Genome Size Evolution and Dynamics in , with Special Focus on the Section .

Insights into genome size dynamics and its evolutionary impact remain limited by the lack of data for many plant groups. One of these is the genus , of which only 53 out of c. 260 species have available genome sizes. In this study, we estimated the C-values for 41 species and subspecies of mainly from the Eastern Mediterranean region. We constructed a phylogenetic framework to shed light on the distribution of genome sizes across subgenera and sections of . Finally, we tested evolutionary models to explore the mode and tempo of genome size evolution during the radiation of section . as a whole displayed a great variety of C-values; however, they were unequally distributed across the subgenera and sections, suggesting that lineage-specific patterns of genome size diversification have taken place within the genus. The evolutionary model that best fitted our data was the speciational model, as changes in genome size appeared to be mainly associated with speciation events. These results suggest that genome size dynamics may have contributed to the radiation of irises. In addition, our phylogenetic analysis provided evidence that supports the segregation of the Lebanese population currently attributed to as a distinct species.