IBONE   05434
INSTITUTO DE BOTANICA DEL NORDESTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Genomic reorganization of species 2n = 20 of Arachis section
Autor/es:
ROBLEDO, GERMÁN
Lugar:
Buenos Aires
Reunión:
Conferencia; V Conferencia Internacional de Leguminosas y VII Encuentro Internacional de Especialistas en Arachis; 2010
Institución organizadora:
Sociedad Argentina de Botánica
Resumen:
Genome types A, B and D proposed for species of section Arachis were originally established based on the karyotype data and cross compatibility assays of few species. Currently, 26 species with 2n = 2x = 20 are included in the section, which were assigned mostly to the A and B genomes. However, the fertility of interspecific hybrids is not consistent with this genomic scheme, and the preliminary studies of molecular cytogenetics on a few species suggest a higher karyotypic heterogeneity. Therefore, in order to re-evaluate the genomic composition of the section we analyzed the distribution patterns of C-DAPI+ heterochromatin and ribosomal genes by FISH in its all (except two) 2n = 20 members. This study revealed five karyotype groups, each one with a distinctive structural organization. Two of these groups correspond to the A and D genomes, while the remainders ones are formed by the species so far assigned to the B genome. This grouping is supported by the fertility data and by bivalent formation at meiotic metaphase in interspecific hybrids, which indicate that there is a high reproductive isolation between species from different karyotype groups. Consequently, on the basis of these karyotype groups we propose the existence of five different genomic types A, B, D, F and K for the species with 2n = 20 of the section .