Resistance Determination Of Helicoverpa Armigera To Bt Toxin(Cry1Ac And Cry2Ab) In Cotton Field Of Northern Xinjiang And Determination Sensitivity Of Ostrinia Furnacalis To Cry1Ab

With a large number of transgenic cottons in many countries commercial cultivated, cotton bollwormand other lepidopteran pests on a continuous selection pressure, may have a certain resistance to Bt toxinprotein. With the extensive application of Bt cotton, the potential resistance of target pests became the mostimportant issue. Given this situation, this paper established the indoor population of bollworm and studieddevelopmental threshold temperature and effective accumulated temperature, using F1screening methodfor the of bollworm populations in northern Xinjiang six cotton growing areas to determinate the sensitivityof the Cry1Ac and Cry2Ab toxin protein.This research using experimental population life table method tostudy whether the Cry1Ab toxin protein has the controlling effects to the Asian corn borer. The results ofthis study are as follows:1. Determination of bollworm developmental threshold temperature and effective accumulatedtemperature:Studies have shown that the developmental threshold temperature of the whole generationcotton bollworm was10.76℃, the degree of effective temperature of516.75days. In the temperature rangeof18~33℃, the developmental duration ofHelicoverpa armigera various growth stages as the temperaturerises significantly shortened.2. Bollworm populations to establish a baseline for sensitive toxin Cry1Ac and the Cry2Ab: cottonbollworm to Cry1Ac and Cry2Ab toxin protein sensitivity monitoring results showed that: the cottonbollworm in northern Xinjiang six regions of Cry1Ac and Cry2Ab achieve varying degrees of resistance;against Cry1Ac most sensitive area is121group, Changji,147mission and Bole the bollworm hasdeveloped resistance to Cry1Ac protein. On the most sensitive area is Cry2Ab Sandy Bay, Bole,121mission bollworm has developed resistance to Cry2Ab protein. Six regions, the Bole area bollwormpopulations to Cry2Ab and Cry1Ac protein produced resistance.3. Effects of Cry1Ab toxin protein on growth and developing of Ostrinia furnacalis (Güenée)(Lepidoptera: Crambidae):The results showed that the Asian corn borer in various developmental stageswas sensitive to high concentration (50μg/mL) of Cry1Ab toxin protein, and insensitive to lowconcentrations (0.1μg/mL) of Cry1Ab toxin protein. Larval duration at10.0μg/mL toxin Cry1Ab weresignificantly lower than other treatments. The pre-oviposition period, eggs laid per female and life span offemale at50.0μg/mL toxin Cry1Ab were significantly lower than non-toxin control. The pupal weight of O.furnacalis at1.0μg/mL toxin Cry1Ab were significantly lower than non-toxin control. The netreproduction rate (R0) at50.0、10.0、1.0、0.1μg/mL toxin Cry1Ab were significantly lower than non-toxincontrol, while the net reproduction rate and average generation period (T) at0.1μg/mL toxin Cry1Ab weresignificantly lower than non-toxin control. Our study indicated that toxin Cry1Ab has a certain impact onthe population growth of O. furnacalis, and has a certain controlling effects of O. furnacalis.