Effects of explant type, culture media and growth regulators on callus induction and plant regeneration of Chinese jiaotou (Allium chinense)

To establish an efficient protocol of shoot regeneration from callus, effects of explant type, culture media and plant growth regulators on callus induction and shoot regeneration of Chinese jiaotou (Allium chinense) were evaluated. The results showed that basal plate was the best explant for callus induction (47.5%) when cultured on B5 medium supplemented with 0.1 mg l−1 6-benzylaminopurine (BA) and 1.0 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D), and B5 was the best medium to induce callus formation with 49.3% of the explants forming callus. The highest callus induction (65.2%) was achieved culturing basal plate on B5 medium supplemented with 0.1 mg l−1 BA and 1.0 mg l−1 2,4-D after 8 weeks of culture. The best callus proliferation was observed on B5 medium with 1.5 mg l−1 2,4-D. Shoots regenerated at the highest frequency of 58.8% with 4.5 shoots when calli were cultured on B5 medium with 0.1 mg l−1 BA and 1.0 mg l−1 a-naphthaleneacetic acid (NAA). This protocol provides a basis for future studies on genetic improvement and could be applied to large-scale multiplication systems for commercial nurseries of Allium chinense.