不同氮肥水平下转Bt基因水稻对褐飞虱和白背飞虱生态适应性的继代影响

在目前氮肥施用量依然偏多的大背景下,氮肥与转 Bt 基因水稻的相互作用是否会对稻田中非靶标节肢动物产生影响是转基因水稻安全评价的重要内容。本研究在室内条件下用0 kg/hm²、100 kg/hm²和250 kg/hm²3个氮肥水平处理的转 Bt 基因水稻T1C-19和T2A-1以及非转基因亲本水稻明恢63,连续饲养褐飞虱和白背飞虱4代,研究在不同氮肥条件下,转 Bt 基因水稻对褐飞虱和白背飞虱生态适应性的继代影响。结果显示,在同一水稻品种上,氮肥的过量施用,显著提高了褐飞虱和白背飞虱的生态适应性,并且随着代数的增加具有一定的累加效果。同一氮肥水平条件下,转 Bt 基因水稻和对照相比对同代褐飞虱和白背飞虱的若虫发育历期、雌虫体质量、成虫寿命、褐飞虱若虫孵化率、存活率均无显著影响。而在100 kg/hm²和250 kg/hm²施氮水平下取食转基因水稻T1C-19的褐飞虱在第1代至第3代的每雌产卵量均显著低于另一转基因品种T2A-1以及对照品种明恢63,但第4代褐飞虱在各品种上的产卵量无显著差异。本研究结果表明,氮肥的施用显著提高了褐飞虱和白背飞虱的生态适应性,供试两种转Bt基因水稻对褐飞虱和白背飞虱的生态适应性无显著影响。这为转基因水稻的安全评价提供了一定的理论依据。

Effects of Bt Rice with cry1C and cry2A on the Ecological Generation Fitness of Rice Brown Planthoppers(Nilaparvata lugens) and Whitebacked Planthoppers (Sogatella furcifera) at Various Nitrogen Rates

In order to evaluate the effects of Bt rice on the generation fitness of non-target pest at different nitrogen rates, as wall as the potential impact of Bt rice and nitrogen fertilizer levels on non-target pest, the brown plantthopper (BPH) (Nilaparvata lugens) and the whitebacked planthopper (WBPH) (Sogatella furcifera), were successively cultured for four generations on Bt rice, T1C-19 with cry1C and T2A-1 with cry2A , and their parental rice Minghui 63, at nitrogen rates of 0, 100 and 250 kg/hm². The results indicated that the ecological fitness of the BPH and WBPH was increased with the increasing nitrogen fertilizer level, including shortened nymph developmental duration, enhanced fecundity, prolonged longevity, increased nymph survival rate, female weight, egg hatchability and population growth rate. There were significant differences in rice planthopper nymphal development duration, body weight of female adult, fecundity and population growth rate for four successive generations under different nitrogen rates. Transgenic Bt rice, T1C-19 and T2A-1, had no significant effect on the fitness of BPH and WBPH at the same generations and nitrogen rates, except the BPH fecundity. BPH fecundity on transgenic Bt rice T1C-19 at the nitrogen levels of 100 kg/hm² and 250 kg/hm²(N) was lower compared with the transgenic Bt rice T2A-1 and its parent Minghui 63 from the first generation to the third generation, but no significant difference was found among varieties at the fourth generation at three nitrogen rates. No significant difference was found on the fitness of BPH and WBPH with the generation increase, between non-transgenic Bt rice and transgenic Bt rice. Therefore, the present study demonstrated that nitrogen fertilizer levels exerted a significant influence on the ecological fitness of the rice planthoppers with the generation increase, while transgenic Bt rice didn't.