Intersubgeneric cross in Nymphaea spp. L. to develop a blue hardy waterlily

Five waterlily cultivars, with good pod setting and completely formed flowers, from the subgenus Nymphaea (hardy waterlily) were used as pod (female) parent. Waterlilies from subgenera Anecphya (2 entities) and Brachyceras (20 entities), specifically the blue-flowered ones, were used as pollen (male) parent for transferring blue-flowered characteristic to the hardy waterlily. Hybridization of subgenus Nymphaea with subgenus Anecphya was unsuccessful. A successful crossing was obtained between the subgenera Nymphaea and Brachyceras, yielding one pod with 244 seeds, from which only 39 seeds germinated and yielded 20 good intersubgeneric hybrid plants. The characteristics of the hybrids were categorized by their flower colors into two groups, a pink-flowered group with 17 hybrids and a blue-flowered group with 3 hybrids. In the blue-flowered group, there was a prominent one with beautiful blue-purple flower, which was determined by PCR-RFLP markers to be a hybrid between Nymphaea and Brachyceras subgenera, as well as inherited some plant characteristics, for example, ovary carpel, leaf (pad), rootstock, position of flower at flowering from the parent. The blue-purple flowered hybrid had important characteristics inherited from the hardy waterlily (subgenus Nymphaea); therefore, the hybrid has been named Nymphaea 'Siam Blue Hardy' to honor the birth place and its distinct flower color.