A seed production method for improving the survival rate of northern oysters in summer
By building self-cultivation and hybrid oyster groups in the northern sea area, and selecting the sea area with the highest summer survival rate for hybridization and backcrossing, the problem of low summer survival rate in northern oysters is solved, and a significant increase in oyster survival rate and reduced industrial risks are achieved.
Patent Information
- Application Number
- CN202311019627.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-14
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2043-08-14
AI Technical Summary
Northern oysters have significant survival rates in summer, and the prior art is difficult to steadily improve their survival rates in multiple sea areas.
The self-cultivation population GG and hybrid population GA were constructed through artificial insemination, and co-cultivated in multiple northern sea areas to test the summer survival rate. The population with the highest ratio was selected as parents, and further hybridization and backcrossing were constructed to construct the population GG*GA to improve the summer survival rate of oysters.
It significantly improves the summer survival rate of northern oysters, reduces the risks of the oyster industry, and has the advantages of strong environmental targeting, low costs and short cycles.
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of shellfish genetic breeding, and in particular relates to a seed production method for improving the summer survival rate of northern oysters. Background Art
[0002] Currently, the primary oyster cultivated in northern my country is the Crassostrea gigas, the world's most cultivated oyster (China Aquatic Products, 2021). The causes of large-scale oyster die-offs during summer are complex and a key constraint to the development of the global oyster industry. Genetic improvement and the cultivation of new germplasm are crucial for improving oyster survival rates during the summer.
[0003] The summer survival rate of the same oyster germplasm varies significantly across different aquaculture areas, and existing resistant strains are insufficiently stable. Therefore, there is an urgent need to cultivate oyster germplasm with consistently excellent summer survival rates suitable for use in multiple typical waters of northern my country. Therefore, this paper systematically studies the differentiated summer survival rates of different oyster strains across multiple typical northern waters, and proposes a seed production method that effectively improves the summer survival rate of northern oysters. Summary of the Invention
[0004] The invention aims to solve the increasingly significant summer mortality phenomenon of oysters in northern my country and proposes a seed production method for improving the summer survival rate of northern oysters.
[0005] To achieve the above purpose, the present invention adopts the following technical solutions:
[0006] A seed production method for improving the summer survival rate of northern oysters is characterized by: collecting the main cultured oysters in northern and southern my country as basic populations, using artificial fertilization to respectively construct a self-propagated population GG of the main cultured northern oysters and a hybrid population GA of the two oysters; the two populations are co-cultured in multiple northern sea areas, and their summer survival rates are tested; individuals from the two populations cultured in a northern sea area are selected as parents based on the summer survival rates, and then artificial fertilization is used to respectively construct population GG and population GG*GA; the two populations are co-cultured in multiple northern sea areas, and their summer survival rates are tested; based on the ratio of the summer survival rate of population GG*GA to that of population GG in each sea area, individuals from population GG*GA in the sea area with the highest ratio are selected as oyster germplasm with improved summer survival rate in the north.
[0007] The summer survival rate of the germplasm selected by the above method is more than 40% higher than that of the main oyster varieties cultured in the north.
[0008] The basic population of oysters cultured in the north is collected from the top 10% of long oysters by weight in the northern oyster farming areas where large-scale deaths occur in summer, and the basic population of oysters cultured in the south is collected from the wild Fujian oysters naturally distributed in the intertidal zone and high tide area of the southern Fujian sea area as the parent population.
[0009] The female parents of the hybrid population GA are female individuals of the northern oyster Crassostrea gigas, and the male parents are male individuals of the Fujian oyster.
[0010] The self-propagated group GG and the hybrid group GA of the two oysters are cultured simultaneously in each of the multiple northern sea areas, and the summer survival rate ratio of the group GA to the group GG in each culture sea area is tested, and the group in the sea area with the highest ratio is selected for use.
[0011] The parents of the GG*GA group are both from the sea area with the highest summer survival rate ratio between the GA group and the GG group in the aquaculture sea area, wherein the female parents are female individuals of the long oyster (i.e., the main oyster cultured in the north), and the male parents are male individuals of the GA group.
[0012] The constructed group GG and group GG*GA are cultured in multiple northern sea areas, and group GG and group GG*GA are cultured at the same time in each northern sea area. The ratio of the summer survival rate of group GG*GA and group GG in each sea area is tested, and the group in the sea area with the highest ratio is selected.
[0013] The summer survival rate mentioned in the present invention refers to the ratio of oysters that survive the summer to the total number of oysters that originally survived the summer. Compared with the existing technology, the present invention has the following advantages and positive effects:
[0014] This study proposes to obtain germplasm that improves the summer survival rate of northern oysters by utilizing inter-subspecific hybridization and backcrossing to differentiate summer survival traits. Cultivation of this germplasm significantly increases the summer survival rate of northern Chinese oysters. Compared to conventional selective breeding techniques, this method offers advantages such as strong environmental specificity, low cost, short cycle time, and high efficiency. In summary, this method can rapidly improve the summer survival rate of northern Chinese oysters and significantly reduce the risks of the oyster industry. DETAILED DESCRIPTION
[0015] The present invention will be further described below in conjunction with specific examples. It should be understood that the following examples are provided to further illustrate the present invention, rather than to limit the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalents fall within the scope limited by the appended claims of the application.
[0016] The northern long oyster used in the embodiment of the present invention is the long oyster in the Qingdao sea area in northern my country, specifically the long oyster cultivated in the Huangdao sea area of Qingdao City, which can be obtained through public channels.
[0017] Example 1:
[0018] In November 2019, 8,000 long oysters were randomly collected in the Huangdao sea area of Qingdao City, where a large-scale death occurred in the summer. The top 10% of 800 individuals were selected based on individual weight as the selection criterion as the alternative parents of long oysters; in April 2020, 1,000 adult shellfish of the Fujian oyster group cultured at the high tide level of the intertidal zone in Zhangzhou were collected as alternative parents of Fujian oysters.
[0019] In March 2020, the two groups were placed in indoor seawater maturation tanks at 10°C and 15°C, respectively. The temperature of both groups was raised by 0.5-1.5°C daily. When the water temperature of the maturation tank for the long oyster reached 22°C and that of the Fujian oyster reached 26°C, the gonads of both groups reached synchronous maturation. 100 individuals from each group were randomly collected, and the gonads of each individual, including the long oyster and the Fujian oyster, were collected. The sex of each individual was determined under a microscope, and eggs or sperm were collected from each individual. After the eggs were matured in seawater for 30 minutes, sperm-contaminated individuals or hermaphrodites were removed. A certain amount of eggs from each individual in the same group were pooled and divided into equal portions equal to the number of males required for mating. Sperm from each individual was used for artificial insemination with the pooled eggs. After hatching, equal numbers of D-type larvae from each group were collected and pooled together to form a single group. The above methods were used to construct GG and GA populations respectively, in which the female and male parents of the GG population were both long oyster populations, the female parents of the GA population were female individuals of long oysters, and the male parents were male individuals of Fujian oysters.
[0020] Each population was propagated using conventional artificial oyster seeding methods and then tested for summer survival using clamp-rope culture in the Huangdao, Qingdao, Jimo, Weihai, Rongcheng, and Muping districts of Yantai. Two populations were cultured simultaneously in each district. The ratios of GA to GG summer survival rates for the Huangdao, Qingdao, Jimo, Weihai, Rongcheng, and Muping districts were 2.62, 1.86, 1.63, and 2.32, respectively. From these four districts, individuals from the two Huangdao, Qingdao, and Rongcheng districts with the highest GA to GG summer survival ratios were selected as parents.
[0021] In February 2021, GG and GA populations cultured in the Huangdao waters of Qingdao were collected. 600 individuals weighing more than 50g with intact shells were selected as candidate parents. The collected GG populations were placed in indoor seawater maturation tanks at 10°C, and the GA populations were placed in indoor seawater maturation tanks at 15°C. The temperature of each population was increased by 0.5-1.5°C daily, and the temperature was increased synchronously for 30-60 days to achieve synchronous gonadal maturation. 100 individuals with mature gonads were randomly collected from the GG and GA populations, and the gonads of each individual were collected. The sex of each individual was determined under a microscope, and eggs or sperm were collected from each individual. After the eggs were placed in seawater for 30 minutes to mature, sperm-contaminated or hermaphroditic individuals were removed. A certain amount of eggs from each individual in the same group were pooled and divided equally into a number of portions equal to the number of males required for mating. Sperm from each individual was then artificially inseminated with the pooled eggs. After hatching, equal amounts of D-type larvae from each group were pooled together to form a single group. Using this method, GG and GG*GA groups were constructed. The female and male parents of the GG group were both from the Crassostrea gigas population in the Huangdao area of Qingdao. The female parents of the GG*GA group were female Crassostrea gigas populations in the Huangdao area of Qingdao, and the male parents were males from the GA population in the Huangdao area of Qingdao. During the juvenile period, the groups were cultured with ropes in Qingdao Jimo Sea Area, Weihai Rongcheng Sea Area and Yantai Muping Sea Area for summer survival rate tests. That is, two groups were cultured in each sea area at the same time, and the summer survival rates of the two groups in the tested sea areas reached a significant level of difference. Among them, the ratios of the summer survival rates of the groups GG*GA to the group GG in Qingdao Huangdao Sea Area, Weihai Rongcheng Sea Area and Yantai Muping Sea Area were 2.11, 1.63 and 1.47 respectively, that is, the summer survival rate of the group GG*GA was 47%-111% higher than that of the group GG. The Huangdao Sea Area with the highest ratio was selected as the excellent germplasm, and the GG*GA group in Qingdao Huangdao Sea Area was obtained as the oyster germplasm with improved summer survival rate in the north.
[0022] Comparative Example:
[0023] In November 2019, 8,000 long oysters were randomly collected in the Huangdao sea area of Qingdao City, where a large-scale death occurred in the summer. The top 10% of 800 individuals were selected based on individual weight as the selection criterion as the alternative parents of long oysters; in April 2020, 1,000 adult shellfish of the Fujian oyster group cultured at the high tide level of the intertidal zone in Zhangzhou were collected as alternative parents of Fujian oysters.
[0024] In March 2020, the two groups were placed in indoor seawater maturation tanks at 10°C and 15°C, respectively. The temperature of both groups was raised by 0.5-1.5°C daily. When the water temperature of the maturation tank for the long oyster reached 22°C and that of the Fujian oyster reached 26°C, the gonads of both groups reached synchronous maturation. 100 individuals from each group were randomly collected, and the gonads of each individual, including the long oyster and the Fujian oyster, were collected. The sex of each individual was determined under a microscope, and eggs or sperm were collected from each individual. After the eggs were matured in seawater for 30 minutes, sperm-contaminated individuals or hermaphrodites were removed. A certain amount of eggs from each individual in the same group were pooled and divided into equal portions equal to the number of males required for mating. Sperm from each individual was used for artificial insemination with the pooled eggs. After hatching, equal numbers of D-type larvae from each group were collected and pooled together to form a single group. The above method was used to construct GG and AG populations respectively, where the female and male parents of the GG population were both long oyster populations, the female parents of the AG population were female individuals of the Fujian oyster, and the male parents were male individuals of the long oyster.
[0025] Each population was propagated using conventional artificial oyster seeding methods and then tested for summer survival using clamp-line culture in the Huangdao, Weihai, and Muping, Yantai, waters. Two populations were cultured simultaneously in each waters. The ratios of summer survival rates of the AG to GG populations in the Huangdao, Weihai, and Muping, Yantai, waters were 1.98, 1.78, and 2.00, respectively. Individuals from the two populations in the Huangdao, Qingdao, waters with the second highest AG to GG ratio were selected as parents.
[0026] In February 2021, GG and AG groups cultured in the Huangdao sea area of Qingdao were collected, and 600 individuals weighing more than 50g with intact shells were selected as candidate parents. The collected GG groups were placed in an indoor seawater maturation pool at 10°C, and the AG groups were placed in an indoor seawater maturation pool at 15°C. The temperature of each group was increased by 0.5-1.5°C every day, and the temperature was increased synchronously for 30-60 days to achieve synchronous gonadal maturation of each group. 100 individuals with mature gonads were randomly collected from the GG and AG groups, and the gonads of each individual were collected. The sex of each individual was distinguished under a microscope, and the eggs or sperm of each individual were collected. After the eggs were placed in seawater for 30 minutes to mature, sperm-contaminated or hermaphroditic individuals were removed. A certain amount of eggs from each individual in the same group were mixed and then divided into equal portions equal to the number of males required for mating. Sperm from each individual was used for artificial insemination with the mixed eggs. After hatching, equal amounts of D-type larvae from each group were mixed to form a single group. The above methods were used to construct GG and GG*AG groups, respectively. The female and male parents of the GG group were both from the Crassostrea gigas population in the Huangdao area of Qingdao. The female parents of the GG*AG group were female Crassostrea gigas from the Huangdao area of Qingdao, and the male parents were male individuals from the AG group in the Huangdao area of Qingdao. During the juvenile period, the groups were cultured with ropes in Qingdao Jimo Sea Area, Weihai Rongcheng Sea Area and Yantai Muping Sea Area for summer survival rate tests. That is, two groups were cultured in each sea area at the same time, and the summer survival rates of the groups in the tested sea areas all reached a significant level of difference. Among them, the ratios of the summer survival rates of the GG*AG groups to the GG groups in Qingdao Huangdao Sea Area, Weihai Rongcheng Sea Area and Yantai Muping Sea Area were 1.38, 1.65 and 1.28 respectively. It was concluded that the GG*AG group in Qingdao Huangdao Sea Area is an oyster germplasm with improved summer survival rate in the north.
[0027] Combining Example 1 and the comparative example, it can be found that the summer survival rate of oysters of the group GG*GA in Example 1 is significantly higher than that of the comparative group GG*AG in all tested sea areas. The main differences are the mating methods of the hybrid group GA or AG parents of the two embodiments and the standards for selecting the sea areas of the group GA or AG as parents. This shows that only when the female parents of the hybrid GA are female individuals of the long oyster and the male parents are male individuals of the Fujian oyster, and the parents of the two groups in the sea area with the highest ratio of the summer survival rate of the group GA to the group GG are selected for hybridization, and mating and parent selection are performed according to the steps of this patent, can the summer survival rate of oysters be significantly improved.
[0028] The above are only specific embodiments of the invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using the concept shall be deemed as an infringement of the protection scope of the present invention.
Claims
1. A method for producing seeds to improve the survival rate of northern oysters during summer, characterized by: Oysters cultured in northern and southern my country were collected as base populations, and artificial insemination was used to construct a self-propagated population GG of the northern main cultured oyster and a hybrid population GA of the two oysters. The two populations were co-cultured in multiple northern sea areas, and their summer survival rates were tested. Based on the summer survival rates, individuals from the two populations cultured in a certain northern sea area were selected as parents. Artificial insemination was then used to construct populations GG and GG*GA, respectively. The two populations were co-cultured in multiple northern sea areas, and their summer survival rates were tested. Based on the ratio of the summer survival rates of population GG*GA to population GG in each sea area, individuals from the population GG*GA in the sea area with the highest ratio were selected as oyster germplasm with improved summer survival rates in the north. The female parents of the hybrid population GA are female individuals of the northern oyster Crassostrea gigas, and the male parents are male individuals of the Fujian oyster.
2. The method for producing seeds for improving the survival rate of northern oysters during summer according to claim 1, characterized in that: The basic population of oysters cultured in the north is collected from the top 10% of long oysters by weight in the northern oyster farming areas where large-scale deaths occur in summer as the parent population of northern oysters; the basic population of oysters cultured in the south is collected from the wild Fujian oysters naturally distributed in the intertidal zone and high tide area of the southern Fujian sea area as the parent population.
3. The method for producing seeds for improving the survival rate of northern oysters during summer according to claim 1, characterized in that: The self-propagated group GG and the hybrid group GA of the two oysters are cultured simultaneously in each of the multiple northern sea areas, and the summer survival rate ratio of the group GA to the group GG in each culture sea area is tested, and the group in the sea area with the highest ratio is selected for use.
4. The method for producing seeds for improving the survival rate of northern oysters during summer according to claim 1 or 3, characterized in that: The parents of the GG*GA group are both from the sea area with the highest summer survival rate ratio between the GA group and the GG group in the aquaculture sea area, wherein the female parent is the female individual of the long oyster, and the male parent is the male individual of the GA group.
5. The method for producing seeds for improving the survival rate of northern oysters during summer according to claim 1, characterized in that: The constructed group GG and group GG*GA are cultured in multiple northern sea areas, and group GG and group GG*GA are cultured at the same time in each northern sea area. The ratio of the summer survival rate of group GG*GA and group GG in each sea area is tested, and the group in the sea area with the highest ratio is selected.