1. Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, 53113 Bonn, Germany
2. Department of Statistics, Iowa State University, Ames, Iowa 50011-1210
3. Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68588
4. Department of Agronomy and Center for Plant Genomics, Iowa State University, Ames, Iowa 50011-3650
5. Department of Molecular Biology, Max-Planck-Institute for Developmental Biology, 72076 Tuebingen, Germany
6. Institute for Crop Science, Biostatistics Unit, University of Hohenheim, 70599 Stuttgart, Germany