Abstract: Maize (Zea mays L. ) embryogenic calli were cultured on N6 medium and treated respectively with different concentrations of herbicide Basra and amino acids. The NH4+ concentrations and weight increase of maize calli were measured. Statistical analysis revealed that callus weight increased less when cultured on N6 medium with 4 mg/L of Basta while Nih+ concentration reached its peak when cultured on N6 with 8 mg/L of Basta. Therefore 6 mg/L of Basta was considered as the optional dosage for selection of transgenic calli L-arginine and L-glutamic acid significantly reduced the NH4+ concentration in maize calli while L-proline had little effects on NH4+ concentration even though it enhanced callus weight enormously.

Key words: Maize embryogenic calli, N6 medium, Amino acids, Herbicide, NH4+