转基因抗虫棉田棉蚜种群消长关键因素分析

Key factors affecting the population dynamics of Aphis gossypii in transgenic insect-resistant cotton fields

为研究转基因抗虫棉田棉蚜种群动态的主要影响因素,在河北省南皮县采用罩网和开放式观测相结合的方法,以亲本常规棉为对照,对转Bt基因棉田和转Bt+CpTI双价基因棉田棉蚜自然种群消长的关键因素进行了分析。与常规棉相比,单、双价抗虫棉对天敌捕食和寄生、病原物、风雨等生物和非生物因素对棉蚜种群的自然控制作用均未产生显著影响;各因素中,除自然死亡及未知因素死亡外,天敌捕食对棉蚜自然种群的控制作用最强,风雨的作用次之,天敌寄生和病原物的作用则较弱。单价抗虫棉田棉蚜的发育历期和产仔量均与亲本常规棉田无显著差异,但双价抗虫棉田棉蚜的发育历期较对照显著延长,产仔量则无显著差异。由此表明,捕食性天敌对单、双价抗虫棉田非靶标害虫棉蚜具有较好的自然控制作用,是影响棉蚜自然种群数量动态的关键因素;单、双价抗虫棉的抗蚜性存在一定差异。

By cage experiments, life tables of cotton aphid, Aphis gossypii, in transgenic cotton fields （cvs. GK12 and SGK321 ） were established to evaluate key factors affecting aphid populations. These studies were carried out in Nanpi County, Hebei Province in July, 2004 with the non-transgenic parental cotton varieties （cvs. Simian3 and Shiyuan321 ） as control. It showed that both GK12 and SGK321 had no significant impacts on natural control efficacy of the biological and non-biological death factors of cotton aphids. Except for the factor of natural death and others, predation was the key factor affecting population dynamics of cotton aphid. Rain ranked the second, parasitism by insects and pathogens had weak control efficacy. Except that cotton aphid had longer developmental period in SGK321 field, transgenic cotton GK12 and SGK321 had no adverse impacts on development and fecundity of cotton aphids. It indicated that predation was the key factor affecting population dynamics of cotton aphids in GK12 and SGK321 and their respective parental cotton fields. And impacts of GK12 and SGK321 on development and fecundity of cotton aphids were different.