Transgenic Dendranthema (Chrysanthemum)

The chrysanthemum (Dendranthema grandiflora) is a complex hybrid from species endogenous in East Asia. In this region the genus Dendranthema is endogenous. The species intercross readily (Shimotomai 1933) provided the ploidy levels match and, over the years, numerous spontaneous and man-made mutants and hybrids have been selected to create the abundance of flower colors and shapes known today (Machin and Scopes 1978). Most of these developments took place in Asia, but from 1930 onwards, Europe and the USA became strongly involved as well, mainly because the development of all-yearround (AYR) flowering in which, by manipulating daylength, plants can be induced to flower at any time of the year. Flowers could be offered to the public continuously, which created an enormous demand and stimulated commercial production all over the world (Table 1).