Ploidy chimeras (2x/4x) find their origin in more than one cell. At least one of the original cells was diploid, at least one was tetraploid. The number of chimeras provides a good indication of the efficiency of the treatments. As was already clear, the ‘direct sowing’ method is not efficient. Both other treatments induce the development of a larger group of chimeras than of tetraploids. In treatment 1, chimerical tissue develops from meristem cells; in treatment 3 from stem tissue