Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 319

Clonal propagation can be a natural process or artificially conducted.

 Natural clonal propagationClones are common in nature. Clonal propagation is important for many herbaceous species as well as woody perennial plants throughout the world. The genera Prunus and Populus produce clones by suckering, while Betula, Carpinus, Corylus, Quercus, Salix, and Tilia are all genera with the ability to self‐coppice.

 Artificial clonal propagationSome crops are commercially produced by clonal propagation using various parts (e.g. tubers, corms, bulbs, stolons, etc.). Some species are obligated to this mode of propagation because they have lost their capacity to flower (e.g. leek, some potato cultivars). However, some of these species that are produced clonally as a preference may also have viable sexual reproduction as an option (e.g. potato, strawberry). In fact, some species with flowering capabilities have a long tradition of being reproduced clonally (e.g. apple, roses, ornamental trees, and shrubs). Plants derived from true seeds of those same species often have a long juvenile stage, and take a long time to reach commercially interesting size (orchids, tulips, chrysanthemum, potato). Artificial methods of clonal propagation include cuttings, grafting, and the more sophisticated laboratory technique of tissue culture. For orchids, in vitro clonal propagation is the only commercially viable method of micropropagation.Clonal multiplication of the cultivar is very important in horticulture and silviculture (tree production). The first step in clonal propagation is to identify and select a genetically superior (elite) plant. The part of the plant used as a propagule varies among species and includes stem, roots, bulbs, and stolons as stated previously.