The multi-trait selection method mainly includes

There are three traditional multi-trait selection methods, namely sequential selection, independent elimination and index selection.

(1) Series selection sequential selection method, also known as single selection method, refers to selecting and improving multiple characters selected in the scheme one by one, and selecting one or several generations for each character. When the selected single character achieves the desired selection effect, the selection of that character will be stopped, and then the second character will be selected. After reaching the goal, the third role will be selected, and so on.

This method is not only time-consuming, but also has the genetic antagonism between characters and the regression effect of natural selection, and the effect is often not ideal.

(2) Independent elimination method Independent elimination method, also known as independent level method, determines a selection standard for each production trait of the animal to be selected. For example, when selecting laying hens, selection criteria are formulated for three important traits: egg number, egg weight and body weight. ?

Although this method is superior to the sequential selection method, it is easy to eliminate most of the individuals with good traits, and only some of them are insufficient. On the other hand, individuals with average performance are retained, which affects the selection effect.

(3) The comprehensive index method of index selection is to give appropriate weights to the selected traits according to their genetic basis and economic importance, and then integrate them into an index, and select them according to the level of the index. Therefore, the comprehensive species index method has the best selection effect and is the most widely used selection method in animal breeding. In practical application, it is difficult to achieve the expected effect in theory by selecting comprehensive indicators.