1. Functional Plant Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan
2. Toyama Prefectural Agricultural, Forestry and Fisheries Research Center, Toyama, Toyama 939-8153, Japan
3. Rice Applied Genomics Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan