Bt水稻對(duì)非靶標(biāo)稻薊馬及其捕食者的風(fēng)險(xiǎn)性評(píng)價(jià).pdf

1、The transgenic crops have widely been adopted in different parts of the world and its area under cultivation is going to be increased day by day. Although the Bt crops have been found to control the lepidopterans and oth

2、er chewing insects pests attacking in the past but besides that their status has also been controversial as they can also interact with eco-system in terms of their effects on non-target arthropods such as non-target ins

3、ects, natural enemies, soil dewelling organisms and others.Bt rice has not been allowed in China for its commercial production because of its concerns regarding environment as far as its effect on environment is concerne

4、d. A large number of experiments are needed to test its feasibility to bring it in the field but besides that the effect on natural enemies needs some tier based studies including laboratory and other studies if needed.

5、IN the past several experiemtns have been conducted tO observe the effects of Bt tocin on lepidopterans and other target insects and has been found successful in the laboratory as well as field trials.But its effect on n

6、on-target insects really needs a lot of research and approach.to understand exactly the phenomena. So in our laboratory long term experiments are going on since start of trials and this study is also based on that studie

7、s including the effects of Bt rice on non-target thrips and their potential predator. 1. Laboratory Experiments conducted to observe life parameters of S. biformis The development (life parameters including nymphal insta

8、rs duration, pre-pupal and pupal duration) ,reproduction(fecundity, duration of egg laying, total number of eggs)of Stenchaetothrips biformis (Bagnall), the most important rice seedling insect pests and one ofnontarget i

9、nsect species of Bt rice, were evaluated on six transgenic Bt rice lines including Huachi B1 ;Huachi B6, KMD1 ;KMD2,TT-9-3; TT-9-4 were evaluated (expressing the Cry l Ab or Cry l Ab/Cry 1 Ac protein) and their non-Bt co

10、rrespondent parental cultivars including, Xiushui-11, IR-72 under laboratory conditions. Laboratory results revealed that larval and pupal development duration as well as preoviposition period were longer, oviposition pe

11、riod and female adult longevity were shorter, and total number of eggs laid were lower when thrips were fed on all tested Bt rice varieties as compared to their respective controls. 2. Two years field observations of Pou

12、lation abundance of S. biformis The population abundance of Stenchaetothrips biformis (Bagnall), the most important rice seedling insect pests and one of nontarget insect species of Bt rice,were evaluated on six transgen

13、ic Bt rice lines (expressing the CrylAb or Cryl Ab/CrylAc protein) and their non-Bt correspondent parental cultivars under field conditions for two years. In the field, population of the thrips in Bt and non-Bt plots was

14、 monitored using the plastic bag and beat plant methods. The patterns of population dynamics of thrips, in the field, were similar on all tested Bt rice lines and their respective control, however, thrip individuals coll

15、ected in the Bt plots were numerically less than those in the non-Bt plot almost at the entire rice growth stages in 2008. A numerical and even statistical lower average density of all individuals of thrip larvae and adu

16、lts occurred across the entire sampling period in Bt rice plots,and thrip individuals in Bt rice plots, at some sampling dates, were also statistically less. While the population desnsity in 2009 was not significantly di

17、fferent. 3.Protein test conducted to observe the presence of Bt toxin ELISA was performed to observe the presence of Bt toxin in the thrips and its possible effects on the thrips although the thrips as sucking insects ha

18、ve no specific site if action of Bt toxin in digestive system. 4.Population densities of four thrips species attacking panicle of rice over two years period The population abundance ofthrips attacking panicles office suc

19、h as Haplothrips aculeatus (Fabricius),Frankliniella intonsa(Trybom), Frankliniella tenuicornis (Uzel)were observed on six transgenic Bt rice lines (expressing the CrylAb or Cryl Ab/Cryl Ac protein) and their non-Bt corr

20、espondent parental cultivars under field conditions. In the field, population of all thrips in Bt and non-Bt plots was monitored using the plastic bag and beat plant methods. The patterns of population dynamics of all th

21、rips, in the field, were similar on all tested Bt rice lines and their respective control, however, thrip individuals collected in the Bt plots were numerically less than those in the non-Bt plot almost at the entire ric

22、e growth stages.A numerical and even statistical lower average density of all individuals of thrip larvae and adults occurred across the entire sampling period in Bt rice plots, and thrip individuals in Bt rice plots, at

23、 some sampling dates, were also statistically less. 5.Popualtion densities of Orius tantilus in the field The population abundance of Orius tantilus in the field were observed by using three sampling methods such as taki

24、ng the whole plant into plastic bag, beat plate, ad color traps method using three types of colors and guessing the best color for the monitoring of bugs.Overall no significant or non-significant difference was observed

25、in Bt and non-Bt fields and their population was found more or less same in Bt and non-Bt rice fields. 6.Observing the life parameters of Orius tantilus in the field O.tantilus were reared into laboratory to observe the

26、life parameters on thrips which were reared on KMD transgenic rice lines expressing expressing the Cryl Ab protein. So to guess either the Bt toxin can affect upto third trophic level or not. The results revealed no clea

27、r difference when the O. tantilus were reared on the transgenic rice or their control instead same performance was observed on transgenic and non-transenic rice, stating that Bt rice is not affecting the non-target as we

28、ll as their natural enemies hence not interacting with the environment. 7.Observing population densities ofS. biformis, four other thrips species attacking panicle, and their generalist predators Orius similis by Color t

29、raps One year field experiment was conducted to observe the field population densities of S. biforrnis attacking the rice seedling stage and other four thrips species attacking panicle office and their generalist predato