Population selection should be paid attention to in efficient goose breeding.

A "population" is an abbreviation for a specific population such as a taxa, strain, variety, or genus. Population selection is based on whether the mating partner belongs to the same or different population. Population selection can be divided into purebred breeding and crossbreeding, and crossbreeding can be further divided into breeding hybridization and economic hybridization:

Pure breeding is a method to improve the performance of the population by means of seed selection, strain breeding and improvement of breeding conditions within the range of the population. Its basic task is to maintain and develop the excellent characteristics of a population, increase the proportion of excellent individuals in the population, overcome some shortcomings of the population, and achieve the purpose of maintaining the purity of the population and improving the quality of the whole population. Pure breeding has two functions.

One is to consolidate heredity, so that the inherent good quality of the population can be maintained for a long time, and rapidly increase the number of excellent individuals of the same type.

The second is to improve the existing quality, so that the population level continues to rise steadily.

Crossbreeding, referred to as "hybridization," is the selection of individuals from different populations for breeding. Interbreeding between different varieties is often called "crossing"; interbreeding between different strains is called "interline crossing"; interbreeding between different species or genera is called "distant crossing". There are usually several types of hybridization:

stepwise hybridization

Progressive hybridization (improved hybridization, modified hybridization, absorption hybridization) refers to the hybridization of high-yield male birds with low-yield female birds, and the obtained hybrid female birds are then hybridized with high-yield male birds. Generally, low-yield varieties can be rapidly and effectively transformed by continuous 3 ~4 generations. Progressive hybridization is often used when it is necessary to completely modify the production performance of a population (variety, strain) or change the direction of production performance. When crossing, attention should be paid to:

According to improve production performance or change production performance aspects of the selection of appropriate improved varieties.

Rigorous genetic testing of introduced improved male birds.

Cross generations should not be too many, lest the proportion of exotic bloodlines is too large, resulting in hybrid adaptation to the local decline.

introhybridization

Introgression hybridization is to introduce no more than 1/4 of the foreign blood into the local range of the original population in order to overcome individual shortcomings while maintaining the original population. When the production performance of original population basically meets the needs, local defects are not easy to overcome under pure propagation, and then it is appropriate to adopt introduction hybridization. Note that when carrying out introhybridization:

In view of the original population's concrete shortcoming, carries on the introduction hybridization experiment, determines the introduction male bird variety.

The male birds introduced into the population are strictly selected.

breeding cross

Crossbreeding refers to the crossbreeding of two or more populations and the selection and fixation of the hybrid offspring to produce a variety that meets the needs. When the original varieties can not meet the needs, and no foreign varieties can be completely replaced, breeding hybridization is often used. Attention should be paid to:

Exotic varieties are required to have good production performance and strong adaptability.

Cross parents should not be too many, in case the genetic basis is too mixed, resulting in fixation difficulties.

When hybridization appears ideal type, it should be fixed in time.

Matching utilization of line hybridization

The breeding of specialized lines and the production of hybrid lines are the inevitable requirements of modern goose farming. The purpose of establishing the line is to carry out the line mating hybridization, utilize its heterosis, improve the production performance of geese, and cultivate the commercial line with characteristics. The key of selecting ideal mating line is to test combining ability, and after mating with certain model or program, the mating line with best combining ability and highest economic benefit can be selected, and the commercial goose with strong heterosis can be produced for market demand. There are two lines matching, three lines matching and four lines matching.

Determination of combining force: combining force can be divided into general combining force and special combining force:

According to genetic principle, GCA reflects the average breeding value of hybrid parent population, and its basis is additive effect of gene. Therefore, the improvement of GCA mainly depends on the pure breeding of parent lines. The GCA of traits with high heritability was easy to improve, while that of traits with low heritability was difficult to improve. Special combining ability reflects the difference between the average genotype value of hybrid population and the average breeding value of parents, and its basis is the non-additive effect of genes, that is, dominant effect and epistatic effect. Therefore, the improvement of SCA should mainly depend on the selection of hybrid combinations. For characters with high heritability, the SCA of each combination will not have great difference, whereas for characters with low heritability, the SCA can have great difference. In production, the combination with strong heterosis can be selected through the determination of special combining ability among lines.

From the genetic point of view, the more strains participate in the mating, the broader the genetic base, the more excellent traits of the hybrid offspring, and the stronger the hybrid heterosis of the commercial goose. However, the more strains participating in the matching, the more investment in strain breeding, pure propagation and seed conservation and hybrid seed production. With the development of modern poultry breeding technology, some foreign breeding companies have changed from four-line mating to three-line or two-line mating in recent years.