PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

Wheat is a globally consumed important grain crop. Its cultivation is affected by the abiotic stresses, especially in the resource poor countries like Bangladesh. Therefore, development of stress-tolerant wheat varieties is very important for food and nutrition security of the ever increasing population. The study was designed to optimize the in vitro callogenesis and regeneration protocol for six wheat genotypes of Bangladesh using mature embryos as explants. Murashige and Skoog (MS) medium supplemented with four different concentrations of 2,4-D for in vitro callogenesis and four different concentrations cytokinin (BAP and TDZ) for regeneration was used. The results showed significant deference (P < 0.01) among the wheat varieties, treatments and their interaction on callus induction and shoot regeneration. The Callus induction frequency and callus weight, increased with the increase in the concentration of 2,4-D from 1.5 to 2.5 mg/l in all genotypes. In BARI Gom-25, BARI Gom-27  and BARI Gom-31 callogenesis declined with the highest concentration (3.0 mg/l) of 2,4-D. The highest callus induction frequency was achieved in BARI Gom-27 (88.36%) at 2.5 mg/l of 2,4-D. Moreover, callus size and callus weight were highest at 2.5 mg/l of 2,4-D. The highest frequency of shoot regeneration was found in BARI Gom-27 (67.02%) on medium supplemented with TDZ (1.0 mg/l) + 2,4-D (0.1 mg/l) followed by BARI Gom-31 (63.54%). Using BAP (1.0 mg/l) and 2,4-D (0.1 mg/l), BARI Gom-32 (56.27%) and BARI Gom-30 (50.01%) showed lower shoot regeneration. TDZ treated calli exhibited the highest regeneration capability and shoot number than BAP in all wheat genotypes. In conclusion, this study revealed that 2.5 mg/l 2,4-D showed the highest callus induction and a combination of 2,4-D and TDZ showed the highest shoot regeneration and a higher number of shoots per callus. This regeneration protocol could be utilized in genetic transformation for the improvement of wheat.