1. Institute for Genomic Diversity
2. Department of Plant Biology, and
3. Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas 77843 and
4. United States Department of Agriculture–Agricultural Research Service, Cropping Systems Research Laboratory, Lubbock, Texas 79415
5. Department of Plant Breeding and Genetics, Cornell University, Ithaca, New York 14853