The advent of genetic engineering has revolutionized agriculture remarkably with the development of superior insect-resistant crop varieties harboring resistance against insect pests. Bacillus thuringiensis (Bt) has been used as a main source for insect-resistant genes. | Turkish Journal of Agriculture and Forestry Turk J Agric For (2015) 39: 531-548 © TÜBİTAK doi: Review Article Insect-resistant transgenic crops: retrospect and challenges 1, 2 1, 1 Allah BAKHSH *, Saber Delpasand KHABBAZI , Faheem Shahzad BALOCH **, Ufuk DEMİREL , 1 3 2 3 Mehmet Emin ÇALIŞKAN , Rüştü HATİPOĞLU , Sebahattin ÖZCAN , Hakan ÖZKAN 1 Department of Agricultural Genetic Engineering, Faculty of Agricultural Sciences and Technologies, Niğde University, Niğde, Turkey 2 Department of Field Crops, Faculty of Agriculture, Ankara University, Ankara, Turkey 3 Department of Field Crops, Faculty of Agriculture, Çukurova University, Adana, Turkey Received: Accepted: Published Online: Printed: Abstract: The advent of genetic engineering has revolutionized agriculture remarkably with the development of superior insect-resistant crop varieties harboring resistance against insect pests. Bacillus thuringiensis (Bt) has been used as a main source for insect-resistant genes. In addition to Bt endotoxins, various plant lectins and other non-Bt genes from different sources have also been introduced in crop plants of economic importance. The insect-resistant crops have made a huge economic impact worldwide since their commercial release. The cultivation of insect-resistant cultivars has resulted both in increased crop productivity and in decreased environmental pollution. Although insect-resistant crops have been allowed to be commercialized following proper biosafety guidelines and procedures, still these crops face many challenges in order to be fully adopted and accepted. The degradation kinetics of Bt proteins, horizontal and vertical gene flow, effects on nontarget insects or organisms, antibiotic resistance, and some other unintended effects have been noted and discussed. Although no concrete evidence regarding any significant hazard of genetically .
