metacentric (m) + 6 submetacentric (sm) chromosomes for H. darwinii and 20 m + 8 sin chromosomes for H. quareimana. The two populations of H. lahue subsp. amoena showed with 26 m + 16 sm chromosomes and 36 m + 20 sin chromosomes. H. darwinii had a bimodal karyotype. H. darwinii showed one satellited pair whereas the remaining species two (always in short in chromosome arms). Moreover, the 2n=56 population of H. lahue subsp. amoena one satellite on the long arms. No CMA(-)/DAPI(+) bands were detected in any species, but CMA(+)/DAPI(-)bands associated with nucleolar organizing regions (NOR) were found in all cases. The locations of the 18-5.8-26S rDNA sites in all species coincided with CMA(+)/DAPI(-) bands. Our data Suggest that karyotypic diversification