This Small Business Innovation Research (SBIR) Phase I project seeks to develop a homologous recombination or gene targeting system for plants. Gene targeting offers great promise for harnessing the biosynthetic capacity of plants to produce compounds of commercial value. A major limitation in implementing this technology is the low frequency of homologous recombination. This project plans to overcome this limitation through the use of a proprietary method to introduce chromosome breaks at specific target loci. Chromosome breaks greatly enhance localized homologous recombination, and experiments are designed to modify a plant gene to confer herbicide resistance. Success of these experiments will provide the foundation for developing an efficient system of gene targeting for use in a variety of important crop species. This technology will be a powerful tool for studying gene function, modifying genomes, and engineering biosynthetic pathways. The commercial application of this project will be in the development of new crop varieties, that better withstand pests, have enhanced food value, and produce compounds of industrial importance