Abstract: Factors influencing foxtail millet (Setaria italica Beauv. ) embryogenic calli transformation by particle bombardments were studied using the method of Gus transient expression with JQ-700 gene gun. Relatively high numbes of Gus transient expression unites were obtained when the quantity of plasmid DNA added to microprojectles was 4 μg/mg tungsten powder and the concentration of CaCl₂ and spermidine used to absorb DNA to microprojectles were 1.5 mol and 40 mmol respectively. The velocity of the microprojectles and the distance between the calli being bombarded and the stopping plate of JQ-700 gene gun optimized in this report were 400-450 m/s and 7cm. The quantity of calli used per treatment was also a factor influencing gene delivery and 1-2g of calli per treatment gave higher Gus transient expression. The promoter derived from maize ubiquitin produced significantly more Gus foci compared to the CaMV35s Promoter.

Key words: Foxtail millet embryogenic calli, Particle bombardment, Gus transient expression, Parameter optimizing