Abstract: With increased cultivation area of transgenic plants worldwide, the ecological risks of cultivating transgenic plants have received wide concerns. One of the risks is the occurrence and consequences of gene flow between transgenic plants and their relatives. Here, we reviewed the ratio and the maximum occurrence distance of gene flow for transgenic oilseed rape (Brassica napus), cotton (Gossypium hirsutum), maize (Zea mays), soybean (Glycine max), rice (Oryza sativa), and wheat (Triticum aestivum). The former four species have been commercially released, while the latter two species have not been commercially released yet. We introduced some possible means in mitigating the occurrence of gene flow from transgenic plants to their relatives. The ratio of pollen-mediated gene flow is affected by genetic relationship between species, overlap time of flowering, wind speed and direction, and other factors. The maximum occurrence distance of gene flow is affected by climate, pollinators, geographical environment and other factors. The ratio of gene flow was negatively related with distance between donor and recipient plants (y=-0.59x-0.46, R²=0.25, P<0.01; logarithmic-conversion), and the ratio was high in closely related species. To reduce the occurrence ratio of gene flow between transgenic plants and their relatives, policy-makers should adopt a “partition management” strategy and pay more attention on the ecological risks of post-gene flow in the framework of biosafety assessment of transgenic plants.

Key words: transgenic plant, gene flow, wild relative, ecological risk