Jaap M. van Tuyl, K. Sande, R. Diën, D. Straathof, Hein M.C. van Holsteijn
To overcome pre-fertilization barriers in interspecific hybridization programs with Lilium species many methods have been studied: application of growth regulators, heating the style before pollination, cut-style pollination and application of mentor pollen. These methods are applied successfully in hybridization programs.

After fertilization, embryo abortion and/or endosperm degeneration can cause barriers in different stages of development. Using the embryo rescue technique embryos can be saved by in vitro culture, starting 40–70 days after pollination. To improve the embryo rescue technique, an ovary- and ovule culture technique is being investigated, starting as early as 5 days after pollination. The ovaries were cut in 3–4 mm thick slices or in longitudinal parts. Incubation took place at 25°C in the dark. The influence of sucrose, NAA, pH and the presence of anthers on the medium were studied. Observations on the swelling of the ovules and subsequently on the number of germinating ovules were performed.

The results showed a positive influence of the anthers on the medium. A high concentration of sucrose, NAA and a high pH were favourable. The treatments with the most swollen ovules produced the largest number of growing embryos. Interspecific hybrids could be obtained by this ovary culture method in a much higher percentage than with the usual embryo rescue procedures. The ovary culture method looks promising for overcoming embryo abortion.

van Tuyl, Jaap M., Sande, K., Diën, R., Straathof, D. and van Holsteijn, Hein M.C. (1990). OVERCOMING INTERSPECIFIC CROSSING BARRIERS IN LILIUM BY OVARY AND EMBRYO CULTURE. Acta Hortic. 266, 317-322
DOI: 10.17660/ActaHortic.1990.266.41

Acta Horticulturae