Development and Evaluation of Growth Stage Specific Selection Scheme with Multiple Commercial Indian Bread Cultivars

In the present study, hpt (hygromycin phosphotransferase) was used as selectable marker system. Selection scheme was optimized with mature embryonic axes/mature embryos as explants. Hygromycin B was used as the selection agent, a total of nine concentration regimes ranging from 0–50 mg/l were used. Preliminary experiments were conducted with PBW343, the most widely grown Indian bread wheat cultivar with comparatively good tissue culture response. Callus induction percentage and the rate of callus proliferation were used as the criteria to select the effective concentration of the hygromycin B. Further, the effective selection concentration of the hygromycin was evaluated post Agrobacterium infection in a view to optimize the selection scheme in accordance to transformation procedure. In a separate experiment, effect of genotype on hygromycin selection regime was further tested with three more wheat cultivars. Finally, to evaluate the effect of genotype the protocol was further extended to three more commercial and elite Indian bread Wheat cultivars. The procedure allows effective adoption of the selection scheme for range of genotypes with minimal modification. On the basis of results hygromycin in the concentration range of 25-40mg/l could be used for the selection of the transgenic cells over wider range of genotypes.