转Bt基因棉花国抗62对棉铃虫生长发育的影响及田间抗虫效果

为了明确新疆第一个自主转Bt基因棉花品种国抗62对棉铃虫Helicoverpa armigera生长发育影响及田间抗虫效果，2005年进行了室内生物测定和田间小区试验。在室内以国抗62（转Cry1Ac基因棉花）和中棉35（对照常规棉花）的叶片饲喂棉铃虫幼虫，从幼虫发育历期、体重、存活率、化蛹等方面，分析了棉铃虫生长发育动态。结果表明，国抗62对棉铃虫生长发育的抑制作用非常显著。与对照相比，取食国抗62的棉铃虫幼虫1～6龄龄期分别延长了1.0，7.8，8.2，17.8，20.3和＞21.3天；幼虫发育到6龄时存活率仅为2.6%，最终无一化蛹，而对照幼虫发育到6龄时存活率为91.8%，最终化蛹率为89.8%。田间小区调查结果显示国抗62对第2代棉铃虫有非常好的抗虫效果：两个品种棉田棉铃虫落卵量无显著差异，但国抗62棉田比对照棉田虫口数量降低85.7%，顶尖被害率降低94.4%，蕾铃被害率降低95.1%，差异达到显著和极显著水平。但国抗62对第3代棉铃虫的田间抗虫效果欠佳。棉铃虫在新疆棉田以第2代为害为主，因此，国抗62能够起到有效的控制作用。

Effect of transgenic Bt cotton GK62 on the development of cotton bollworm and its resistant efficiency in fields

The effects of transgenic Bt cotton GK62 on the larval development of cotton bollworm,Helicoverpa armigera,and its resistant efficiency in field were detected in Xinjiang,China in 2005.The foliages of GK62(carrying Cry1Ac gene)and ZHONGMIAN35(conventional non-Bt cotton)were used to feed the cotton bollworm larvae in the laboratory.The results showed that the developmental duration,body weight and survival rate of larvae fed on GK62 were significantly different from those of the control.The developmental durations of 1st-6th instar larvae fed with GK62 were delayed by 1.0,7.8,8.2,17.8,20.3 and over 21.3 days,respectively;the survival rate of larvae developed from 1st to 6th instar was only 2.6%,and none of them pupated successfully,while the survival rate and pupation rate of the control larvae were 91.8% and 89.8%,respectively.Field investigations revealed that GK62 cotton showed significant resistance to the damage by the second-generation cotton bollworm.Although there was no significant difference in the egg density of cotton bollworm laid on the cotton plants between GK62 and the control,the number of the cotton bollworm larvae attacking the GK62 and the damaged rates of tops and squares of GK62 were significantly lower than those of the control,decreasing by 85.7%,94.4% and 95.1%,respectively.But GK62 was less effective to third-generation cotton bollworm in field.These results suggested that GK62 can be used effectively to resist the damage by the second-generation cotton bollworm in Xinjiang.