Caracterização citogenética de genótipos de Heliconia L. (Heliconiaceae)

Abstract

Helinonia L. (family Heliconiaceae) comprises about 207 species, mostly of Neotropical origin, with elevated ornamental interest. Their identification is performed with difficulty and several species are recognized as synonyms. This study aimed to characterize cytogenetically 10 genotypes of Heliconia, using fluorochrome staining with DAPI and CMA and FISH with rDNA 45S and 5S probes. The karyotypes were symmetric, with 2n = 2x = 24 chromosomes for diploid species, with average length ranging from 0.88 to 3.35 μm. In relation to CMA/DAPI staining and FISH, CMA+/DAPI0/rDNA 5S proximal sites were observed in two and three small chromosomes in diploid and triploid genotypes, respectively. For CMA++/DAPI-/rDNA 45S sites, two or four sites per genotype were observed. For H. psittacorum diploid populations, two subterminal sites with distended satellite were found, and, for H. spathocircinata, four terminal sites without satellite were found. Heliconia psittacorum x H. spathocircinata hybrids (‘Golden Torch Adrian’ e ‘Golden Torch’), as expected, showed three labeled chromosomes, two similar to H. spathocircinata and one to H. psittacorum. For 'Suriname Sassy' and 'Sassy', three terminal sites with satellite similar to diploid H. psittacorum were observed. Heliconia bihai had two chromosomes with proximal sites. Similarly, H. caribaea x H. bihai cv. Jacquinii hybrid showed two proximal sites CMA++/DAPI-/DNAr 45S, but with size and morphology chromosome heteromorphism. The distribution of 5S and 45S rDNA sites, both CMA positive, corroborated the triploid origin for 'Sassy Suriname' and 'Sassy' genotypes from diploid genotypes H. psittacorum as well as the hybrids H. psittacorum x H. spathocircinata ('Golden Torch' and 'Golden Torch Adrian') and H. caribaea x H. bihai cv. Jacquinii from their respective parents.