Abstract: 【Objective】The aim of this research was to establish a high frequency plants regemeration system for summer squash (Cucurbita pepo L.) via in vitro gynogensis, in order to provide a quick way to abtain self-bred lines for summer squash F1 breeding.【Method】Unpollinated ovules from summer squash ovaries were cultured on N6 medium and supplemented with 2, 4 - D, NAA, BA. After the embryoids were obtained, they were transplanted into N6 medium without growth regulators, and the regenerated plants would be obtained.【Result】120 embryonary sac plants were regenerated in this research. Among them, 41 plants were died of reduced growth, 8 plants died of studying the regenerated method, 71 plants survived after transplanting into soil. In these survived plants, 42 have normal fertility and 10 of them had obtained self-bred fruits and seeds; 29 have abnormal fertility . The statistical results showed that ovules development stage, medium, material genetype and material planting season had significant effects on the embryoids inductivities.【Conclusion】The embryoids came from the cells of embryonary sac, the regenerated plants are embryonary sac plants. 3 mediums had been selected for high inducticities. Ovules from one day before anthesis and the day of anthesis had higher inducticities and the materials planted in autumn was the best for induction of embryoids.

Key words: Summer squash (Cucurbita pepo L.), Unpollinated ovules, in vitro culture, Embryonary sac plant