A novel interspecific hybrid plant between Hydrangea scandens ssp. chinensis and H. macrophylla via ovule culture

In the genus Hydrangea, H. macrophylla is the most popular species. For this species, numerous cultivars with showy colorful flowers have been bred since the early 1900s through selection of natural mutants and intraspecific crosses among a limited number of early ancestral varieties. Although breeding of H. macrophylla has been successful, further improvements in flower shape, flower color, and growth habit are desirable. H. scandens ssp. chinensis is a small shrub that is native to South and Southeast Asia and valued for its evergreen foliage, winter flowering and broad adaptability in mild climates. Cross-pollination between H. scandens ssp. chinensis and H. macrophylla, and subsequent ovule culture, resulted in the production of an interspecific hybrid plant. The hybridity of this plant was confirmed by RAPD analysis. The hybrid plant had flower and leaf morphologies intermediate between the two parental species. Since the hybrid showed more vigorous growth than both parents, had evergreen foliage, and flowered in winter, it has sufficient horticultural merit for commercialization and may be suitable for greenhouse culture.