Flow cytometric analysis of DNA content in Hosta reveals ploidy chimeras

Nuclear DNA content in 84 Hosta cultivars was measured by flow cytometry. A s an internal standard we used the closely related Agave americana, the lat ter 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 k nown so far; H. ventricosa. Small forms of the tetraploid H. ventricosa tur ned out to be triploid hybrids. Three other triploids were discovered. Thre e 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 case s 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 ge neral, 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.