IN VITRO REGENERATION OF TROPICAL QUALITY PROTEIN MAIZE

Abstract

Experiments on genetic transformation require well-defined protocols for callus induction and plant regeneration but few tropical maize genotypes are capable of inducing and regenerating fertile plants. In the present work, nine tropical maize inbred lines selected for high-quality protein were evaluated for the capacity of embryogenic calli formation and plant regeneration. High quality protein maize is an important component in monogastric animal nutrition due to the increased amounts of essential amino acids. Basically, culture media similar to those proposed by Chu et al. (1975) were used, but containing different concentrations of Dicamba (15 or 30 mM), L-proline (6 or 25 mM)and silver nitrate (0 or 88 mM). Calli produced were classified as types I and II. The highest percentage of embryogenic calli was obtained in the medium supplemented with 30 mM Dicamba, 25 mM, L-proline and 88 mM silver nitrate. The line HGZ-A18 presented 100% of type II embryogenic calli. These calli were transferred to magentaTM with four different media. This line presented 71.4% of regenerated plants when applied the medium containing N6 salts supplemented with 1.0 mg.L-1 BAB and 0.5 mg.L-1 AIB, resulting in 75% of fertile plants in the greenhouse.

Keywords

• Quality protein maize lines
• tissue culture
• immature embryos
• somatic embryogenesis
• Zea mays