Question: Where were the most basic classification categories of cultivated plants governed by the ICNCP developed?

full_context: Document 1: List of Rhododendron species: This List of "Rhododendron" species includes species of the genus "Rhododendron", which is in the plant family Ericaceae. Depending on the source, there are anywhere from 800 to over 1,100 wild species. The vast majority of "Rhododendron" species are native to the eastern Himalaya and southeast Tibet, along with the islands of Java, Sumatra, Borneo, New Guinea, and the Philippines. The rest are broadly spread throughout the northern hemisphere in relatively small isolated populations, including Japan, northwestern North America, the Appalachian, and the Caucasus Mountains.
Document 2: Trial garden: A garden grown specifically for the purpose of testing and evaluating plants is called a trial garden. Universities, plant breeders, and garden-industry companies frequently have trial gardens, as do many private and public botanical gardens and professional garden journalists. In the classic trials model, newly developed varieties of plants are compared with the closest similar industry standard plant throughout their life cycle—from germination/propagation through maturity, from seed to harvest. By growing new varieties side-by-side with existing ones, researchers can determine whether these new varieties are indeed better, and, if so, in what respects.
Document 3: List of onion cultivars: There are dozens of cultivars of the onion ("Allium cepa"), one of the most widely cultivated species of the genus "Allium", But there are also other species cultivated as 'onions'. Many are named after the first person to breed them, or the locality they came from. Different localities often use their own common names for cultivars that are genetically almost identical. Sometimes different cultivars are known by the same common name (for example the name 'Chinese chives' could be referring to "Allium odorum" or "Allium tuberosum").
Document 4: Fragaria × Comarum hybrids: There are several commercially important hybrids between "Fragaria" and "Comarum" species in existence, but they have not yet received formal botanical names as hybrids between those genera. Both "Fragaria" and "Comarum" have at different times been considered to be part of the genus "Potentilla", and these hybrids have been named Potentilla" x "rosea, or are sometimes referred to as "Fragaria" × "Potentilla" hybrids.
Document 5: Mutation breeding: Mutation breeding, sometimes referred to as "variation breeding", is the process of exposing seeds to chemicals or radiation in order to generate mutants with desirable traits (or lacking undesirable ones) to be bred with other cultivars. Plants created using mutagenesis are sometimes called mutagenic plants or mutagenic seeds. From 1930 to 2014 more than 3200 mutagenic plant varieties were released that have been derived either as direct mutants (70%) or from their progeny (30%). Crop plants account for 75% of released mutagenic species with the remaining 25% ornamentals or decorative plants. However, although the FAO/IAEA reported in 2014 that over 1,000 mutant varieties of major staple crops were being grown worldwide, it is unclear how many of these varieties are currently used in agriculture or horticulture around the world, as these seeds are not always identified or labeled as being mutagen or having a mutagenic provenance.
Document 6: Rosa × odorata: Rosa" × "odorata or Rosa odorata is a member of the genus "Rosa" native to Yunnan in Southwest China, whose taxonomy has been confused. It has been considered to be hybrid between "Rosa gigantea" and "Rosa chinensis", or as a quite rare wild species that includes "R. gigantea". The wild forms are cultivated to some extent. 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.
Document 7: Catawbiense hybrid: A catawbiense hybrid is a hybrid of the plant genus "Rhododendron", derived from crosses of American species "Rhododendron catawbiense" and "Rhododendron maximum" with European and Asian species "R. arboreum", "R. caucaseum" and "R. ponticum".
Document 8: Abutilon × hybridum: Abutilon" × "hybridum is a species name used for a wide variety of different types flowering plants of uncertain origin in the genus "Abutilon". Because of the uncertainty surrounding the name, they are often considered a cultivar group: Abutilon x Hybridum Group or Abutilon Hybridum Group. They are cultigens, not occurring in the wild. As with the larger "Abutilon" genus generally, they have been referred to by the common names Chinese lantern, and parlour maple.
Document 9: Grex (horticulture): The term grex (pl. greges or grexes; abbreviation gx), derived from the Latin noun "grex, gregis" meaning 'flock', has been coined to expand botanical nomenclature to describe hybrids of orchids, based solely on their parentage. Grex names are one of the three categories of plant names governed by the International Code of Nomenclature for Cultivated Plants; within a grex the "cultivar group" category can be used to refer to plants by their shared characteristics (rather than by their parentage), and individual orchid plants can be selected (and propagated) and named as cultivars.
Document 10: Plumeria rubra: Plumeria rubra is a deciduous plant species belonging to the genus "Plumeria". Originally native to Mexico, Central America, Colombia and Venezuela, it has been widely cultivated in subtropical and tropical climates worldwide and is a popular garden and park plant, as well as being used in temples and cemeteries. It grows as a spreading tree to 7 – high and wide, and is flushed with fragrant flowers of shades of pink, white and yellow over the summer and autumn. Its common names include frangipani, red paucipan, red-jasmine, red frangipani, common frangipani, temple tree, or simply plumeria.
Document 11: Reseda minoica: Reseda minoica is a species of flowering plants of the genus "Reseda" found in the eastern Mediterranean region. It was described in 2013 by Santiago Martín-Bravo and Pedro Jiménez-Mejías at the Pablo de Olavide University in Spain. The species has long been confused with closely related species such as "R. odorata", "R. orientalis" and "R. balansae", to which it bears a striking resemblance. However, the species can be differentiated from other species by its floral parts. Taxonomic and molecular analyses have further revealed that it is the maternal species of common mignonette ("R. odorata"), one of the most common sources of fragrance since Ancient Roman times.
Document 12: Weed: A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place". Examples commonly are plants unwanted in human-controlled settings, such as farm fields, gardens, lawns, and parks. Taxonomically, the term "weed" has no botanical significance, because a plant that is a weed in one context is "not" a weed when growing in a situation where it "is" in fact wanted, and where one species of plant is a valuable crop plant, another species in the same genus might be a serious weed, such as a wild bramble growing among cultivated loganberries. Many plants that people widely regard as weeds also are intentionally grown in gardens and other cultivated settings, in which case they are sometimes called beneficial weeds. The term "weed" also is applied to any plant that grows or reproduces aggressively, or is invasive outside its native habitat. More broadly "weed" occasionally is applied pejoratively to species outside the plant kingdom, species that can survive in diverse environments and reproduce quickly; in this sense it has even been applied to humans.
Document 13: Cultivar group: A cultivar group – represented in a botanical name by the symbol Group or Gp (previously cultivar-group) – is a formal category for cultivated plants that share a defined characteristic according to the "International Code of Nomenclature for Cultivated Plants" ("ICNCP"). "Group" or "Gp" is always written with a capital "G" in a botanical name, or "epithet". The cultivar group is not italicized in a plant's name. The "ICNCP" introduced the symbol "Group" in 2004, as a replacement for the lengthy and hyphenated "cultivar-group", which had previously been the category's name since 1995. The non-standard abbreviation cv. group is also sometimes encountered.
Document 14: Botanical name: A botanical name is a formal scientific name conforming to the "International Code of Nomenclature for algae, fungi, and plants" (ICN) and, if it concerns a plant cultigen, the additional cultivar or Group epithets must conform to the "International Code of Nomenclature for Cultivated Plants" (ICNCP). The code of nomenclature covers "all organisms traditionally treated as algae, fungi, or plants, whether fossil or non-fossil, including blue-green algae (Cyanobacteria), chytrids, oomycetes, slime moulds and photosynthetic protists with their taxonomically related non-photosynthetic groups (but excluding Microsporidia)."
Document 15: Cultivar: The term cultivar most commonly refers to an assemblage of plants selected for desirable characteristics that are maintained during propagation. More generally, "cultivar" refers to the most basic classification category of cultivated plants governed by the ICNCP. Most cultivars have arisen in cultivation, but a few are special selections from the wild.
ground_truth: China