1. Graduate School of Science and Technology Niigata University Ikarashi‐ninocho 950‐2181 Niigata Japan
2. Institute of Agrobiological Sciences National Agriculture and Food Research Organization 1‐2, Oowashi Tsukuba Ibaraki 305‐8634 Japan
3. Department of Molecular Biology and Genetics Aarhus University 8000 Aarhus Denmark
4. Plant Cytogenetics, Department of Gene Function and Phenomics National Institute of Genetics 1111 Yata Mishima Shizuoka 411‐8540 Japan
5. Department of Technology Development Kazusa DNA Research Institute Kisarazu Chiba 292‐0818 Japan
6. Institute of Crop Science National Agriculture and Food Research Organization 2‐1‐2, Kannondai Tsukuba Ibaraki 305‐8518 Japan
7. Center for Sustainable Resource Science RIKEN Yokohama Kanagawa 230‐0045 Japan
8. Graduate School of Life Sciences Tohoku University Katahira, Aoba‐ku Sendai Miyagi 980‐8577 Japan