转Bt基因抗虫棉杂交后代的抗性表现与抗虫育种策略

以转Bt基因抗虫棉选系为抗虫亲本 ,以各种类型的陆地棉常规品种 (系 )为非抗虫亲本杂交 ,研究了大量杂交组合不同世代群体在大田自然感虫条件下的抗棉铃虫性表现。结果表明 ,F1代均表现高抗棉铃虫 ,抗性不分离 ;同一杂交方式不同非抗虫亲本的F2 群体 ,以及年际间 ,抗株与不抗株的分离比例相差很大 ,说明亲本的遗传背景及不同的环境条件对转Bt基因抗虫棉杂交后代的抗性表现有较大影响 ;从F3～F5株行 ,随着世代的递增和连续进行抗性选择 ,抗性纯合株行的比例迅速上升 ,而分离株行不抗虫株的比例迅速降低 ,在田间棉铃虫自然协迫条件下 ,通过连续多代进行抗性选择 ,可使抗性迅速趋于稳定 ,至F5代可获得综合性状较为理想、抗性纯合、稳定的株系。结合前期研究结果及抗虫育种实践 ,提出了棉花转基因抗虫育种策略

Bollworm resistance performance of hybrid offspring and breeding strategy for Bt transgenic cotton

The Bt transgenic cotton line had been used as bollworm resistant parent and crossed with normal cotton varieties or lines The bollworm resistance performance of a number of hybrid offspring populations in different generations had been studied in the field by natural biological identification The results showed that F 1 generation was high resistant to bollworm without segregation; the resistance segregated in the F 2 generation and the segregating ratio of resistant and un-resistant plants greatly differed as normal parents varied; from F 3 to F 5 lines, the ratio of homozygous plant-row in resistance were increased and the ratio of un-resistant plants in segregated plant-row were decreased rapidly Based on former studies and breeding practice, the strategy of bollworm resistant breeding of transgenic cotton were discussed