Don was active in global agriculture affairs, particularly in areas of plant breeding methods, germplasm conservation, and intellectual property. He continued to pursue field research that led to significant advances in the understanding of the basis for corn hybrid yield improvement over the decades since the 1930’s. Don was a member of the National Academy of Sciences, and a Distinguished Fellow of the Iowa Academy of Science. He was a Fellow of the American Association for the Advancement of Science, the American Society of Agronomy, and the Crop Science Society. In 2006 he received the Presidents Award from the Crop Science Society of America.