Bt Research 2024, Vol.15, No.1, 30-41 http://microbescipublisher.com/index.php/bt 37 vegetative insecticidal proteins (Vip) in transgenic corn has shown promise in maintaining pest susceptibility where other Bt proteins have failed (Tabashnik and Carrière, 2017; Tabashnik et al., 2023). 7.2 Integration with other biotechnologies The integration of Bt transgenic crops with other biotechnologies has been pivotal in enhancing their effectiveness and sustainability. Combining Bt traits with other genetic modifications, such as RNAi-based traits for viral resistance, has been shown to improve pest and disease management (Anderson et al., 2019). Additionally, the use of Bt crops within diversified Integrated Pest Management (IPM) systems has proven beneficial. IPM strategies that incorporate Bt crops can reduce the need for chemical insecticides, thereby lowering environmental impact and promoting agricultural sustainability (Mabubu et al., 2016; Anderson et al., 2019). The use of hybrid genes, gene pyramiding, and sterile insect techniques are some of the strategies employed to delay pest resistance and maintain the efficacy of Bt crops (Carrière et al., 2015; Koul, 2020). 7.3 Advances in genetic engineering Advances in genetic engineering have significantly contributed to the development and sustainability of Bt transgenic crops. Techniques such as cisgenesis, intragenesis, zinc-finger nuclease technology, and oligonucleotide-directed mutagenesis (ODM) have enabled more precise genetic modifications, enhancing the performance and safety of transgenic crops (Rios, 2015). The use of Agrobacterium-mediated plant transformation has been particularly effective in developing stable transgenics, which are crucial for long-term sustainability (Koul, 2020). Moreover, the application of meta-analysis in evaluating the performance of transgenic crops has provided robust evidence of their benefits over conventional crops, including higher yields, lower production costs, and reduced pesticide use (Rios, 2015). These technological advancements underscore the importance of continued innovation and regulatory support to maximize the potential of Bt transgenic crops in sustainable agriculture. 8 Long-term Ecological and Economic Sustainability 8.1 Evaluating long-term ecological impact The long-term ecological impact of Bt transgenic crops is a critical area of study, given their widespread adoption and the potential for unintended consequences on non-target organisms and soil health. Research has shown that while Bt crops have been effective in reducing the reliance on chemical pesticides, they also pose risks such as the development of pest resistance and potential impacts on soil enzymatic activities and non-target organisms. For instance, studies have documented an increase in pest resistance to Bt crops over time, with cases of resistance rising significantly from 2005 to 2020 (Carrière et al., 2015; Tabashnik and Carrière, 2017) . This resistance can undermine the ecological benefits of Bt crops by necessitating the use of additional pest control measures, potentially leading to increased chemical pesticide use and associated environmental impacts. Moreover, the impact of Bt crops on soil health has been a subject of extensive research. A global meta-analysis revealed that Bt crops can alter soil enzymatic activities, with significant increases in enzymes such as dehydrogenase and urease when Bt residues are incorporated into the soil (Gassmann and Reisig, 2022). These changes in soil enzyme activities can affect nutrient cycling and soil fertility, which are crucial for long-term agricultural sustainability. Additionally, the effects of Bt crops on non-target soil invertebrates have been systematically reviewed, showing no significant overall impact on their population abundances and biomasses (Krogh et al., 2020). However, the variability among different invertebrate orders and the heterogeneity of study results suggest that more research is needed to fully understand the long-term ecological consequences of Bt crop cultivation. 8.2 Assessing economic viability over time The economic viability of Bt transgenic crops over the long term is influenced by several factors, including pest
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