Cultivar

Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue culture, or carefully controlled seed production.

[1] Similarly, the world's agricultural food crops are almost exclusively cultivars that have been selected for characters such as improved yield, flavour, and resistance to disease, and since the advent of genetic engineering in the 1970's,[2] and its advent in crop breeding in the 1980's, very few wild plants are used as commercial food sources.

[4] Cultivars form a major part of Liberty Hyde Bailey's broader group, the cultigen,[5] which is defined as a plant whose origin or selection is primarily due to intentional human activity.

The 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 Theophrastus (370–285 BC), the "Father of Botany", who was keenly aware of this difference.

[23]Which 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 horticulture, agriculture, and forestry.

Cultivars that are produced asexually are genetically identical and known as clones; this includes plants propagated by division, layering, cuttings, grafts, and budding.

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 witch's broom.

[27] Seed-raised cultivars may be produced by uncontrolled pollination when characteristics that are distinct, uniform and stable are passed from parents to progeny.

However, the International Code of Nomenclature for Cultivated Plants 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.

"[30] However, retired transgenic varieties such as the fish tomato, which are no longer being developed, do not run into this obstacle and can be given a cultivar name.

In addition, cultivars may be associated with commercial marketing names referred to in the Cultivated Plant Code as "trade designations" (see below).

'King Edward' is the cultivar epithet, which, according to the Rules of the Cultivated Plant Code, is bounded by single quotation marks.

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.

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.

[45] The use of legal protection for cultivars can be controversial, particularly for food crops that are staples in developing countries,[46] or for plants selected from the wild and propagated for sale without any additional breeding work; some people consider this practice unethical.

The formal scientific name of a cultivar, like Solanum tuberosum 'King Edward', is a way of uniquely designating a particular kind of plant.

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.

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.

many ICRAs have also recorded trade designations and trademarks used in labelling plant material, to avoid confusion with established names.

Each ICRA also ensures that new names are formally established (i.e. published in hard copy, with a description in a dated publication).

They record details about the plant, such as parentage, the names of those concerned with its development and introduction, and a basic description highlighting its distinctive characters.