Where were the most basic classification categories of cultivated plants governed by the ICNCP developed?
Rosa × odorata:  Cultivars were developed in China in ancient times from "R. chinensis" crosses, and these have been important in the ancestry of the tea-scented China roses, also called tea roses, and their descendants the hybrid tea roses. Cultivar:  More generally, "cultivar" refers to the most basic classification category of cultivated plants governed by the ICNCP.
China