抗草丁膦转基因油菜与野芥菜的抗性回交3代子1代和子2代的适合度

如果抗除草剂转基因油菜的抗性基因渗入到野芥菜中,会给野芥菜的防除带来很大困难。因此在抗除草剂转基因油菜环境释放前对抗性基因向野芥菜的渗入开展深入的研究非常必要。以抗草丁膦转基因油菜与野芥菜的携带抗性基因回交3代子1代和子2代(BC3mF2和BC3pF2及BC3mF3和BC3pF3,m表示以野芥菜为母本的回交后代,p表示以野芥菜为父本的回交后代)为材料,在田间条件下研究了它们在不同密度(低密度为15株/区,高密度为30株/区)及不同种植比例(单种,野芥菜与回交后代以4:1、3:2、1:1混种)时的适合度成分和总适合度。结果表明,无论是低密度还是高密度条件下,单种时BC3F2和BC3F3的总适合度均与野芥菜无显著差异。低密度混种时,在4:1和3:2下,只有BC3mF3的总适合度与野芥菜无显著差异,其余各后代的总适合度均显著小于野芥菜;以1:1混种时,只有BC3mF2和BC3mF3的总适合度与野芥菜无显著差异。高密度混种时,3个比例混种下4种供试回交后代的总适合度均显著小于野芥菜。相关性分析结果表明,BC3mF3的各适合度成分都与混种比例不相关。表明携带抗性基因的BC3F2和BC3F3在野外都具有生存定植的可能性,且BC3mF3定植的可能性较其他供试回交后代更大。因此在防范转基因油菜基因逃逸的策略上,在防范初始杂交发生的同时,也应该防范回交后代的产生。

Fitness of resistant backcross generation (BC3F2-3) between glufosinate-resistant transgenic oilseed rape and wild Brassica juncea

One of the concerns about releasing transgenic herbicide-resistant oilseed rape (Brassica napus,AACC=38) is that herbicide-resistant (HR) transgenes from transgenic oilseed rape may escape to wild Brassicajuncea.If this happens,wild B.juncea with the HR trait might pose new problems for weed control.Therefore,it is necessary to evaluate gene flow from HR transgenic oilseed rape to wild B.juncea before it is released.The fitness components and composite fitness of BC3mF2,BC3pF2,BC3mF3 and BC3pF3 (m =backcross progeny obtained with wild B.juncea as maternal plants;p=backcross progeny obtained with wild B.juncea as paternal plants.) between glufosinate-resistant transgenic oilseed rape and wild B.juncea under different densities and different planting proportions were measured in the field.In pure plots,the composite fitness of BC3F2 and BC3F3 were not different to wild B.juncea either at low density (15 plants/plot),or high density (30 plants/plot).In mixed plots,at low density under 4 ∶ 1,3 ∶ 2 proportions,the composite fitness of the backcross generations was lower than that of wild B.juncea except for BC3mF3,which was similar to wild B.juncea.Under 1 ∶ 1 proportion,the composite fitness of the backcross generations was lower than that of wild B.juncea except for BC3mF2 and BC3mF3,which were similar to wild B.juncea.At high density,the composite fitness of all backcross generations was lower than that of wild B.juncea irrespective of proportions.There was no correlation between fitness components of BC3mF3 and planting density.BC3F2 and BC3F3 between glufosinate-resistant transgenic oilseed rape and wild B.juncea have the ability to establish in field,particularly BC3mF3.Therefore,hybridization between transgenic oilseed rape and wild B.juncea,including backcrosses between wild B.juncea and F1 or subsequent generations,should be prevented.