Rapid breeding method of sex-limited egg color silkworm variety

Abstract

The invention discloses a rapid breeding method of a sex-limited egg color silkworm variety, the whole breeding process is simple in operation technology, the selection of male and female eggs can be completed by adopting a technical route, and only the male backcross of a practical strain is needed after the parent generation P is hybridized to G4; the test cross inspection method is simple, the operability is high, and the detection selection method is accurate; the method also has the advantage of short breeding time, the breeding time is shortened by 5 generations compared with the prior art, the third white egg gene w3 is simultaneously introduced into the original-original mother strain of the current excellent practical variety through hybridization, backcross and test cross modes to obtain the sex-limited white egg original-original mother strain with excellent characters (10 generations of breeding), and finally the sex-limited white egg original-original mother strain is hybridized according to the original practical variety seed production form to obtain the sex-limited white egg original-original mother strain. The variety is a sex-limited egg color variety with excellent economic characters (black eggs are female eggs, and white eggs are male eggs).

Description

Technical Field

[0001] The invention relates to the technical field of silkworm breeding, and in particular to a method for rapid breeding of sex-limited egg-color silkworm varieties. Background Art

[0002] my country's sericulture industry has a long history, and it is an important part of the integrated development of industry and agriculture. The selection and breeding of excellent silkworm varieties is an important technology to support the development of the silk industry. Realizing the control of the sex of silkworms is of great significance to the production of silkworms: cocoon breeding can realize the separation of male and female silkworms, without the need for pupae identification, alleviating the contradiction between centralized employment and the shortage of technical workers for pupae identification, and saving production costs; the proportion of male and female silkworms can be appropriately adjusted according to the characteristics of silkworm seeds to improve the seed production coefficient; silk cocoon breeding can realize the separation of male and female silkworms, and separate reeling, improving the quality of raw silk; female silkworms can also be used to produce dead silkworms, increasing the yield of dead silkworms; raising male silkworms exclusively, with a high leaf-silk conversion rate, male silkworm cocoons can be used to reel high-quality raw silk, and male moths can be used for other medicinal purposes, etc., to improve economic benefits.

[0003] The sex determination of silkworms is female heterogametic, that is, the sex chromosomes of female silkworms are ZW type, and the sex chromosomes of male silkworms are ZZ type. Among them, the W chromosome has the function of completely determining femaleness. Using the female determination function of the W chromosome, domestic and foreign scholars have carried out research on the creation of a sex-limited system for silkworms. The breeding methods for silkworm varieties that achieve sex control include: sex-limited markings, sex-limited cocoon colors, sex-linked red ants, balanced lethal male silkworms, sex-limited egg colors, etc.

[0004] However, each method has certain limitations:

[0005] (1) Sex-limited spotted varieties are sex-limited in larval spotted varieties. They need to be sexed and raised separately during the 3rd to 5th instar larval stages of the silkworms, which requires a lot of labor. Due to the shortage of labor, sex-limited silk production is basically not feasible to identify male and female silkworms. (2) Sex-limited cocoon color varieties have yellow female cocoons and white male cocoons. Yellow cocoons can be used to reel colored silk or make "golden" silk quilts. At present, this type of variety can only be promoted and applied as a special variety, and the market share is extremely small. (3) Sex-linked red ants. High temperature induction of greening causes the death of female silkworms, which can be used to raise male silkworms exclusively. However, the utilization rate of silkworm seeds is only 50%, and the production cost is high. At the same time, high temperature induction of greening may induce silkworm diseases. (4) Balanced lethal silkworm varieties. Female silkworms die during the induction period or the first instar. Male silkworms can be raised exclusively, but they have certain limitations in large-scale production. Mainly because all female silkworms die, the number of silkworms per silkworm seed is only half of that of ordinary silkworm seeds, resulting in a doubling of silkworm seed production costs. (5) Existing sex-limited egg color technology, such as the method for breeding sex-limited white egg silkworm varieties suitable for separate rearing of male and female silkworms and separate reeling of male and female cocoons disclosed in the Chinese patent application publication specification CN114190339B, uses the Chinese system of existing excellent silkworm varieties and the Chinese sex-limited white egg material as materials, and introduces the sex-limited white egg gene through hybridization and backcrossing to obtain the sex-limited white egg Chinese system with excellent traits; uses the Japanese system of existing excellent silkworm varieties and the Japanese sex-limited white egg material as materials, and introduces the sex-limited white egg gene through hybridization and backcrossing to obtain the sex-limited white egg Japanese system with excellent traits; hybridizes the obtained sex-limited white egg Chinese system and Japanese system with excellent traits to obtain a hybrid, which is a sex-limited white egg variety with excellent economic traits and suitable for separate rearing of male and female silkworms and separate reeling. This invention breeds four times a year, and the breeding of sex-limited white egg silkworm varieties and strains can be completed within four years. However, the G1 to G9 generations of males and females are separated into two technical routes, which is relatively complicated to operate. In the process of breeding male silkworms, hybridization, backcrossing, and self-pollination are carried out alternately, and the mating order is complicated and prone to errors. Therefore, a rapid breeding method for limited sex egg color silkworm varieties is urgently needed. Summary of the invention

[0006] The purpose of the present invention is to provide a method for rapid breeding of sex-limited egg-color silkworm varieties, which solves the problems raised in the above-mentioned background technology.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions:

[0008] A method for rapidly breeding a sex-limited egg-color silkworm variety comprises the following steps:

[0009] S1. Use the male (black eggs ZZ++) of the current practical variety and the female (white eggs ZW +w3 w3 / w3) hybrid G1 (F1) silkworm eggs show black eggs (ZW +w3 + / w3, ZZ+ / w3);

[0010] S2, G1 (F1) mixed breeding, female silkworms (ZW +W3 + / w3) was backcrossed with a male of a practical variety (ZZ++), and the G2 (BC1) eggs were black eggs (ZW +w3 ++、ZW +w3 + / w3, ZZ++, ZZ+ / w3);

[0011] S3, G2 (BC1) mixed breeding, female silkworms (ZW +w3 ++、ZW +w3 + / w3) was backcrossed with a male of a practical variety (ZZ++), and the G3 (BC2) eggs were black eggs (ZW +w3 ++、ZW +w3 + / w3, ZZ++, ZZ+ / w3);

[0012] S4 and G3 (BC2) were used for single moth rearing. Ten moth rearing areas were randomly numbered and the female moths (ZW +w3 ++、ZW +w3 + / w3) were backcrossed with male silkworms of practical varieties to produce backcross silkworms G4 (BC3), and the other part was tested with male white egg material (ZZ w3 / w3) or male moths (ZZ++, ZZ+ / w3) were tested with female white egg material (ZW +w3 w3 / w3) to conduct test mating (test cross) and observe the egg color of the test cross silkworm eggs when they change to the inherent color. If the test cross egg color is completely black, the backcross silkworm species G4 (BC3) (♀ZW +w3 ++;♂ZZ++) elimination, such as the test cross silkworm eggs have white eggs in the moth area, the corresponding backcross silkworm species G4 (BC3) (♀ZW +w3 ++、ZW +w3 + / w3; ♂ZZ++, ZZ+ / w3) selection, the test cross in the rearing moth area only needs to test cross females or test cross males, and the test cross method can be determined according to the number of females and males in the rearing single moth area and the sex-limited white egg material;

[0013] S5, G4 (BC3) single moth breeding, repeat step 4, select the moth selection area G5 (BC4) (♀ZW +w3 ++、ZW +w3 + / w3; ♂ZZ++, ZZ+ / w3);

[0014] S6, G5 (BC4) single moth breeding, self-fertilization to produce G6 (black eggs: ZW +w3 ++、ZW +w3 + / w3, ZW +w3 w3 / w3, ZZ++, ZZ+ / w3; white egg: ZZw3 / w3);

[0015] S7, select the G6 moth area with black and white eggs for mixed breeding, and continue self-pollination, or separate the black and white eggs and raise them separately and then self-pollinate. +w3 w3 / w3) mates with white-egg male moths (ZZ w3 / w3), the ratio of black and white eggs produced is about 1:1, which is the selected G7 generation (ZW +w3 w3 / w3, ZZ w3 / w3);

[0016] Single moth breeding of S8, G7-G10 generations uses conventional breeding methods, combining moth area selection with individual selection, stabilizing the biological and economic traits of the strain, focusing on the silk quality of cocoons in spring, and the robustness in summer and autumn; G10 self-pollination breeds the original mother stock of the limited sex white egg practical strain with stable biological traits and excellent economic traits;

[0017] S9. The original mother stocks bred are mated according to the mating method of the original practical strains, and the first-generation hybrids are economically excellent sex-limited egg silkworm varieties, black eggs are female eggs, and white eggs are male eggs. During the conventional breeding of G9-G10, combination hybridization experiments are carried out. If there are new combinations with outstanding economic traits, they can be combined into new economically excellent sex-limited egg silkworm varieties.

[0018] Further preferably, the individual selection in step S8 includes individual weighing to select the total cocoon amount, cocoon layer amount, cocoon layer rate and using the ZHJ-20 intelligent live pupa reeling machine to perform live pupa reeling to select individual silk length, relaxation, fineness and knotting.

[0019] In summary, the present invention has the following beneficial effects:

[0020] First, the operation technology of the present invention is simple, and the selection of male and female eggs can be completed by one technical route. After P hybridization to G4, only the male backcross of the practical strain needs to be performed.

[0021] Secondly, the test cross inspection method of the present invention is simple and easy to operate, and the detection and selection method is accurate.

[0022] Third, the breeding time of the present invention is short. The breeding time is shortened by 5 generations compared with the prior art. Through hybridization, backcrossing and test cross, the third white egg gene w3 is simultaneously introduced into the original mother stock of the current excellent practical variety to obtain the limited sex white egg original mother stock with excellent traits (10 generations of breeding). Finally, hybridization is carried out according to the seed production form of the original practical variety to obtain the economic trait excellent limited sex egg variety, in which the black eggs are female eggs and the white eggs are male eggs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the breeding process of the limited-sex egg-color silkworm variety in the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0025] Embodiment 1, the rapid breeding method of "Yunxia 3" and "Yuncan 11" limited sex egg color silkworm varieties, comprises the following steps:

[0026] S1, respectively use the original female male (S1A, Xinxiu B, etc.) (black eggs ZZ++) of the current practical varieties "Yunxia No. 3" and "Yuncan No. 11" and the female (white eggs ZW +w3 w3 / w3) hybrid G1 (F1) silkworm eggs show black eggs (ZW +w3 + / w3, ZZ+ / w3);

[0027] S2, G1 (F1) mixed breeding, female silkworms (ZW +W3 + / w3) was backcrossed with a male of a practical variety (ZZ++), and the G2 (BC1) eggs were black eggs (ZW +w3 ++、ZW +w3 + / w3, ZZ++, ZZ+ / w3);

[0028] S3, G2 (BC1) mixed breeding, female silkworms (ZW +w3 ++、ZW +w3 + / w3) was backcrossed with a male of a practical variety (ZZ++), and the G3 (BC2) eggs were black eggs (ZW +w3 ++、ZW +w3 + / w3, ZZ++, ZZ+ / w3);

[0029] S4 and G3 (BC2) were used for single moth rearing. Ten moth rearing areas were randomly numbered and the female moths (ZW +w3 ++、ZW +w3 + / w3) were backcrossed with male silkworms of practical varieties to produce backcross silkworms G4 (BC3), and the other part was tested with male white egg material (ZZ w3 / w3) or male moths (ZZ++, ZZ+ / w3) were tested with female white egg material (ZW +w3 w3 / w3) to conduct test mating (test cross) and observe the egg color of the test cross silkworm eggs when they change to the inherent color. If the test cross egg color is completely black, the backcross silkworm species G4 (BC3) (♀ZW +w3 ++;♂ZZ++) elimination, such as the test cross silkworm eggs have white eggs in the moth area, the corresponding backcross silkworm species G4 (BC3) (♀ZW +w3 ++、ZW +w3 + / w3; ♂ZZ++, ZZ+ / w3) selection, the test cross in the rearing moth area only needs to test cross females or test cross males, and the test cross method can be determined according to the number of females and males in the rearing single moth area and the sex-limited white egg material;

[0030] S5, G4 (BC3) single moth breeding, repeat step 4, select the moth selection area G5 (BC4) (♀ZW +w3 ++、ZW +w3 + / w3; ♂ZZ++, ZZ+ / w3);

[0031] S6, G5 (BC4) single moth breeding, self-fertilization to produce G6 (black eggs: ZW +w3 ++、ZW +w3 + / w3, ZW +w3 w3 / w3, ZZ++, ZZ+ / w3; white egg: ZZw3 / w3);

[0032] S7, select the G6 moth area with black and white eggs for mixed breeding, and continue self-pollination, or separate the black and white eggs and raise them separately and then self-pollinate. +w3 w3 / w3) mates with white-egg male moths (ZZ w3 / w3), the ratio of black and white eggs produced is about 1:1, which is the selected G7 generation (ZW +w3 w3 / w3, ZZ w3 / w3);

[0033] Single moth breeding in the S8, G7-G10 generations uses conventional breeding methods, combining moth area selection with individual selection, stabilizing the biological and economic traits of the strain, focusing on the silk quality of cocoons in spring, and the robustness in summer and autumn; G10 self-pollination breeds the original mother stocks of the limited-sex white egg practical strains with stable biological traits and excellent economic traits ("S1A limited", "Xinxiu B limited", etc.), and the breeding process is shown in Tables 1 and 2;

[0034] S9. The bred original mother stocks are mated according to the mating method of the original practical breed, and the first-generation hybrids are the economically excellent sex-limited egg silkworm varieties "Yunxia No. 3 Limit" and "Yuncan No. 11 Limit" (black eggs are female eggs, and white eggs are male eggs).

[0035] It should also be noted that: during the conventional breeding of G9~G10, combination hybridization experiments are carried out simultaneously. If there are new combinations with outstanding economic traits, they will be new restricted egg color varieties.

[0036] Table 1 Breeding of original mother species-limited white egg S1A-limited

[0037]

[0038] Note: S1A is the original mother seed of the current economic and practical variety "Yunxia No. 3"

[0039] Table 2 Breeding of original mother species limited white egg rookie B limited

[0040]

[0041]

[0042] Note: Xinxiu B is the Japanese original mother seed of the current economic and practical variety "Yuncan No. 11"

[0043] Tables 1 and 2 only list the process of introducing and breeding the sex-limited genes into one of the original mother stocks of "Yunxia No. 3" and "Yuncan No. 11". In actual operation, the third white egg gene w3 is simultaneously introduced into the eight original mother stocks of the current excellent and practical varieties "Yunxia No. 3" and "Yuncan No. 11", and hybridization, backcrossing and test cross are performed. In G9 and G10, in addition to conventional breeding, hybridization experiments are carried out at the same time. Finally, hybridization is carried out in the form of seed production of the original practical varieties, namely, the economically excellent sex-limited egg color varieties "Yunxia No. 3" and "Yuncan No. 11" (black eggs are female eggs, and white eggs are male eggs); in the hybrid combination experiment, if there is a new combination with outstanding economic traits, it is a new sex-limited egg color variety.

[0044] This specific embodiment is only an explanation of the present invention, not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A method for rapid breeding of sex-limited egg color silkworm varieties, characterized in that: The following steps are involved: S1. Use the male (black eggs ZZ++) of the current practical variety and the female (white eggs ZW +w3 w3 / w3) hybrid G1 (F1) silkworm eggs show black eggs (ZW +w3 + / w3, ZZ+ / w3); S2, G1 (F1) mixed breeding, female silkworms (ZW +W3 + / w3) and the male of the practical variety (ZZ++), the G2 (BC1) eggs are black eggs (ZW +w3 ++、ZW +w3 + / w3, ZZ++, ZZ+ / w3); S3, G2 (BC1) mixed breeding, female silkworms (ZW +w3 ++、ZW +w3 + / w3) was backcrossed with a male of a practical variety (ZZ++), and the G3 (BC2) eggs were black eggs (ZW +w3 ++、ZW +w3 + / w3, ZZ++, ZZ+ / w3); S4 and G3 (BC2) were used for single moth rearing. Ten moth rearing areas were randomly numbered and the female moths (ZW +w3 ++、ZW +w3 + / w3) were backcrossed with male silkworms of practical varieties to produce backcross silkworms G4 (BC3), and the other part was tested with male white egg material (ZZ w3 / w3) or male moths (ZZ++, ZZ+ / w3) were tested with female white egg material (ZW +w3 w3 / w3) to conduct test mating (test cross) and observe the egg color of the test cross silkworm eggs when they change to the inherent color. If the test cross egg color is completely black, the corresponding backcross silkworm species G4 (BC3) (♀ZW +w3 ++;♂ZZ++) elimination, such as the test cross silkworm eggs have white eggs in the moth area, the corresponding backcross silkworm species G4 (BC3) (♀ZW +w3 ++、ZW +w3 + / w3; ♂ZZ++, ZZ+ / w3) selection, the test cross in the rearing moth area only needs to test cross females or test cross males, and the test cross method can be determined according to the number of females and males in the rearing single moth area and the sex-limited white egg material; S5, G4 (BC3) single moth breeding, repeat step 4, select the moth selection area G5 (BC4) (♀ZW +w3 ++、ZW +w3 + / w3; ♂ZZ++, ZZ+ / w3); S6, G5 (BC4) single moth breeding, self-fertilization to produce G6 (black eggs: ZW +w3 ++、ZW +w3 + / w3, ZW +w3 w3 / w3, ZZ++, ZZ+ / w3; white egg: ZZ w3 / w3); S7, select the G6 moth area with black and white eggs for mixed breeding, and continue self-pollination, or separate the black and white eggs and raise them separately and then self-pollinate. +w3 w3 / w3) mates with white-egg male moths (ZZ w3 / w3), the ratio of black and white eggs produced is about 1:1, which is the selected G7 generation (ZW +w3 w3 / w3, ZZ w3 / w3); Single moth breeding of S8, G7-G10 generations uses conventional breeding methods, combining moth area selection with individual selection, stabilizing the biological and economic traits of the strain, focusing on the silk quality of cocoons in spring, and the robustness in summer and autumn; G10 self-pollination breeds the original mother stock of the limited sex white egg practical strain with stable biological traits and excellent economic traits; S9. The bred original mother stocks are mated according to the mating method of the original practical breed, and the first-generation hybrids are the economically excellent sex-restricted egg silkworm varieties, in which black eggs are female eggs and white eggs are male eggs. While the conventional breeding of G9~G10 is in progress, combination hybridization experiments are carried out. If there are new combinations with outstanding economic traits, they can be combined into new economically excellent sex-restricted egg silkworm varieties.

2. The method for rapid breeding of sex-limited egg-color silkworm varieties according to claim 1, characterized in that: The individual selection in step S8 includes individual weighing to select the total cocoon amount, cocoon layer amount, cocoon layer rate and using the ZHJ-20 intelligent live pupa reeling machine to select the individual silk length, relaxation, fineness and knotting.

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