APPLICATION OF OVULE CULTURE TO THE PRODUCTION OF INTERGENERIC OR INTERSPECIFIC HYBRIDS IN BRASSICA AND RAPHANUS

Abstract

To examine the usefulness of ovule culture for the production of intergeneric or interspecific hybrids in Brassica and Raphanus, experiments were carried out in 1978 and 1979. Ten to 20 days after pollination, ovules were inoculated on basic White's (1963) agar medium supplemented with 150ml/l coconut milk, 2.5mg/l naphthaleneacetic acid (NAA) and 2.5mg/l kinetin. Germinated embryos were transferred to basic Murashige and Skoog's (1962) medium supplemented with 0.5mg/l NAA and 2.5mg/l kinetin. After being cultured on filter paper bridges sustained by Murashige and Skoog's (1962) liquid medium, seedlings were transferred to pots. Of 14 cross combinations tested in 1978, 5 combinations gave hybrids by ovule culture, among which 4 combinations did not produce hybrids by the usual crossing method. In 1979, cultures were focused on the crosses between the B. campestris and the B. oleracea groups. The ovule culture was superior to the embryo and ovary cultures in terms of the production rate of hybrids, when B. oleracea was used as the female parent. When B. oleracea was used as the male parent, the ovule culture gave a better result than the embryo culture, but was less effective than the ovary culture. The way to improve the yield of hybrids was discussed.