【作者】 张桂芝；

【导师】 赤国彤；

【作者基本信息】 河北农业大学 ， 农业昆虫与害虫防治， 2004， 硕士

【摘要】 本试验以2368.91倍的小菜蛾对虫螨腈的抗性品系（RR）与敏感品系（SS）进行杂交，F₁代进行自交，及F₁代与亲本回交，结果表明，杂交后的显性度（D）分别为0.5517和0.5402，说明小菜蛾对虫螨腈的抗性遗传是常染色体、不完全显性遗传，而且可能是由多基因控制的。杂交后代的抗性基因频率明显下降。 通过比较抗性品系与敏感品系的生物学特性发现，除抗性品系的幼虫历期有所延长，蛹期缩短，单雌平均产卵量明显低于敏感品系外，其余各指标与敏感品系差异均不显著。敏感品系的净增殖率为55.4，抗性品系的净增殖率为25.2，因此抗性品系相对于敏感品系具有0.45的适合度。因此小菜蛾对虫螨腈的抗性品系在生长发育和繁殖上均存在生存的不利性。 对抗性品系在停止喷药，消除选择压的条件下饲养9代，发现小菜蛾对虫螨腈的抗性水平一直呈下降趋势。从F₁代～F₃代，抗性衰退速度较为缓慢，从F₃代～F₆代，抗性衰退相对较快，从F₇代～F₉代，抗性衰退速度又趋向于缓慢，至第九代，抗性倍数下降了7～8倍，抗性倍数由2368.91倍下降到305.38倍。 通过对小菜蛾抗性品系和敏感品系点药前后呼吸速率进行测定，结果发现，抗性品系与敏感品系受虫螨腈处理后，呼吸速率显著不同，抗性品系受处理前后的呼吸速率变化不大，而敏感品系受处理前后的呼吸速率的变化较为显著。说明抗性品系小菜蛾的耐药性高于敏感品系小菜蛾。F₁代和F₂代受处理前后呼吸速率的变化介于抗性品系与敏感品系之间，回交后代点药后与点药前的差异明显大于F₁代和F₂代点药前后的差异。由此可以初步判定，小菜蛾呼吸速率的变化与敏感性恢复有关。 经过各种群的酯酶、羧酸酯酶、谷胱甘肽-S-芳基转移酶活性测定，结果显示，抗性品系的酯酶比活力略高于敏感品系，但两者之间并无明显差异。杂交代的酯酶活力均低于敏感品系，表现没有一定的规律性。抗性品系与敏感品系的谷胱甘肽-S-芳基转移酶活性存在一定差异。抗性品系小菜蛾的谷胱甘肽-S-芳基转移酶活性明显低于敏感品系，仅为敏感品系的0.5775倍，其杂交后代的谷胱甘肽-S-芳基转移酶活性介于两亲本之间，比抗性亲本有所升高，由此可以初步判定，小菜蛾对虫螨腈的抗性与酯酶及羧酸酯酶活性无关，与谷胱甘肽-S-芳基转移酶活性有关。 用聚丙烯酰胺凝胶电泳分析各品系的酯酶同工酶，在抗性品系的酶带中发现一条特征性酶带，说明抗性品系可能有新酶出现。更多还原

【Abstract】 The genetics of resistance to chlorfenapyr were carried out on susceptible laboratory strains and resistant strains (2368.91 X ) of diamondback moth, Plutella xylostella. The LD50 and probit regression lines of susceptible and resistant parents and their F1 hybrids, F1-backcross progeny and F2-masscross progeny were assessed in order to determine inheritance character. The result showed that the degree of dominance of FRS and FSR were 0.5517 and 0.5402 respectively. It suggested that the resistance of diamondback moth to chlorfenapyr was autosomal, incompletely dominant and probably polygenic control. The resistance gene frequency decreased significantly.The research was taken to two different ’strains in the terms of developmental and reproducetive characterstics under artifitial climate condition. Life tables of the resistant strain and the susceptible strain were constructed. The results indicated that the resistant strain possessed some developmental disadvantage including prolonged larva duration, and reproductive disadvantage including lower mean number of eggs per female. The intrinsic rate of natural increase in the resistant and susceptible strain calculated by establishing life table were 25.2 and 55.4, respectively. Rate of relative fitness of resistant strain was 0.45 based on comparing with that of susceptible strain.The resistance ratios (RR) of Plutella xylostella declined when the resistant strain was reared on fresh cabbage leaves in the laboratory. From F1 to F3, resistance reversion rate was slow. From F4 to F6, resistance reversion rate was fast relatively. From F7 to F9, there was a tendency for declining slowly once again. After 9 generation, the resistance ratios were over 7-8 folds from 2368.91 folds to 305.38 folds.Great difference was found between the two strains in rate of respiration after treated by insecticide chlorfenapyr, the resistant strain showed little variation treated by insecticide, but the susceptible strain showed great decrease treated by insecticide. The difference of F1 hybrids and F2-masscross progeny treated varied between those of the resistant strain and susceptible strain, backcross progeny while the difference of treated by insecticide was greater than those of F1 and F2. So it was estimated that the variation of respiration rate was related to resistance reversion.The activity of 3 enzymes (esterase, carboxylesterase and glutathione-S-transferase)from two strains were determined. The results showed that the activity of esterase and carboxylesterase of the resistant strain has no distinct difference compared with those of the susceptible strain, and those of F1 hybrids, F2 and BC were all lower than those of the susceptible strain and there were not any regularities.The activity of glutathione-S-transferase of the resistant strain was lower than that of the susceptible strain, was 0.5775-fold compared with the susceptible strain, while that of other strains between that of the resistant strain and susceptible strain and greater than that of the resistant strain. The results indicated that the glutathione-S-transferase contributed to resistance of diamondback moth to Chlorfenapyr.The esterase of hemolymph of the diamondback moth was analysed by polyacrylamide gelelectrophoresis (PAGE). In contrast to the susceptible strain, there was a special enzyme band in the resistant strain, the results indicated that perhaps there was a new enzymes.更多还原