Gene flow from transgenic oilseed rape to Chinese conspecific landrace under field conditions and its implication for China

摘要

Quantifying pollen-mediated gene flow from genetically modified (GM) crops to non-GM crops or to related weedy species is vital for assessing the environmental impact of GM crops. This study quantifies the gene flow that occurs from transgenic oilseed rape (OSR) to nearby Chinese landrace Xiangyou 15 in the agricultural fields of Jianli county, Hubei province, southern China, in 2004. Natural hybridization events between the two species were detected using GFP-meter in the field. The influence of the wind on pollen dispersal and gene flow were also evaluated. Pre liminary results from this field showed that gene flow from transgenic OSR to nearby Chinese landrace crop occurred at a considerable rate. The maximum gene flow frequency observed was 16.17% at nearest to the common border. The minimum gene flow frequency observed was 0 or 0.03%. Moreover,frequencies of the gene flow decreased significantly with distance from the pollen sources. The results also indicated that the dominant wind of the region might strongly influence the gene flow rate between transgenic and non-transgenic plants. Therefore, isolation measures should be considered when deploying transgenic OSR in the coexist regions of non-GM OSR. The traditional agronomc system presented in this region could facilitate the gene flow as more pollen sources present, where crops are planted in many small patched farmlands adjacent to each other. It is suggested that the level oftransgene escape (gene flow) will be high if transgenic OSR or any other cultivar is planted in such system. Management practices employed by the growers, as well as protocols followed for the isolation distances are needed to iminimize gene flow.