种植转 Bt基因抗虫棉后 ,由于田间用药次数大幅度减少 ,田间昆虫量明显增加 ,异交率也随之提高。 Bt基因在棉花中表现为显性遗传 ,与非抗虫棉的杂交一代仍表现为抗虫 ,且生长势较强 ,自交后则分离出不抗虫的植株。采用“三圃制”生产转 Bt基因抗虫棉原种 ,需每年大量选单株 ,还 After transplanting transgenic Bt cotton, the amount of insect in the field obviously increased and the out-crossing rate also increased due to the drastic reduction of the frequency of medication in the field. The Bt gene showed dominant inheritance in cotton, and the hybrid generation with non-resistant cotton still showed resistance to insects and strong growth potential. Insect-resistant plants were isolated after selfing. The use of “three Pu system” to produce transgenic Bt cotton varieties, each year a large number of selected strains, but also