I study hybridization and introgression of wild and cultivated plants using molecular markers. Especially I analyze those the distinction of which from native plants are now difficult due to their naturalizaion in pre-modern times. I also study the distinction and origin of cultivars using molecular genotying. In addition, I study the problems in denomination and nomenclature of cultivated plants as a member of the Internationl Commission for the Nomenclature of Cultivated Plants.

Infrorescence of a tree cultivated as ‘Somei-yoshino’ at the Koshikawa Botanical Gardens, University of Tokyo. I demonstrated that this individual has different genotype from true ‘Somei-yoshino’, the clonallity of the latter cultivar is verified by molecular markers.