Abstract: Flowering and breeding characteristics are important for understanding the plant population reproduction characteristics. In this paper, the flowering dynamics were observed in the fields and the breeding system of Incarvillea sinensis var. przewalskii was studied by using the data of pollen/ovule ratio(P/O), pistil recipient phase, out-crossing index(OCI), pollen viability and bagging experiments. The results showed that the flowering period of I.sinensis var. przewalskii population lasted about three months (from June to September). The life span of individual flower was generally 2-3 d. During the flowering course, the stamen matured before pistil and there was obvious herkogamy. The flowering course for one flower of this species can be divided into four periods based on the flower morphology and anther dehiscence: initial dehiscence, full dehiscence, terminal dehiscence, withering period. The pollen/ovule ratio of I.sinensis var. przewalskii is about 331.3, and its outcrossing index is 5. Combining with the result of emasculation, bagging and artificial pollination, the breeding system of this species was determined to be out-crossing, partially self-compatible and entomoplily plays a larger role in the process of pollination. According to bagging experiments and field observations, it can be inferred that the species is insect pollination.

Key words: Incarvillea sinensis var. przewalskii, flowering dynamics, breeding system, adaptation