Composite breeding method for high-yield crassostrea hongkongensis with neat shell shape

Abstract

The invention relates to a composite breeding method for high-yield crassostrea hongkongensis with a tidy shell shape. Comprising the following steps: (1) constructing a basic group and a core group: constructing the core group by taking a wild group with rich genetic diversity as the basic group and taking body weight and shell type indexes as indexes; (2) large-scale family construction; (3) filial generation performance determination and next-generation parent selection: when the first-generation breeding family is bred to 337 + / -10 days old, selecting next-generation parents from the first-generation breeding family by taking body weight and shell type indexes as indexes; and (4) constructing breeding families from the second generation to the fourth generation. Compared with an existing parent breeding method in which 3-year adult specifications are needed, the method has the advantages that parent selection is advanced to 337 + / -10 days old, the breeding process can be remarkably improved, one generation can be bred in one year, and the breeding period of crassostrea hongkongensis is shortened. The growth speed of crassostrea hongkongensis is remarkably increased, the breeding yield is increased, the shell shape attractiveness is improved, and economic benefits are improved.

Description

Technical Field

[0001] The invention relates to the technical field of oyster breeding, and in particular to a method for composite breeding of high-yield Hong Kong oysters with neat shell shapes. Background Art

[0002] Hong Kong oysters (Crassostrea hongkongensis), formerly known as "Near River Oysters", are sweet and tender in taste, and are deeply loved by consumers. They have become one of the three major varieties of oyster farming in my country, with an annual output of 1.85 million tons, accounting for 29.83% of the total oyster production in the country (China Fisheries Yearbook, 2023). For a long time, the seedlings of Hong Kong oysters have all come from natural seedlings collected from the sea area, and the parents are wild populations that have not been genetically improved. The seedlings grow slowly, the survival rate of aquaculture is low, the yield is low, and the shell shape of the cultivated oyster products is low, and the overall benefit is not high. The lack of high-yield and high-quality seedlings has become a bottleneck problem restricting the development of the Hong Kong oyster industry.

[0003] The growth rate of Hong Kong oysters is slow, and it takes 3 years to reach commercial specifications, which means that its breeding cycle is long. It takes 3 years to complete one generation of breeding. According to the national technical specifications for the approval of new aquatic varieties, at least 4 generations of continuous breeding are required, and the breeding process of new Hong Kong oyster varieties will take up to 12 years. In addition, the shell shape of Hong Kong oysters varies greatly. In an industrial survey, it was found that its shell shape index I (shell length / shell height) ranges from 0.25 to 1.10, and the coefficient of variation is 30.95%. There is a lack of breeding technology for the uniformity of its shell shape. In view of this, the present invention provides a method for the composite breeding of high-yield and uniform shell-shaped Hong Kong oysters. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for composite breeding of high-yield Hong Kong oysters with uniform shell shapes.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A method for composite breeding of high-yield Hong Kong oysters with uniform shell shape comprises the following steps:

[0007] (1) Construction of basic population and core population: The wild population with rich genetic diversity is used as the basic population, and the body weight and shell type index are used as indicators to construct the core population;

[0008] (2) Large-scale family construction: using the core group as parents, selecting individuals with full glands, using artificial insemination to construct the first-generation breeding family, and cultivating and raising the offspring in the first-generation breeding family;

[0009] (3) Determination of offspring performance and selection of next-generation parents: The first-generation breeding family is cultivated to 337±10 days of age, and the next-generation parents are selected from the first-generation breeding family based on body weight and shell shape index;

[0010] (4) Construction of second to fourth generation breeding families: According to the records of steps (2) and (3), the construction of second to fourth generation breeding families is carried out in sequence. When the offspring in the fourth generation breeding family are grown, genetically stable, high-yielding Hong Kong oysters with uniform shell shape are obtained.

[0011] The beneficial effects of the present invention are:

[0012] (1) Compared with the existing parent breeding method which requires 3 years to reach adult size, the present invention advances the parent selection to 337±10 days of age, which can significantly improve the breeding process, achieve 1 generation per year, and shorten the breeding cycle of Hong Kong oysters.

[0013] (2) The composite breeding method of Hong Kong oysters of the present invention can significantly improve the growth rate of Hong Kong oysters, increase the aquaculture yield, enhance the beauty of the shell shape, and improve the economic benefits.

[0014] (3) The method of the present invention is simple, easy to operate, low-cost, has broad market prospects, and is suitable for large-scale promotion in production.

[0015] Based on the above technical solution, the present invention can also be improved as follows.

[0016] Furthermore, the number of the basic population in step (1) is greater than 5000.

[0017] The beneficial effects of adopting the above further scheme are: since a large basic population can provide more genetic variation, it is helpful to select individuals with excellent traits and increase genetic diversity; a large basic population can reduce the possibility of inbreeding because there are more options to avoid mating between closely related individuals, reducing the risk of inbreeding.

[0018] Furthermore, in step (1), the top 5-15% of individuals, preferably 10%, in terms of weight and shell type index I=0.50-0.67 (wherein the value I=shell length / shell height) are selected from the basic population to construct a core population.

[0019] The beneficial effect of adopting the above further scheme is: individuals with the largest body weight and the most beautiful shell shape are obtained as parents.

[0020] Furthermore, in step (2), the number of the first generation breeding families is greater than 100.

[0021] The beneficial effects of adopting the above further scheme are: since more breeding families mean richer genetic backgrounds, it helps to maintain and increase the genetic diversity of the entire breeding population; selection is carried out among multiple breeding families, which can increase the intensity and efficiency of selecting excellent traits; genetic bottleneck refers to the loss of genetic diversity due to a reduction in population size, and a larger number of families can reduce this risk and reduce genetic bottlenecks.

[0022] Further, step (3) includes the following specific steps:

[0023] (3-1) When the first generation of selected families are cultured to 337±10 days of age, the next generation of selected families are selected based on the average body weight of each of the first generation of selected families;

[0024] (3-2) Using body weight and shell shape index as indicators, the next generation of parents is selected from the first generation breeding families that have been selected.

[0025] The beneficial effect of adopting the above further scheme is: through two high-pressure selections, first select at the breeding family level, and select the family with the fastest growth rate and the highest yield; then select at the individual level within the family, and through two selections, select the individuals with the largest weight and the most regular shell shape in the family of this generation, which will significantly improve the breeding effect.

[0026] Furthermore, step (3-1) specifically includes: when the first generation breeding families are cultivated to 337±10 days of age, the first generation breeding families ranked top 5 to 15% are selected based on the average body weight of each of the first generation breeding families.

[0027] Furthermore, step (3-1) specifically includes: when the first generation breeding families are cultivated to 330 days of age, the first generation breeding families ranked in the top 10% are selected based on the average body weight of each of the first generation breeding families.

[0028] Further, step (3-2) specifically includes: using body weight and shell type index I=0.50-0.67 as indicators, selecting the next generation of parents from the selected first generation breeding families, and the number of the first generation parents selected is less than 8% of the total number of the selected first generation breeding families.

[0029] Further, the specific method for determining the age of 337±10 days in step (3) is: using the animal growth model to analyze and fit the growth curve of Hong Kong oysters, the results show that the age of inflection of Hong Kong oyster weight is 337±10 days, and the inflection weight is 55.32±5g, indicating that the weight growth rate of Hong Kong oysters at 337±10 days reaches the maximum, which can be used as an important parameter for early selection in the selection and breeding of Hong Kong oysters. Among them, the animal growth model includes three models: Logistic, Gompertz and VonBertalanffy, and the equations of the three models are all fitted and analyzed using SPSS software.

[0030] The beneficial effect of adopting the above further scheme is that the optimal selection time for the weight of Hong Kong oysters was determined to be 337±10 days of age. Compared with the traditional 3-year selection of parents, the breeding cycle of each generation is shortened by 2 years.

[0031] Furthermore, the animal growth model includes at least one of Logistic, Gompertz and Von Bertalanffy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the breeding roadmap of the present invention;

[0033] Figure 2 This is a diagram before the breeding of the present invention (shell type index 0.25-1.10, coefficient of variation = 30.95%);

[0034] Figure 3 This is the figure after breeding of the present invention (shell index 0.50-0.67, coefficient of variation = 8.74%);

[0035] Figure 4 This is a comparison chart between the growth rates of the Hong Kong oysters cultivated by the present invention and common oysters. DETAILED DESCRIPTION

[0036] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased through regular channels.

[0037] Example

[0038] First, it was determined that 330 days of age was the best time for parent selection for Hong Kong oysters, while in the traditional breeding process, at least three years are needed to carry out parent selection; then, while breeding high-yield traits, a breeding method for simultaneous composite shell shape traits was provided. This method can not only achieve the breeding of one generation of Hong Kong oysters per year, but also achieve the breeding of shell shape traits at the same time, significantly shortening the breeding process of Hong Kong oysters and improving breeding efficiency.

[0039] This embodiment relates to a method for composite breeding of high-yield and uniform-shelled Hong Kong oysters, comprising the following steps: Figure 1 ):

[0040] (1) Construction of basic population and core population: The wild population with rich genetic diversity is used as the basic population, and the body weight and shell type index are used as indicators to construct the core population;

[0041] (2) Large-scale family construction: using the core group as parents, selecting individuals with full glands, using artificial insemination to construct the first-generation breeding family, and cultivating and raising the offspring in the first-generation breeding family;

[0042] (3) Determination of offspring performance and selection of next-generation parents: The first-generation breeding family is cultivated to 337±10 days of age, and the next-generation parents are selected from the first-generation breeding family based on body weight and shell shape index;

[0043] (4) Construction of second to fourth generation breeding families: According to the records of steps (2) and (3), the construction of second to fourth generation breeding families is carried out in sequence. When the offspring in the fourth generation breeding family are grown, genetically stable, high-yielding Hong Kong oysters with uniform shell shape are obtained.

[0044] The present embodiment provides a method for composite breeding of high-yield Hong Kong oysters with uniform shell shape, including the following specific steps:

[0045] (1) The process of determining the best time to choose the age

[0046] ① The growth curve of Hong Kong oyster was analyzed and fitted using three animal growth models: Logistic, Gompertz and Von Bertalanffy (Table 1). The results showed that all three models could fit the weight growth curve of Hong Kong oyster well (R 2 >0.980), among which the Von Bertalanffy model had the best fitting effect (R 2 =0.992) (Table 2). In the Von Bertalanffy model, the inflection point age of Hong Kong oysters was 337.21 days old, and the inflection point weight was 55.32 g, indicating that the growth rate of oyster weight reached the maximum value at 337±10 days old, which can be used as an important parameter for early selection in the selective breeding process of Hong Kong oysters.

[0047] Table 1 Three growth models

[0048]

[0049]

[0050] ② The results of the correlation analysis of body weight at 200, 330, 540 and 700 days of age showed that after 330 days of age, there was a high positive correlation between different ages and body weight (P<0.001) (Table 3). Therefore, it was determined that for body weight traits, selection after 330 days of age was effective.

[0051] Table 2 Growth model of Hong Kong oyster

[0052]

[0053] Table 3 Correlation coefficients of weight at different ages of Hong Kong oysters

[0054]

[0055] Table 4 Correlation coefficients among quantitative traits of Hong Kong oysters

[0056]

[0057] Table 4 * Indicates significant correlation (P<0.05); ** Indicates extremely significant correlation (P<0.01).

[0058] As can be seen from Table 4, there is a significant positive correlation between the different traits of Hong Kong oysters, especially shell height and body weight. The correlation coefficient is the largest, reaching 0.841, and P < 0.01, reaching an extremely significant level.

[0059] (2) Construction of basic groups and core groups

[0060] In 2015, 5,800 wild Hong Kong oysters were collected from Maowei Sea in Guangxi. Based on the results of phenotypic trait measurements, 570 individuals with the largest body weight and excellent shell shape traits (shell shape index of 0.50-0.67) were selected to construct a core breeding group.

[0061] Among them, the phenotypic traits are measured by using a vernier caliper to measure the shell height, shell length, shell width and other dimensional traits. The weight trait is measured using an electronic balance. In this breeding process, the shell index I (value I = shell length / shell height) is used as the second auxiliary selection index. Combined with the previous market research, the shell type with the highest market recognition (shell index I range of 0.50-0.67) is selected as the selection target.

[0062] (3) Large-scale family construction

[0063] The selected core group was used as the parent, individuals with full glands were selected, and artificial insemination was used to construct a first-generation breeding family (F1 generation family). The male-female ratio was 1:1, and 115 full-sib families of F1 generation were constructed. The offspring were cultivated according to the Hong Kong oyster larvae cultivation method and cultivation method, with specific reference to patents ZL201922461189.5 and CN201711373547.6.

[0064] (4) Offspring performance measurement and parent selection

[0065] When the F1 generation families were cultivated to 330 days of age, the first generation parents (F1 parents) were selected. This selection simultaneously retained the individuals with the largest weight (high yield) and the best shell index (I = 0.50-0.67), and was carried out in two steps: family selection and individual selection; during family selection, 11 F1 generation families with the largest average weight were selected. Individual selection was carried out among the selected F1 generation families, and individuals with a shell index of 0.50-0.67 were retained. The number of selected individuals was less than 8% of the total number of the selected F1 generation family population.

[0066] (5) Construction of second to fourth generation breeding families (F2-F4 families)

[0067] After the parents were selected using the F1 parent selection method, full-sib F2 generation families were constructed according to the records in steps (3) and (4), and so on. From 2016 to 2018, 122, 135, and 129 families were constructed for the F2-F4 generations, respectively.

[0068] (6) Obtaining excellent new strains

[0069] When the offspring of the F4 generation family are grown, genetically stable, high-yield, and uniformly shaped Hong Kong oysters can be obtained. Performance test results show that the average weight of the F4 generation family is 143.93±12.86g, 21.53% higher than that of the control group, and the uniformity of the shell shape is 91.22±6.80%, while the uniformity of the shell shape of the control group is 43.53±2.58% ( Figure 2 and 3 ).

[0070] Comparison with the control group: Comparison of the growth rate of the Hong Kong oyster cultivated by the present invention with that of the common oyster (control group) ( Figure 4 ).

[0071] In summary, compared with the existing parent selection and breeding that requires 3 years of adult specifications, the present invention advances the parent selection to 337±10 days of age, which can significantly improve the breeding process, achieve 1 generation of breeding per year, and shorten the breeding cycle of Hong Kong oysters. The method of composite breeding of Hong Kong oysters of the present invention significantly improves the growth rate of Hong Kong oysters, increases the aquaculture output, improves the shell shape, and improves economic benefits. The method of the present invention is simple, easy to operate, low-cost, has broad market prospects, and is suitable for large-scale promotion in production.

[0072] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for composite breeding of high-yield and uniform-shelled Hong Kong oysters, characterized in that: The steps include: (1) Construction of basic population and core population: The wild population with rich genetic diversity is used as the basic population, and the body weight and shell type index are used as indicators to construct the core population; (2) Large-scale family construction: using the core group as parents, selecting individuals with full glands, using artificial insemination to construct the first-generation breeding family, and cultivating and raising the offspring in the first-generation breeding family; (3) Determination of offspring performance and selection of next-generation parents: The first-generation breeding family is cultivated to 337±10 days of age, and the next-generation parents are selected from the first-generation breeding family based on body weight and shell shape index; (4) Construction of second to fourth generation breeding families: According to the records of steps (2) and (3), the construction of second to fourth generation breeding families is carried out in sequence. When the offspring in the fourth generation breeding family are grown, genetically stable, high-yielding Hong Kong oysters with uniform shell shape are obtained.

2. A method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to claim 1, characterized in that: The number of the base population in step (1) is greater than 5,000.

3. The method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to claim 1, characterized in that: In step (1), the top 5 to 15% of individuals in terms of body weight and shell type index I=0.50-0.67 are selected from the basic population to construct a core population.

4. The method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to claim 1, characterized in that: In step (2), the number of the first generation breeding families is greater than 100.

5. A method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to any one of claims 1 to 4, characterized in that: Step (3) includes the following specific steps: (3-1) When the first generation of selected families are cultured to 337±10 days of age, the next generation of selected families are selected based on the average body weight of each of the first generation of selected families; (3-2) Using body weight and shell shape index as indicators, the next generation of parents is selected from the first generation breeding families that have been selected.

6. A method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to claim 5, characterized in that: Step (3-1) specifically includes: cultivating the first generation breeding families to 337±10 days of age, and selecting the first generation breeding families ranked top 5-15% based on the average body weight of each of the first generation breeding families.

7. A method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to claim 5, characterized in that: Step (3-1) specifically includes: when the first generation breeding families are cultured to 330 days of age, the first generation breeding families ranked in the top 10% are selected based on the average body weight of each of the first generation breeding families.

8. The method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to claim 5, characterized in that: Step (3-2) specifically includes: selecting the next generation of parents from the first generation of breeding families retained based on body weight and shell type index I=0.50-0.67, wherein the number of the first generation of parents selected is less than 8% of the total number of the first generation of breeding families retained.

9. The method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to claim 1, characterized in that: The specific method for determining the age of 337±10 days in step (3) is as follows: the growth curve of Hong Kong oysters was analyzed and fitted using an animal growth model. The results showed that the inflection point of the weight of Hong Kong oysters was 337±10 days, indicating that the weight growth rate of Hong Kong oysters reached the maximum value at 337±10 days.

10. A method for composite breeding of high-yield and uniform-shelled Hong Kong oysters according to claim 9, characterized in that: The animal growth model includes at least one of Logistic, Gompertz and Von Bertalanffy.

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