Breeding of oenamental plants through interspecific hybridization, somatic hybridization and genetic transformation

In ornamental crops, constant demands always exist for producing new cultivars in the market. Therefore, it is important to broaden the genetic variability through the suitable and available breeding strategies for each target ornamental plant. In our laboratory, we have been trying to evaluate the usefulness of plant biotechnologies such as tissue culture, embryo rescue, protoplast fusion and genetic transformation as the means for broadening the genetic variability and for creating the novel useful germplasm to the breeders of ornamental crops. So far, interspecific hybrids have been produced in the different groups of plants such as Primula, Cosmos, Kalanchoe, Dianthus and Begonia with the aid of embryo rescue technique. Some of theproducts of these interspecific hybridizations have successfully been utilized to produce commercially available cultivars. Somatic hybrids have also been produced in Dianthus and Primula based on our successful establishment of plant regeneration systems from protoplasts. In some somatic hybrids in Dianthus, progeny plants were successfully obtained by self-pollination Triploid plants were also produced by fusing mesophyll protoplast and egg cell protoplast in Petunia. In our laboratory, genetictransformation systems have successfully been established in various ornamental crops such as orchids (Phalaenopsis,Cymbidium, Dendrobium, Cattleya, Vanda), Nierembergia, Petunia, Lilium, Dahlia, Begonia, Primula, Matthiola and Viola.By utilizing these transformation systems, transgenic plants of useful traits such as insect-resistant stock, blue dahlia and dwarf, disease resistance and blue flower phalaenopsis have already been produced. Base on the results of these studies, future prospectives on the application of plant biotechnology for the ornamental plant breeding will be described.