Karyotypic stability in asparagus (Asparagus officinalis L.) cultivars revealed by rDNA in situ Hybridization.

• Autor(a) principal: MELO, N. F. de
• Data de Publicação: 2001
• Outros Autores: GUERRA, M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
• Texto Completo: http://www.alice.cnptia.embrapa.br/alice/handle/doc/134506
• topic: Variabilidade; DNAr; Genetic; Genotypes; rDNA; Asparagus Officinalis; Aspargo; Cruzamento; Genética; Genótipo; Hibridação; Variedade; hybridization; variability; varieties

Four asparagus cultivars were cytologically studied by conventional staining and in situ hybridization, in order to evaluate both the variability among cultivars and the distribution pattern of 18S-25S rRNA genes. lhe mitotic and meiotic analysis with conventional chromosome staining did not show heteromorphisms or differences between cultivars. In situ hybridization with 18S and 25S rONA probes showed 6 chromosomes with 18S-25S rONA sites in the 4 studied genotypes. lhe New Jersey, Waltam Washington and G4X 14 cultivars presented 4 chromosomes with larger subterminal sites and 2 with interstitial sites of smaller size. In the Oeco cultivar, heteromorphism was verified in the size of the rONA sites, which were larger and subterminal in 3 chromosomes, and small and interstitial in 3 other chromosomes. lhe results suggest that asparagus cultivars may present only small differences in the number and distribution of rONA loci,