CN102301969A - Method for cultivating hybridized and backcrossed marine product fries - Google Patents

Abstract

The present invention relates to a method for cultivating sea hybrid backcross commercial seedlings, which is characterized by selecting excellent individuals from the first-generation family or population of hybrids of purple scallops and bay scallops that only develop in the female area, and synchronously promoting them with the excellent individuals of bay scallops. Then use the method of conventional drying in the shade and temperature stimulation to induce the ovulation of the first generation of hybrid offspring to obtain unfertilized eggs; at the same time stimulate the oviposition and ovulation of the bay scallop, and then use a 500-mesh sieve to filter the bay scallop semen; the above-mentioned hybrid offspring The eggs of the first generation are fertilized with the sperm of the bay scallop, and after the fertilized eggs are hatched, they are cultivated according to conventional methods, and the backcross seedlings of sea hybrids with a shell height of more than 1.5 cm can be obtained for commercial breeding. The sea hybrid backcross commercial seed cultivated by the present invention has the characteristics of bay scallop and purple scallop at the same time, and has significant advantages over purple scallop in terms of growth, individual size and temperature tolerance, so it can be used in northern sea areas, such as Qingdao, Dalian and other sea areas are cultivated, and the output of the year is more than 50% higher than that of bay scallops.

Description

Breeding method of sea hybrid backcross commercial seed

technical field

The invention belongs to the breeding technology of shellfish aquaculture, and in particular relates to a method for cultivating sea hybrid backcross commercial seedlings.

Background technique

Bay scallops (Argopecten irradians irradians) are native to the Atlantic coast of the United States and were introduced to my country in 1982. The bay scallop grows fast, has a wide range of temperature adaptability, and has strong stress resistance. It is very suitable for farming in the northern seas of my country. At present, the output and farming area account for more than 50% of the scallop farming in my country. Due to the long-term inbreeding after the introduction, the germplasm of bay scallops has been severely degraded during the breeding process, showing that the size of commercial shellfish is getting smaller and smaller, and the mortality rate in the breeding process is high. For example, in 2007, the mortality rate of bay scallop broodstock reached about 70%. , so the scallop farming industry urgently needs genetic improvement of bay scallops, among which cross-breeding is one of the most effective methods.

The inventor introduced the purple scallop (Argopecten purpuratus) from Peru for the first time in 2007. The purple scallop is a fast-growing medium-sized scallop native to the South Pacific. Both belong to the genus Argopecten with the bay scallop. They have the same number of chromosomes and are both hermaphrodites. However, they complement each other in terms of individual size, growth and temperature adaptability. Therefore, the inventors crossed the purple scallop with the bay scallop to produce two kinds of hybrid offspring generation: orthogonal (purple scallop ovum and bay scallop sperm fertilization) and reverse cross (sea scallop ovum and purple scallop sperm fertilization). The first generation of hybrids grows faster, and the individuals are larger. Some individuals only develop in the female area, and only release eggs when they are sexually mature and are fertile (Wang Chunde et al., 2009. Studies on interspecific hybridization of purple scallops and bay scallops. Marine Science, 33(10 ): 84-87; Chunde Wang et al., 2011. Introduction of the Peruvian scallop and its hybridization with the bay scallop in China, Aquaculture, 2011, 310: 380-387).

Further studies have shown that although the first generation of hybrids can produce greater heterosis, there are still two major difficulties in large-scale promotion. First of all, because the temperature adaptation range of the imported purple scallop is very narrow, it cannot spend summer in Qingdao and the sea area south of it, and it cannot survive winter in the sea area north of Qingdao. difficulty. Secondly, since bay scallops and purple scallops are both hermaphroditic scallops and release sperm and eggs at the same time, the eggs are easily polluted by the same kind of sperm, and it is difficult to obtain a large number of unfertilized eggs for interspecific hybridization, resulting in the commercial seedlings obtained The proportion of true hybrid offspring is greatly reduced, which greatly limits the increase in yield.

Contents of the invention

The purpose of the present invention is to provide a practical method for cultivating commercial sea hybrid backcross seedlings, so as to make up for the deficiencies in the existing technology of producing hybrid scallop commercial seedlings by using purple scallops and bay scallops.

The present invention is based on the following ideas: 1) Firstly, the conventional method of cultivating bay scallops from 4°C to 19°C before laying eggs is abandoned, and by studying the temperature adaptation characteristics of the first generation of hybrid scallops , specially selected to cultivate the first generation of hybrid broilers from 10°C, and gradually increased to 17°C before spawning; 2) In the first generation of hybrids of purple scallops and bay scallops, some individuals only developed in the female area and the eggs discharged were fertile , so that the purple scallop can be replaced by a fertile individual of the hybrid offspring that is easy to cultivate, and a large number of unfertilized eggs with fertilization ability can be obtained conveniently; 3) The sperm and eggs of the bay scallop are different in size, and can be obtained by filtering with 500 mesh sieves Egg-free semen; 4) 100% backcross commercial seed can be obtained by backcrossing unfertilized eggs of the first generation of hybrids with bay scallop sperm, which can realize convenient and efficient production of hybrid seed; finally 5) the obtained The sea hybrid backcross commercial seed of the invention has significant advantages in growth, individual size and temperature tolerance.

The technical scheme of the present invention is: select excellent individuals from the first generation of hybrid families or populations of purple scallops and bay scallops that only develop in the female area, and promote ripening synchronously with the excellent individuals of hermaphroditic bay scallops; then use conventional shade drying and temperature stimulation The method of inducing the ovulation of the first generation of hybrids above to obtain unfertilized eggs; at the same time stimulating the oviposition and ovulation of bay scallops, and then filtering with a 500-mesh sieve to obtain the bay scallop semen; fertilizing the eggs of the first generation of hybrids obtained above with the sperm of bay scallops After the fertilized eggs are hatched, carry out larval cultivation and intermediate cultivation of seedlings according to conventional methods to obtain commercial seedlings of sea hybrid backcross with significant heterosis; Gradually increase to 17°C before eggs.

The sea hybrid backcross commercial seed cultivated by the present invention has the characteristics of bay scallop and purple scallop at the same time, and has significant advantages over purple scallop in terms of growth, individual size and temperature tolerance, so it can be used in northern sea areas such as Qingdao, Dalian and other sea areas. Farming, and the annual output can be increased by more than 50% compared with the bay scallop.

Detailed ways

Operation method or steps of the present invention are as follows:

1) Selection and maturation of parent scallops: select large individual hybrid scallops from the families or populations of orthogonal (fertilization of purple scallop ova and bay scallop sperm) or inverse cross (fertilization of bay scallop ova and purple scallop sperm), and select Large individual bay scallop broodstock were brought into the water body of the nursery room at the beginning of January, the stocking density was 100/m ³ , and the broodstock was selected to be bred from 10°C. Feed single-celled algae such as Phaeodactylum tricornutum and flat algae with a concentration of 2-3 million cells/ml 6 times a day, 15 liters/m ³ each time, change one-third of the water every day, and pour water every 6 days. Once the pool is continuously inflated with an air compressor. Cultivate at 10°C for 10 days and then the gonads start to expand and then start to heat up, increasing the temperature by 0.5°C every day. When the temperature rises to 17°C, the gonads are close to maturity. Gradually increase the amount of bait until the scallops reach sexual maturity.

2) Cultivation of sea hybrid backcross commercial seedlings: select more than 50 scallops with mature gonads, large individuals, and only the first generation of scallops with gonads developed in the female area, and dry them in the shade for 30 minutes. In the cement pool of seawater, make it spawn. Then select more than 20 bay scallops with mature gonads, place them in a plastic bucket with seawater at 23°C in advance, and filter them with a 500-mesh sieve after laying eggs and ejaculating to collect the semen without bay scallop eggs. Add a small amount of bay scallop semen to the eggs, stir to mix the sperm and eggs evenly, observe under a microscope so that there are 5-6 sperm around each egg, place the fertilized eggs in a dark environment for incubation, and carry out larval cultivation and seedlings according to conventional methods Intermediate cultivation can obtain sea hybrid backcross commercial seedlings with a shell height of more than 1.5 cm, which can be used for commercial cultivation.

Example 1

Mature purple scallops were collected at the end of March 2008, and purple scallop eggs were obtained after temperature stimulation. After insemination with the sperm of bay scallops, the first generation seedlings of purple scallops (eggs) and bay scallops (sperm) were obtained, and adult shellfish were obtained. In the spring of 2009, scallops that are large in size and only developed in the female area will be selected from the above-mentioned first-generation hybrid scallops, and the eggs will be obtained after drying in the shade and temperature stimulation, and fertilized with the sperm of the bay scallop, and the first-generation hybrid and bay scallop backcross commercial seedlings. By the end of November, 2009, the shell height, shell length, shell width and body weight of the backcross commercial seed of the present invention were 26.5%, 27.5%, 16.2% and 91.30% larger than the bay scallop selfing population cultivated in the same period respectively (Table 1 ).

Table 1 Comparison of the phenotypes of sea hybrid backcross commercial seedlings and bay scallop populations in the same period (n=30)

Claims (2)

1. the assorted breeding method of commodity seed of backcrossing in sea is characterized in that selecting from the hybridization first filial generation family of purple scallop and bay scallop or the defect individual of the only female district growth in the colony, with the synchronous accelerating of hermaphroditic bay scallop defect individual; Dry in the shade and the thermal stimulus method is induced the individual ovulation in above-mentioned hybridization first filial generation with conventional again, obtain unfertilized egg; Stimulate bay scallop laying eggs row smart simultaneously, take 500 mesh sieve thin,tough silk then and filter acquisition bay scallop seminal fluid; With the ovum and the fertilization of bay scallop sperm of the hybridization first filial generation of above-mentioned acquisition, carry out larvae cultivation and seed intermediate rearing according to conventional method behind the incubating oosperm, promptly obtain to have the remarkable heterotic sea commodity seed of backcrossing of mixing; Above-mentioned synchronous accelerating is to cultivate hybridization first filial generation parent shellfish since 10 ℃, before laying eggs, brings up to 17 ℃ gradually.

2. the extra large assorted breeding method of commodity seed of backcrossing is characterized in that concrete steps are following:

1) selection of close shellfish and accelerating: from the family that obtained with purple scallop ovum and bay scallop sperm or bay scallop ovum and the fertilization of purple scallop sperm or colony, select big individual hybridization first filial generation scallop; Select big individual bay scallop parent shellfish simultaneously; Including in the seedling rearing room water body at the beginning of 1 month, storing up density is 100/m ³, select to cultivate close shellfish since 10 ℃; Dividing the concentration of throwing something and feeding for 6 times every day is the unit cell algae such as Phaeodactylum tricornutum and flat algae of 200-300 ten thousand cells/ml, and 15 liters/m throws something and feeds at every turn ³, change water 1/3rd every day, fell a pond in per 6 days, use the air compressor continuous charge; After 10 days sexual glands of 10 ℃ of cultivations begin to expand, begin to heat up, improve 0.5 ℃ every day, sexual gland is near ripe when waiting to be raised to 17 ℃, and the feeding volume that increases bait gradually reaches sexual maturity up to scallop;

2) cultivation of the assorted commodity seed of backcrossing in sea: select 50 above gonadal maturations, the individual first filial generation parent shellfish that only has female district to grow than big and sexual gland, dry in the shade stimulation 30 minutes places the cement pit that adds 23 ℃ of seawater in advance with these scallops, and it is laid eggs; Select the bay scallop of 20 above gonadal maturations again; Place the Plastic Drum that adds 23 ℃ of seawater in advance; The smart back of the row of laying eggs is with 500 purpose silk cover filterings; Collect the seminal fluid that does not contain the bay scallop ovum; In the ovum of hybridization first filial generation, add a spot of bay scallop seminal fluid then; Stirring mixes smart ovum; Microscopically has 5-6 sperm around observing and making each ovum; Fertilized egg is placed hatching under the dark surrounds; Carry out larvae cultivation and seed intermediate rearing by conventional method, promptly get the assorted commodity seed of backcrossing in the sea that is used for the commercialization breed.