Breeding method for effectively improving cocoon quality of natural green cocoon

Abstract

The application discloses a breeding method for effectively improving natural green cocoon quality, and belongs to the technical field of breeding of Bombyx mori varieties, and comprises the following steps: using natural green cocoon preservation varieties and high-quality white cocoon basic varieties, adopting a common breeding method of hybridization and backcross to obtain a first natural green cocoon strain; selecting the natural green cocoon preservation varieties and the high-quality white cocoon basic varieties, and adopting a common breeding method of single hybridization to obtain a second natural green cocoon strain; in order to improve cocoon quality and further make cocoon quality reach a breeding target, realizing mechanical reeling of natural green cocoon, the second natural green cocoon strain and the first natural green cocoon strain are used to obtain a third natural green cocoon strain with better cocoon quality by using a single hybridization method of natural green cocoon strain x natural green cocoon strain. The application effectively improves cocoon quality of the natural green cocoon of the middle strain or the Japanese strain, realizes mechanical reeling of the natural green cocoon in Guangxi, and fills the gap of poor cocoon quality of the natural green cocoon in Guangxi and the inability of mechanical reeling.

Description

Technical Field

[0001] This invention relates to the field of silkworm breeding technology. More specifically, this invention relates to a breeding method for effectively improving the quality of natural green cocoons from Chinese and Japanese silkworm breeds. Background Technology

[0002] Silk is one of the products of ancient Chinese civilization. In people's general impression, natural silk is "pure white and smooth," and most of the silk on the international market is currently white silk. China has a long history of using colored cocoons, and its resources of colored cocoon varieties are abundant. Records of using colored cocoons can be found in almost the entire process of sericulture development. Naturally colored cocoon silk is the queen of natural fibers, with bright colors, noble and elegant. Its pigment comes from mulberry leaves, is a natural pigment, non-toxic and harmless, and has a soft and bright color. Fabrics made from it do not require dyeing, avoiding the environmental pollution caused by printing and dyeing.

[0003] Silkworm cocoon colors can be divided into three main categories: white cocoons with little or no pigment; yellow-red cocoons formed by the deposition of carotenoids, such as golden cocoons, flesh-colored cocoons, pink cocoons, and rust-colored cocoons; and green cocoons formed by the deposition of flavonoid compounds.

[0004] Natural green silkworm cocoons possess superior moisturizing, UV-absorbing, and antibacterial properties, along with a powerful antioxidant effect—more than 30 times higher than cotton fiber, unmatched by any other colored silk. Using green silkworm cocoons to make underwear or cosmetics offers excellent skincare benefits. Controlling the formation of flavonoid pigments in green cocoons can not only lower blood lipids, improve microcirculation, and enhance immunity, but also promote vasodilation, provide antioxidant effects, and slow aging. Furthermore, the silkworm pupae from green cocoons are highly nutritious and have a wide range of uses, potentially increasing the profitability of silkworm farming. Therefore, natural green cocoons have extremely high research and application value.

[0005] Currently, the cultivation of green cocoon varieties is mainly achieved through genetic methods. For example, Chinese Patent No. CN 102986602 B discloses a method for cultivating natural green cocoon silkworm varieties, which achieves the cultivation of green cocoon silkworm varieties by introducing specific genes. However, the naturally preserved green cocoon varieties in the variety resources have thin cocoon layers and many defective cocoons such as thin-headed cocoons, pointed-headed cocoons, and cottony cocoons, which cannot be mechanically reeled and do not meet the conditions for direct promotion and application. Therefore, practical modification is necessary. Summary of the Invention

[0006] One objective of this invention is to provide an effective breeding method for improving the quality of natural green cocoons from Chinese or Japanese breeds, thereby enabling the mechanical reeling of natural green cocoons, especially those from Guangxi.

[0007] The breeding of Chinese or Japanese natural green cocoon varieties generally adopts the following methods: hybridization and backcrossing between natural green cocoon preservation varieties and white cocoon base varieties, or single hybridization between natural green cocoon preservation varieties and white cocoon base varieties.

[0008] (1) Hybridization and backcrossing of natural green cocoon preservation varieties with white cocoon base varieties: Select white cocoon base varieties with excellent comprehensive traits and natural green cocoon preservation varieties with dark green cocoon color and strong resistance for hybridization and backcrossing. The quality of the natural green cocoon strains bred has been improved, but it has not met the breeding target requirements. In addition, there are many poor cocoons with light color, thin head cocoons, and cotton, and the cocoon shape is not uniform enough, so mechanical reeling is not possible.

[0009] (2) Single hybridization method between natural green cocoon preservation varieties and white cocoon base varieties: Natural green cocoon preservation varieties with dark green cocoon color and strong resistance were selected and hybridized with white cocoon base varieties with excellent comprehensive traits. The quality of the natural green cocoon strains was significantly improved, the cocoon color was dark green, the rate of poor cocoon thin head cocoon and the rate of cotton cocoon were significantly reduced, and the total cocoon weight, cocoon layer weight and cocoon layer rate were improved. However, the cocoon shape was not uniform enough and the expected breeding goal was not achieved.

[0010] The breeding method of this invention for effectively improving the quality of natural green cocoons of Chinese or Japanese lines involves two additional steps compared to conventional breeding methods. It combines a natural green cocoon strain bred through a single cross between a preserved natural green cocoon variety and a basic white cocoon variety, with another natural green cocoon strain bred through a cross and backcross between the preserved natural green cocoon variety and a basic white cocoon variety. This is achieved through a single cross ("natural green strain × natural green cocoon strain") under high temperature and humidity conditions, and through systematic selection. This further improves the quality of the natural green cocoons and fixes the overall traits, resulting in a Chinese or Japanese natural green cocoon strain. The total cocoon weight, cocoon layer weight, and cocoon layer rate are significantly increased; the cocoon color is deep and uniform; the cocoon shape is neat; and the rate of thin-headed cocoons is low, achieving the expected breeding goals.

[0011] To achieve these objectives and other advantages according to the present invention, a breeding method for effectively improving the quality of natural green cocoons is provided, applicable to both Chinese and Japanese natural green cocoons, comprising:

[0012] The first natural green cocoon strain was formed by selecting a white cocoon base variety with excellent comprehensive traits and a natural green cocoon preservation variety, and by using hybridization and backcrossing breeding methods and systematic selection to improve the cocoon quality and comprehensive traits of the natural green cocoon.

[0013] The second natural green cocoon strain was formed by selecting a natural green cocoon variety with dark green cocoon color and strong resistance, and a white cocoon base variety with excellent comprehensive traits. Through single crossbreeding and systematic selection, the quality of natural green cocoons and comprehensive traits were improved and fixed.

[0014] The second and first natural green cocoon strains were selected, and a single crossbreeding method of natural green cocoon strain × natural green cocoon strain was adopted. Through systematic selection, the cocoon quality and comprehensive traits of the natural green cocoons were further improved and fixed to form a third natural green cocoon strain with better cocoon quality.

[0015] This invention provides a breeding method for effectively improving the quality of natural green cocoons from China, comprising:

[0016] Hybridization and backcrossing of the white cocoon base variety with the preserved Chinese natural green cocoon variety: Selecting the Chinese white cocoon base variety and the preserved Chinese natural green cocoon variety with excellent comprehensive traits, and adopting the breeding method of Chinese × Chinese hybridization and backcrossing, through systematic selection, the cocoon quality and comprehensive traits of the Chinese natural green cocoon were improved and fixed to form the first Chinese natural green cocoon strain; the total cocoon weight, cocoon layer weight, and cocoon layer rate were improved, but did not meet the breeding target requirements, and there were many poor cocoons such as thin-headed cocoons and cottony cocoons, and the cocoon color was light, which could not be mechanically reeled, and further improvement is needed;

[0017] Japanese natural green cocoon preservation varieties and Chinese basic varieties were crossbred: Japanese natural green cocoon preservation varieties with deep green cocoon color and strong resistance and Chinese white cocoon basic varieties with excellent comprehensive traits were selected. A Japanese × Chinese single crossbreeding breeding method was adopted. After systematic selection, the cocoon quality and comprehensive traits of Chinese natural green cocoons were improved and fixed to form a second Chinese natural green cocoon strain. The total cocoon weight, cocoon layer weight and cocoon layer ratio were significantly improved, and the poor cocoons such as thin-headed cocoons and cottony cocoons were significantly reduced. The cocoon color was deep green, but the cocoon shape was not uniform enough and needed further improvement.

[0018] Chinese natural green cocoon strain and Chinese natural green cocoon strain single hybridization: In order to further improve the cocoon quality of Chinese natural green cocoons and make the cocoon quality of Chinese natural green cocoons reach the breeding target, the second Chinese natural green cocoon strain and the first Chinese natural green cocoon strain were selected, and the Chinese × Chinese single hybridization breeding method was used again. Through systematic selection, the cocoon quality of Chinese natural green cocoons was further improved and the comprehensive traits were fixed to form a third Chinese natural green cocoon strain with better cocoon quality. The total cocoon weight, cocoon layer weight, and cocoon layer rate were further improved. There were no cotton cocoons, the thin-head cocoon rate was greatly reduced, the cocoon color was dark green, and the cocoon shape was uniform, which met the breeding target requirements.

[0019] This invention provides a breeding method for effectively improving the quality of Japanese natural green cocoons, comprising:

[0020] The first Japanese natural green cocoon strain was formed by selecting a Japanese white cocoon base variety with excellent comprehensive traits and a Chinese natural green cocoon preservation variety, and by using Japanese × Chinese hybridization and backcrossing breeding methods. Through systematic selection, the cocoon quality and comprehensive traits of the Japanese natural green cocoon were improved and fixed.

[0021] The second Japanese natural green cocoon strain was formed by selecting a Japanese natural green cocoon variety with dark green cocoon color and strong resistance, and a Japanese white cocoon basic variety with excellent comprehensive traits. The breeding method of Japanese × Japanese single hybridization was adopted, and through systematic selection, the cocoon quality and comprehensive traits of the Japanese natural green cocoon were improved and fixed.

[0022] The second Japanese natural green cocoon strain and the first Japanese natural green cocoon strain were selected. A single crossbreeding method of Japanese natural green cocoon strain × Japanese natural green cocoon strain was adopted. Through systematic selection, the cocoon quality and comprehensive traits of the Japanese natural green cocoon strain were further improved to form a third Japanese natural green cocoon strain with better cocoon quality.

[0023] Furthermore, the selected natural green cocoon strains were combined with four-way hybrid combinations and then subjected to laboratory identification.

[0024] In one embodiment, the third Chinese natural green cocoon strain is hybridized with the third Chinese natural green cocoon strain to obtain the Chinese original strain, the third Japanese natural green cocoon strain is hybridized with the third Japanese natural green cocoon strain to obtain the Japanese original strain, and the Chinese original strain and the Japanese original strain are hybridized to obtain a quaternary hybrid combination, which is then identified in the laboratory.

[0025] Preferably, the breeding of Chinese and Japanese natural green cocoon varieties is similar. Taking the breeding of Chinese natural green cocoon varieties as an example, the breeding method of the first Chinese natural green cocoon variety is as follows:

[0026] The Chinese white cocoon basic variety A (8M235) was crossbred with the Chinese natural green cocoon preserved variety B (Green 1) for several generations. During the selection process, Chinese green cocoons that meet the selection objectives were strictly selected and mixed-color cocoons were eliminated. The best selection was made for three generations or more, including at least two generations of mixed moth area selection and one generation of single moth area selection.

[0027] After several generations of hybridization and selection, the cocoons were backcrossed with the Chinese white cocoon basal variety A for several generations. Strict selection was made to retain the Chinese green cocoons that met the breeding objectives and to eliminate the mixed-color cocoons. The best selection was carried out for three generations or more, and the best selection was carried out in single-moth areas.

[0028] After several generations of backcrossing and selection, the cultivar A, a basic white cocoon variety, is backcrossed and selected for several more generations. The cultivar A, which meets the selection objectives, is strictly selected to obtain the first natural green cocoon variety of the Chinese line. After three or more generations of selection, the best cultivar A is selected from mixed moth areas.

[0029] The preferred breeding method for the second-generation natural green cocoon strain is as follows:

[0030] Japanese natural green cocoon preservation variety C was crossbred with Chinese white cocoon base variety D for several generations. During the breeding process, Chinese green cocoons that meet the breeding objectives were strictly selected and discarded, resulting in the second Chinese natural green cocoon strain.

[0031] The preferred breeding method for the third-generation natural green cocoon strain is as follows:

[0032] The second and first natural green cocoon strains were crossbred and bred for several generations. During the breeding process, dark green cocoons that met the breeding objectives were strictly selected and light green cocoons were eliminated to obtain the third natural green cocoon strain.

[0033] The preferred breeding methods for Chinese-style natural green cocoon varieties that effectively improve cocoon quality are as follows:

[0034]

[0035]

[0036] Among them, □ represents the mixed moth breeding area, and 〇 represents the single moth breeding area; 8M235 is the Chinese white cocoon basic variety A, Green 1 is the Chinese natural green cocoon preservation variety B, Cocoon Color Green is the Japanese natural green cocoon preservation variety C, Zhenfeng 8M10 is the Chinese white cocoon basic variety D, B8M3 Green is the first Chinese natural green cocoon strain, Green Zhen 10 is the second Chinese natural green cocoon strain, and Green M is the third Chinese natural green cocoon strain.

[0037] The breeding process of the Japanese natural green cocoon variety that effectively improves cocoon quality according to the present invention is as follows:

[0038] Japanese white cocoon basic variety × Chinese natural green cocoon preservation variety Japanese natural green cocoon preservation variety × Japanese white cocoon basic variety

[0039]

[0040]

[0041] Among them, □ represents breeding in mixed moth areas, and 〇 represents breeding in single moth areas.

[0042] Among them, 7M235 is the basic variety of Japanese white cocoons, C108 is the Chinese natural green cocoon preservation variety, cocoon color green is the Japanese natural green cocoon preservation variety, and 9day76 is the basic variety of Japanese white cocoons preservation.

[0043] The present invention has at least the following beneficial effects:

[0044] 1. The method for breeding Chinese-type natural green cocoon varieties of this invention is the first to adopt a breeding method of "selecting a second Chinese-type natural green cocoon strain and a first Chinese-type natural green cocoon strain, and then using a Chinese × Chinese single-single hybridization breeding method to obtain a third Chinese-type natural green cocoon strain," which effectively improves the cocoon quality of Chinese-type natural green cocoons. The method for breeding Japanese-type natural green cocoon varieties of this invention is the first to adopt a breeding method of "selecting a second Japanese-type natural green cocoon strain and a first Japanese-type natural green cocoon strain, and then using a Japanese × Japanese single-single hybridization breeding method to obtain a third Japanese-type natural green cocoon strain," which effectively improves the cocoon quality of Japanese-type natural green cocoons. The above methods enable the mechanical reeling of natural green cocoons, especially those from Guangxi, filling the gap in the poor quality of Guangxi natural green cocoons and their inability to be mechanically reeled.

[0045] 2. This invention uses a Chinese white cocoon base variety with excellent comprehensive traits and a Chinese natural green cocoon preservation variety with low total cocoon yield and cocoon layer ratio but strong resistance and relatively uniform cocoon shape to breed the first Chinese natural green cocoon strain through hybridization and backcrossing; and uses a Japanese white cocoon base variety with excellent comprehensive traits and a Chinese natural green cocoon preservation variety with high cocoon layer ratio, relatively uniform cocoon shape but lighter cocoon color and poor resistance to breed the first Japanese natural green cocoon strain through hybridization and backcrossing.

[0046] The second Chinese (or Japanese) natural green cocoon was bred by a single crossbreeding selection method using a Japanese natural green cocoon variety with bright cocoon color and strong resistance and a Chinese (or Japanese) white cocoon base variety with excellent comprehensive traits. The cocoon color, cocoon shape and other comprehensive shapes of the Chinese (or Japanese) natural green cocoon were improved.

[0047] The first (or Japanese) strain of natural green cocoons and the second (or Chinese) strain of natural green cocoons were then crossbred again to select a third (or Chinese) strain of natural green cocoons with better cocoon quality. The resulting third (or Chinese) strain of natural green cocoons has significantly improved cocoon quality, surpassing that of the first (or Chinese) strain of natural green cocoons and the second (or Chinese) strain of natural green cocoons.

[0048] In one embodiment, the obtained third-lineage natural green cocoons are dark green in color, oval in shape, uniform in shape, and moderately wrinkled. The rate of thin-headed poor cocoons is 8.34%, which is 79.14 and 9.21 percentage points lower than that of the first-lineage natural green cocoons and the second-lineage green cocoons, respectively. There are no poor cocoons such as pointed-headed cocoons or cottony cocoons. The pupal survival rate is 93.10%, which is 32.06 and 2.31 percentage points higher than that of the first-lineage natural green cocoons and the second-lineage green cocoons, respectively. The total cocoon weight is 1.37g, which is 9.60% and 3.00% higher than that of the first-lineage natural green cocoons and the second-lineage green cocoons, respectively. The cocoon layer weight is 0.272g, which is 19.30% and 9.68% higher than that of the first-lineage natural green cocoons and the second-lineage green cocoons, respectively. The cocoon layer rate is 19.93%, which is 1.47 and 1.17 percentage points higher than that of the first-lineage natural green cocoons and the second-lineage natural green cocoons, respectively.

[0049] In one embodiment, the obtained third-day natural green cocoons are dark green in color, with a shallow waist, uniform shape, and moderate shrinkage. The rate of thin-headed defective cocoons is 9.71%, which is 76.68 and 15.49 percentage points lower than that of the first-day natural green cocoons and the second-day natural green cocoons, respectively. There are no defective cocoons such as pointed-headed cocoons or cottony cocoons. The pupal survival rate is 91.95%, which is 19.88 and 8.51 percentage points higher than that of the first-day natural green cocoons and the second-day natural green cocoons, respectively. The total cocoon weight is 1.40g, which is 35.10% and 21.51% higher than that of the first-day natural green cocoons and the second-day natural green cocoons, respectively. The cocoon layer weight is 0.275g, which is 38.89% and 27.91% higher than that of the first-day natural green cocoons and the second-day natural green cocoons, respectively. The cocoon layer rate is 19.63%, which is 0.54 percentage points higher than that of the first-day natural green cocoons and 0.98 percentage points higher than that of the second-day natural green cocoons.

[0050] 3. The quaternary hybrid combination formed by the present invention was tested in the laboratory. The cocoon color was dark green and uniform. The total cocoon weight was 1.53g, the cocoon layer weight was 0.311g, the cocoon layer rate was 20.32%, the length of the silk in the first cocoon was 805 meters, the purity was not significantly different from that of the No. 2 variety from Guangdong and Guangxi, and the reeling rate was 98.78%. This invention realizes that natural green cocoons in Guangxi can be mechanically reeled.

[0051] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0052] Figure 1 The image shows a silkworm from the third type of natural green cocoon of the present invention.

[0053] Figure 2 The image shows a third type of natural green cocoon, M, from the present invention.

[0054] Figure 3 Image of the first natural green cocoon 8M3 of the present invention;

[0055] Figure 4 Image of the second type of natural green cocoon from Green Town 10 of the present invention;

[0056] Figure 5 The image shows the first Japanese-made natural green cocoon 7M3 green cocoon of this invention;

[0057] Figure 6 This is an image of the second type of Japanese natural green cocoon of the present invention, with a green color and a cocoon size of 9 days and 76.

[0058] Figure 7 Image of the third type of natural green cocoon (green cocoon color, 9 days 76), 7M3 green, of the present invention;

[0059] Figure 8This is an image of the quaternary hybrid cocoon of the present invention. Detailed Implementation

[0060] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0061] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0062] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0063] The parent lines used are from the following sources:

[0064] The basic variety of Chinese white cocoon, 8M235, is a Chinese variety selected and preserved by the Guangxi Zhuang Autonomous Region Sericulture Technology Extension Station. It has excellent overall morphology. It was obtained by systematically selecting and breeding a cross between the parent of Guican No. 2 (8810) and the parent of Guican F95 (35).

[0065] The Chinese-style natural green cocoon variety, Green 1, is a variety selected and preserved by the Sericulture Technology Extension Station of Guangxi Zhuang Autonomous Region. It was bred by crossing DAR·Cocoon Green × CVDAR. DAR is the parent of Guican N2, Cocoon Green is the parent of Guican 15, and CVDAR is a silkworm variety with strong resistance to silkworm blood pustulosis.

[0066] The Japanese-style natural green cocoon variety, Cocoon Color Green, is a variety selected and preserved by the Guangxi Zhuang Autonomous Region Sericulture Technology Extension Station. It is the parent of Guican No. 15.

[0067] The basic variety of Chinese white cocoon, Zhenfeng 8M10, is a variety selected and preserved by the Guangxi Zhuang Autonomous Region Sericulture Technology Extension Station. It was bred by crossing the parent of Guican No. 8 (Xiu) with the Chinese variety (Zhenfeng). The Chinese variety (Zhenfeng) was bred by crossing the Chinese variety (Zhen) with the Chinese variety (97 Qiufeng). 97 is the parent of Guican F95, and Qiufeng is the parent of Qiufeng × Baiyu.

[0068] The Japanese white cocoon basic variety 7M235 is a Chinese variety selected and preserved by the Guangxi Zhuang Autonomous Region Sericulture Technology Extension Station, with excellent overall morphology. It was obtained by systematically selecting and breeding a hybrid of the parent of Liangguang No. 2 (7532) and the parent of Guican F95 (35).

[0069] The basic variety of Japanese white cocoon, 9775-10, is a variety selected and preserved by the Guangxi Zhuang Autonomous Region Sericulture Technology Extension Station. It was bred by crossing the preserved variety 9775-10 with the Japanese variety 76HN02. The Japanese variety (76HN02) was bred by crossing the parent (76) of Guican F95 with the parent HN02 of Guican N2.

[0070] The Chinese-style natural green cocoon preservation variety C108 is a variety selected and preserved by the Guangxi Zhuang Autonomous Region Sericulture Technology Extension Station.

[0071] Example 1

[0072] A breeding method for effectively improving the quality of natural green cocoons from China includes:

[0073] Crossbreeding and backcrossing of Chinese white cocoon basic varieties with Chinese natural green cocoon preservation varieties: 8M3 Green: {[(8M235×Green1)F5×8M235]F5×8M235}F 10 The breeding program selected the excellent Chinese white cocoon cultivar "8M235" bred by the Guangxi Sericulture Station and the preserved Chinese natural green cocoon cultivar "Lv1". Using a "Chinese × Chinese" hybridization and backcrossing method, and under high temperature and humidity conditions of 24.6℃ and 74% humidity, systematic selection was conducted to improve the uniformity of the green cocoons. The first Chinese natural green cocoon strain (8M3 Green) is formed by fixing the uniformity of the round cocoon shape and comprehensive traits.

[0074] Japanese natural green cocoon variety and Chinese basic variety single cross Green Town 10: Cocoon color green × Zhenfeng 8M10F 13 The study selected the Japanese natural green cocoon variety "Cocoon Green" (Cocoon Green), known for its deep green cocoon color and strong resistance, preserved by the Guangxi Sericulture Station, and the Chinese white cocoon basic variety "Zhenfeng 8M10" (Zhenfeng 8M10), which boasts excellent comprehensive traits, and used a "Japanese × Chinese" single cross breeding method. Under high temperature and humidity conditions of 24.6℃ and 74% air humidity, systematic selection was conducted to improve the uniformity of the deep green cocoon color. The second Chinese natural green cocoon strain (Lvzhen 10) was formed by fixing the uniformity of the round cocoon shape and its overall characteristics.

[0075] The first Chinese natural green cocoon variety coefficient was obtained by single-crossing the second Chinese natural green cocoon variety, Green M: Green Town 10 × 8M3 Green F9. The Chinese natural green cocoon variety “Green Town 10”, selected by single-crossing, was crossed with the Chinese natural green cocoon variety “8M3 Green”, selected by hybridization and backcrossing. The two varieties were then crossed again by single-crossing (Chinese × Chinese). Under high temperature and high humidity conditions of 24.6℃ and 74% humidity, the uniformity of dark green cocoon color, uniformity of Chinese cocoon shape, and overall traits were improved through systematic selection to obtain the Chinese natural green cocoon variety (Green M).

[0076] The breeding process is as follows:

[0077]

[0078]

[0079] Among them, □ represents breeding in mixed moth areas, and 〇 represents breeding in single moth areas.

[0080] Example 2

[0081] A breeding method for effectively improving the quality of Japanese natural green cocoons includes:

[0082] Crossbreeding and backcrossing of Japanese white cocoon basic varieties with Chinese natural green cocoon preserved varieties 7M3 green: {[(7M235×C108)F5×7M235]F5×7M235}F 10

[0083] The breeding program selected the Japanese white cocoon cultivar "7M235," with its excellent comprehensive traits, bred by the Guangxi Sericulture Station, and the preserved Chinese natural green cocoon cultivar "C108." Using a Japanese × Chinese hybridization and backcrossing method, and under high temperature and humidity conditions of 24.6℃ and 74% humidity, systematic selection was conducted to improve the uniformity of the green cocoons. The first Japanese-made natural green cocoon strain (7M3 Green) is formed by fixing the uniformity of the round cocoon shape and its overall characteristics.

[0084] Japanese natural green cocoon variety and Japanese basic variety single cross: Cocoon Green · 9 Days 76: Cocoon Green × 9 Days 76F 13

[0085] The study selected the Japanese natural green cocoon variety "Cocoon Green" (Cocoon Green), known for its deep green cocoon color and strong resistance, preserved by the Guangxi Sericulture Station, and the Japanese white cocoon basic variety "9 Days 76" (9 Days 76), which exhibits excellent comprehensive traits, and used a "Japanese × Japanese" single crossbreeding method. Under high temperature and humidity conditions of 24.6℃ and 74% air humidity, systematic selection was conducted to improve the uniformity of the deep green cocoon color. The second-generation natural green cocoon strain (cocoon color green · 9 days 76) was formed by fixing the uniformity of the round cocoon shape and the overall characteristics.

[0086] A single cross between the first and second natural green cocoon varieties (cocoon color green · 9 days 76) · 7M3 green: cocoon color green · 9 days 76 × 7M3 green F9

[0087] The Japanese natural green cocoon variety “Cocoon Color Green 9 Days 76”, bred through single crossbreeding, and the Japanese natural green cocoon variety “7M3 Green”, bred through hybridization and backcrossing, were again subjected to single crossbreeding (day × day). Under high temperature and high humidity conditions of 24.6℃ and 74% humidity, systematic selection was carried out to improve the uniformity of dark green cocoon color, the uniformity of cocoon shape, and the overall traits, thus forming a third Japanese natural green cocoon strain ((Cocoon Color Green 9 Days 76) · 7M3 Green).

[0088] The breeding process is as follows:

[0089]

[0090]

[0091] Among them, □ represents breeding in mixed moth areas, and 〇 represents breeding in single moth areas.

[0092] Test results

[0093] Chinese and Japanese green-cocoon silkworm varieties and the control "Liangguang No. 2" were crossbred in both directions and under the same environmental conditions and conventional rearing methods. Each variety was collected in 5 separate areas. After the fourth instar, the number of silkworms was determined, with 300 silkworms per area and 3 areas per variety. The number of diseased and dead silkworms was recorded during the silkworm rearing period and in the cocoon, and the number of dead cocoons was recorded during the pupal stage. The cocoon color, cocoon shape uniformity, number of thin-headed cocoons, number of cottony cocoons, number of pointed-headed cocoons, total cocoon weight, cocoon layer weight, and cocoon layer ratio were investigated.

[0094] The feeding results are compared below:

[0095] Table 1: Results of Silkworm Variety Breeding

[0096]

[0097]

[0098] As shown in Table 1 above, the preserved variety of natural green cocoon cultivar "Green 1" exhibits a high pupa survival rate, good resistance, short oval cocoon shape, relatively uniform shape, few pointed cocoons, and a dark green color. However, the total cocoon weight, cocoon layer weight, and cocoon layer ratio are low, and the rate of thin-headed poor cocoons is 100%, making mechanical reeling impossible. This invention utilizes hybridization and backcrossing of the superior Chinese white cocoon base variety with the preserved variety of natural green cocoon cultivar "Green 1" to obtain the first Chinese natural green cocoon strain 8M3Green, which has a short cocoon shape. The cocoons are round and relatively uniform, with fine wrinkles. The total cocoon weight, cocoon layer weight, and cocoon layer rate have increased significantly, by 26.26, 46.15, and 2.6 percentage points respectively compared to Green 1. There are no pointed cocoons, and the rate of defective cocoons is 6.90%, which is 15.11 percentage points lower than Green 1. However, the cocoons are light green, and the rate of thin-headed cocoons is as high as 87.48%, making mechanical reeling impossible. Moreover, the pupal survival rate is only 61.04%, indicating poor resistance. Further improvement is needed.

[0099] The preserved Japanese natural green cocoon variety "Cocoon Green" has a deep green cocoon color and strong resistance, but its cocoon layer quantity, cocoon layer ratio, cocoon shape, thin-headed cocoons, soft cocoons, and cocoon shape uniformity are relatively poor. This invention uses a Chinese white cocoon base variety with excellent comprehensive traits and the preserved Japanese natural green cocoon variety "Cocoon Green" for single-cross breeding and improvement, resulting in the second Chinese natural green cocoon line, Green Town 10. Green Town 10 has a deep green cocoon color and a good cocoon shape. The cocoons are round and relatively uniform in shape, with moderate shrinkage and wrinkling. The rate of thin-headed cocoons is 17.55%, there are no pointed-headed cocoons, the rate of soft cocoons is 1.76%, the pupal survival rate is 90.79%, the total cocoon weight is 1.33g, the cocoon layer weight is 0.248g, and the cocoon layer rate is 18.76%, showing significant improvement. However, there are still a relatively large number of thin-headed cocoons and soft cocoons, and the cocoon layer rate is not high enough, failing to meet the breeding objectives.

[0100] To significantly improve cocoon quality and meet the needs of mechanized silk reeling, this invention further crossbred the first Chinese-line natural green cocoon variety 8M3 Green and the second Chinese-line natural green cocoon variety Green Town 10 to obtain the third Chinese-line natural green cocoon variety Green M. Green M exhibits significantly improved cocoon quality, superior to both the first Chinese-line natural green cocoon variety 8M3 Green and the second Chinese-line natural green cocoon variety Green Town 10. The cocoons are dark green, oval-shaped, uniform, with moderate shrinkage, and a thin-head cocoon (defective cocoon) rate of 8.34%, which is 79.14 and 9.21 percentage points lower than the first Chinese-line natural green cocoon variety 8M3 Green and the second Chinese-line natural green cocoon variety Green Town 10, respectively. There are no pointed-head cocoons, cottony cocoons, or other defective cocoons. The pupal survival rate is 93.10%, which is 32.06 and 2.31 percentage points higher than the first Chinese-line natural green cocoon variety 8M3 Green and the second Chinese-line natural green cocoon variety Green Town 10, respectively. The total cocoon weight is 1.3. The cocoon weight was 7g, an increase of 9.60% and 3.00% compared to the first-line natural green cocoon variety 8M3 and the second-line natural green cocoon variety Lvzhen 10, respectively. The cocoon layer weight was 0.272g, an increase of 19.30% and 9.68% compared to the first-line natural green cocoon variety 8M3 and the second-line natural green cocoon variety Lvzhen 10, respectively. The cocoon layer rate was 19.93%, an increase of 1.47 and 1.17 percentage points compared to the first-line natural green cocoon variety 8M3 and the second-line natural green cocoon variety Lvzhen 10, respectively. The cocoon quality was significantly improved, making it suitable for mechanical reeling.

[0101] The obtained third-day natural green cocoons were dark green in color, with a shallow waist, uniform shape, and moderate shrinkage. The rate of thin-headed cocoons (inferior cocoons) was 9.71%, which was 76.68 and 15.49 percentage points lower than that of the first-day and second-day natural green cocoons, respectively. There were no pointed-headed cocoons, cottony cocoons, or other inferior cocoons. The pupal survival rate was 91.95%, which was 19.88 and 8.51 percentage points higher than that of the first-day and second-day natural green cocoons, respectively. The total cocoon weight was 1.40g, which was 35.10% and 21.51% higher than that of the first-day and second-day natural green cocoons, respectively. The cocoon layer weight was 0.275g, which was 38.89% and 27.91% higher than that of the first-day and second-day natural green cocoons, respectively. The cocoon layer rate was 19.63%, which was 0.54 percentage points higher than that of the first-day natural green cocoons and 0.98 percentage points higher than that of the second-day natural green cocoons.

[0102] like Figure 8 As shown, the third natural green cocoon strain was used in a four-way hybrid combination (specifically, the third Chinese natural green cocoon strain was hybridized with another third Chinese natural green cocoon strain to obtain the Chinese original strain, the third Japanese natural green cocoon strain was hybridized with another third Japanese natural green cocoon strain to obtain the Japanese original strain, and the Chinese original strain and the Japanese original strain were hybridized to obtain the four-way hybrid) for laboratory testing. The cocoons were dark green and uniform in color. The total cocoon weight after reciprocal cross was 1.57g, the cocoon layer weight was 0.323g, the cocoon layer rate was 20.58%, the silk length of the first cocoon after reciprocal cross was 805 meters, the purity was not significantly different from that of the Liangguang No. 2 strain, and the reeling rate was 98.7%, realizing that Guangxi natural green cocoons can be mechanically reeled. The silk quality test results are as follows:

[0103] Table 2 Silk Quality Results

[0104]

[0105] like Figure 1 The image shown is of a silkworm from the third type of natural green cocoon of the present invention. Figure 2 The image shown is of a natural green cocoon (Green M) from the third generation of the Chinese system. The top image shows the cocoon in the cluster, and the bottom image is a close-up of the cocoon after it has been picked. As you can see, there are no cottony cocoons, very few thin-headed cocoons, the cocoons are dark green, and the cocoons are uniform in shape.

[0106] Figure 3 The image shows 8M3 green cocoons, which are natural green cocoons of the first generation. Among them, there are many poor cocoons such as pointed and thin-headed cocoons and cottony cocoons. The cocoon color is light and the quality of the cocoons still needs to be improved.

[0107] Figure 4 The image shows a second type of natural green cocoon from the present invention, Green Town 10. The cocoon color has become slightly darker green, but the cocoon shape is not uniform enough. Some are longer and some are shorter, and the quality of the cocoons still needs to be improved.

[0108] Figure 5The image shows the first Japanese-made natural green cocoon 7M3 green of this invention; it can be seen that the cocoon color is light and the cocoon quality still needs to be improved.

[0109] Figure 6 The image shows the second type of natural green cocoon of the present invention, with a green color of 9 days and 76. The cocoon color is relatively dark green, but the cocoon shape is uneven and the cocoon quality still needs to be improved.

[0110] Figure 7 The image shows the third type of natural green cocoon (green cocoon color, 9 days 76) of the present invention, 7M3 green; the cocoon color is bright green and the cocoon shape is uniform.

[0111] Figure 8 The image shows the quaternary hybrid cocoon of this invention; it can be mechanically reeled, producing high-quality silk.

[0112] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A breeding method for effectively improving the quality of natural green cocoons, characterized in that, This method is applicable to both Chinese and Japanese natural green cocoons, including: First, a first natural green cocoon strain is developed by selecting a white cocoon base variety with excellent overall traits and a preserved natural green cocoon variety, using hybridization and backcrossing, and through systematic selection to improve and fix the cocoon quality and overall traits of the natural green cocoon; Second, a second natural green cocoon strain is developed by selecting a preserved natural green cocoon variety with deep green cocoon color and strong resistance and a white cocoon base variety with excellent overall traits, using single hybridization, and through systematic selection to improve and fix the cocoon quality and overall traits of the natural green cocoon; Third, a third natural green cocoon strain with even better cocoon quality is developed by selecting the second and first natural green cocoon strains, using a single hybridization method of natural green cocoon strain × natural green cocoon strain, and through systematic selection to further improve and fix the cocoon quality and overall traits of the natural green cocoon. Specifically, for Chinese-type natural green cocoons, the following methods are employed: First, a first Chinese-type natural green cocoon strain is formed by selecting a Chinese-type white cocoon base variety with excellent overall traits and a Chinese-type natural green cocoon preservation variety, using Chinese-Chinese crossbreeding and backcrossing, and through systematic selection to improve and fix the cocoon quality and overall traits. Second, a second Chinese-type natural green cocoon strain is formed by selecting a Japanese-type natural green cocoon preservation variety with deep green cocoon color and strong resistance, and a Chinese-type white cocoon base variety with excellent overall traits, using Japanese-Chinese single crossbreeding, and through systematic selection to improve and fix the cocoon quality and overall traits. Third, a third Chinese-type natural green cocoon strain with even better cocoon quality is formed by selecting the second and first Chinese-type natural green cocoon strains, using a Chinese-type natural green cocoon strain × Chinese-type natural green cocoon strain single crossbreeding, and through systematic selection to further improve and fix the cocoon quality and overall traits. For Japanese natural green cocoons, the following methods are employed: First, a first Japanese natural green cocoon strain is developed by selecting a Japanese white cocoon base variety with excellent overall traits and a Chinese natural green cocoon variety with relatively uniform cocoon shape and high cocoon layer ratio, using Japanese × Chinese hybridization and backcrossing, followed by systematic selection to improve and fix the cocoon quality and overall traits. Second, a second Japanese natural green cocoon strain is developed by selecting a Japanese natural green cocoon variety with deep green cocoon color and strong resistance, and a Japanese white cocoon base variety with excellent overall traits, using Japanese × Japanese single hybridization, followed by systematic selection to improve and fix the cocoon quality and overall traits. Third, a third Japanese natural green cocoon strain with even better cocoon quality is developed by selecting the second and first Japanese natural green cocoon strains, using Japanese natural green cocoon strain × Japanese natural green cocoon strain single hybridization, followed by systematic selection to further improve and fix the cocoon quality and overall traits. The breeding method for the first natural green cocoon strain is as follows: Step 1: Crossbreed the white cocoon base variety with the naturally preserved green cocoon variety for several generations, strictly selecting green cocoons that meet the breeding objectives and discarding variegated cocoons; Step 2: After several generations of crossbreeding, backcross with the white cocoon base variety for several generations, strictly selecting green cocoons that meet the breeding objectives and discarding variegated cocoons; Step 3: After several generations of backcrossing, backcross with the naturally preserved green cocoon variety for several generations, strictly selecting green cocoons that meet the breeding objectives to obtain the first natural green cocoon strain. The second natural green cocoon strain is bred by crossbreeding natural green cocoon varieties with white cocoon base varieties for several generations. During the breeding process, green cocoons that meet the breeding objectives are strictly selected and mixed-color cocoons are eliminated to obtain the second natural green cocoon strain. The breeding method for the third natural green cocoon variety is as follows: the second natural green cocoon strain and the first natural green cocoon strain are crossbred and bred for several generations. During the breeding process, dark green cocoons that meet the breeding objectives are strictly selected and light green cocoons are eliminated to obtain the third natural green cocoon strain. For Chinese-type natural green cocoons: the basic variety of Chinese-type white cocoons is 8M235, the preserved variety of Chinese-type natural green cocoons is Green 1, the preserved variety of Japanese-type natural green cocoons is Cocoon Green, and the basic variety of Chinese-type white cocoons is Zhenfeng 8M10; For Japanese-type natural green cocoons: the basic variety of Japanese-type white cocoons is 7M235, the preserved variety of Chinese-type natural green cocoons is C108, the preserved variety of Japanese-type natural green cocoons is Cocoon Green, and the basic variety of Japanese-type white cocoons is 9 Day 76.

2. The breeding method for effectively improving the quality of natural green cocoons as described in claim 1, characterized in that, The selected third natural green cocoon strain is then combined with a four-way hybrid, specifically: the third Chinese natural green cocoon strain is hybridized with the third Chinese natural green cocoon strain to obtain the Chinese original strain; the third Japanese natural green cocoon strain is hybridized with the third Japanese natural green cocoon strain to obtain the Japanese original strain; and the Chinese original strain and the Japanese original strain are hybridized to obtain a four-way hybrid combination.

3. The breeding method for effectively improving the quality of natural green cocoons as described in claim 1, characterized in that, In the first step of the selection and breeding of the first natural green cocoon strain, three or more generations are selected, including at least two generations of mixed moth area selection and one generation of single moth area selection; in the second step, three or more generations are selected, using single moth area selection; in the third step, three or more generations are selected, using mixed moth area selection; in the selection and breeding of the second natural green cocoon strain, ten generations are selected, including at least two generations of mixed moth area selection and several generations of single moth area selection; in the selection and breeding of the third natural green cocoon variety, ten generations are selected, including at least two generations of mixed moth area selection and several generations of single moth area selection.

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