Types of Crosses in Plant Breeding
The presence of hereditary variability allows combining certain hereditary traits in one organism through various systems of crossing, as well as getting rid of undesirable properties.
The main method for controlling combinatorial variability in breeding is the selection of forms according to economically valuable properties for crossing.
Classification of Crossing Types and Breeding Methods
When breeding, various systems of crosses are used, which are understood to be divided into related crosses, often called inbreeding, or inbreeding, and unrelated, sometimes called outbreeding.
A variety of outbreeding is crossbreeding (crossbreeding). Inbreeding is an English term; in Russian literature it is more often used to denote closely related breeding in animals; inbreeding is a German term used to denote forced self-pollination in cross-pollinated plants. However, in order to avoid confusion, one term can be used – inbreeding.
In livestock breeding, crossbreeding is divided into two types in accordance with the task of breeding animals: breeding (factory) and industrial (commercial). For breeding purposes and breeding, that is, breeding new breeds and improving breed properties, both inbreeding and outbreeding are used. To increase livestock productivity, industrial crossing based on existing breeds is used. Similar types of crosses are used in modern plant breeding for breeding or maintaining varieties and for obtaining a marketable product. For example, crosses used in sugar beet or watermelon to produce triploid seeds are typically industrial.
The use of a particular crossbreeding system in breeding depends on what type of variability is used for breeding purposes and what tasks are solved. For example, if cross-matching of selected forms (combinational variability) does not give an effect, then resort to the use of mutational variability or to polyploidy. At the same time, the system of crosses is changed.