Cytogenetic evidences on the evolutionary relationships between the tetraploids of the section Rhizomatosae and related diploid species (Arachis, Leguminosae)

摘要: Rhizomatosae is a taxonomic section of the South American genus Arachis, whose diagnostic character presence rhizomes in all its species. This particular evolutionary interest because it has three polyploid (A. pseudovillosa, A. nitida and glabrata, 2n = 4x = 40) only one diploid burkartii, 2n = 2x = 20) The phylogenetic relationships these species as well polyploidy nature origin tetraploids are still controversial. present study provides an exhaustive analysis karyotypes rhizomatous six closely related sections Erectoides Procumbentes by cytogenetic mapping DAPI/CMA heterochromatin bands 5S 18-26S rDNA loci. Chromosome banding showed variation DAPI distribution pattern, which, together with number loci, allowed characterization studied here. bulk chromosomal markers suggest that tetraploid constitute natural group may have at least common ancestor. data analyzed evidenced species-A. burkartii-has karyotype pattern different from those tetraploids, showing not likely genome donor non-monophyletic Rhizomatosae. Thus, should be excluded R genome, which remain exclusively for burkartii. Instead, features compatible (E species), suggesting hypothesis multiple origins tetraploids. In addition, closer to discussed.