Creation of New Flower Colors in Ornithogalum Via Interspecific Hybridization

Additional index words. embryo rescue, breeding, pot-plant, carotenoids Abstract. Embryo rescue was successfully applied to develop hybrids between Ornithogalum dubium Houtt. (short inflorescence with orange flowers) and O. thyrsoides Jacq. (tall inflorescences with white flowers). Meiosis in these hybrids showed abnormalities such as univalents, laggards, and bridges. The F, hybrids were partially fertile, and F 2 and BC1 progeny were produced. The backcross hybrids segregated for flower color and, inflorescence traits and introgressed seedlings with orange pigmented flowers on tall inflorescences were obtained in the population. Several Ornithogalum species produce long lasting cut flowers and are commercially grown in the United States and Europe. The most commonly grown species is O. thyrsoides, characterized by a tall 20 to 90 cm long raceme with a tight cluster (short pedicels) of between 10 to 70 flowers, 3 to 5 cm in diameter. The perianth is yellow-white to white with a dark greenish or brown center that fades with age (Obermeyer, 1978; R.D. Pienaar, personal commu- nication). Another species, O. dubium, is noted for its bright yellow to deep orange-pigmented flowers. There is also a form with white flowers. The colored form of O. dubium produces a short 10 to 25 cm long raceme with a loose cluster (long pedicels) of between 5 and 25 flowers, 2 to 3 cm in diameter. The white form of O. dubium (formerly known as O. alticolum) is taller (up to 70 cm) and often confused with O. thyrsoides (Obermeyer, 1978; R.D. Pienaar, personal communication). Our goal was to extend the color spectrum of the commercial cut-flower types and to develop new pot-plant forms through interspecific hybridization of O. dubium and O. thyrsoides. The initial crosses were consistent with those of Pienaar (1963) and Van Niekerk and Pienaar (1968) who found that the interspecific crosses between most of these two species did not produce mature viable seed. This paper describes the use of in vitro, ovule-rescue in obtaining interspecific hybrids and the carotenoid analysis of their flowers. Materials and Methods