转基因棉生长前期不同叶位叶片对甜菜夜蛾种群增长的影响

Effects of Leaf Position of Transgenic Cotton on the Population Growth of Spodoptera exigua in the Early Growth Stage

【目的】近年来,棉花成为甜菜夜蛾(Spodoptera exigua Hübner)的主要寄主之一,主要受害部位为叶片。随着转基因棉的推广种植,明确其不同叶位叶片对甜菜夜蛾种群增长的影响对有效防治甜菜夜蛾具有重要意义。【方法】以转cry1A基因棉国抗12(GK12)、转cry1Ac基因棉新棉33B和转cry1A+Cp TI基因棉SGK321,以及它们的亲本对照泗棉3号、DP5415和石远321为材料,研究3种不同类型转基因棉生长前期不同叶位叶片对甜菜夜蛾种群增长的影响,并以实验种群生命表形式加以描述。【结果】(1)转基因棉GK12和SGK321对甜菜夜蛾种群增长有一定的抑制作用,尽管随着取食叶位的不同,抑制作用存在一定的差异,但其种群趋势指数均远大于1。(2)取食同一转基因棉花品种不同叶位叶片后,对甜菜夜蛾幼虫至蛹期的死亡率、蛹质量及产卵量虽有一定的影响,但叶位间不存在明显的变化趋势。(3)取食新棉33B和SGK321的甜菜夜蛾种群趋势指数明显低于对应的常规对照棉,而取食国抗12的甜菜夜蛾种群趋势指数与对照品种泗棉3号差异不显。【结论】取食所研究的3类转基因抗虫棉不同叶位叶片后,甜菜夜蛾的种群仍呈增长趋势,应加强转基因棉田甜菜夜蛾的防控。

[Objective]Cotton has recently become one of the main hosts of Spodoptera exigua(Hübner),a moth species that damages the leaves of plants.With the widespread application and popularization of transgenic insect-resistant cotton,it is essential to understand the significance of leaf position on the population growth of S.exigua to effectively manage this pest.Leaf position was determined by the preference of this pest for the upper and middle leaves of cotton.[Method]To study the effects of different leaf positions on S.exigua population growth,we used three different kinds of transgenic cotton(transgenic cry1 A cotton GK12,transgenic cry1 Ac cotton Nu COTN 33 B,and transgenic cry1 A+CpTI cotton SGK321).We tested these three transgenic cotton varieties alongside their corresponding parental non-Bt transgenic cotton varieties(Simian 3,DP5415,and Shiyuan 321)as controls,respectively.We describe our results in the form of a population life table.[Result](1)GK12 and SGK321 had an inhibitory effect on S.exigua,which exhibited some differences with the change of feeding position.The population trend index was substantially larger than 1.(2)Although there was an influence on the growth and reproduction of S.exigua after feeding on different leaf positions of the same transgenic cotton,the results show no apparent trend of change among leaf positions.(3)The population index of S.exigua that fed on Nu COTN 33 B and SGK321 showed a lower tendency than that on conventional cotton varieties,but there was no significant difference between the population index for the S.exigua that fed on GK12 and Simian 3.[Conclusion]The population growth of the S.exigua that fed at different leaf positions on the three varieties of transgenic cotton increased throughout the experiment.This continuous population growth indicates that the transgenic cotton crops require additional management actions to control of the pest species,S.exigua.