Breeding method for improving production performance of Qingxi black turtles

Abstract

The invention discloses a breeding method for improving the production performance of Qingxi black soft-shelled turtles. The body surfaces of Zhejiang black soft-shelled turtles obtained through backcross seed production and group subculture breeding are similar to those of the Qingxi black soft-shelled turtles, the backs of the Zhejiang black soft-shelled turtles are blue green, the Zhejiang black soft-shelled turtles are accompanied with golden sesame spot-shaped stripes, the bellies of the Zhejiang black soft-shelled turtles are dark gray, and the Zhejiang black soft-shelled turtles are obviously different from common Chinese soft-shelled turtles in appearance. The two main production performances, namely the culture survival rate and the growth speed, are greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aquatic breeding, and in particular relates to a breeding method for improving the production performance of Qingxi black softshell turtle. Background Art

[0002] Qingxi black turtle, a rare species originating from the Taihu Lake Basin, is a new species bred by selectively selecting black individuals from the Taihu flower turtle. Its external features are a unique black-gray abdomen, which is highly recognizable, rich in nutritional value, and has huge market potential. It is rated as one of the top ten famous aquatic breeding species in Zhejiang Province. However, its shortcomings are also obvious. 1. It has a cruel and aggressive personality. Under the high-density breeding mode, self-mutilation is relatively serious, resulting in a low survival rate in breeding; 2. Compared with the Japanese strain of Chinese soft-shelled turtle and the Taihu flower turtle, its growth rate is slower, resulting in lower production, which seriously restricts its promotion and expansion. To this end, based on the many years of breeding and production of Qingxi black turtle and Japanese strain of Chinese soft-shelled turtle, we have selected a body color feature that is very similar to Qingxi black turtle through backcrossing seed production + group succession breeding; under the high-density breeding mode, a new black turtle variety (tentatively named "Zhewu No. 2") with a high survival rate and a faster growth rate is used for breeding promotion and application. Summary of the invention

[0003] In view of the problems existing in the prior art, the purpose of the present invention is to provide a breeding method for improving the production performance of Qingxi black softshell turtle, which is specifically achieved by the following method:

[0004] 1. Backcross seed production

[0005] (1) Construction of the parent used in hybrid breeding - Zhexin Flower Softshell Turtle (F1 generation)

[0006] The purpose of this stage is to integrate the genes of the Japanese strain of Chinese soft-shelled turtle to increase the growth rate of the offspring. Using the existing Japanese strain of Chinese soft-shelled turtle (variety registration number: GS03-001-2007) and Qingxi black soft-shelled turtle (variety registration number: GS-01-003-2008) as the selection lines, the Japanese strain of Chinese soft-shelled turtle with a faster growth rate is selected as the female parent and the Qingxi black soft-shelled turtle is selected as the male parent for hybridization. The male-female ratio is controlled at 7:1, and the hybrid first generation (F1 generation) is obtained, namely the Zhejiang New Flower Soft-shelled Turtle (variety registration number: GS02-005-2015), whose abdominal pattern and body color characteristics are intermediate between the parents. The female offspring of the Zhejiang New Flower Soft-shelled Turtle are selected as the female parent for subsequent backcross breeding and are raised separately.

[0007] (2) Select Zhexin Flower Turtle as the female parent and Qingxi Black Turtle as the male parent for backcrossing to obtain the second generation of hybrid offspring (F2 generation, G0 generation used for subsequent breeding)

[0008] The purpose of this stage is to purify the body color traits of the offspring and increase the growth rate. After three years of breeding, the offspring with fast growth rate were selected as the subsequent breeding population. According to the characteristics of maternal inheritance of the body color characteristics of Chinese soft-shelled turtle, the Zhejiang New Flower Turtle was selected as the female parent and the Qingxi Black Turtle was selected as the male parent for backcross breeding. The male-female ratio was controlled at 7:1 to obtain the second generation of backcross (F2 generation). At this time, the characteristics of pattern and body color appeared in the offspring - that is, one kind of abdominal pattern and body color was similar to the Qingxi Black Turtle, defined as the group F2-1, which accounted for about 1 / 4; one kind of abdominal pattern and body color was similar to the Zhejiang West Flower Turtle, defined as the group F2-2, which accounted for about 3 / 4. The F2-1 group was selected as the subsequent succession breeding parent (G0 generation) for breeding and seed preservation.

[0009] 2. Group Succession Breeding

[0010] (1) The G0 population is selected to obtain the G1 generation

[0011] The purpose of this stage is to purify the pattern and body color traits of the offspring while taking into account the improvement of growth rate. After three years of breeding, the G0 generation group selects the offspring individuals with fast growth rate as the subsequent breeding group, and the male-female ratio is controlled at 7:1 to obtain the next generation (G1 generation) of successive breeding. At this time, the separation of pattern and body color traits appears in the next generation, that is, one abdominal pattern and body color similar to the Qingxi black softshell turtle is defined as the G1-1 group, which accounts for about 1 / 2; one abdominal pattern and body color is similar to the Zhejiang flower softshell turtle, which is defined as the G1-2 group, which accounts for about 1 / 2. The G1-1 group is selected as the subsequent breeding parent for breeding and seed preservation.

[0012] (2) Subsequent breeding of the G1 population to obtain the G2 generation

[0013] The purpose of this stage is to purify the body color traits of the offspring while taking into account the improvement of growth rate. After three years of breeding, the G1 generation group selects the offspring individuals with fast growth rate as the subsequent breeding group, and the male-female ratio is controlled at 7:1 to obtain the second generation (G2 generation) of successive breeding. At this time, the second generation of offspring showed separation of patterns and body color traits, that is, one abdominal pattern and body color similar to the Qingxi black softshell turtle was defined as the G2-1 group, which accounted for about 9 / 10; one abdominal pattern and body color similar to the Zhejiang flower softshell turtle was defined as the G2-2 group, which accounted for about 1 / 10. The G2-1 group was selected as the subsequent breeding parent for breeding and seed preservation.

[0014] (3) The G2 population is selected to obtain the G3 generation

[0015] The purpose of this stage is to purify the body color traits of the offspring and take into account the improvement of growth rate. After three years of cultivation, the G2 generation group selects the offspring individuals with fast growth rate as the subsequent breeding group, and the male-female ratio is controlled at 7:1 to obtain the third generation (G3 generation) of successive breeding. At this time, there will be no separation of the traits of pattern and body color in the third generation, that is, all the abdominal patterns and body colors are similar to the Qingxi black turtle and are defined as the G3 group, with a pattern and body color purification rate of 100%. The G3 group is cultivated and seed preserved as the subsequent breeding parent.

[0016] (4) The G3 population was selected to obtain the G4 generation

[0017] The purpose of this stage is mainly to increase the growth rate. After three years of breeding, the G3 generation group selects the offspring individuals with fast growth rate as the subsequent breeding group, with a retention rate of 50%, and the male-female ratio is controlled at 7:1, to obtain the fourth generation (G4 generation) of successive breeding. At this time, there will be no separation of the characteristics of pattern and body color in the fourth generation, that is, all the abdominal patterns and body colors are similar to those of the Qingxi black turtle, which is defined as the G4 group, and the pattern and body color purification rate is 100%. The G4 group is used as the subsequent breeding parent for breeding and seed preservation.

[0018] (5) Subsequent breeding of the G4 population to obtain the G5 generation

[0019] The purpose of this stage is mainly to increase the growth rate. After three years of breeding, the G4 generation group selects the offspring individuals with fast growth rate as the subsequent breeding group, with a retention rate of 20%, and the male-female ratio is controlled at 7:1, to obtain the fifth generation (G5 generation) of successive breeding. At this time, there will be no separation of patterns and body color in the fourth generation, that is, all abdominal patterns and body colors are similar to those of Qingxi black soft-shelled turtles and are defined as the G4 group, with a pattern and body color purification rate of 100%. The body color and growth rate of the G5 generation have been greatly improved compared with the Qingxi black soft-shelled turtle.

[0020] The external features of the "Zhewu No. 2" bred by the present invention are basically similar to those of the Qingxi black turtle, but compared with the Qingxi black turtle, the back of the "Zhewu No. 2" is green with golden sesame-like spots and the abdomen is dark gray. Compared with the common Chinese soft-shelled turtle, it is easy to distinguish. By integrating the genes of the Japanese strain of Chinese soft-shelled turtle, the breeding survival rate, growth rate and individual reproductive capacity of the "Zhewu No. 2" are greatly improved.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The body color of "Zhewu No. 2" and Qingxi black soft-shell turtle is basically similar, and it is easy to distinguish and identify it from the common Chinese soft-shell turtle;

[0023] 2) Under the high-density breeding mode, the survival rate of the G4 generation of "Zhewu 2" was 21.54% higher than that of the Qingxi black turtle;

[0024] 3) Under the high-density breeding mode, the growth rate of the G4 generation of "Zhewu 2" increased by 11.10% compared with the Qingxi black soft-shell turtle. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the overall breeding technology roadmap for "Zhewu No. 2";

[0026] Figure 2 The statistics of breeding effects of body color and pattern traits of black turtles in G0-G3 generations;

[0027] Figure 3 This is the external morphology of the parents, Zhejiang New Flower Turtle and offspring during the breeding process of "Zhewu No. 2". DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with specific embodiments.

[0029] Embodiment: The breeding of "Zhewu No. 2", its breeding process is as follows Figure 1 The external morphology of the parents, Zhexin Flower Turtle and offspring during the breeding process is shown in Figure 3 shown.

[0030] Step 1: Constructing the parent used in backcross breeding --- Zhexin Flower Turtle (F1 generation)

[0031] In order to integrate the high survival rate and fast growth rate of the Japanese strain of Chinese soft-shelled turtle into the black soft-shelled turtle, 60 Qingxi black soft-shelled turtles were selected as males and 350 Japanese strains of Chinese soft-shelled turtles were selected as females for cross breeding, and the female parent used in subsequent backcross breeding, the Zhejiang New Flower Soft-shelled Turtle, was obtained. The abdomen of the Zhejiang New Flower Soft-shelled Turtle has large black spots; under the same breeding conditions, the growth rate of young turtles of the same size after 16 months of breeding is more than 14.0% higher than that of the female parent and 35% higher than that of the male parent (hybrid advantage).

[0032] Step 2: Construct the parent used for successive breeding --- successive generation line (G0 generation)

[0033] In order to further purify the unique body color traits of black soft-shelled turtles and improve their growth rate, 1,600 Zhexin flower soft-shelled turtles with faster growth rates were selected as female parents and 400 Qingxi black soft-shelled turtles as male parents for hybrid seed production to obtain parents for subsequent sub-generation breeding. Body color and pattern traits will separate in this group, and the offspring with body color characteristics similar to Qingxi black soft-shelled turtles will be selected for seed preservation and used as the G0 generation for subsequent sub-generation breeding.

[0034] Step 3: Body color purification and breeding

[0035] In order to obtain offspring with body color characteristics similar to those of black soft-shell turtles and a faster growth rate, 4,000 offspring similar to black soft-shell turtles and larger in size were selected from the G0 offspring, and a parent ratio of 7:1 between male and female was adopted for subgeneration group selection. 50% of the resulting G1 offspring were similar to the Qingxi black soft-shell turtle, with body color and pattern characteristics of a completely black abdomen; 50% were similar to the Zhexin flower soft-shell turtle, with body color and pattern characteristics of large black spots on the abdomen.

[0036] 2,000 large-sized turtles similar to the black turtle were selected from the G1 offspring, and a male-female ratio of 7:1 was used for subgeneration group selection. 90% of the resulting G2 offspring were similar to the Qingxi black turtle, with a body color and pattern characterized by a completely black abdomen; 10% were similar to the Zhexin flower turtle, with a body color and pattern characterized by large black spots on the abdomen.

[0037] 2,000 G2 offspring with larger bodies similar to black turtles were selected and bred in succession using a male-female ratio of 7:1. The resulting G3 offspring were basically all similar to Qingxi black turtles, with a body color and pattern characteristic of a completely black abdomen.

[0038] After three generations of successive breeding, the body color purification effect reached 99%. 25 "Zhewu No. 2" and Qingxi black turtles were randomly selected, and the abdominal colors of the two were quantitatively analyzed using the CR400 colorimeter of CHROMA METER. The abdominal colors of the two were basically similar. The body color traits of Zhejiang No. 2 and Qingxi black turtle during the breeding process are statistically shown in Figure 2. Figure 2 and Table 1.

[0039] Table 1. Statistical table of abdominal color index of "Zhewu 2-G3" and Qingxi black softshell turtle (n=25)

[0040]

[0041] Note: L indicates the depth of color, a indicates red-green, and b indicates yellow-blue

[0042] Step 4: Breeding for faster growth

[0043] After three consecutive generations of breeding, the pattern and body color characteristics of "Zhewu No. 2" are basically similar to those of Qingxi Black Turtle. Since "Zhewu No. 2" incorporates the genes of the Japanese strain of Chinese soft-shelled turtle, the G3 generation of "Zhewu No. 2" has shown the effect of breeding to increase growth rate. In 2016, under the ecological breeding mode of the sun greenhouse, the stocking density was 4 / m 2 Under the conditions, the specific growth rate of the G3 generation of "Zhewu 2" in the juvenile turtle stage (1 year of breeding) was 4.89% higher than that of the Qingxi black turtle; in the young turtle stage (2 years of breeding), its specific growth rate was 14.14% higher than that of the Qingxi black turtle (see Table 2).

[0044] Table 2: Growth comparison between the “Zhewu 2” breeding line and Qingxi black turtle

[0045]

[0046] 4,800 larger individuals were selected from the G3 offspring, and a parent ratio of 7:1 between male and female was adopted for successive group breeding. After one year of breeding, the larger offspring of the G4 offspring were selected as reserve parents for separate breeding. After another two years of breeding, the offspring of individual replacement were selected as parents. The cumulative retention rate at this stage was 50%.

[0047] 8,000 larger individuals were selected from the G4 offspring, and a parent ratio of 7:1 between males and females was adopted for successive group breeding. After one year of breeding, the larger offspring of the G5 offspring were selected as backup parents for separate breeding. After two years of breeding, the offspring of individual replacement were selected as parents. The cumulative retention rate at this stage was 20%. After five generations of successive breeding, a new variety of black soft-shelled turtle with a high survival rate and fast growth rate was obtained - "Zhewu No. 2". In 2022, under the temperature-controlled breeding mode in cement pools, the stocking density will be 18 / m 2 Under the conditions of , the growth rate of the G4 generation of "Zhewu 2" in the juvenile turtle stage (9 months of breeding) was 11.10% higher than that of the Qingxi black turtle; under high-density breeding, its survival rate was 21.54% higher than that of the Qingxi black turtle (see Table 3).

[0048] Table 3: Growth comparison between the “Zhewu 2” breeding line and Qingxi black turtle

[0049]

Claims

1. A breeding method for improving the production performance of Qingxi black softshell turtle, characterized in that The breeding method comprises the following steps: 1) Backcross seed production 1-1) Select the Japanese strain of Chinese soft-shell turtle with a faster growth rate as the female parent and the Qingxi black soft-shell turtle as the male parent for hybridization to obtain the hybrid first generation, namely the Zhejiang New Flower Soft-shell Turtle F1 generation; 1-2) Select Zhexin Flower Turtle as the female parent and Qingxi Black Turtle as the male parent for backcrossing to obtain the second generation of hybrids, i.e., F2 generation, as the G0 generation used for subsequent breeding; among the G0 generation population, the population with abdominal patterns and body colors similar to those of Qingxi Black Turtle is defined as G0-1 ​​population; the population with abdominal patterns and body colors similar to those of Zhexi Flower Turtle is defined as G0-2 population; 2) Group succession breeding 2-1) Select the G0-1 ​​population as the subsequent succession breeding parent, and obtain the G1 generation with separated traits of pattern and body color after population breeding; among the G1 generation population, the population with abdominal pattern and body color similar to Qingxi black softshell turtle is defined as the G1-1 population; the population with abdominal pattern and body color similar to Zhejiang flower softshell turtle is defined as the G1-2 population; 2-2) Selecting the G1-1 population as the subsequent breeding parent for breeding and seed preservation, obtaining the G2 generation with separated traits of pattern and body color in the successive breeding, and defining the G2-1 population with abdominal pattern and body color similar to that of Qingxi black softshell turtle; defining the G2-2 population with abdominal pattern and body color similar to that of Zhejiang flower softshell turtle; 2-3) Select the G2-1 population as the subsequent breeding parent for breeding and seed preservation, and obtain the G3 generation with all abdominal patterns and body colors similar to those of the Qingxi Black Turtle; the patterns and body colors of the individuals in this generation are basically similar to those of the Qingxi Black Turtle, and there is no separation of pattern and body color traits; 2-4) The G3 generation population is used as the subsequent breeding parent for breeding and seed preservation to obtain the G4 generation with all abdominal patterns and body colors similar to the Qingxi black softshell turtle; 2-5) The G4 generation group is used as the subsequent breeding parent for breeding and seed preservation, and the G5 generation with all abdominal patterns and body color similar to the Qingxi Black Turtle is obtained through continuous breeding, that is, the improved Qingxi Black Turtle.

2. The method for breeding a Qingxi black softshell turtle for improving its production performance as claimed in claim 1, characterized in that In each step of backcross seed production and group succession breeding, the male-female ratio is controlled at 7:

1.

3. The method for breeding a Qingxi black softshell turtle for improving its production performance as claimed in claim 1, characterized in that Each group of G0, G1, G2, G3, and G4 must undergo three years of breeding before being used as breeding parents.

4. The method for breeding a Qingxi black softshell turtle for improving its production performance as claimed in claim 1, characterized in that In step 1-1), the purpose is to purify the body color and shape of the offspring and to increase the growth rate.

5. The method for breeding a Qingxi black softshell turtle for improving its production performance as claimed in claim 1, characterized in that Step 2-1) focuses on purifying the pattern and body color traits of the offspring while taking into account increasing the growth rate; Step 2-2) and Step 2-3) both focus on purifying the body color traits of the offspring while taking into account increasing the growth rate; Step 2-4) and Step 2-5) both focus on increasing the growth rate.

6. The method for breeding a Qingxi black softshell turtle for improving its production performance as claimed in claim 1, characterized in that The improved Qingxi black turtle that was bred has a green back with golden sesame-like markings and a dark gray abdomen.

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