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To accomplish interspecific hybrid breeding of bush type squash with good flesh quality, refinement of ovule culture protocol was made to enhance embryo rescue in the interspecific crosses. Four combinations including reciprocals were made between C. moschata (´Seoulmadi´ and ´Puthobag´) and C. pepo (´Ford Zucchini´), and the immature embryos were rescued to get hybrids. While the embryos in intact ovules did not germinate when plated on artificial media, those of cut ovules germinated well. It was thought that the halved ovule culture method will enhance the embryo culture efficiency in interspecific hybridization of Cucurbit family. For embryo germination, 27℃ was better than 23℃, and the medium containing half-strength MS salts supplemented with 35g/ℓ sucrose showed good results. C. pepo was a better seed parent than C. moschata for the interspecific crosses; it showed higher fruit setting and better embryo development. The 10-day-old embryos showed more than 40% of germination in the crosses with C. pepo as the seed parent, but the percentages of germination decreased rapidly afterwards. Therefore, the hybrid embryos were thought to abort rapidly from 10 days after pollination.
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