Abstract:

Through the field observation and experimental study，the outcrossing index（OCI），pollen vitality and stigma receptivity，the ratio of pollen and ovule（P/O），artificial pollination and bagging were investigated to understand the flower structure and reproduction system in Freesia hybrida. The results showed that the stamen of Freesia hybrida was closed to the lateral side of the style and about 2 mm shorter than the stigma. The relative position between the stamen and gynoecium was unchanged during the whole flowering stage. In addition，the stamen and gynoecium of Freesia hybrida mature at different times，the highest period of receptivity stigma was not synchronized with the peak stage of pollen viability. The OCI and P/O are 5 and 1 614，respectively. Taking the results of the artificial pollination experiment together，it indicated that reproduction system of Freesia hybrida was facultative outcrossing with outcrossing as the main breeding form and self-pollination as auxiliary form. Artificial pollination on fruit set rate was higher than the natural pollination.

Key words: Freesia hybrida, floral organ structure, outcrossing index, the ratio of pollen and ovule（P/O）, breeding system