Plant regeneration via somatic embryogenesis of tropical maize (Zea mays L.) commercial hybrid lines

Four commercial tropical maize genotypes (H627, H625, H513 and DLC1) were screened in vitro for callus initiation and plant regeneration from immature embryos. Callus was initiated on N6 medium supplemented with varying concentrations of 2,4-D, 3% sucrose, 10 mg l-1 silver nitrate, 100 mg l-1 casein hydrolysate and 2.875 mg l-1 proline. The induction of embryogenic and primary callus highly dependend on the concentration of 2,4-D, genotype and day after pollination of immature embryos. H627 displayed the highest percentage of embryogenic callus formation from immature embryos 16 days after pollination (45.1%) and 20 days after pollination (28.3%). The percentage of embryogenic and primay callus initiated from immature embryos 16 days after pollination was significantly higher compared to 20 days after pollination (