Flow cytometric analysis of DNA content in Hosta reveals ploidy chimeras

Nuclear DNA content in 84 Hosta cultivars was measured by flow cytometry. As an internal standard we used the closely related Agave americana, the latter was calibrated against other reference species. Propidium iodide values were 20% higher than DAPI values, indicating a lower AT/GC ratio for Hosta. Ten new tetraploid plants were found in addition to the only tetraploid known so far; H. ventricosa. Small forms of the tetraploid H. ventricosa turned out to be triploid hybrids. Three other triploids were discovered. Three supposed tetraploids turned out to be diploid. In five plants the ploidy levels of the germ layers L1 and L3 appeared to be different. In these cases thick leaves coincides with a tetraploid DNA content. The DNA contents as measured in these ploidy chimeras coincide with differences in leaf colour, thus giving an opportunity to analyze the build-up of Hosta plants. In general, analysis of the nuclear DNA content can be used as a simple means to increase the possibilities for creating new cultivars in this economically important perennial.