Of the two different concentrations of sucrose (2% and 5%, w/v)
used in the presence of different media (MS, GB5, LS and CHE’), the medium with 5% sucrose was proved to be better for the formation of callus, which was friable and creamy in color. The combination of 4 mg/L TDZ + 4 mg/L NAA with 5% sucrose was superior, as friable callus was initiated on the crocus species, within 20 days. Although callus also formed in the presence of 2% sucrose using the same medium, the texture was relatively hard. The media containing 5% sucrose showed about 10% increased callus formation frequencies than those of 2% sucrose containing media (Table 1).