Modeling the Gene Flow of Genetically Modified Crops: A Case Study on Paddy Rice

基因改造技術自1973年試驗成功以來，無論在科學發展與社會議題上皆受到深切關注，農業也在1984年獲得基改菸草後正式踏入基因改造科技領域。基因改造技術雖具有許多優點，在發展基改作物之同時卻可能存在影響生物多樣性之基因流佈風險，故各國對種植基改作物設有不同之規範。主要國家雖設定不同之種植隔離距離以避免基因流佈風險，卻未提出足夠之科學證據以說明訂定標準，本研究建立基因改造水稻之基因流佈風險分析模型，提供政府在進行相關基因改造水稻種植規範時參考。本研究蒐集國內外田間試驗資料，建立水稻基因流佈風險資料庫，以不同三種模型進行分析，估計結果顯示對數-對數模型最能適當描述基因流佈率與距離間之關係，利用此估計結果，進一步探討在不同基因流佈係數與標準差之下，基因流佈風險的範圍。為進一步將氣候因素如風速、風向、大氣穩定度等納入考量，本研究雖以高斯煙羽模型(Gaussian plume model, GPM)為基礎，但由於過去研究在進行花粉擴散模擬時之變數設定之假設有誤，故本研究針對水稻之生物特性做修正，建立新的水稻花粉擴散模型，並將基因流佈風險議題往前推至花粉擴散層面。證實花粉擴散與基因流佈情形間存在相關性，若利用花粉擴散模型模擬之結果，以花粉等濃度線進行隔離田區之規劃將較以固定隔離距離規劃隔離田區之方式更具經濟效益，節省農地與隔離成本之浪費。Since the first success in 1973, genetic engineering has kept catching people concern no matter in the science or social issues. And because of the success in genetic modified tobacco in 1984, agriculture had steped in the region of genetic modified. Although there’re advantages in genetic engineering, it also has some risks that we cannot ignore such as gene flow. Thus, governments have setted different regular with repect to genetic modified crops planting. The main countries decided to set the isolation distance or/and the GM threshold. However, there’s no sufficient scientific evidence had provided to explain their setting standards. According to this, our study established a model of gene flow analysis on genetically modified rice, in order to provide the government some information on the GMO-about law setting process. To establish the gene flow database of paddy rice, our study first collected field trials data from literatures, then using different models to find out the relationship between gene flow and isolation distances under different variable sets. Base on the results, the double-log type had the best ability in explaning the relation between gene flow and isolation distances. Further, we used the results to discuss the range of gene flow under different coefficients of isolation distances and standard errors. To including the weather factor, such as windspeed, wind direction, and atmospheric stability, etc., we established the pollen dispersion model of paddy rice based on Gaussian Plume Model (GPM) made the gene flow issue extend to the pollen dispersion level. In the simulating process, we found that the assumption used before had a huge mistake. Thus, our study corrected the assumption used before according to the paddy rice’s biological characters. The result proves that the issue of pollen dispersion is important for the issue of gene flow. Further, if we use the iso-density curves from the simulation results, we can make a more effective, land-saving and cost-saving isolation region