Embryogenic and non-embryogenic cell lines of Daucus carota cloned from meristematic cell clusters: relation with cell ploidy determined by flow cytometry.

The presence of totipotent and non-totipotent cells in embryogenic carrot cell suspension cultures was examined by cloning of cell microclusters. Forty clones were isolated and the distribution of their embryogenic potential was studied. Nonembryogenic, weakly and highly embryogenic cell lines were selected. After one year of subculture a second cloning round showed that the highly embryogenic and the non-embryogenic cell lines were homogenous and stable. A measurement of ploidy levels of clones by flow cytometry showed that the embryogenic clones were all diploid whereas the non-embryogenic were diploid or tetraploid. Hence, for our strain, there was a strict relationship between the tetraploid state and the inability to produce somatic embryos.