BT作物的昆虫抗药性管理.pptVIP

Insect Resistance Management for Bt CropsBt作物的昆虫抗药性管理 IRM: why is it important?IRM的重要性 Maintaining the efficacy of Bt, a low-risk pesticide, is beneficial for the following reasons: 维持低风险杀虫剂Bt的功效有如下的优点: Bt replaces higher risk pesticides Bt杀虫剂可以代替其他高风险性的杀虫剂 Less exposure of nontarget organisms to superficially applied pesticides 降低非目标生物暴露于杀虫剂的可能性 Use of Bt crops may provide greater profits to farmers, due to reduced use of insecticides 由于减少了杀虫剂的使用,Bt作物可以给农民带来更大的收益 Critical components of IRM planIRM计划的重要组成成分 Pest biology 害虫生物学 Dose 剂量 Cross-resistance 抗性转移 Refuge 避难所 Modeling 建立模型 Resistance monitoring 抗性监测 Remedial action 矫正措施 Compliance assurance 确保规范性 Grower education 种植者教育 Pest biology害虫生物学 Important factors include: Number of insect generations per year Host range Insect movement and dispersal patterns Mating and ovipositional behavior Population dynamics 要点包括: 每年害虫繁殖的代数 宿主的范围 害虫移动和分布的模式 交配和产卵行为 种群动态 Pest biology: an example害虫生物学举例 European corn borer (ECB), Ostrinia nubilalis 1-4 generations per year Polyphagous (prefers corn) Movement: Larvae - can move from plant-to-plant within a field Adults - mostly local movement, but some long distance migratory movement can occur 欧洲玉米螟(ECB) 每年繁殖1-4代 杂食性(偏好玉米) 移动 幼虫可以在同一田地内不同植株上移动 成虫大部分在本地活动,但也有可能进行长距离迁移 Dose 剂量 Dose = the amount of toxin expressed over time by a transgenic crop, relative to the susceptibility of a target pest; can be determined through field efficacy trials or laboratory bioassays 剂量=转基因作物在一定时间内表达的毒素的量, 和目标害虫的敏感性相关; 通常由田间功效实验或实验室生物测试所决定. High dose = at least 25x the amount of toxin needed to kill all susceptible target insects; preferred over low dose events for refuge-based IRM strategies 高剂量=至少为杀死所有敏感目标害虫剂量的25倍; 在以避难所为基础的昆虫抗性管理策略中，使用高剂量遗传事件体要比低剂量遗传事件体好 Dose assumptions剂量假设 Three genotypes for resistance/susceptibility (SS, rS, rr) Resistance (rr) is recessive and rare Refuge supplies SS (homozygous susceptible) genotype Random mating: rr x SS → rS rS x SS → rS or SS SS and rS susceptible to hi