Why is it necessary to pay attention to population matching in efficient goose raising?

“Population” is the short name for a breeding group such as a line, strain, breed or species. Population matching is matching based on whether the two mating parties belong to the same or different populations. Population matching is divided into two major categories: purebred breeding and crossbreeding, and crossbreeding can be further divided into breeding crossbreeding and commercial crossbreeding:

Purebred breeding, abbreviated as “pure breeding”, refers to a method of improving population performance within the scope of the population itself through measures such as selection and matching, line breeding, and improvement of rearing conditions. Its basic task is to maintain and develop the excellent characteristics of a population, increase the proportion of excellent individuals within the population, overcome certain shortcomings of the population, and achieve the goal of maintaining population purity and improving the quality of the entire population. Pure breeding has the following two functions.

First, it consolidates heredity, allowing the population's inherent excellent qualities to be maintained over the long term and rapidly increasing the number of excellent individuals of the same type.

Second, it improves existing quality, allowing the population level to rise steadily and continuously.

Crossbreeding, abbreviated as “crossing”, is the selection of individuals from different populations for mating. Mating between different breeds is often called “crossbreeding”; mating between different lines is called “line crossing”; mating between different species or different genera is called “distant hybridization”. Crossbreeding types usually include the following:

Grading up

Grading up (improvement crossing, transformation crossing, absorption crossing) refers to crossing high-yielding excellent breed male poultry with low-yielding breed female poultry, and the resulting hybrid offspring female poultry are then crossed with high-yielding excellent breed male poultry. Generally, 3 to 4 generations of continuous crossing can rapidly and effectively transform a low-yielding breed. When it is necessary to thoroughly transform the production performance of a certain population (breed, line) or to change the direction of production performance, grading up is commonly used. When carrying out crossing, attention should be paid to:

Select a suitable improved breed according to improving production performance or changing the direction of production performance.

Conduct strict genetic testing on introduced improved male poultry.

The number of crossbred generations should not be too many, so as to avoid an excessive proportion of foreign bloodlines, which would lead to a decline in the adaptability of the hybrids to the local area.

Introductory crossing

Introductory crossing is the introduction of no more than 1/4 foreign blood into a local area of the original population, so as to overcome individual shortcomings while maintaining the original population. When the production performance of the original population basically meets the need and local shortcomings are difficult to overcome under pure breeding, introductory crossing should be adopted. When carrying out introductory crossing, attention should be paid to:

Conduct introductory crossing trials targeting the specific shortcomings of the original population, and determine the breed of introduced male poultry.

Strictly select the male poultry of the introduced population.

Formation crossbreeding

This refers to crossing two or more populations with each other, selecting the superior ones from the hybrid offspring and fixing them, to breed a breed that meets the need. When the original breed cannot meet the need and no foreign breed can completely replace it, formation crossbreeding is often adopted. When carrying out formation crossbreeding, attention should be paid to:

Foreign breeds are required to have good production performance and strong adaptability.

The crossbreeding parents should not be too many, so as to prevent the genetic basis from becoming too mixed, which would make fixation difficult.

When an ideal type appears in the cross, it should be fixed in a timely manner.

Supporting use of line crossing

The cultivation of specialized lines and the production of crossbreeding supporting lines are inevitable requirements of modern goose raising production. The purpose of establishing lines is to carry out line supporting crosses, use their heterosis, improve the production performance of geese, and cultivate distinctive commercial supporting lines. The key to selecting ideal supporting lines lies in combining ability testing, and after supporting according to a certain model or procedure of lines, the supporting line with the best combining ability and the highest economic benefit can be selected, producing commercial geese with strong heterosis for the market need. Line supporting models mainly include two-line supporting, three-line supporting and four-line supporting.

Combining ability testing: Combining ability can be divided into two types: general combining ability and specific combining ability:

According to genetic principles, in fact what general combining ability reflects is the level of the average breeding value of the crossbreeding parent population, and its basis is the additive effect of genes. Therefore, the improvement of general combining ability mainly depends on pure breeding selection of parent lines. For traits with high heritability, general combining ability is relatively easy to improve; while for traits with low heritability, general combining ability is not easy to improve. What specific combining ability reflects is the difference between the average genotypic value of the hybrid population and the average breeding value of the parents, and its basis is the non-additive effect of genes, namely dominance effect and epistatic effect. Therefore, improving specific combining ability should mainly rely on the selection of cross combinations. For traits with high heritability, the specific combining ability of each combination will not differ greatly; conversely, for traits with low heritability, specific combining ability can differ greatly. In production, through testing the specific combining ability between lines, supporting combinations with strong heterosis can be selected.

Analyzed from the perspective of genetics, the more lines involved in supporting, the broader their genetic basis, the more excellent traits of the parents are combined in the hybrid offspring, and the stronger the heterosis of the commercial geese produced. However, the more lines involved in supporting, the greater the investment inevitably required for line cultivation, pure breeding conservation and crossbreeding seed production. With the continuous progress and improvement of modern poultry breeding technology, some foreign breeding companies, starting from economic benefits, have in recent years changed from four-line supporting to three-line or two-line supporting for commercial generation production.