EtymologyThe word ''cultivar'' originated from the need to distinguish between wild plants and those with characteristics that arose in cultivation, presently denominated ''cultigens''. This distinction dates to the Greek philosopher (370–285 BC), the "Father of Botany", who was keenly aware of this difference. Botanical historian Alan Morton noted that Theophrastus in his ' (''Enquiry into Plants'') "had an inkling of the limits of culturally induced () changes and of the importance of genetic constitution" (''Historia Plantarum'', Book 3, 2, 2 and ''Causa Plantarum'', Book 1, 9, 3). The uses as its starting point for modern the names in ' (1707–1778) ' (tenth edition) and ' (fifth edition). In ''Species Plantarum'', Linnaeus enumerated all plants known to him, either directly or from his extensive reading. He recognised the rank of (botanical "variety", a rank below that of and ) and he indicated these varieties with letters of the , such as α, β, and λ, before the varietal name, rather than using the abbreviation "var." as is the present convention. Most of the varieties that Linnaeus enumerated were of "garden" origin rather than being wild plants. In time the need to distinguish between wild plants and those with variations that had been cultivated increased. In the nineteenth century many "garden-derived" plants were given horticultural names, sometimes in Latin and sometimes in a vernacular language. From ''circa'' the 1900s, cultivated plants in were recognised in the Scandinavian, Germanic, and Slavic literature as ''stamm'' or ''sorte'', but these words could not be used internationally because, by international agreement, any new denominations had to be in Latin. In the twentieth century an improved international was proposed for cultivated plants. of in , created the word ''cultivar'' in 1923 when he wrote that:
The cultigen is a species, or its equivalent, that has appeared under domestication – the plant is cultigenous. I now propose another name, cultivar, for a botanical variety, or for a race subordinate to species, that has originated under cultivation; it is not necessarily, however, referable to a recognized botanical species. It is essentially the equivalent of the botanical variety except in respect to its origin.In that essay, Bailey used only the rank of species for the cultigen, but it was obvious to him that many domesticated plants were more like botanical varieties than species, and that realization appears to have motivated the suggestion of the new category of ''cultivar''. Bailey created the word ''cultivar''. It is generally assumed to be a blend of ''cultivated'' and ''variety'' but Bailey never explicitly stated the and it has been suggested that the word is actually a blend of ''cultigen'' and ''variety''. The ''cultivar'' was promoted as "euphonious" and "free from ambiguity".This ignored its prior use as a transitive verb in denoting "to farm, to cultivate, to grow, or to practice"
CultigensThe words ' and ''cultivar'' may be confused with each other. A ''cultigen'' is any plant that is deliberately selected for or altered in cultivation, as opposed to an '; the ''Cultivated Plant Code'' states that cultigens are "maintained as recognisable entities solely by continued propagation". Cultigens can have names at any of many taxonomic ranks, including those of , , , , , and cultivar; and they may be plants that have been altered in cultivation, including by , but have not been formally denominated. A cultigen or a component of a cultigen can be accepted as a cultivar if it is recognisable and has stable characters. Therefore, all cultivars are cultigens, because they are cultivated, but not all cultigens are cultivars, because some cultigens have not been formally distinguished and named as cultivars.
Formal definitionThe ''Cultivated Plant Code'' notes that the word cultivar is used in two different senses: first, as a "classification category" the cultivar is defined in Article 2 of the ''International Code of Nomenclature for Cultivated Plants'' (2009, 8th edition) as follows: ''The basic category of cultivated plants whose nomenclature is governed by this Code is the cultivar.'' There are two other classification categories for cultigens, the and the . The ''Code'' then defines a ''cultivar'' as a "taxonomic unit within the classification category of cultivar". This is the sense of ''cultivar'' that is most generally understood and which is used as a general definition.
''A cultivar is an assemblage of plants that (a) has been selected for a particular character or combination of characters, (b) is distinct, uniform and stable in those characters, and (c) when propagated by appropriate means, retains those characters.''
Different kindsWhich plants are chosen to be named as cultivars is simply a matter of convenience as the category was created to serve the practical needs of , , and . Members of a particular cultivar are not necessarily genetically identical. The ''Cultivated Plant Code'' emphasizes that different cultivated plants may be accepted as different cultivars, even if they have the same genome, while cultivated plants with different genomes may be regarded as the same cultivar. The production of cultivars generally entails considerable human involvement although in a few cases it may be as little as simply selecting variation from plants growing in the wild (whether by collecting growing tissue to propagate from or by gathering seed). Cultivars generally occur as and food crops: ' '' and ''Malus'' '' are cultivars of apples propagated by cuttings or , ' 'Red Sails' and ''Lactuca'' 'Great Lakes' are lettuce cultivars propagated by seeds. Named cultivars of ' and ' plants are cultivars produced by or division.
ClonesCultivars that are produced asexually are genetically identical and known as ; this includes plants propagated by , , , , and . The propagating material may be taken from a particular part of the plant, such as a lateral branch, or from a particular phase of the life cycle, such as a juvenile leaf, or from aberrant growth as occurs with . Plants whose distinctive characters are derived from the presence of an intracellular organism may also form a cultivar provided the characters are reproduced reliably from generation to generation. Plants of the same (which have mutant tissues close to normal tissue) or graft-chimeras (which have vegetative tissue from different kinds of plants and which originate by grafting) may also constitute a cultivar.
Seed-producedSome cultivars "come true from seed", retaining their distinguishing characteristics when grown from seed. Such plants are termed a "variety", "selection" or "strain" but these are ambiguous and confusing words that are best avoided. In general, asexually propagated cultivars grown from seeds produce highly variable seedling plants, and should not be labelled with, or sold under, the parent cultivar's name. Seed-raised cultivars may be produced by uncontrolled pollination when characteristics that are distinct, uniform and stable are passed from parents to progeny. Some are produced as "lines" that are produced by repeated self-fertilization or inbreeding or "multilines" that are made up of several closely related lines. Sometimes they are s which are the result of a deliberate repeatable single cross between two pure lines. A few F2 hybrid seed cultivars also exist, such as ''Achillea'' 'Summer Berries'. Some cultivars are plants, which retain their genetic composition and characteristics under reproduction. Occasionally cultivars are raised from seed of a specially selected provenance – for example the seed may be taken from plants that are resistant to a particular disease.
Genetically modifiedGenetically modified plants with characteristics resulting from the deliberate implantation of genetic material from a different may form a cultivar. However, the notes, "In practice such an assemblage is often marketed from one or more lines or multilines that have been genetically modified. These lines or multilines often remain in a constant state of development which makes the naming of such an assemblage as a cultivar a futile exercise." However, retired transgenic varieties such as the , which are no longer being developed, do not run into this obstacle and can be given a cultivar name. Cultivars may be selected because of a change in the level of a plant which may produce more desirable characteristics.
Cultivar namesEvery unique cultivar has a unique name within its denomination class (which is almost always the genus). Names of cultivars are regulated by the ''International Code of Nomenclature for Cultivated Plants'', and may be registered with an (ICRA). There are sometimes separate registration authorities for different plant types such as roses and camellias. In addition, cultivars may be associated with commercial marketing names referred to in the ''Cultivated Plant Code'' as "trade designations" (see below).
Presenting in textA ''cultivar name'' consists of a (of a genus, , infraspecific , interspecific or intergeneric hybrid) followed by a cultivar . The cultivar epithet is enclosed by single quotes; it should not be italicized if the botanical name is italicized; and each of the words within the epithet is (with some permitted exceptions such as conjunctions). It is permissible to place a cultivar epithet after a common name provided the common name is botanically unambiguous. Cultivar epithets published before 1 January 1959 were often given a form and can be readily confused with the in botanical names; after that date, newly coined cultivar epithets must be in a modern vernacular language to distinguish them from botanical epithets. : Examples of correct text presentation: :: ' 'Elegans' :: ' 'Aureomarginata' (pre-1959 name, in form) :: ''Chamaecyparis lawsoniana'' 'Golden Wonder' (post-1959 name, ) :: ' 'Akebono' (post-1959 name, ) :: Apple 'Sundown' : Some incorrect text presentation examples: :: ''Cryptomeria japonica'' "Elegans" (double quotes are unacceptable) :: ''Berberis thunbergii'' cv. 'Crimson Pygmy' (this once-common usage is now unacceptable, as it is no longer correct to use "cv." in this context; ''Berberis thunbergii'' 'Crimson Pygmy' is correct) :: ''Rosa'' cv. 'Peace' (this is now incorrect for two reasons: firstly, the use of "cv."; secondly, "Peace" is a trade designation or "selling name" for the cultivar ''R.'' 'Madame A. Meilland' and should therefore be printed in a different typeface from the rest of the name, without quote marks, for example: ''Rosa''
Peace.) Although "cv." has not been permitted by the since the 1995 edition it is still widely used and recommended by other authorities.
Group namesWhere several very similar cultivars exist they can be associated into a ''Group'' (formerly ''Cultivar-group''). As Group names are used with cultivar names it is necessary to understand their way of presentation. Group names are presented in normal type and the first letter of each word capitalised as for cultivars, but they are not placed in single quotes. When used in a name, the first letter of the word "Group" is itself capitalized.
Presenting in text:: ''Brassica oleracea'' Capitata Group (the group of cultivars including all typical s) :: ''Brassica oleracea'' Botrytis Group (the group of cultivars including all typical s) :: ''Hydrangea macrophylla'' Groupe Hortensia (in French) = ''Hydrangea macrophylla'' Hortensia Group (in English) : Where cited with a cultivar name the group should be enclosed in parentheses, as follows: :: ''Hydrangea macrophylla'' (Hortensia Group) 'Ayesha'
Legal protection of cultivars and their namesSince the 1990s there has been an increasing use of legal protection for newly produced cultivars. expect legal protection for the cultivars they produce. According to proponents of such protections, if other growers can immediately propagate and sell these cultivars as soon as they come on the market, the breeder's benefit is largely lost. Legal protection for cultivars is obtained through the use of Plant breeders’ rights and plant Patents but the specific legislation and procedures needed to take advantage of this protection vary from country to country.
Controversial use of legal protection for cultivarsThe use of legal protection for cultivars can be controversial, particularly for food crops that are staples in developing countries, or for plants selected from the wild and propagated for sale without any additional breeding work; some people consider this practice .
Trade designations and selling namesThe formal scientific name of a cultivar, like ''Solanum tuberosum'' ‘King Edward’, is a way of uniquely designating a particular kind of plant. This scientific name is in the public domain and cannot be legally protected. Plant retailers wish to maximize their share of the market and one way of doing this is to replace the cumbersome Latin scientific names on plant labels in retail outlets with appealing marketing names that are easy to use, pronounce, and remember. Marketing names lie outside the scope of the ''Cultivated Plant Code'' which refers to them as "trade designations". If a retailer or wholesaler has the sole legal rights to a marketing name then that may offer a sales advantage. Plants protected by (PBR) may have a "true" cultivar name – the recognized scientific name in the public domain – and a "commercial synonym" – an additional marketing name that is legally protected. An example would be ''Rosa'' = 'Poulmax', in which ''Rosa'' is the genus, is the trade designation, and ‘Poulmax’ is scientific cultivar name. Because a name that is attractive in one language may have less appeal in another country, a plant may be given different selling names from country to country. Quoting the original cultivar name allows the correct identification of cultivars around the world. The main body coordinating plant breeders' rights is the (, UPOV) and this organization maintains a database of new cultivars protected by PBR in all countries.
International Cultivar Registration AuthoritiesAn ''International Cultivar Registration Authority'' (ICRA) is a voluntary, non-statutory organization appointed by the ''Commission for Nomenclature and Cultivar Registration'' of the International Society of Horticultural Science. ICRAs are generally formed by societies and institutions specializing in particular plant genera such as ''Dahlia'' or ''Rhododendron'' and are currently located in Europe, North America, China, India, Singapore, Australia, New Zealand, South Africa and Puerto Rico. Each ICRA produces an annual report and its reappointment is considered every four years. The main task is to maintain a register of the names within the group of interest and where possible this is published and placed in the public domain. One major aim is to prevent the duplication of cultivar and Group epithets within a genus, as well as ensuring that names are in accord with the latest edition of the ''Cultivated Plant Code''. In this way, over the last 50 years or so, ICRAs have contributed to the stability of cultivated plant nomenclature. In recent times many ICRAs have also recorded trade designations and trademarks used in labelling plant material, to avoid confusion with established names.Se
See also* *
Bibliography* * * * * * * * * *
External links* Sale point of th