Quick Identification of Chromosomal Ploidy of Mulberry Cells by Flow Cytometry

Chromosome doubling of mulberry induced by chemical and physical methods usually occurs in portions of meristematic cells. The induced mulberry tissues could form mixoploid individual plants through asexual reproduction. In order to identify the percentage of cell ploidy among mixoploid individuals quickly and accurately,we detected the chromosomal ploidy of leaf,bud and stem respectively by flow cytometry at DNA level. The detection results of diploid and triploid mulberry were consistent with those examined by chromosome tabletting method. However,among the tested mulberry which was identified as tetraploid by chromosome tabletting method,only sample 403-1 was identified as tetaploid by flow cytometry,while sample 403-9 was identified as triploid and the others were found to be mixoploid with different proportions of diploid and tetraploid cells. Moreover,the proportions of ploidy cells varied between individual plants and different organs. These results showed that chromosomal ploidy of mulberry can be detected accurately by flow cytometry,which would facilitate researches on the formation mechanism of mulberry mixoploidy and the asexual separation and purification regularity of polyploidy,expedite screening for excellent individual plants,and improve breeding efficiency for polyploid mulberry.