Chromosome number, karyotype, and genome size investigation in seven Hosta taxa (Asparagaceae)

To infer the cytological evolutionary mechanism of the genus Hosta, we analyzed chromosome numbers and karyotypes obtained via Feulgen staining, and measured genome size by flow cytometry. While the chromosome number of all the studied plants was consistently 2n= 60, the total haploid chromosome length varied from 55.37 mu m in H. jonesii to 76.22 mu m in H. yingeri. Bimodal karyotypes in chromosome size variation were observed in all Hosta taxa studied. The C-value was relatively high in all studied taxa, ranging from 7.94 pg C-1 in H. minor to 10.92 pg C-1 in H. kikutii var. polyneuron, further supporting the evolution of variable genome sizes in Hosta. The comprehensive cytological results provide a framework for detailed molecular cytogenetic and phylogenomic analyses, thereby enhancing our understanding of diversification in Hosta, independent of stable chromosome numbers.