Karyotype diversity and genome size in the Cyphomandra clade of Solanum L. (Solanaceae).

This article focuses on the cytogenetic and genome size characteristics of the Cyphomandra clade within the genus Solanum L., a group distinguished by notably large chromosomes and genome sizes compared to other Solanum species. Through karyotype analysis using CMA/DAPI banding and ribosomal DNA fluorescence in situ hybridization (FISH), alongside flow cytometry genome size estimation of 12 Solanum species (eight from Cyphomandra and four from related clades), the study found conserved chromosome numbers (mostly 2n = 24) and symmetrical karyotypes across species, with Cyphomandra species exhibiting significantly larger chromosomes and genomes. The distribution and number of heterochromatic bands and rDNA sites varied but did not fully explain genome size differences, suggesting that the accumulation of other repetitive sequences, such as transposable elements, likely contributes to genome expansion in this clade. These findings support the characterization of the Cyphomandra clade by its large genome and chromosome size and highlight the need for further research into repetitive DNA to understand its karyotype evolution within Solanum.