Maize is the most important grain crop in the world. Genetic engineering technology has been used to enhance its various agronomical traits. The transformation of maize is a crucial step in the application of gene technologies to improve maize. The choice of genotype and explant material influences the transformation efficiency and the production of stable transgenic plants. Immature embryos of Hi IIA were infected with Agrobacterium tumefaciens LBA4404 including superbinary vectors (bar and GUS or GFP genes). The transformation efficiency was based on transgenic calli induction from immature embryos on the selection medium with 3 mg/L bialaphos. The transformation efficiency varied from 1.01 to 2.74%. The integration and expression of bar, GUS, and GFP genes were confirmed in T₀ and T₁ generations of transgenic plants using genomic PCR and the bar strip test. In addition, herbicide resistance in T₁ transgenic plants was observed when leaves and whole plants were treated with Basta. These results suggest that the successful Agrobacterium-mediated transformation of Hi IIA will improve further opportunities for functional genomic and genome editing studies in maize.

Recently, several attempts have been undertaken to develop breeding technologies by combining new biotechnologies. Gene-editing technology is currently one of the most interesting areas. The plant breeding methods using this technique have the advantage of greatly improved accuracy and efficiency of the plant genetic correction compared with conventional breeding methods, which has raised expectations for the useful application of this technology as a cutting-edge breeding technology. Although not all countries around the world currently have established appropriate regulation policies on crops developed with gene-editing technology, the number of cases in which GMO regulations are not applied on a case-by-case basis according to the scientific background is growing. However, Korea has not yet established policies on which criteria should be applied to crops generated from the application of gene-editing technology. As the number of cases of crop development and commercialization using gene-editing technology is expected to increase in the near future, it will be necessary to prepare reasonable policies to support developers and seed industries in Korea to ensure harmonization with international regulatory policy trends.