Sex determination in dioecious plants Melandrium album and M. rubrum using high-resolution flow cytometry

High-resolution flow cytometry was used to analyze nuclear DNA content in dioecious plants Melandrium album and M. rubrum. Very low coefficients of variation (0.53-0.70%) of G0/1 peaks were obtained after the analysis of nuclei isolated by chopping leaf tissues. In both species, females have lower DNA content than males due to sex chromosome heteromorphism. This made it possible to discriminate peaks belonging to female and male nuclei on the same histogram and permitted unambiguous sex identification in both species. The results indicated the possibility of diagnosing sex also in other heterogametic dioecious plants. The assay described here might be interesting in any area where rapid sex identification is required at an early stage of plant development.