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2-During the plant transformation efficiency studies in the japonica(Xiushui-11)and indica rice cultivar(XC-95),the role of various factors responsible for virulence of Agrobacterium such as virulence induction medium(VIM),acetosyringone(AS),cell density and co-cultivation time,pH,carbon sources and light was assessed to establish a better transformation system for the rice cultivars used in the experiments.MS and AB media(as VIM)for japonica and indica rice,respectively,100μM AS,A6000.4-0.6for10-15minutes,pH6.0(VIM and COM),use of sucrose or glucose and dark conditions during co-cultivation period were found to be ideal for transformation process. 3-A number oftransgenic lines were developed harboring the Cry1A(c)gene either alone or in combination with CpTi,driven by CaMV35S or a tissue specific promoter,RSuS-1,mediated by Agrobacterium tumefaciens genetic transformation in japonica and indica rice.PCR analysis and histochemical assay revealed the successful transformation event in the tested transgenic lines.The transgenic construct strictly followed the Mendelian inheritance principle(3∶1)in the subsequent generations as demonstrated by hygromycin assay result. So far,the history of transgenic crops can be included in two parts.The first era deals with the development of such novel crops.As the time went on,various social,environmental and technical issues related to transgenic crops took their birth.The genetic engineering of crop plants is now moving towards the course of correction.Of the agronomic traits improved by using transgenic plants,genetic resistance to pests has attracted considerable attention.Now a days,a number of approaches to pest control via genetic engineering have been developed and genetically engineered crops expressed insecticidal characteristics.Use of Bacillus thuringiensis genes encodingδendotoxins with insecticidal characteristics is the major approach.In the Part-Ⅰof this dissertation,various strategies to combat issues faced by transgenic crops,approaches for pest control by genetic engineering and the application of Bacillus thuringiensisδendotoxins have been reviewed with significant details.