The bar gene (herbicide-resistance gene as a selectable marker) cassette (bar gene, Cauliflower mosaic caulimovirus (CaMV) 35S promoter and nos terminator) was released from plasmid pAB6 using Hind III-digestion and subcloned into the Hind III-digested plasmid pRHA1 to create the plasmid pRHA2 via the microprojectile bombardment transformation system.