The National BioResource Project (NBRP)-Wheat, the Japanese gene bank of wheat and its relatives, is aimed to promote wheat sciences by providing high quality genetic materials. Currently, the NBRP-Wheat stores and supplies more than 12,000 wild species, landraces, and experimental strains of wheat. The main body of collections of wild species and landraces derived from several expeditions Kyoto University made to the heart of wheat domestication areas since Kihara’s first expedition in 1955. Some of them are hardly available at the collection sites today. In addition to the primary tasks to maintain and distribute the genetic resources, we have surveyed genetic diversity among wheat accessions. We established the core collections representing 3,500 hexaplod (AABBDD), 1,900 tetraploid (AABB and AAGG), and 300 diploid (AA) wheat accessions stored in NBRP-Wheat. The hexaploid core collection, consisting of 188 accessions of Triticum aestivum, T. spelta, T. compactum, T. sphaerococcum, T. macha and T. vavilovii, was intensively genotyped by DArTseq markers and consisted of 20,186 SNPs and 60,077 present and absent variations. Overall, the core collection was divided into seven clusters. Non-admixture accessions in each cluster indicated that the clusters reflect the geographic distribution of the accessions (Takenaka et al., 2018). We analyzed genetic factors controlling seed morphology in hexaploid wheat by utilizing the core collection. We found two principal components (PCs) of the seven measurements explain more than 96% of the variation in the core collection accessions. The correlation coefficients between the principal components and characters indicate that the PC1 is related to grain size and PC2 to grain shape for which, we found mutually exclusive marker-trait associations on 18 and 13 chromosomes, respectively by genome-wide association studies. The analysis indicated that the hexaploid core collection is a useful genetic tool to dissect complex traits in wheat such as grain morphology analyzed here (Yoshioka et al., 2019). Currently, we are developing a nested-association mapping (NAM) population representing genetic diversity of East Asian wheat accessions. Twenty four parental accessions, selected from the core collection based on genetic diversity, were crossed with Norin 61 wheat whose genome is currently de novo sequenced by the International Wheat 10+ Genome Project. The most advanced individual of the NAM population is currently in the F4 generation. Our goal is to release the East Asian hexaploid wheat NAM population with more than 3,000 individuals collectively in the F6 or more advanced generations to the research community.