Crops feed the world, but these have been improved by human beings through history by classical and modern breeding methodologies. In order to produce new breeding varieties, we must utilize the genetic resources, such as local varieties and wild relatives. In the laboratory of Plant Breeding, we mainly use wild rice plants as research materials. We focus on identification and characterization of useful genes and quantitative trait loci from wild rice. We also try to understand the nature of wild rice by revealing genetic variation among natural populations in tropical Asian countries and clarifying the domestication process.