One-year-old shoots with leaves removed were cut into 4 cm lengths with one or two nodal segments and washed with running water for 30 min. These were then surface-sterilized by immersion in 70% (v/v) ethanol for 45 sec followed by 0.1% (w/v) mercuric chloride (HgCl2) solution for 10–15 min and then washed three times with sterile distilled water. Afterwards, nodal segments 1.0–1.5 cm long were excised aseptically from the shoots and placed in shoot induction media.