Semi-quantitative PCR was done using nptII gene primers (nptIIF-5′ATGATGGATACTTTCTCGGCAGG3′ and nptIIR-5′TATGACTGGGCACAACAGACAAT3′). Genomic DNA was isolated from individual transformed callus lines converted into plantlets using DNeasy Plant Mini Kit, Qiagen. After heating the genomic DNA at 94 °C for 2 min, the reaction proceeded with 30 cycles of 95 °C for 30 s (denaturation), 60 °C for 30 s (annealing) and 72 °C for 30 s (extension). A final elongation step was carried out at 72 °C for 5 min. To rule out the presence of Agrobacterium contamination in transgenic shoots generated after transformation, PCR amplification was carried out with Kan-gene specific primers, lying outside the T-DNA borders, present in the backbone of binary vector ( Fig. 2 and Fig. 4). Primers used for PCR amplification were KanF-5′GCAGAAGGCAATGTCATACC3′ and KanR-5′AGGCTCTTTCACTCCATCG3′). PCR products were separated using agarose gel electrophoresis and visualized under UV light. Transformation frequency was calculated by dividing the number of PCR positive transformants by the total number of callus pieces inoculated with Agrobacterium × 100 as follows: