Describing a nucleus that contains more than two sets of chromosomes (see diploid) or a cell or organism containing such nuclei. For example, triploid plants have three sets of chromosomes and tetraploid plants have four. Polyploidy is far more common in plants than in animals; many crops, in particular, are polyploid. For example, bread wheat is an allohexaploid (6n) containing two sets of chromosomes from each of three ancestral species, making six sets of chromosomes in total. Polyploidy can be induced chemically with colchicine, e.g. in plant breeding to produce new hybrid species. See also allopolyploid; autopolyploid.