CALLUS INDUCTION AND PLANT REGENERATION IN ONION (Allium cepa L.) FROM SHOOT TIP EXPLANT

Abstract

An efficient protocol for callus induction and plant regeneration was established from shoot tip explant in onion (Allium cepa L.). Shoot tip from field-grown onion bulbs of Taherpuri and Indian cultivars were used as experimental materials in this investigation. Different concentrations of 2, 4-0 or NAA were used in MS medium for callus induction. The highest percent (86.6%) of callus induction was 86.6 in Taherpuri and in Indian (80%) cultivar in MS media containing 1.5 mg/I of 2,4-0 within fourteen to sixteen days of culture. Different concentrations and combinations of cytokinins (BAP and KIN) and auxins (NAA and lBAl were used for primary establishment of shoot tip. Maximum shoot proliferation was obtained after subculturing the callus in MS medium supplemented with 1.5 mg/l KIN + 1.5 mg/I of BAP within 20 days of callus culture. The highest percentage (100%) of root induction was achieved in Taherpuri cultivar on medium supplemented with 1.0 mg/l of NAA from in vitro raised shoots. Regenerated plantlets were successfully transferred on to the natural condition and showed healthy growth.