Variability of DNA content and karyotype in cell cultures of an interdihaploid <i>Solanum tuberosum</i>

Karyological and DNA cytophotometric observations were carried out to follow nuclear events in cell cultures of an interdihaploid potato, genotype H2578, 2n=2x=24. The percentage of polyploid cells increased in leaf calluses, but decreased and then remained at a constant level when these cells were cultured in suspension. These suspension cultures did not survive, maybe because they did not become tetraploid. Another suspension culture proliferated with hypotetraploid cells only. Unlike the DNA contents of their interphase nuclei, the karyotypes varied considerably because of numerical and structural chromosome mutations