First, the significance of breeding Breeding is the selection of species, people use the inherent genetic variability of the organism, in accordance with the predetermined breeding goals selection and inferior. From the group, select excellent individuals as species, eliminate poor individuals, and genetically improve future generations. The phenomenon of heredity and variation is common in living things. The former makes the species relatively stable and the latter changes the species. Changes caused by changes in biological genetic material are heritable mutations, and environmental-induced mutations are not inherited. The basic point of selection is to select heritable variant traits. We select individuals with traits that meet people’s wishes as parents, and continue to indi- cate steadily according to the same breeding goal in the handed down generation. It takes 10 to 20 years for fish to be selected from the same generation by generation. Get fine varieties. For example, the head of Putoutou Pujiang No. 1 is a new breed that has been bred by Shanghai Fisheries University for 15 years.
Breeding is a very important foundation work and the earliest breeding method used in human production practice. In the Fish Culture Classic that was allegedly written by Fan Li, it involved the breeding and matching of carp. Breeding can be used to create new varieties in the most independent way. It is also the only way for other breeding methods to cultivate new varieties. It is necessary to select the individual that meets breeding objectives from the breeding offspring. Any breeding method must ultimately be selected through breeding. And adopt this series of production processes. In this sense, breeding is one of the most basic production processes for breeding. A stereotyped fine variety may also appear mixed and degraded, and the homozygosity of the variety can be improved through breeding and the purpose of purification and rejuvenation can be achieved. Therefore, breeding is also an effective way for elite varieties to maintain their good traits.
Second, the choice of the basis of the traits and standard fish selection should use some of the more important economic traits, - the choice of genetic effects is more obvious, and the measurement of large and relatively easy to appear as the main basis.
1. The economic traits are mainly measured from the point of view of the value of food, the nutritional content of food, and the longevity of human health. The fattening performance is mainly the pseudo-growth rate, growth multiplier, bait coefficient, and ornamental value of various fishes (refers to ornamental species such as goldfish, Jiujiang wolfberry, rainbow trout, and other species with high ornamental value).
2. The stress-resistance traits are mainly from strong cold resistance (such as allogynogenetic silver crucian carp), low incidence (such as rainbow trout), strong disease resistance (such as herring, squid) and endurance to adverse environments and other complex living conditions. Under the adaptation and other aspects to choose.
3. The developmental performance is mainly selected from the aspects of body shape, body weight, fullness, constitution and sexual maturity.
4. Comprehensive traits were selected from the aspects of body shape, appearance, physical health, group status, and presence or absence of abnormalities.
Third, the basic methods of breeding Breeding methods are more, the most basic is the population breeding and individual breeding.
1. Breeding (mixed selection)
Stage-by-stage, multi-generational (at least four generations) introduction of original species breeding populations, artificial breeding of fry, pond grading feeding, step-by-step screening, large-scale breeding; outbreaks, lakes, purse seine ecological breeding to raise the original reserve broodstock. In the artificial breeding of fry, the key is to choose the breeding parents, resolutely stop the adverse selection, try to avoid inbreeding, and strictly implement the artificial propagation technology operating procedures. In cultivating the large-scale breeding stage, the key is to select the technical requirements of mixed selection in each stage of growth and to progressively screen and implement the survival of the fittest. In the process of cultivating the original reserve broodstock, the key is to use ecological breeding techniques, with a long sloping speed, using natural baits as the main, according to germplasm standards, once a year to choose, choose the best and the best.
According to germplasm standards such as morphological characteristics, age growth and reproductive performance of various types of breeding, the original species and breeding seedlings were introduced, and the ponds were graduated by ponds and undulated, the lakes were surrounded by lakes, and the reservoirs were stocked in two modes. Gradual screening, making its germplasm characteristics fully expressed, based on the use of mixed selection techniques, reasonably determine the selection strength, breeding of broodstock, adherence to stage selection, multi-generation breeding, to achieve the purpose of improving quality. For the majority of farmers to provide healthy, disease-resistant high-quality pollution-free high-quality seed.
2. Individual selection: Select individuals from different types of mixed populations, then establish individuals according to individuals, then select the family with good traits as the parents of progeny, and eliminate the negative families. This will improve the genetic comprehensiveness of the breed from generation to generation, that is, it will produce new varieties with stable and good traits.
Breeding is a very important foundation work and the earliest breeding method used in human production practice. In the Fish Culture Classic that was allegedly written by Fan Li, it involved the breeding and matching of carp. Breeding can be used to create new varieties in the most independent way. It is also the only way for other breeding methods to cultivate new varieties. It is necessary to select the individual that meets breeding objectives from the breeding offspring. Any breeding method must ultimately be selected through breeding. And adopt this series of production processes. In this sense, breeding is one of the most basic production processes for breeding. A stereotyped fine variety may also appear mixed and degraded, and the homozygosity of the variety can be improved through breeding and the purpose of purification and rejuvenation can be achieved. Therefore, breeding is also an effective way for elite varieties to maintain their good traits.
Second, the choice of the basis of the traits and standard fish selection should use some of the more important economic traits, - the choice of genetic effects is more obvious, and the measurement of large and relatively easy to appear as the main basis.
1. The economic traits are mainly measured from the point of view of the value of food, the nutritional content of food, and the longevity of human health. The fattening performance is mainly the pseudo-growth rate, growth multiplier, bait coefficient, and ornamental value of various fishes (refers to ornamental species such as goldfish, Jiujiang wolfberry, rainbow trout, and other species with high ornamental value).
2. The stress-resistance traits are mainly from strong cold resistance (such as allogynogenetic silver crucian carp), low incidence (such as rainbow trout), strong disease resistance (such as herring, squid) and endurance to adverse environments and other complex living conditions. Under the adaptation and other aspects to choose.
3. The developmental performance is mainly selected from the aspects of body shape, body weight, fullness, constitution and sexual maturity.
4. Comprehensive traits were selected from the aspects of body shape, appearance, physical health, group status, and presence or absence of abnormalities.
Third, the basic methods of breeding Breeding methods are more, the most basic is the population breeding and individual breeding.
1. Breeding (mixed selection)
Stage-by-stage, multi-generational (at least four generations) introduction of original species breeding populations, artificial breeding of fry, pond grading feeding, step-by-step screening, large-scale breeding; outbreaks, lakes, purse seine ecological breeding to raise the original reserve broodstock. In the artificial breeding of fry, the key is to choose the breeding parents, resolutely stop the adverse selection, try to avoid inbreeding, and strictly implement the artificial propagation technology operating procedures. In cultivating the large-scale breeding stage, the key is to select the technical requirements of mixed selection in each stage of growth and to progressively screen and implement the survival of the fittest. In the process of cultivating the original reserve broodstock, the key is to use ecological breeding techniques, with a long sloping speed, using natural baits as the main, according to germplasm standards, once a year to choose, choose the best and the best.
According to germplasm standards such as morphological characteristics, age growth and reproductive performance of various types of breeding, the original species and breeding seedlings were introduced, and the ponds were graduated by ponds and undulated, the lakes were surrounded by lakes, and the reservoirs were stocked in two modes. Gradual screening, making its germplasm characteristics fully expressed, based on the use of mixed selection techniques, reasonably determine the selection strength, breeding of broodstock, adherence to stage selection, multi-generation breeding, to achieve the purpose of improving quality. For the majority of farmers to provide healthy, disease-resistant high-quality pollution-free high-quality seed.
2. Individual selection: Select individuals from different types of mixed populations, then establish individuals according to individuals, then select the family with good traits as the parents of progeny, and eliminate the negative families. This will improve the genetic comprehensiveness of the breed from generation to generation, that is, it will produce new varieties with stable and good traits.
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