Method for breeding all-male tetraploid crucian carp

Abstract

The present application relates to fish breeding technology field, especially to a kind of all-male tetraploid crucian carp breeding method, comprising the following steps: with gynogenesis homologous diploid crucian carp as female parent, and androgenesis homologous diploid crucian carp as male parent, artificial delivery is carried out;Wherein, the gynogenesis homologous diploid crucian carp sex chromosome type is XX, produces non-reduction diploid egg, and the androgenesis homologous diploid crucian carp male individual sex chromosome type is XY or YY, produces non-reduction diploid sperm;Artificial insemination is carried out, and the obtained zygote is hatched, and cultured to sexual maturity, and the surviving offspring is all-male tetraploid crucian carp population.The present application is based on the characteristics that gynogenesis homologous diploid crucian carp and androgenesis homologous diploid crucian carp both produce non-reduction gametes, artificial insemination is carried out, and all-male tetraploid crucian carp can be prepared on a large scale.The all-male tetraploid crucian carp only needs 120 days of age to reach sexual maturity, can stably produce diploid sperm, and the reproductive performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fish breeding, in particular to a method for breeding all-male tetraploid crucian carp. BACKGROUND

[0002] Fish unisexual breeding refers to the cultivation of a single-sex fish population through artificial intervention or genetic regulation technology to meet the demand for specific gender fish in aquaculture. Unisexual breeding is of great significance in aquaculture. For example, all-male populations generally grow faster and are larger, which can shorten the breeding cycle and reduce production costs. All-female populations may have higher economic value in some species, such as egg production. Common methods of fish unisexual breeding include the use of exogenous hormones to induce sex reversal, gynogenesis and androgenesis, and the combination of gene editing and sex marker assisted breeding technology. The most widely used unisexual breeding technology at present is the combination of gynogenesis and sex reversal technology, which is also a way to obtain all-female fish. A variety of fish have achieved artificial sex reversal, such as Oryzias latipes, Cyprinus carpio, Carassius auratus, and Clarias batrachus, making it possible to prepare unisexual fish populations. However, the conventional unisexual breeding scheme cannot control the proportion of sex reversal when feeding experimental fish with exogenous hormones, and it also causes pollution to the water environment. Especially for gynogenetic fish with a long sexual maturation period, the breeding cycle is long and there are many uncontrollable factors. The preparation of ordinary all-male fish usually requires a series of processes such as "sex reversal-gynogenesis-super-male fish-all-male fish", which has a longer cycle and more uncontrollable factors than the preparation of all-female fish population. How to avoid the above risks and quickly breed all-male / all-female populations is a research hotspot in aquaculture at present.

[0003] For a long time, the main research object of fish unisexual breeding is diploid, and there are few researches on polyploid fish, especially tetraploid fish. The main reason is that it is too difficult to artificially breed tetraploid fish which is hereditarily stable and can produce gametes. The preparation of tetraploid fish has been a hot and difficult point in the field of aquaculture at home and abroad. At present, there are many reports on the preparation of tetraploid fish by physical and chemical methods, such as tetraploid rainbow trout, tetraploid Megalobrama, tetraploid Paralichthys olivaceus, etc. However, the tetraploid fish prepared by these methods cannot form a stable strain. In addition, biological methods such as distant hybridization are considered to be effective methods for creating tetraploid fish which can produce gametes and are hereditarily stable, such as the creation of tetraploid fish such as heterologous tetraploid crucian carp, homologous tetraploid crucian carp, etc. On the basis of the creation of these tetraploid fish, they can be genetically improved by using techniques such as gynogenesis and androgenesis. The improved tetraploid fish has obvious advantages in sperm production, egg carrying capacity and stress resistance. As high-quality germplasm resources, especially male tetraploid fish, can produce more diploid gametes, and are more valuable in production and application. At present, there are few reports on all-male tetraploid fish, and there is no successful case of successfully breeding all-male tetraploid fish in the prior art. The reason is that there are few available diploid gametes. Common diploid economic fish usually produces haploid gametes, and the embryo is diploid after fertilization. It is difficult to obtain surviving tetraploid offspring by inhibiting the first cleavage and other technical means to double the chromosome number of diploid embryos, and it cannot be guaranteed whether it is a single sex. It needs to be cultured by hormone or temperature control in the later stage, and it is possible to obtain a single sex population, but the operation period is too long and the risk is too large. The present application effectively avoids the above risks, fully utilizes the existing diploid gamete resources, and directly obtains a large number of all-male tetraploid fish population without chromosome doubling treatment, hormone feeding or temperature control treatment, which solves the technical difficulties faced by technical personnel in the field. SUMMARY

[0004] The present application provides a method for breeding all-male tetraploid crucian carp, which aims to fill the gap in the breeding scheme of male tetraploid fish.

[0005] In order to achieve the above purpose, the present application provides a method for breeding all-male tetraploid crucian carp, comprising the following steps:

[0006] The gynogenesis homologous diploid crucian carp is used as the female parent, and the androgenesis homologous diploid crucian carp is used as the male parent to induce parturition artificially. The gynogenesis homologous diploid crucian carp has a sex chromosome type of XX and produces non-reduced diploid eggs with a gamete type of XX. The androgenesis homologous diploid crucian carp has a sex chromosome type of XY or YY in male individuals and produces non-reduced diploid sperm with a gamete type of XY or YY.

[0007] The fertilized eggs obtained by artificial insemination of the aneuploid diploid eggs and aneuploid sperm are hatched and cultured to sexual maturity, and the offspring that survive are all-male tetraploid crucian carp populations with sex chromosome karyotypes of XXXY or XXYY.

[0008] Preferably, the gynogenetic isogenic diploid crucian carp is gynogenetic from the isogenic tetraploid crucian carp, is an all-female population, has a somatic cell chromosome number of 100, and can stably produce aneuploid diploid eggs with a chromosome number of 100.

[0009] Preferably, the androgenetic isogenic diploid crucian carp is androgenetic from the isogenic tetraploid crucian carp, has a somatic cell chromosome number of 100, and the male individuals can stably produce aneuploid diploid sperm with a chromosome number of 100.

[0010] Preferably, the artificial induction of spawning includes injection of oxytocin into the female and male parents.

[0011] Preferably, the artificial insemination specifically includes the following steps:

[0012] S1, after the gynogenetic isogenic diploid crucian carp is in estrus, the fish body is wiped dry with a dry towel, and the eggs are squeezed out of the fish body and placed in a pre-dried basin;

[0013] S2, the semen of the androgenetic isogenic diploid crucian carp is squeezed into the basin in step S1, and is stirred and mixed evenly with a dry feather to allow fertilization.

[0014] More preferably, in step S1, the gynogenetic isogenic diploid crucian carp with healthy signs and well-developed gonads is selected. The genomes of the gynogenetic isogenic diploid crucian carp and the androgenetic isogenic diploid crucian carp are derived from the isogenic tetraploid crucian carp, and the genome of the hybrid offspring has better compatibility during fusion, which is conducive to improving the hatching rate.

[0015] Preferably, the hatching specifically includes: dispersing and paving the fertilized eggs in a culture dish containing clean water, and hatching at room temperature in still water; and the culture specifically includes: after hatching, the obtained seedlings are transferred to a plastic basin for further culture for 2-4 days, and then transferred to a pre-fertilized pond for breeding to sexual maturity.

[0016] Preferably, the sexual maturity time is 105-130 days of age, the hatching rate is 69.5-80%, and the survival rate is 65-70%.

[0017] More preferably, the sexual maturity time is 120 days of age.

[0018] During breeding and detection, the all-male tetraploid crucian carp bred by the present application shows the improved characteristics of significantly and stably shortened sexual maturity time, and when detected at 120 days of age, the fry have basically reached sexual maturity, significantly improving the breeding efficiency.

[0019] Preferably, after the fry is bred to sexual maturity, the breeding method further comprises ploidy detection and gender detection on the surviving offspring.

[0020] Preferably, the ploidy detection specifically comprises: using a flow cytometry DNA content detection method and / or a kidney tissue lymphocyte chromosome ploidy detection method, wherein the average DNA content of the somatic cells of the surviving offspring is between 190 and 215, and the number of somatic chromosomes is all 200, that is, the surviving offspring is tetraploid.

[0021] Preferably, the gender detection specifically comprises at least one of the following two schemes:

[0022] Scheme 1: Directly squeezing white semen from the sexually mature individual to determine that it is male.

[0023] Scheme 2: Performing a dissection experiment on the sexually mature population, and determining that it is male if there is obvious testis tissue.

[0024] Preferably, the semen obtained by the gender detection is detected by using the flow cytometry DNA content detection method, and it is determined that the sperm of the all-male tetraploid crucian carp population is diploid by the average DNA content of the semen being between 90 and 110.

[0025] The above scheme of the present application has the following beneficial effects:

[0026] (1) The present application is based on the characteristics that both the gynogenetic homologous diploid crucian carp and the androgenetic homologous diploid crucian carp produce apomictic gametes, fully utilizes the excellent germplasm resources, artificially inseminates the two, and realizes the large-scale preparation of all-male tetraploid crucian carp, innovates the method for large-scale preparation of tetraploid fish, and selects the male parent and the female parent whose genomes are derived from the homologous tetraploid crucian carp, which has better compatibility and is beneficial to improve the hatching rate and the survival rate.

[0027] (2) The ordinary male homologous tetraploid crucian carp needs one year to reach sexual maturity, but the all-male tetraploid crucian carp obtained by the breeding method of the present application only needs 120 days to reach sexual maturity, can stably produce diploid sperm, and the breeding performance is improved, and the breeding cycle is significantly shortened.

[0028] (3) The all-male tetraploid crucian carp is an important germplasm resource for producing triploid, and can provide sufficient diploid gamete resources for large-scale preparation of high-quality triploid fish. The present application has important theoretical and production significance in the research on genetic mechanisms of fish sex determination, sex control breeding, and large-scale breeding of polyploid fish.

[0029] Other beneficial effects of the present application will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The flowchart shows the breeding process of all-male tetraploid crucian carp in Examples 1-3;

[0031] Figure 2 The image shows the average DNA content of blood cells and chromosome diagram of all-male tetraploid crucian carp in Example 1.

[0032] Figure 3 The images show the morphology and histological characteristics of the testes of the all-male tetraploid crucian carp in Example 1.

[0033] Figure 4 This is a graph showing the average DNA content in the semen of all-male tetraploid crucian carp in Example 1. Detailed Implementation

[0034] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] Example 1:

[0039] This embodiment provides a method for cultivating all-male tetraploid crucian carp. The flowchart for cultivating all-male tetraploid crucian carp is as follows: Figure 1The cultivation experiment of all-male tetraploid crucian carp was carried out in three batches in the fish breeding valley of Xuefeng Mountain in Shaoyang City, Hunan Province from March 2022 to July 2022. The total experiment lasted for 5 months.

[0040] Each batch of all-male tetraploid crucian carp cultivation specifically includes the following steps:

[0041] (1) Artificial induction and fertilization: In the breeding season, 10 healthy and well-developed gynogenetic homologous diploid crucian carps and 10 male androgenetic homologous diploid crucian carps were selected, and a mixture of chorionic gonadotropin (HCG) 400-600 IU / kg, luteinizing hormone releasing hormone analogue (LRH-A) 6-8 μg / kg and domperidone (DOM) 1 mg / kg was injected for artificial induction. The injection dose of male individuals was half of that of females; after the gynogenetic homologous diploid crucian carps came into heat, the fish body was wiped dry with a dry towel and the eggs were squeezed out from the fish body and placed in a pre-dried basin. The sperm of the androgenetic homologous diploid crucian carp was squeezed in, and the mixture was stirred with a dry feather to make it fertile.

[0042] (2) Incubation and feeding: The fertilized eggs were dispersed and laid flat in a culture dish containing clean water, and incubated at room temperature in still water. After hatching, more than 20,000 fry were obtained and transferred to a plastic basin for further culture for 2-4 days. The average hatching rate of the three batches was about 74.36%. After the fish fry appeared the waist point, they were transferred to a pre-fertilized pond for feeding until they reached sexual maturity at 120 days of age. The surviving offspring were 100% all-male tetraploid crucian carp population, and the average survival rate of the three batches was about 67.06%. The specific hatching conditions are shown in Table 1:

[0043] Table 1 Fish fry cultivation conditions of Example 1

[0044]

[0045] (3) Detection of offspring ploidy and sex: The ploidy and gonadal development of the offspring fed to 120 days of age were detected; flow cytometry DNA content detection method and kidney tissue lymphocyte chromosome ploidy detection method were used, and the results are shown in Figure 2 The average DNA content of the surviving offspring somatic cells was 204.02, and the somatic cell chromosome number was 200, i.e. the surviving offspring were tetraploid. Figure Two Peak 2 in the figure is the most concentrated and largest number of sample detection of average DNA content, which can be judged as the average DNA content of the sample; although peak 1 reads the corresponding data, it may be a fragmented DNA sample, etc., and cannot be used as a representative of the average DNA content of the sample; the corresponding data read by peak 3 is the DNA content of the somatic cells in the process of mitosis, which is in a doubled state.

[0046] The mature individuals are directly squeezed out of the white semen to determine the male, or the dissection experiment is performed on the sexually mature population, and the presence of obvious testis tissue determines the male. All surviving individuals are detected, and all are males. The testis shape and testis histology of the all-male tetraploid crucian carp are shown in Figure 3 .

[0047] The semen obtained by the gender detection is detected by flow cytometry DNA content detection method, and the sperm of the all-male tetraploid crucian carp population is determined to be diploid by the average DNA content of the semen. The average DNA content of the semen of the all-male tetraploid crucian carp is shown in Figure 4 . The specific value is 101.60 shown by peak 1, and the average DNA content of the semen is about half of the average DNA content of the somatic cells Figure 2 . Therefore, it can be determined that the sperm produced by the all-male tetraploid crucian carp population is diploid.

[0048] Figure 4 Peak 1 is the interval with the most concentrated and largest number of average DNA contents in the semen for loading detection, which can represent the average DNA content of the semen of the all-male tetraploid crucian carp. Peak 2 shows 199.57, which may be the DNA content of sperm cells in different development periods, or a small part of somatic cells may be taken out (contaminated) during the process of taking the semen sample.

[0049] Through the above detection, it can be determined that the offspring of the gynogenetic homologous diploid crucian carp and the androgenetic homologous diploid crucian carp is 100% male tetraploid, which can reach sexual maturity at 120 days of age and can stably produce diploid sperm.

[0050] Example 2

[0051] The present embodiment provides a method for cultivating all-male tetraploid crucian carp. The cultivation flow chart of all-male tetraploid crucian carp is shown in Figure 1 . Three batches of all-male tetraploid crucian carp cultivation experiments were carried out in Xuefengshan Fish Seed Breeding Valley in Shaoyang City, Hunan Province from March 2023 to July 2023, and the total experiment lasted for 5 months.

[0052] Each batch of all-male tetraploid crucian carp cultivation specifically includes the following steps:

[0053] (1) Artificial induction of spawning and fertilization: In the breeding season, 10 healthy and well-developed gynogenetic homologous diploid crucian carp and 10 androgenetic homologous diploid crucian carp were selected, and a mixed induction agent of chorionic gonadotropin (HCG) 400-600 IU / kg, luteinizing hormone releasing hormone analogue (LRH-A) 6-8 μg / kg and domperidone (DOM) 1 mg / kg was injected for artificial induction of spawning. The injection dose of the male individual was half of that of the female. After the gynogenetic homologous diploid crucian carp was in estrus, the fish body was wiped dry with a dry towel, and the eggs were squeezed out of the fish body and placed in a pre-dried basin. The sperm of the androgenetic homologous diploid crucian carp was squeezed into the basin, and the mixture was stirred with a dry feather to make it fertile.

[0054] (2) Incubation and feeding: The fertilized eggs were dispersed and laid flat in a culture dish containing clean water, and incubated at room temperature in still water. After hatching, more than 10,000 fry were obtained and transferred to a plastic basin for further culture for 2-4 days. The average hatching rate of the three batches was about 73.42%. After the fry appeared the waist point, they were transferred to a pre-fertilized pond for feeding until they reached sexual maturity at 120 days of age. The survival offspring was a 100% all-male tetraploid crucian carp population, and the average survival rate of the three batches was about 68.04%. The specific incubation conditions are shown in Table 2:

[0055] Table 2 Fish fry cultivation conditions of Example 2

[0056]

[0057] (3) Detection of offspring ploidy and sex: The ploidy and gonadal development of the offspring fed to 120 days of age were detected. The flow cytometry DNA content detection method and the kidney tissue lymphocyte chromosome ploidy detection method were used to detect the average DNA content of the somatic cells of the surviving offspring, which was between 190 and 215, and the number of somatic cell chromosomes was 200, i.e. the surviving offspring was tetraploid.

[0058] The sexually mature individuals were directly squeezed out of the white semen to determine the males, or the sexually mature population was dissected, and those with obvious testicular tissue were determined to be males. All surviving individuals were detected and found to be all males.

[0059] The semen obtained from the sex detection was detected by flow cytometry DNA content detection method, and the sperm of the all-male tetraploid crucian carp population was determined to be diploid by the average DNA content of the semen. The average DNA content of the semen of the all-male tetraploid crucian carp was between 90 and 110, which was about half of the average DNA content of the somatic cells. Therefore, it can be determined that the sperm produced by the all-male tetraploid crucian carp population is diploid. Through the above detection, it can be determined that the offspring of the gynogenetic homologous diploid crucian carp and the androgenetic homologous diploid crucian carp is 100% male tetraploid, which can reach sexual maturity at 120 days of age and can stably produce diploid sperm.

[0060] Example 3:

[0061] The present embodiment provides a method for cultivating all-male tetraploid crucian carp. The flow chart of cultivating all-male tetraploid crucian carp is shown in FIG. 1. Three batches of all-male tetraploid crucian carp were cultivated in the Xuefeng Mountain Fish Seed Breeding Valley in Shaoyang City, Hunan Province from April 2024 to August 2024, and the total experimental duration was 5 months. Figure 1

[0062] The cultivation of each batch of all-male tetraploid crucian carp specifically includes the following steps:

[0063] (1) Artificial induction of parturition and fertilization: In the breeding season, 10 female gynogenetic homologous diploid crucian carps and 10 male androgenetic homologous diploid crucian carps with healthy signs and well-developed gonads were selected, and a mixed parturition agent of chorionic gonadotropin (HCG) 400-600 IU / kg, luteinizing hormone analogue (LRH-A) 6-8 μg / kg, and domperidone maleate (DOM) 1 mg / kg was injected for artificial induction of parturition. The injection dose for male individuals was half of that for female individuals. After the female gynogenetic homologous diploid crucian carps were in estrus, the fish bodies were wiped dry with a dry towel, and the eggs were squeezed out of the fish bodies and placed in a pre-dried basin. The sperm of the male androgenetic homologous diploid crucian carp was squeezed in, and a dry feather was used to stir and mix them to allow fertilization.

[0064] (2) Incubation and feeding: The fertilized eggs were dispersed and laid flat in a culture dish containing clean water, and incubated at room temperature in still water. After hatching, more than 10,000 fry were obtained and transferred to a plastic basin for further cultivation for 2-4 days. The average hatching rate of the three batches was about 74.10%. After the fry appeared the waist point, they were transferred to a pre-fertilized pond for feeding until they reached sexual maturity at 120 days of age. The surviving offspring were all-male tetraploid crucian carp populations, and the average survival rate of the three batches was about 68.47%. The specific incubation conditions are shown in Table 3.

[0065] Table 3 Fish fry cultivation conditions in Example 3

[0066]

[0067] (3) Detection of offspring ploidy and sex: The ploidy and gonadal development of the offspring fed to 120 days of age were detected. The flow cytometry DNA content detection method and the kidney tissue lymphocyte chromosome ploidy detection method were used to detect the average DNA content of the somatic cells of the surviving offspring, which was between 190 and 215, and the number of somatic cell chromosomes was 200, indicating that the surviving offspring were tetraploid.

[0068] The sexually mature individuals were directly squeezed out of white sperm to determine their sex, or the sexually mature population was dissected, and those with obvious testicular tissue were determined to be male. All surviving individuals were detected, and all were found to be male.

[0069] ​The sperm obtained by the gender detection is detected by flow cytometry DNA content detection method, and the sperm of the all-male tetraploid crucian carp population is determined to be diploid by the average DNA content of the sperm. The average DNA content of the sperm of the all-male tetraploid crucian carp is between 90 and 110, and the average DNA content of the sperm is about half of the average DNA content of the somatic cells. Therefore, it can be determined that the sperm produced by the all-male tetraploid crucian carp population is diploid. Through the above detection, it can be determined that the hybrid offspring of the gynogenetic homologous diploid crucian carp and the androgenetic homologous diploid crucian carp is 100% male tetraploid, which can reach sexual maturity at 120 days old and can stably produce diploid sperm.

[0070] Overall, the all-male tetraploid crucian carp prepared by the method is a major breakthrough in the process of fish unisexual breeding research. Compared with the method of preparing unisexual population by sex reversal technology, the unisexual breed can be obtained faster, and the impact of hormone feeding on the environment in the process of sex reversal is also avoided. By using the characteristics that both the gynogenetic homologous diploid crucian carp and the androgenetic homologous diploid crucian carp produce apomeiotic gametes, the two are crossed to prepare a tetraploid crucian carp population on a large scale, which innovates the method of large-scale preparation of tetraploid fish. Moreover, compared with ordinary male homologous tetraploid crucian carp, the all-male tetraploid crucian carp population has a significantly shortened sexual maturation time and improved reproductive performance. The all-male tetraploid crucian carp is an important germplasm resource for producing triploid, which can provide sufficient diploid gamete resources for large-scale preparation of high-quality triploid fish. These have important theoretical and production significance in the research of fish gender determination genetic mechanism, sex control breeding, and large-scale breeding of polyploid fish.

[0071] The above is the preferred embodiment of the present application. It should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. A method for cultivating all-male tetraploid crucian carp, characterized in that, Includes the following steps: Using gynogenetic homologous diploid crucian carp as the maternal parent and androgenetic homologous diploid crucian carp as the paternal parent, artificial spawning was induced. The gynogenetic homologous diploid crucian carp had a XX karyotype, producing unreduced diploid eggs with XX gamete types. The male androgenetic homologous diploid crucian carp had an XY or YY karyotype, producing unreduced diploid sperm with XY or YY gamete types. The gynogenetic homologous diploid crucian carp developed from the gynocytes of homologous tetraploid crucian carp, forming an all-female population with 100 chromosomes in their somatic cells and stably producing unreduced diploid eggs with 100 chromosomes. The androgenetic homologous diploid crucian carp developed from the androgenetic cells of homologous tetraploid crucian carp, with 100 chromosomes in their somatic cells, and their males stably producing unreduced diploid sperm with 100 chromosomes. Artificial insemination was performed on the above-mentioned unreduced diploid eggs and unreduced diploid sperm. The resulting fertilized eggs were hatched and cultured until sexual maturity. The surviving offspring were the all-male tetraploid crucian carp population, and their sex chromosome karyotype was XXXY or XXYY.

2. The method according to claim 1, characterized in that, The artificial induction of labor involves injecting oxytocin into both the mother and father.

3. The method according to claim 1, characterized in that, The artificial insemination process specifically includes the following steps: S1. After the homologous diploid crucian carp with gynogenesis has started to mate, dry the fish with a dry towel and squeeze the eggs out of the fish and place them in a pre-dried basin. S2. Squeeze the semen of the androgenetic homologous diploid crucian carp into the basin in step S1, and stir it with dry feathers to fertilize it.

4. The method according to claim 1, characterized in that, The incubation process specifically includes: spreading the fertilized eggs evenly in a petri dish containing clean water and incubating them in still water at room temperature; the cultivation process specifically includes: after hatching, transferring the resulting fry to a plastic basin for further cultivation for 2-4 days, and then transferring them to a pre-fertilized pond for rearing until sexual maturity after the fry have developed a tail.

5. The method according to claim 4, characterized in that, The fish fry reach sexual maturity at 105-130 days of age, with a hatching rate of 69.5-80% and a survival rate of 65-70%.

6. The method according to claim 4, characterized in that, After the fish fry are raised to sexual maturity, the breeding method also includes ploidy and sex testing of the surviving offspring.

7. The method according to claim 6, characterized in that, The ploidy detection specifically includes: using flow cytometry DNA content detection and / or kidney tissue lymphocyte chromosome ploidy detection. The average DNA content of the surviving offspring somatic cells is between 190 and 215, and the somatic cell staining number is 200, that is, the surviving offspring are tetraploid.

8. The method according to claim 6, characterized in that, The gender detection specifically includes at least one of the following two methods: Option 1: Directly squeeze out white semen from sexually mature individuals to determine if they are male; Option 2: Conduct anatomical experiments on sexually mature groups, and identify males by the presence of obvious testicular tissue.

9. The method according to claim 8, characterized in that, The semen obtained from the sex determination was analyzed using flow cytometry DNA content detection. The average DNA content of the semen was between 90 and 110, which confirmed that the sperm of the all-male tetraploid crucian carp population was diploid.

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