转基因抗虫棉的抗性鉴定

Preliminary Studies on the Tests of the Bt transgenic Cotton Resistance to Insects

１９９４～１９９５年采用棉铃虫初孵幼虫鉴定Ｒ１、Ｒ２、Ｒ３代Ｂｔ转基因棉花２０００多株次，筛选出Ｒ１代抗虫效果达８０％以上的单株１１个，占参测株６．２１％；Ｒ２代（株系）１５个，占参测株系１３．８９％；Ｒ３代３７５株，占参测株７１．２９％。１２份材料进入复鉴，８份材料在罩笼接虫中，百株活虫数及被害蕾铃率平均比对照分别减少８８％～１００％及９０％～１００％；叶、蕾饲喂棉铃虫３龄幼虫，毒性效果均在８０％以上，３龄棉铃虫幼虫取食抗虫棉后，取食量、排泄量及体长和体重增长率比对照减少５０％～１０７％，第四天出现死虫，且对红铃虫亦有较强的抗性。

The bioassay with neonate larvae of bollworm were used to test the resistance of 2 000 Bt transgenic cotton plants in R 1,R 2 and R 3 generations in 1994-1995. 80% reduction of damage as well as mortality were taken as criterion of resistance. 11 plants in R 1, 15 lines in R 2 and 375 plants in R 3 were selected as resistant lines which was 6 21%,13 89% and 71 29% in respective generations .Then 12 lines from R 3 were repeated in Cage test by releasing bollworm moth in cage.The results showed that 8 lines in which the number of living larvae and infested squares and bolls decreased 88%-100%,90%-100% than that in check ,respectively, Leaves,squares and bolls from those resistant lines were fed to third instar larvae of bollworm, the motality of larvae reached above 80%.Those resistant lines also expressed good resistance to pink bollworm. The third instar larvae of bollworm fed with those resistant lines of Bt transgenic cotton,the rate of feeding,excreting,body length and weight decreased 50%-107% than that in check.The larvae would die within 4 days.