Impact Of Bt Rice Grain On Physicochemical Parameters Of Rice And Arthropod Community In The Storage

To evaluate the biosafety of transgenic Bacillus thuringiensis (Bt) rice (followed asBt rice) during the storage, a serial of studies on Bt rice expressing Cry1Ab/Cry1Ac geneand its parent rice (control) were conducted in the warehouse of urban entomologyinstitute of Huazhong Agricultural University.First, the changes in germination trend, germination percentage, free fatty acid (FFA)and viscosity of the Bt rice was observed at intervals during 24 months storage period atambient temperature and relative humidity. Result showed that as storage period wasprolonged, there was no significant difference between the physicochemical properties ofBt rice and the control, FFA increased, while germination percentage, and viscosity of ricedecreased. However, rates of changes of FFA and germination rate in Bt rice were lowerthan in control rice. Our observations were therefore suggestive that transgenic Bt riceused in this study had long term storability.Second, the change of content of Bt toxin in Bt rice were tested by ELISA method atthe different storage time. The results showed that as storage period was prolonged, thecontent of Bt toxin was always significant higher in the kernel than in the husk, howeverit were not decreased both in the kernel and in the husk 4 years after stored.Third, the impact of Bt rice on the development of Sitotroga cerealella, angoumoisgrain moth, was investigated by life table method. The results suggested that there was nonegative effects on the development of this storage pest except the development time oflarva and pupa delayed significantly compared with those reared on the control rice.Fourth, the impact of Bt rice on the arthropod community in the storage were studiedby sampling in the Bt rice and the control per 15 days during the 12 months storageperiod. The results showed that Bt rice had no negative effect on the diversity, richness ofspecies, evenness and concentration of the arthropod community. The dominate specieson Bt rice and the control was similar: Rhizopertha dominica in the early sampling,Lipascelis bostrychophilus in the middle and later sampling. The damage caused bystorage insect was significant lower on the Bt rice than on the control, however, itincreased both on two rice varieties as the storage time was prolonged.In short, all the results of this study show that Bt rice was safe for the arthropodcommunity during the storage.