EN
Ovary culture has been widely used to overcome the fertilization barrier of interspecific hybridizations. In order to understand the relation between ovary culture and the growth temperature of hybrid siliques, three sets of interspecific hybridization were carried out in the field. Hybrid siliques in each set of hybridizations were excised at 10, 15, and 20 days after pollination and temperature from pollination to excision was recorded. No significant correlation was found between hybrid embryo yield in ovary culture and the average temperature. However, a significant quadratic correlation between the efficiency of ovary culture and the effective accumulated temperature (EAT) was observed. It indicated a rise-andfall relation between the optimal excision time and the growth temperature of hybrid siliques. Our data suggested that EAT is a more reliable indicator than silique age to determine the optimal time for excisinghybrid B. napus 9 B. oleracea siliques for ovary culture.