One of the biggest limitations in significantly altering the composition of corn grain to meet the needs of the end-user has been achieving these goals while maintaining commercially acceptable yield and agronomics in the resulting varieties. The purpose of this presentation is to describe a novel com production method developed by DuPont Quality Grains. This method ... the TopCross® Grain Production System ... has enabled the efficient production of high oil com on a large and growing commercial scale. In order to do this, it is first necessary to describe some fundamentals of com inheritance and reproduction.