Effect of Callus Age on In Vitro Shoot Regeneration in Sugarcane

Callus cultures raised from furled leaf explants of sugarcane variety CoS 99259 were grown through subcultures on agar gelled (8.0 g/l) Murashige and Skoog's nutrient medium containing 2, 4-dichlorophenoxyacetic acid (4.0 mg/l). The well grown calli maintained on aforesaid medium at low temperature (about 10°C) for different periods (i.e. 3, 6, 9, 12, 15, and 18 months) were subsequently transferred to MS regeneration medium for shoot regeneration. The results showed that the frequency of shoot formation decreased with the increasing age of callus. Maximum shoot regeneration (68.8%) was recorded in 3-month old callus followed by 6-month (41.5%) old calli. No shoot regeneration could be induced in 18-month old callus showing a complete loss of morphogenic competence in the tissues. The highest (21.4) number of shoots per culture was also obtained in callus stored for 3 months, which decreased with the increasing period of storage.