Grain yield in corn has improved constantly over the past century due to many factors including improved genetics, the advent of hybrid seed production, changes in agronomic practices, and implementation of biotechnology. In 2012, Minnesota corn growers produced corn on nearly 9 million acres statewide, and harvested approximately 1.4 billion bushels of grain. While dramatic improvements have been made, the ceiling for grain yield has not been reached. Understanding the genetic basis of corn grain yield and yield component traits, such as seed size, is important for making continued progress in corn grain yield potential. Some mutants that effect overall seed and/or endosperm development have been identified in corn; however, the genetic basis of seed size variation and other yield component traits is still largely unknown. Our aim is to understand the genetic basis of corn grain yield by characterizing the genetic basis of grain yield component traits and determining the relationship of those traits with grain yield. It is anticipated that results from this project will be used by corn breeders to develop higher yielding hybrids that are also more stable across environments.