Inheritance of Bluish Flower Color of Transgenic Chrysanthemum by Interspecific Hybrids

Bluish transgenic chrysanthemums have already been produced and are expected to be commercialized. As domesticated chrysanthemum (Chrysanthemum morifolium) is known to cross with wild species native to Japan, the risk of transgene flows into the wild population must be considered. However, little research has been conducted on the crossability of transgenic chrysanthemums or on the heritability of the transgenes involved. In this study, we investigated artificial cross-pollination between color-modified chrysanthemums and the wild species Chrysanthemum japonense var. japonense. Relatively high seed set rates of 28.8%-53.5% were achieved. Based on a comparison between the size and shape of the flowerheads and leaves of the seedlings and the parent plant, most seedlings were assumed to be hybrids. Polymerase chain reaction was applied to amplify the Campanula F3'5'H gene fragment. The segregation and inheritance of the transgenes were confirmed. Some transgenic progeny exhibited a modified flower color similar to that of the parent. The progeny were also demonstrated to have accumulated anthocyanins specific to the parent plant. The results confirmed the transmission of the transgenes to the interspecific progeny. The modified anthocyanins then produced petals of similar color. To prevent unintended environmental consequences, techniques are needed to reduce the possibility of transgene flow to native chrysanthemum species. This will be a necessary precursor to the commercialization of bluish chrysanthemums in East Asia, specifically Japan.