Wheat is the world's most widely grown staple food, meeting the nutritional needs of more than 35% of the human population. The development of transgenic wheat is slow worldwide due to the lack of a suitable transformation system. The availability of a reproducible regenerative system through tissue culture is a major bottleneck in the wheat improvement program. The present study deals with the efficient and reproducible Agrobacterium-mediated transformation system in wheat is established. The mature embryos of three commercially bred wheat genotypes from Pakistan i.e., Faisalabad 2008, Galaxy 2012 and NARC-443, were used to establish an efficient and stable transformation system. In callus induction, each variety responded differently to different concentrations of 2,4-D. Faisalabad 2008 and Galaxy2012 showed the highest callus induction of 83% and 71%, respectively, at three mg/l of 2, 4-D, while NARC-443 showed 65 % callus induction at 3.5 mg/l of 2, 4-D with different BAP concentrations were used to develop shoots and roots. Faisalabad 2008 and Galaxy 2012 showed significantly higher regeneration rates of 61% and 54% with 3.0 mg/l of BAP, while NARC-443 had the highest regeneration at 41% with 2.0 mg/l. The average fresh calli weights for Galaxy 2012, Faisalabad 2008, and NARC-443 were 0.58 g, 0.46 g, and 0.43 g, respectively. Fresh calli weights correlated significantly and positively with dry weights. The expression of GUS in the transgenic leaves was confirmed by histochemical analysis of β-glucuronidase. Tissue culture protocol optimization in wheat varieties, Faisalabad 2008, Galaxy 2012, and NARC-443 showed transformation efficiencies of 1.3%, 0.8%, and 0.3%, respectively. The current results will help in the selection of wheat cultivars that best respond to tissue culture and crop improvement through transgenic development.  

Keywords: Triticum aestivum, Callus induction, Regeneration, Agrobacterium tumefaciens