Background: The genus Fragaria comprises species at ploidy levels ranging from diploid (2n = 2x = 14) to
decaploid (2n = 10x = 70). Fluorescence in situ hybridization with 5S and 25S rDNA probes was performed to
gather cytogenetic information that illuminates genomic divergence among different taxa at multiple ploidy levels,
as well as to explore the evolution of ribosomal RNA genes during polyploidization in Fragaria.