Callus induction and whole plant regeneration in sub-tropical maize (Zea mays L.) using mature embryos as explants

Abstract

Thirteen sub-tropical maize genotypes were evaluated for in vitro callus induction and whole plant regeneration. Seeds were germinated on MS-based medium supplemented with 10 mg l–1 picloram and 3.0 mg l–1 BAP which induced the formation of nodes. The developed nodes were excised about 0.25 cm above and below and were split longitudinally into two halves. The split nodes were placed on the callusing medium supplemented with 2.2 mg l–1 picloram and 0.5 mg l–1 2, 4-D, the cut surface facing down and touching the media. Among the thirteen genotypes, embryogenic calli were induced in seven genotypes ranging between 10.78- 65.65%. Out of seven genotypes, only one genotype i.e., VQL 2 regenerated in to a whole plant with a frequency of 34% on MS basal medium under 80 μM m–2 s–1 of light intensity. Regeneration medium and light intensity played key role for the initiation of somatic embryogenesis and regeneration of whole plants. Survival efficiency of in vitro regenerated plantlets was found to be 95% out of which 85% of the plants grew normally without any morphological abnormality.