【作者】 万鹏；

【导师】 吴孔明；

【作者基本信息】 中国农业科学院 ， 农业昆虫与害虫防治， 2004， 硕士

【摘要】 自20世纪90年代后期以来，转Bt基因棉成为了世界范围内用来控制棉花害虫的重要工具。我国的华北棉区及长江流域棉区也先后对Bt棉逐步放开。为了摸清Bt棉在长江中游棉区的抗虫表现，更好地发挥Bt棉在长江中游棉区棉花害虫综合治理中的作用，本文以中国农科院生物技术中心提供的转Bt基因棉GK19(含Cry1A基因)和美国孟山都公司提供的转Bt基因棉BG1560(含Cry1Ac)为材料，研究了它们在长江中游棉区毒蛋白的季节性表达规律，对棉铃虫(Helicoverpa armigera)、红铃虫(Pectinophora gossypiella Saunders)、斜纹夜蛾(Spodoptera lituraFabricius)的抗性，以及对主要的非靶标害虫棉蚜(Aphis gossypii Glove)的生长发育及种群动态的影响。 结果表明，在长江中游棉区，Bt棉毒蛋白的表达量随Bt棉组织、生育期及品种的不同而呈显著变化(P＜0.05)，但无年度间的差异(P=0.8362)。一般而言，杀虫蛋白的含量在棉花生长发育的前期较高，到中期时有所下降，但到晚期时则又有回升。在大多数标样日期里，Bt棉叶、蕾、花瓣及花柱内毒蛋白的含量要高于子房和铃。与BG1560相比，GK19对毒蛋白的表达在整个生长季节内的变化更大。 用Bt棉各组织对棉铃虫的室内饲喂表明，Bt棉对棉铃虫表现出了较好的杀虫活性，其对棉铃虫的杀虫活性及体重抑制率随组织器官及棉花生长季节的不同而不同，主要表现为繁殖器官大于营养器官，前期活性高于后期活性。对Bt棉田棉铃虫幼虫的种群动态进行调查表明：与常规棉相比，Bt棉GK19田内棉铃虫幼虫数量在2001年和2002年里分别下降了92.04％和81.85％，BG1560田内棉铃虫的数量下降了96.84％和91.80％。但两Bt棉田棉铃虫的落卵量与常规棉田无显著差异(P＞0.05)，棉铃虫幼虫在Bt棉各组织上的分布与常规棉田也基本相同。 对Bt棉田红铃虫的卵密度及幼虫密度的调查显示，两Bt棉田与常规棉田的红铃虫卵密度无显著差异(P＞0.05)，但是幼虫密度则显著低于常规棉田。与常规棉相比，Bt棉GK19对各代红铃虫的控制效果为73.14-100％，BG1560的控制效果为89.42-100％，它们均高于化防田54.32-87.83％的控制效果。 通过室内饲喂Bt棉的不同组织和使用Bt杀虫剂对斜纹夜蛾进行毒力测定表明，取食不同品种棉叶、花瓣和花心的斜纹夜蛾的死亡率无显著差异，但取食Bt棉BG1560棉蕾的斜纹夜蛾的死亡率显著高于其它相应的处理。Bt杀虫剂对斜纹夜蛾的LC50高达1170Pm。大田调查表明，两Bt棉田斜纹夜蛾幼虫的种群动态与非Bt棉田的无显著差异。 室内生测和大田试验表明，与常规棉泗棉3号相比，Bt棉6K19和BG1560对棉蚜的存活率、生活历期及繁殖力均无显著影响，Bt棉与常规棉田棉蚜的发生动态及为害情况也一致。 对Bt棉在长江中游棉区对各种主要靶标及非靶标害虫影响的系统评价表明，在长江中游棉区种植Bt棉，将有助于控制该地区的棉铃虫和红铃虫的危害，减少棉田农药的使用次数，控制棉蚜的暴发，使棉田生态系统朝良性的方向发展。但同时我们也发现，由于Bt棉对棉田斜纹夜蛾几乎无毒杀作用，这有可能导致斜纹夜蛾成为Bt棉田的主要害虫，从而威胁Bt棉在该地区的成功使用。因此，有必要对该地区Bt棉田斜纹夜蛾的发生规律及种群动态进行跟踪调查，并对其灾变规律开展研究，以期能有效地控制其在Bt棉田的为害。更多还原

【Abstract】 Bt transgenic cotton has been a worldwide important tool to control pests of cotton field since 1990s. Today, north China and Yantz River valley have deployed Bt cotton gradually. In order to undertand resistance level of Bt cotton to targeted insects in Yantz River valley and make the best use of its control effecicency to pests in this region, seasonal expression profile of insecticidal protein of two Bt cotton lines carrying a CrylA gene from Bacillus thuringiensis subsp. kurstaki (Berliner), developed, respectively, by Monsanto Co. and Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, and their influence on targeted pests and non-targeted pests were investigeted.Results showed that the toxin content in Bt cotton changed significantly over time, and that the structure, growth stage, and cultivar were significant sources of variability (P < 0.05), but there was no significant difference between the two years (P = 0.8362). Generally, insecticidal protein levels were high during the early stages of cotton growth; they declined in mid-season, and rebounded in late season. On most dates sampled, the toxin contents in leaf, square, petal and stamens (including non-ovule pistil tissue) were much higher than those in ovule and boll. Compared to BG1560, the expression of CrylAc/CrylAb protein in GK19 was more variable during the whole growth period of cotton.Bioassay fed on structures of two Bt transgenic cotton lines to cotton bollworm (Helicoverpa armigera) indicated that there were significant differences of resistance levels among various structures and developmental stages of both Bt transgenic cotton lines. In general, resistance level of reproduction organs were higher than leaves in two lines, and it decreased gradually as cotton growth from July to September; The field evaluation on larval population dynamics of H. armigera in Bt and conventional cotton showed that the larval densities in GK19 and BG1560 fields decreased, respectively, 92.04% and 81.85% in 2001, and 96.84% and 91.80% in 2002. However, egg densities of cotton bollworm in two Bt cotton fields were no significant difference from conventional lines, and distrubiton of cotton bollworm larvae on structures of two Bt cotton was similar to that on structures of conventional cotton.Survey on egg density and larval population dynamics of pink bollworm in Bt and non-Bt cotton fields showed that there were no significant differences in egg density among the two Bt cotton lines and conventional cotton lines, but larval densities on both Bt lines were significantly lower than on the conventional lines in both years. In comparison with the larval density on a conventional line without chemical control, the control efficacy in different growth stages of two Bt cotton lines were 73 - 100% for GK19 and 89 - 100% for BG1560, they were higer than control efficiency of 54 - 88% for chemically treated conventional cotton.Bioassay fed on structures of Bt cotton lines and Bt formulation, effects of Bt cotton on survival of common cutworm were studied. Results showed that mortalities of common cutworm fed on leaf, petal, and flower heart among lines were no difference, but compared with correponding treatments, mortality of common cutworm fed square of BG1560 was higher. LC50 of common cutworm to Bt insecticide was 1170PPm. Investigation in field displayed that larval densities in two Bt cotton lines were nosignificant difference from conventional cotton line. The life table analysis in the laboratory showed that there were no significant differences in survival rate, nympha duration, and fecundity between laboratory populations of aphids fed on Bt and non-Bt cotton. The field surveys also indicated that there were no significant differences in population dynamics of aphids and its damages to different cotton lines between Bt cotton and conventional cotton fields.By systematic evaluation on resistance of Bt cotton planted in Mid-Yangtze River valley to major targeted pests and potential impact on population dynamics of non-targeted更多还原