【作者】 李国平；

【导师】 何运转； 吴孔明；

【作者基本信息】 河北农业大学 ， 农业昆虫与害虫防治， 2003， 硕士

【摘要】 转Bt基因棉花、玉米和马铃薯已在许多国家大规模商业化种植。如同化学农药一样，害虫在持续选择压力下，也将会对Bt毒素产生抗性。现已知至少10种蛾类、2种甲虫和4种蝇类在实验室内对Bt毒素产生了抗性，尤其是小菜蛾在田间自然条件下对Bt制剂产生了抗性。随着Bt作物的推广应用，靶标害虫的潜在抗性成为广泛关注的重要问题。虽然到目前为止，尚未有确凿证据证明靶标害虫自然种群已对Bt植物产生抗性，但已有多个实验室获得了抗Bt植物的害虫品系。为了准确地监测昆虫的抗性动态，近年来在传统的基于标准生物测定确定抗性指标的基础上先后发展了诊断剂量、单对杂交、F₂代检测和分子生物学检测抗性等位基因等抗性监测方法，来明确害虫的抗性水平、地理分布及抗性变化动态，为抗性治理提供依据。 为此，本文利用诊断剂量法对河北省安次县和山东省夏津县大面积种植转Bt基因棉花地区的棉铃虫进行了CrylAc抗性个体的检测，并利用此法对室内筛选的Bt抗性棉铃虫种群进行了抗性遗传方式的初步研究，结果如下： 1．2002年，在安次县和夏津县分别用黑光灯诱集棉铃虫蛾，每个雌蛾单独饲养，待幼虫孵化后，将每个家系的25～35头初孵幼虫分别接在正常饲料和诊断浓度饲料上（1.0μg/ml），进行生长发育速度生测，用来探测非隐性的杂合子和隐性的纯合子基因型。生测结果：分别在安次县的234头和夏津县的420头雌棉铃虫中检测出1个抗性个体，因此保守的估计两地区抗性基因频率分别为0.001068和0.000595。 2．两地区的棉铃虫部分进行了F₂代生测，结果表明目前田间种群可能携带微效的普通抗性基因或为高频率的不太显性的抗性基因，尤其在夏津县更为明显。 3．室内抗性遗传方式研究结果表明：棉铃虫对CrylAc的抗性遗传方式为单基因，常染色体，不完全隐性遗传。 本文对田间棉铃虫种群进行了抗性个体的检测，估计了田间抗性基因频率，对室内Bt抗性种群进行了抗性遗传方式的研究，可为当前转Bt基因棉的科学利用与管理，延缓棉铃虫对Bt棉的抗性演化速度提供重要的理论依据和技术指导。更多还原

【Abstract】 Insect resistant transgenic crops, such as Bt cotton, Bt maize, and Bt potatoes, have become important tools in the globe control of insec pests. Like chemical insecticide, Continuous production of Bt toxin in transgenic plants leads to season-long selection for insect resistance to the Bt insecticidal protein. Laboratory population of at least ten specias of moths, two specials of beetles, and four specials of flies have been exposed repeatedly to Bt more than 50 experiments designed to select for resistance, especially Plutella xylostella development of resistance in the field. The potential risk of Bt resistance in targeted insect pests is threatening the sustainable deployment of Bt crops. Although there are no irrefutable evidence to prove field population of target insect pests to develop resistance to Bt crops, many laboratories have get the strain of pest to Bt crops. Several mentoring methods have been developed in recent years to evaluate early Bt resistance in the field, such as standard bioassay, diagnostic concentration, single pair crossing, p2 screen and molecular methods.Bt cotton has been widely planted in the Yellow River vally of China since 1998.Anci County of Hebei Province and Xiajin County of Shandong Province are two areas where almost 100% of the cotton grown producing CrylAc. These areas were therefore selected for analysis of the frequency of gene coding for resistance to CrylAc in field populations of the bollworm by using diagnostic concentration method, and the resistance inheritance mode was studied also by this method. The results were as follows: In 2002,adult females were collected using light-traps. Females were caged individually and were allowed to lay eggs. At hatch, 25-35 larvae from each female were screened for growth rate on normal artificial diet and on diet contaning l.Oug/ml of CrylAc toxin . This growth rate bioassay was designed to detect non -recessive resistance genes in heterozygous genotypes and to detect recessive resistance genes only when prensent in a homozygous resistant genotypes. The bioassay detected 1 resistant individual out of 234 screened in Anci and 1 resistant individual out of 420 screened inXiajin. These results suggest that a conservative estimate of the resistance gene frequency is 0.001068 in Anci population and 0.00595 in Xiajin population.Some familes in two areas were screened in F2 generation, and result indicated that resistance gene maybe minor genes for CrylAc resistance or less dominant genes for resistance may be at higher frequencies, especially in the Xiajin population.The resitance of the laboratory resistant population of cotton bollworm to CrylAc toxin was determined as an incompletely recessive inheritance controlled by single autosomal allele.This studies screened resistant individual of field population cotton bollworm to CrylAc and estimated resistant gene frequency, and studied the inheritance mode of laboratory resistant to CrylAc, which can provid strategies for pest control and transgenic Bt cotton management.更多还原