以高斯煙羽模式模擬基改玉米之花粉飄散

Abstract

隨著GM作物栽培的迅速增加，世界各國紛紛探討在傳統、有機或GM作物間共存所衍生的問題。由於花粉飄散造成的基因流動會汙染相鄰田間之非基改作物；本研究於2009年於台灣台中霧峰農業試驗所進行春、秋兩期作（2009－1及2009－2）之田間玉米花粉飄散試驗，模擬當地基改玉米花粉飄散與隔離距離及風向之關係，並以修改後的高斯煙羽模式預測種植不同玉米品種所需之最大隔離距離。2009－1模擬花粉貢獻親造成接受親之異交率顯示，於近距離（1 m）下時高達29.3%；隨著距離的增加，異交率迅速下降，當距離為8 m時，異交率已降至4% 以下。而2009－2之模擬結果則顯示距離花粉貢獻親1 m處之接受親受到異交的比率高達32.2%；隨距離增加，異交率也迅速下降，當距離達10 m時，模擬所得之異交率降至4.7%左右。研究發現：不論是那一期作，實際測得之異交率皆介於模擬而得之花粉散佈率及預測異交率之間，例如在2009－1的試驗中，在1.5 m下實際測得之平均異交率為2.52%，而經模擬而得距離花粉貢獻親2 m的花粉散佈率及異交率分別為2.31%及12.44%，此模擬而得之異交率較其他常用經驗模式所預測而得的異交率更為保守，這些資訊將能提供有關單位在未來如開放種植基改玉米時，建立共存栽培措施的參考。 The increasing of commercial cultivation of genetically modified (GM) crops throughout the world encourages the establishment of a coexistence strategy for GM, conventional and organic cultures. The pollen-mediated gene flow from GM crops can result in the adventitious presence of GM material in conventional crop products. This study conducted field experiments in central Taiwan for two crop seasons to detect the effect of the cross-pollination (CP) rate of maize at various distances. A modified Gaussian plume model was applied to establish the relationship between the CP rate of the recipient field and distance from the pollen source. In the first crop season, the CP rate was 29.3% at a distance of 1 m and there was a rapid decrease in the CP rate when increasing the distance from the source. The CP rate was ＜ 4% at a distance of 8 m. In the second crop season, the CP rate was 32.2% at a distance of 1 m and decreased to 4.7% at 10 m. Regardless of the crop seasons, the actual CP rate was between the simulated pollen dispersal frequency (PDF) and simulated CP rate. Taking the first crop season as an example, the actual average CP rate was 2.52%, and 2.31% and 12.44% for the simulated PDF and simulated CP rates, respectively. The simulated CP rate obtained by the modified Gaussian plume model is more conservative than those derived by commonly used empirical models. The findings of this study can provide a reference to relevant administrative units for establishing coexistence measures for GM and non-GM crops and for deciding where to allocate fields for growing GM maize in the future.