A far-cross breeding method of Sichuan-Caian Lagerstroemia indica

Abstract

The application discloses a far-cross breeding method of Sichuan-Caian Lagerstroemia indica, and comprises the following steps: S1, selecting Sichuan-Caian Lagerstroemia indica in full bloom as a male parent and Lagerstroemia indica in full bloom as a female parent; S2, obtaining a de-stemmed flower bud stigma after de-male; S3, smearing the stigma smearing agent on the de-stemmed flower bud stigma before the female parent stigma secretes mucus; and S4, carrying out bagging isolation after bagging and pollination; components of the stigma smearing agent comprise sucrose, indole acetic acid, polyethylene glycol 6000, N-acetyl-L-cysteine and water. The far-cross breeding method of Sichuan-Caian Lagerstroemia indica solves the problem that after pollination of Lagerstroemia indica and Sichuan-Caian Lagerstroemia indica, pollen tubes cannot normally elongate in the style, and fertilization cannot be completed.

Description

Technical Field

[0001] This invention relates to a method for hybridization breeding of plants, specifically a method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou. Background Technology

[0002] Crape myrtle (Lagerstroemia indica L.) is highly favored for its beautiful tree shape, abundant and colorful flowers, long flowering period, and pollution resistance. However, long-term intraspecific hybridization has led to a narrowing of the genetic base of hybrid varieties, and improvements are needed in adaptability, ornamental value, and resistance. Sichuan-Guizhou crape myrtle (Lagerstroemia excelsa) is a deciduous, tall tree belonging to the genus Lagerstroemia in the family Lythraceae. It has a straight trunk, smooth, reddish-brown bark, fragrant, pale yellowish-white flowers, abundant inflorescences, and golden or yellowish-red autumn leaves, making it highly valuable for ornamental purposes and utilization. However, there is a problem of pre-fertilization reproductive impairment in distant hybridization between crape myrtle and Sichuan-Guizhou crape myrtle. This is mainly manifested in the inability of most pollen tubes to elongate within the style after pollen grain germination, resulting in incomplete fertilization. Therefore, technical means are needed to overcome this problem in order to make full use of hybrid vigor, improve the performance of crape myrtle in terms of plant shape, fragrance, adaptability and resistance, and create new variant types or new germplasm to expand genetic variation.

[0003] Currently, there are no systematic studies or solutions for overcoming pre-fertilization reproductive barriers in distant hybridization among Lagerstroemia species. Although other plant species have some successful methods for overcoming distant hybridization barriers, these methods are not necessarily applicable to Lagerstroemia.

[0004] Therefore, it is urgent to provide a distant hybridization breeding method for Lagerstroemia in Sichuan and Guizhou. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou, which solves the problem that the pollen tubes of Lagerstroemia indica and Lagerstroemia indica from Sichuan and Guizhou cannot elongate normally in the style after pollination, thus failing to complete fertilization.

[0006] According to one aspect of the present invention, a method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou is provided, comprising the following steps:

[0007] S1. Select the Lagerstroemia indica var. Sichuan and Guizhou during its peak bloom period as the male parent and the Lagerstroemia indica var. var. florida during its peak bloom period as the female parent;

[0008] S2. After removing the male part, you get the stigma of the flower bud;

[0009] S3. Before the stigma of the female parent secretes mucus, apply the stigma coating agent to the stigma of the emasculated flower buds;

[0010] S4. After bagging and pollination, isolate the product by bagging it again.

[0011] The components of the column head coating agent include: sucrose, indoleacetic acid, polyethylene glycol 6000, N-acetyl-L-cysteine, and water.

[0012] In this invention, the coating agent is applied before the stigma of the female parent secretes mucus. Firstly, the stigma typically secretes mucus to adsorb and fix pollen during natural pollination. To avoid interference with natural pollination, the coating agent is applied before the stigma begins secreting mucus, ensuring the natural pollination process can proceed normally. Secondly, in hybridization breeding, the success of exogenous pollen depends on its contact with the stigma. The mucus secreted by the stigma helps pollen grains adhere to the stigma surface and absorb nutrients, thereby promoting pollen tube growth. The application of the coating agent ensures sufficient contact between the exogenous pollen and the stigma, increasing the chance of binding. Thirdly, the components of the coating agent in this invention improve the environment for the binding of exogenous pollen and the stigma, increasing the success rate of binding.

[0013] The sucrose in the above-mentioned stigma coating provides nutrition for pollen grain germination. Sucrose is a carbohydrate that can serve as an energy source for pollen germination and growth.

[0014] Indoleacetic acid (IAA) is a plant growth regulator that promotes pollen tube elongation and directional growth, enabling it to pass smoothly through the style and reach the ovary to complete the pollination process.

[0015] Polyethylene glycol 6000 (PEG6000) is used as a dispersant to prevent pollen from agglomerating, maintain the dispersed state of pollen, and improve the success rate of exogenous pollen binding to the stigma.

[0016] N-acetyl-L-cysteine ​​can remove reactive oxygen species (ROS) emitted by the stigma, improving the success rate of exogenous pollen binding to the stigma. N-acetyl-L-cysteine ​​has the function of removing ROS. When the stigma receives exogenous pollen, it releases ROS, which can damage the pollen and thus affect pollen tube growth. Therefore, adding N-acetyl-L-cysteine ​​to stigma coating agents helps improve the success rate of exogenous pollen binding to the stigma.

[0017] Sucrose provides nutrients, indoleacetic acid promotes pollen tube elongation, polyethylene glycol 6000 prevents pollen aggregation, and N-acetyl-L-cysteine ​​removes reactive oxygen species. The synergistic effect of these coating agents can increase the success rate and effectiveness of hybridization breeding.

[0018] In some embodiments of the present invention, the process after bagging and isolation further includes: repeated pollination;

[0019] The repeated pollination steps include repeating the operations in steps S3 and S4.

[0020] In some embodiments of the present invention, the repeated pollination process further includes: harvesting the hybrid capsules, sowing, and aseptic domestication.

[0021] In some embodiments of the present invention, the components of the column head coating agent, by weight, include: 150-250 parts sucrose, 0.0025-0.0035 parts indoleacetic acid, 20-30 parts polyethylene glycol 6000, 10-15 parts N-acetyl-L-cysteine, and 1000 parts water.

[0022] The stigma coating agent of the present invention enables pollen and stigma to accept each other, allowing for normal hydration and development of pollen grains and normal elongation of pollen tubes, thereby ultimately completing fertilization.

[0023] In some embodiments of the present invention, the sowing is aseptic sowing, and the culture medium for aseptic sowing includes: MS medium, 1-naphthaleneacetic acid, 6-benzyladenine and gibberellin.

[0024] In some embodiments of the present invention, the culture medium for aseptic seeding, by concentration, comprises: 1 / 2 MS medium, 0.1–0.2 mg / L 1-naphthaleneacetic acid, 0.25–0.75 mg / L 6-benzyladenine, and 45–60 mg / L gibberellin.

[0025] In some embodiments of the present invention, step S2 includes removing the stamens: removing open flowers and buds that cannot open on the same day, and removing the petals and stamens after peeling open the buds.

[0026] In some embodiments of the present invention, step S4 includes bagging the inflorescences of the female parent after emasculation and bagging the inflorescences of the male parent.

[0027] In some embodiments of the present invention, the step of harvesting hybrid capsules includes: harvesting the capsules after the female parent has developed for 120 days following repeated pollination.

[0028] In some embodiments of the present invention, the pollination time is during the peak flowering period in June to July. Detailed Implementation

[0029] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment provides a hybridization breeding method for Lagerstroemia indica from Sichuan and Guizhou, and the specific steps are as follows:

[0032] S1. Selecting Parent Plants: Choose Lagerstroemia indica 'Sichuan-Guizhou' as the male parent and Lagerstroemia indica 'Purple Elf' as the female parent. Ensure that both the male and female parents are in full bloom and their flowers are vigorous in June;

[0033] S2. Demasking: At 4:00 AM on a sunny day, select inflorescences with many flower buds and remove any open flowers and buds that will not open that day. Use sterilized tweezers to peel open the flower buds, then remove the petals and stamens;

[0034] S3. Apply stigma smear agent: Before the stigma of the female plant secretes mucus, use the tip of a brush to dip into the stigma smear agent and apply it to the stigma of the emasculated flower buds. The components of the stigma smear agent are shown in Table 1.

[0035] S4. Bagging: After emasculation, the emasculated inflorescences should be immediately bagged with greaseproof paper bags to prevent pollination by foreign pollen. At the same time, a label indicating the hybridization combination and hybridization time should be attached to the base of the inflorescence. Additionally, the male parent inflorescences also need to be bagged to prevent pollen contamination.

[0036] S5. Artificial pollination: After the pollen has dispersed, gently touch the stigma of the female pistil with the stamen of the male parent, repeating this several times until the stigma of the pistil is visible to the naked eye and has been covered with pollen. After pollination is completed, bag the pistil for isolation.

[0037] S6. Repeat pollination: Repeat steps 3 and 5 after 24 hours;

[0038] S7. Harvesting hybrid capsules: After the development period reaches 120 days, harvest and preserve the mature capsules, keeping them together with the original label without threshing.

[0039] S8. Aseptic sowing: After the capsules are naturally dried, the seeds are extracted, sterilized, and then inoculated onto the growth medium for aseptic culture. The composition of the medium is shown in Table 2. Finally, aseptic seedlings are obtained.

[0040] S9. Aseptic Seedling Acclimation: When the aseptic seedlings have grown to 4-5 true leaves, acclimation is carried out. The day before acclimation, the caps of the culture bottles are opened to harden the seedlings, then they are transplanted into seedling trays filled with sterilized nutrient soil and covered with shade netting to promote seedling growth. After 3 weeks of growth, they are then transplanted into a plastic greenhouse for routine management, ultimately yielding robust crape myrtle hybrid seedlings.

[0041] Examples 2-16

[0042] The difference between Examples 2-16 and Example 1 lies in the composition of the ointment, as shown in Table 1, while the other conditions are the same.

[0043] Examples 17-27

[0044] The difference between Examples 20-37 and Example 1 lies in the composition of the ointment, as shown in Table 2, while the other conditions are the same.

[0045] Comparative Example 1

[0046] This comparative example provides a method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou. The difference between this comparative example and Example 1 is that the stigma coating agent used is hormone IAA, while the other conditions are the same.

[0047] Comparative Example 2

[0048] This comparative example provides a method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou. The difference between this comparative example and Example 1 is that the stigma coating agent used is hormone GA3, while the other conditions are the same.

[0049] Comparative Example 3

[0050] This comparative example provides a method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou. The difference between this comparative example and Example 1 is that the stigma coating agent used is the hormone KIBA, while the other conditions are the same.

[0051] Comparative Example 4

[0052] This comparative example provides a method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou. The difference between this comparative example and Example 1 is that the stigma coating agent used is the hormone NAA, while the other conditions are the same.

[0053] Comparative Examples 5-10

[0054] Comparative Examples 5-10 provide a method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou. The difference between these comparative examples and Example 1 is that the components of the stigma coating agent are different, as shown in Table 1. All other conditions are the same.

[0055] Comparative Example 11

[0056] The difference between this comparative example and Example 10 is that the timing of using the stigma coating agent is after the stigma secretes mucus, while the other conditions are the same.

[0057] Test Example 1

[0058] This test case tested the number of seeds, the number of germinations, and the germination rate of the examples and comparative examples. The specific results are shown in Table 1.

[0059] Table 1. Number of seeds, number of germinated seeds, and germination rate in the examples and comparative examples

[0060]

[0061]

[0062] Test Example 2

[0063] This test case tested the number of seeds, the number of germinations, and the germination rate of the examples and comparative examples under different culture medium conditions, as shown in Table 2.

[0064] Table 2. Number of seeds, number of germinated seeds, and germination rate in the examples and comparative examples

[0065]

[0066]

[0067] Test Example 3

[0068] This test case tested the number of pollinators, the number of results, and the result rate of the comparative example and Example 1. The test results are shown in Table 3.

[0069] Table 3. Pollination number, number of fertilized flowers, and fertility rate under different stigma coating agents.

[0070] Comparative Example 1 200 8 4 Comparative Example 2 200 6 16 Comparative Example 3 200 6 3 Comparative Example 4 200 7 3.5

[0071] Test Example 4

[0072] This test case tested the number of pollinators, the number of results, and the result rate of Comparative Example 11 and Example 10. The test results are shown in Table 4.

[0073] Table 4. Number of pollinators, number of fertile individuals, and fertility rate under different stigma coating agents.

[0074] Example 10 200 42 21 Comparative Example 11 200 3 1.5

[0075] In this invention, by applying a coating agent before the stigma of the female parent secretes mucus, several advantages are achieved. First, the stigma typically secretes mucus to adsorb and fix pollen during natural pollination. To avoid interference with natural pollination, the coating agent is applied before the stigma begins secreting mucus, ensuring that natural pollination can proceed normally. Second, in hybridization breeding, the success of exogenous pollen depends on its contact with the stigma. The mucus secreted by the stigma helps pollen grains adhere to the stigma surface and absorb nutrients, thereby promoting pollen tube growth. The application of the coating agent ensures sufficient contact between the exogenous pollen and the stigma, increasing the chance of binding. Third, the components of the coating agent in this invention improve the environment for the binding of exogenous pollen and the stigma, increasing the success rate of binding.

[0076] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for distant hybridization breeding of Lagerstroemia indica from Sichuan and Guizhou, characterized in that, The steps include the following: S1. Select the Lagerstroemia indica var. Sichuan and Guizhou during its peak bloom period as the male parent and the Lagerstroemia indica var. ... S2. After removing the male part, you get the stigma of the flower bud; S3. Before the stigma of the female parent secretes mucus, apply the stigma coating agent to the stigma of the emasculated flower buds; S4. After bagging and pollination, isolate the product by bagging it again. The components of the column head coating agent are: Sucrose: 150 g / L, indoleacetic acid: 3.5 mg / L, polyethylene glycol 6000: 30 g / L, N-acetyl-L-cysteine: 15 g / L, and water: 1000 g / L; Alternatively, the components of the column head coating agent are: Sucrose: 250 g / L, indoleacetic acid: 2.5 mg / L, polyethylene glycol 6000: 20 g / L, N-acetyl-L-cysteine: 10 g / L, and water: 1000 g / L; or: Alternatively, the components of the column head coating agent are: Sucrose: 250 g / L, indoleacetic acid: 3.5 mg / L, polyethylene glycol 6000: 30 g / L, N-acetyl-L-cysteine: 15 g / L, and water: 1000 g / L; The process after bagging and isolation also includes: repeated pollination; The repeated pollination step includes: repeating the operations in steps S3 and S4; The repeated pollination process also includes: harvesting hybrid capsules, sowing, and aseptic domestication.

2. The hybridization breeding method according to claim 1, characterized in that, The sowing is aseptic sowing, and the culture medium for aseptic sowing is: MS medium, 1-naphthaleneacetic acid, 6-benzyladenine and gibberellin.

3. The hybridization breeding method according to claim 1, characterized in that, The sowing is aseptic sowing, and the culture medium for aseptic sowing, by concentration, is: 1 / 2 MS medium, 0.1-0.2 mg / L 1-naphthaleneacetic acid, 0.25-0.75 mg / L 6-benzyladenine and 45-60 mg / L gibberellin.

4. The hybridization breeding method according to claim 1, characterized in that, In step S2, the emasculation step includes: removing open flowers and buds that cannot open on the same day, and removing petals and stamens after peeling open the buds.

5. The hybridization breeding method according to claim 1, characterized in that, In step S4, the bagging step includes: bagging the inflorescences of the female parent after emasculation and bagging the inflorescences of the male parent.

6. The hybridization breeding method according to claim 1, characterized in that, The steps for harvesting hybrid capsules include: harvesting the capsules 120 days after repeated pollination of the female parent.

7. The hybridization breeding method according to claim 1, characterized in that, The pollination period is during the peak flowering season in June and July.

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