The selection of plants is called the science of creationqualitatively new and improvement of already existing varieties of cultivated plants. The selection is based on its main methods - selection and hybridization. The theoretical basis of selection is the science of genetics.
The peculiarities of plant breeding are determined bysuccessful solution of the tasks that are before it. Very important is the study of varietal, tribal and species diversity of cultures, the influence of the environment on the development of the main features, the patterns of inheritance of these features for hybridization, as well as the features of the selection process and the strategy of artificial selection.
Each plant variety is adapted to some kind ofcertain conditions, and therefore in different localities there are different specialized stations and breeding farms for testing and comparing new varieties of plants.
For plant breeding to be successful,The breeder must have a variety of varieties of raw material. Scientist N.I. Vavilov once collected a huge collection of plant varieties and their ancestors from all over the planet Earth, which is now successfully replenished and is considered the basis for work on the selection of any culture.
N.I. Vavilov identifies seven centers of plant origin: South Asian tropical, East Asian, Mediterranean, South-West Asian, Abyssinian, South American, Central American. The richest regions in terms of the number of cultures are the ancient centers of civilization. In such places, the earliest crop culture, respectively, and plant breeding, and artificial selection are conducted for a longer time. Let us consider in more detail what the concept is.
There are certain methods of plant breeding: selection and hybridization. Selection can be individual and massive.
Mass selection refers to the form of artificialselection, which is used in the selection of so-called "cross-pollinated" plants (rye, corn, sunflower). In this case, the variety is a population that consists of heterozygous individuals, where each seed carries a unique genotype. Due to mass selection, varietal characteristics are preserved and improved, but the results of such selection are very unstable due to uncertain cross-pollination.
Individual selection is used for breedingplants that are pollinated independently (barley, wheat). The offspring retains all the attributes of the parental form without exception and is called the net line (the so-called offspring of one self-pollinated homozygous individual is called). Since mutational processes occur constantly, in fact, homozygous individuals are extremely rare. Under the control of artificial and natural selection, they fall only after the transition to a homozygous state.
Selection of plants by the method of natural selectionplays a very important role. Any plant throughout its life is influenced by certain external factors, so it must be resistant to diseases and pests adapted to water and temperature conditions.
Inbreeding is a closely related crossing. This phenomenon occurs in cross-pollinated plants during self-pollination. For this selection method, plants are selected whose hybrids are capable of giving the maximum effect of heterosis. Such plants for many years are subject to forced self-pollination.
There is also such a method as remote hybridization. This is the name for crossing plants that belong to different species. As a rule, distant hybrids are sterile, so gametes are not formed.
Plant selection also hasmethods, such as the use of somatic mutations, experimental mutagenesis, as well as the selection methods proposed by I.V. Michurin. You can learn more about these and other methods by reading the works of the above-mentioned scientists.