【作者】 王飞；

【导师】 彭少兵；

【作者基本信息】 华中农业大学 ， 作物栽培学与耕作学， 2014， 博士

【摘要】 自上世纪90年代以来,抗虫转Bt基因作物得到广泛研究,原因在于Bt基因的导入可以有效地防治靶标害虫,有利于作物产量潜力的实现和对自然环境的保护。农学家对转Bt基因棉花和玉米的研究表明Bt基因的导入会改变作物的一些农艺(株高、分蘖等)和生理性状(氮、钾及光合代谢)。此外,对转Bt基因棉花的大量研究表明,Bt基因在植株内的表达存在器官间、时空的差异性,并且受多种非生物胁迫的影响,而且这会影响植株对靶标害虫的抗性。到目前为止,对转Bt基因水稻农艺性状的研究较少,有研究表明Bt基因的导入会降低水稻的产量和结实率。本研究以转两种Bt基因crylC*和cry2.A*的明恢63及其非转基因对照明恢63(MH63),和它们与珍汕97A杂交而得的Bt-汕优63和对照汕优63(SY63)为材料。我们通过独立的大田试验比较了在完全控制靶标害虫的条件下,转Bt基因水稻与对照产量的差异及其生理机制,并研究了它们对不同播期、氮肥、钾肥处理的响应。我们还在靶标害虫自然发生的情况下,开展大田试验研究了水稻稻纵卷叶螟发生情况对氮肥施用量的响应,及转Bt基因水稻对靶标害虫抗性受氮肥处理的影响。主要的研究结果如下：(1)MH63(1C*)的产量显著地低于MH63(2A*)和亲本MH63,而MH63(2A*)和对照MH6的产量没有显著差异。MH63(1C*)产量下降的原因是结实率的降低。SY63(1C*.SY63(2A*)和SY63间的产量及产量构成因子均没有显著的差异。本研究表明不同转基因材料与亲本在无虫害条件下的产量差异不同,因此Bt基因的导入对水稻产量的影响不可一概而论。(2)播期试验中,播期处理和品种间对产量及产量构成因子不存在互作效应,即表明Bt-MH63与亲本明恢63对不同播期处理的响应是一致的,Bt基因的导入并未改变明恢63的最适播期。播期试验设置了三个播期,即5月15日、5月25日和6月4日。产量随播期的延后而增加,播期二和三处理的产量显著地高于播期一处理。播期一处理的收获指数显著地低于播期二和播期三处理。产量构成因素中,播期二和三处理的单位面积颖花数、每穗颖花数和结实率都显著地高于播期一处理。MH63(1C*)的产量在三个播期都显著地低于MH63(2A*)和亲本MH63,而MH63(2A*)的产量在第三播期显著地高于亲本MH63。(3)在氮肥试验中,氮肥与品种间对产量没有显著的互作效应,即转Bt基因水稻材料与亲本对氮肥的响应一致。在极端高温胁迫下,两个施用氮肥处理(150和195kg N ha-1)的产量显著地高于不施氮处理,主要是结实率的升高,这表明氮肥施用可以在一定程度上缓解极端高温胁迫对水稻结实率的影响。三个杂交材料在不同氮肥处理下的产量显著地高于三个恢复系材料。三个杂交材料的氮素利用相关指标(氮素籽粒生产效率,氮素收获指数等)显著地高于三个恢复系材料,而MH63(1C*)的氮素籽粒生产效率(NUEg)和氮素收获指数(NHI)显著地低于亲本MH63。(4)钾肥试验设置了三个钾肥处理(0、40和135kg K ha-1),钾肥施用量为135kg ha-1时的产量和钾肥籽粒生产效率显著地低于钾肥施用量为0和45g ha-1处理。成熟期两个Bt-MH63茎秆中的钾素积累量高于亲本MH63,而籽粒中钾的积累量低于亲本MH63.MH63(2A*)籽粒中钾的浓度显著地低于亲本MH63,而两个Bt-MH63和亲本MH63茎秆中钾的浓度差异不显著。MH63(1C*)在钾肥施用量为135kg ha-1时地上部钾素积累量显著高于亲本MH63。在钾肥施用量为0和45kg ha-1时,两个转基因水稻材料的钾素籽粒生产效率均显著地低于亲本。本研究表明Bt基因的导入影响钾素的吸收及在植株内的分配,并且对不同转基因材料的影响不同。(5)水稻稻纵卷叶螟的发生随着氮肥施用量的增加而增加,不施氮处理的白叶率为20%左右,而氮肥施用量为210kg ha-1处理的白叶率为50%左右；不施氮处理的百兜虫量少于400头,而施氮量为210kg ha-1处理百兜虫量可以达到1200头。SY63(1C*).SY63(2A*)和SY63在施氮量为210kg ha-1处理的产量低于施氮量为90和150kg ha-1处理。cry1C*和cry2A*导入到水稻中都能有效地防治稻纵卷叶螟,并且cry1C*：的效果更好。SY63(1C*.SY63(2A*)对SY63的产量优势均为20%左右,SY63(1C*)在施氮量为150kg ha-1处理取得最高产量,而SY63(2A*)在施氮量为90kg ha-1处理取得最高产量。叶片中两种Bt蛋白含量都随着施氮量的增加而增加。本研究表明不同的Bt基因对同一靶标害虫的抗性不同,而转Bt基因水稻产量优势的实现取决于其绝对产量的高低,即产量水平越高越有利于转Bt基因水稻产量优势的实现。(6)综上所述,本研究表明在不喷施杀虫剂的条件下,两种Bt基因在各个氮肥处理下都能有效地防治靶标害虫,而不同Bt基因的抗虫效果不同。不同转Bt基因水稻材料(包括将同一Bt基因转入到不同品种和将不同Bt基因转入到相同品种)与亲本相比,在无虫害胁迫下的农艺性状及其氮、钾代谢会产生一定的差异,但是这些差异各不相同。Bt基因的导入可以有效地防治靶标害虫,减少杀虫剂的施用。但是转Bt基因水稻的栽培管理(如播期的选择、肥料的运筹等)与非转基因品种没有绝对的差异,应根据品种特性制定适宜的管理措施。将Bt基因转入到高产水稻品种配以适宜的栽培管理措施有利于其抗虫效果及产量优势的实现。更多还原

【Abstract】 Due to the advantage in yield and environment protection, Bt transgenic crops have been well studied since1990s. However, the incorporation of Bt genes into the genome of crops resulted into changes in morphological and physiological traits, for examples, plant height, tillering, N metabolism, K potassium and photosynthesis physiology, and etc. There were few field study about the agronomic performance of Bt transgenic rice before this research, although it was found that Bt transgenic rice lead to reduced grain filling percentage. In our study, MH63(1C*), MH63(2A*), MH63, and SY63(1C*), SY63(2A*),SY63were used in the field experiments from2009to2011. We studied the yield differences between Bt rice and non-Bt rice under insect free condition, and compared their response to different planting dates, N fertilizer treatments and K fertilizer treatments. Under natural insect condition, we studied the occurrence of leaffolders, and the yield advantage of Bt rice over non-Bt control at different N treatments. Our main results are as following:(1) Grain yield of MH63(1C*) was significantly lower than that of MH63(2A*) and MH63, and there was no significant difference in grain yield between MH63(2A*) and MH63. The lower grain yield of MH63(1C*) was due to significantly lower grain filling percentage. No significant difference was found in grain yield among the three hybrid varieties (lines). From the growth analysis, there were no significant differences in leaf area index, biomass accumulation and instantaneous photosynthesis between MH63(1C*), MH63(2A*) and MH63. However, MH63(1C*) had significantly lower NSC (non-structural carbohydrates) translocation from the stem to grain during grain filling stage. This was possibly due to the lower content of ZT, IAA and GA3in the spikelets of MH63(1C*).(2) There were three sowing dates in2009, namely May15,25and June4. Grain yield increased as sowing date delayed. Grain yield were significantly lower when sown in May15than the other two, because it had significantly lower spikelets m2, spikelets per panicle, grain filling percentage. The lower spikelets m"2, grain filling and grain yield were possibly due to extreme high temperature at panicle initiation and flowering stage. The reduction in grain yield at sowing date May15in comparison with June4was higher for the Bt-transgenic rice lines. MH63(1C*) had significantly lower grain yield than MH63at all the three sowing dates, while MH63(2A*) had significantly higher grain yield than MH63when sown at June4. There were changes in leaf number, panicle development and tillering between MH63(1C*), MH63(2A*) and MH63.(3) Grain yield of NO treatment was significantly lower than that at N1and N2due to the lower grain filling percentage in2009, while there was no significant difference in grain yield among the three N treatments in2010. Hybrid varieties (lines) had significantly higher grain yield than three restorer lines. MH63(2A*) had significant higher grain yield than MH63when195kg N ha-1was applied, In2010, the three hybrids utilized N more efficiently than the three restorers. MH63(1C*) had significantly lower NUEg and NHI than MH63(2A*) and MH63.(4) There were three K treatments in2009, namely0,45and135kg ha-1. Grain yield and KUEg at135kg ha’1were significantly lower than that at0and45kg ha-1. No significant difference was found in K accumulation in stem and grain between Bt-MH63and MH63at maturity. K concentration in stem were similar for Bt-MH63and MH63, but MH63(2A*) had significantly higher K concentration in grain than MH63. KUEg was significantly lower for MH63(1C*) and MH63(2A*) than MH63when0and45kg ha"1were applied.(5) Damage caused by leaffolders became severe when N fertilizer rate increased. No. of larva per100hills increased from400to1200when N fertilizer rate increased from0to210kg N ha1. Grain yield of SY63(1C*), SY63(2A*) and SY63at N rate of210kg N ha"1was lower than that at90and150kg N ha"1. Incorporation of crylC*and cry2A*into the genome of rice could control leaffolders efficiently, and the efficacy of cry1C*was better than cry2A*. The yield advantage of SY63(1C*) and SY63(2A*) over SY63was all around20%, but they were achieved at different N fertilizers rates. The content of Bt protein in the leaf significantly correlated with N content.(6) In conclusion, the incorporation of Bt genes into rice genome lead to effective control of target insects, and there was variation in the efficacy for different Bt genes. Under free insect condition, Bt transgenic rice showed variation in agronomic and physiological traits in comparison with control, but the change was not consistent for different Bt transgenic rice.更多还原