Dwarf breeding method for broom sorghum

Abstract

The invention belongs to the technical field of sorghum breeding, and particularly relates to a dwarf breeding method for broom sorghum. Comprising the following steps: selecting parents; breeding the parents to obtain treated seeds, soaking the treated seeds in a screening treatment agent for 10-12 hours, taking out the seeds, draining the seeds, drying the seeds, sowing the dried seeds, and screening dwarf plants according to plant heights in a two-leaf one-core period; wherein the formula of each liter of the screening treatment agent is as follows: 2mg-4mg of zinc sulfate, 2mg-4mg of copper sulfate, 1mu g-3 mu g of streptomycin and water for fixing the volume to 1L; and carrying out selfing purification on the screened dwarf plants. According to the method for screening the dwarf plants, the dwarf plants can be screened out in the two-leaf one-core period, the accuracy rate reaches 90% or above, and after three generations of selfing, the situation that the dwarf characters are still stably inherited is 29.4%-47.1% higher than that of a control group. And the screening time and the screening cost of dwarf plants are saved.

Description

Technical Field

[0001] The invention belongs to the technical field of sorghum breeding, and particularly relates to a dwarfing breeding method for broom sorghum. Background Art

[0002] Broom sorghum is an important economic crop, and brooms made from its stalks are widely used in daily life and industrial cleaning. Traditional broom sorghum plants are tall, generally ranging from 2 to 3 meters in height, or even taller. This high plant height can lead to numerous adverse effects during actual cultivation. For one thing, excessively tall plants lead to an unstable center of gravity, making them prone to lodging in the later stages of growth, affecting yield and quality. Furthermore, excessive plant height complicates field management, requiring increased manpower and material resources for operations such as fertilization, pest control, and harvesting. Therefore, dwarfing broom sorghum varieties has become a key approach to addressing these issues. By cultivating dwarf broom sorghum varieties, we can effectively enhance the plant's resistance to lodging, reduce field management costs, and improve planting efficiency, which is of great significance for promoting the sustainable development of the broom sorghum industry.

[0003] Previous sorghum breeding efforts have primarily focused on specific breeding procedures, such as those described in CN115669530B and CN111328710A. These methods involve traditional hybridization and mutagenesis, followed by screening for sorghum with desired traits. Currently, research on dwarf sorghum breeding is limited, and dwarf lines screened from early generations often segregate in subsequent generations due to the presence of heterozygous strains, making it difficult to maintain stable inheritance of the dwarf trait. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a dwarfing breeding method for broom sorghum, which can screen out plants that can stably inherit dwarfing traits, and the screening accuracy is high.

[0005] The object of the present invention is to provide a dwarfing breeding method for broom sorghum, comprising the following steps:

[0006] Step 1, parent selection;

[0007] Step 2: Perform breeding treatment on the parents to obtain treated seeds, and then screen for dwarf plants;

[0008] The method for selecting dwarf plants is as follows:

[0009] After treatment, the seeds are soaked in the screening treatment agent for 10 to 12 hours, taken out, drained, and sown after drying. Dwarf plants are selected based on plant height at the two-leaf and one-heart stage.

[0010] The formula of the screening treatment agent per liter is as follows: 2mg-4mg zinc sulfate, 2mg-4mg copper sulfate, 1μg-3μg streptomycin, and water to 1L; preferably, tap water is used for easy access to water sources;

[0011] One function of zinc sulfate and copper sulfate is to provide nutrients for plant growth. Another function is to synergize with streptomycin. Streptomycin has both antibacterial effects and helps to screen and distinguish dwarf sorghum seeds from sorghum seeds of normal plant height.

[0012] Step three, the selected dwarf plants are self-pollinated for purification.

[0013] Preferably, in the above-mentioned sorghum dwarfing breeding method, the formula of the screening treatment agent per liter is as follows: 3 mg zinc sulfate, 3 mg copper sulfate, 2 μg streptomycin, and water to 1 L.

[0014] Preferably, in the above-mentioned sorghum dwarfing breeding method, the streptomycin is 500,000 units of streptomycin sulfate injection.

[0015] Preferably, in the above-mentioned sorghum dwarfing breeding method, the criteria for sowing and selecting dwarf plants based on plant height at the two-leaf, one-heart stage are as follows:

[0016] 50 to 200 dry seeds are sown in a seedbed. Plant height is measured at the two-leaf, one-heart stage and ranked from lowest to highest by plant height. The top 30% of the ranked plants are considered dwarf plants. It should be noted that the top 30% includes both less than 30% and equal to 30%.

[0017] Preferably, in the above-mentioned sorghum dwarf breeding method, seeds that do not germinate on the 6th day after sowing are removed. Such seeds germinate too late and have poor quality. Removing these seeds in advance can reduce workload.

[0018] Preferably, in the above-mentioned dwarfing breeding method for broom sorghum, the ambient temperature is controlled at 20°C to 30°C after sowing, and seedlings generally emerge in 4 to 6 days.

[0019] Preferably, the selected dwarf plants are self-pollinated for purification for at least three generations to obtain dwarf broom sorghum lines with stable inheritance of traits.

[0020] Preferably, in the above-mentioned sorghum dwarfing breeding method, the breeding treatment of the parents refers to hybrid breeding or mutagenesis treatment.

[0021] Preferably, in the above-mentioned dwarfing breeding method for broom sorghum, the male parent selected for hybrid breeding is American Long Fiber No. 1, and the female parent is Chituo 102;

[0022] The parent subjected to the mutagenesis treatment is Chituo 102.

[0023] Preferably, in the above-mentioned sorghum dwarfing breeding method, the mutagenesis treatment is chemical mutagenesis breeding, such as using ethyl methanesulfonate for mutagenesis breeding, and the specific method of mutagenesis breeding is: soaking the parent seeds in an ethyl methanesulfonate solution with a mass concentration of 0.1 mg / 100 mL to 0.3 mg / 100 mL for 1 hour to 24 hours.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The dwarfing breeding method for broom sorghum of the present invention primarily comprises three steps: parent selection; breeding treatment of the parents to obtain treated seeds, followed by screening for dwarf plants; and self-pollination and purification of the screened dwarf plants. The method for screening for dwarf plants involves soaking the treated seeds in a screening treatment agent for 10 to 12 hours, removing them, draining the water, drying the seeds, and sowing them. Dwarf plants are screened based on plant height at the two-leaf, one-heart stage. The method of the present invention can screen for dwarf plants at the two-leaf, one-heart stage with an accuracy rate exceeding 90%. Furthermore, the rate of stable inheritance of the dwarfing trait after three generations of self-pollination is higher than that of the control group, saving both time and cost in screening for dwarf plants.

[0026] In addition, because the present invention can quickly screen out dwarf broom sorghum plants, it can not only significantly enhance lodging resistance but also reduce costs. In the subsequent breeding process, the dwarf broom sorghum plants are hybridized and backcrossed with varieties with different excellent traits, so that the dwarf varieties not only have dwarfing characteristics, but also have good disease resistance, tolerance to barrenness, salt and alkali resistance and other excellent traits. This allows the dwarf broom sorghum varieties to adapt to different soil and climatic conditions and be planted in a wider range of areas, expanding the planting range of broom sorghum and providing more powerful variety support for industrial development. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the technical roadmap of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below with reference to specific embodiments and drawings.

[0029] In the description of the present invention, unless otherwise specified, all reagents used are commercially available, and all detection methods and field management methods used are conventional techniques in the art.

[0030] The inventive concept of the present invention is as follows:

[0031] In order to overcome the problem that the dwarfing trait screened out by the existing breeding method is poor in stability and that the offspring are separated due to the presence of heterozygous types, making it impossible to effectively maintain the dwarfing effect, the present invention provides a dwarfing breeding method for broom sorghum, see Figure 1 , including the following steps:

[0032] Step 1: Parent selection.

[0033] Step 2: Perform breeding treatment on the parents to obtain treated seeds, and then screen for dwarf plants.

[0034] The method for selecting dwarf plants is as follows:

[0035] After treatment, the seeds are soaked in the screening treatment agent for 10 to 12 hours, taken out, drained, and sown after drying. Dwarf plants are selected based on plant height at the two-leaf and one-heart stage.

[0036] The formula of the screening treatment agent per liter is as follows: 2mg~4mg zinc sulfate, 2mg~4mg copper sulfate, 1μg~3μg streptomycin, and water to make up to 1L.

[0037] Step three, the selected dwarf plants are self-pollinated for purification.

[0038] The dwarf breeding method for broom sorghum and the corresponding method for screening dwarf plants of the present invention can screen out dwarf plants at the two-leaf, one-heart stage with an accuracy rate of over 90%. After three generations of self-pollination, the rate of stable inheritance of the dwarf trait is 29.4% to 47.1% higher than that of the control group, thereby saving the screening time and cost of dwarf plants.

[0039] Preferably, the criteria for sowing and selecting dwarf plants based on plant height at the two-leaf, one-heart stage are as follows:

[0040] 50 to 200 dry seeds are sown in a seedbed, plant heights are measured at the two-leaf and one-heart stage, and the plants are ranked from low to high according to their heights. The top 30% of the plants are dwarf plants.

[0041] The above method can quickly screen out dwarf broom sorghum plants, which can not only significantly enhance lodging resistance but also reduce costs. In the subsequent breeding process, dwarf broom sorghum plants are hybridized and backcrossed with varieties with different excellent traits, so that the dwarf varieties not only have dwarfing characteristics, but also have good disease resistance, tolerance to barrenness, salt and alkali resistance and other excellent traits. This allows dwarf broom sorghum varieties to adapt to different soil and climatic conditions and be planted in a wider range of areas, expanding the planting range of broom sorghum and providing stronger variety support for industrial development.

[0042] Preferably, the breeding treatment of the parents refers to cross breeding or mutagenesis. The mutagenesis treatment is chemical mutagenesis. The chemical mutagenesis is carried out using ethyl methanesulfonate. The specific method of mutagenesis is as follows: soaking the seeds of the parents in a solution of ethyl methanesulfonate at a concentration of 0.1 mg / 100 mL to 0.3 mg / 100 mL for 1 to 2 hours.

[0043] The above-mentioned hybrid breeding methods or mutation breeding methods are common, highly feasible, technically mature methods, and the offspring are more likely to produce plants with target traits.

[0044] The present invention is described below with reference to specific embodiments and experiments.

[0045] Example 1

[0046] This embodiment provides a dwarfing breeding method for broom sorghum, comprising the following steps:

[0047] Step 1: Parent selection

[0048] Collect broom sorghum germplasm from diverse ecological regions, encompassing varieties from tropical, subtropical, and temperate climate zones, to establish a rich and broadly representative germplasm bank. Preliminary planting observations will be conducted on the collected broom sorghum germplasm. During the planting process, environmental factors such as soil conditions, fertilizer application rates, and irrigation frequency will be controlled to ensure the accuracy of experimental results. Key traits such as plant height, culm strength, and branching characteristics will be recorded. From these, materials with shorter plant heights and good agronomic performance will be selected as parents.

[0049] Among them, shorter plant height may refer to a variety that is 15% to 20% shorter than the local main cultivated variety, or may refer to other varieties with shorter plant height.

[0050] Good agronomic traits refer to varieties with strong stem toughness, which are not easy to break under certain external forces and have neat fracture ends after breaking; varieties with many and uniform branches, and the number of branches reaches a certain standard or above; varieties with excellent performance in traits such as ear length, ear stalk length, number of primary branches, and length of primary branches.

[0051] Parent selection is the basis of the entire dwarf breeding method of broom sorghum, and can greatly increase the probability of breeding ideal dwarf broom sorghum varieties.

[0052] In this embodiment, the male parent is selected from the broom sorghum variety American Long Fiber No. 1 with strong stem toughness and a good number of branches. The main characteristics of this variety are as follows: plant height 2.5m to 2.8m, ear length about 56cm, ear stalk length about 30cm, number of primary stalks about 47, and primary stalk length about 52cm.

[0053] The female parent selected was the germplasm material Chituo 102 with dwarfing characteristics and outstanding comprehensive traits. The main traits of this variety are as follows: plant height is about 105 cm, main ear length is about 42 cm, ear stalk length is about 30 cm, primary stalk length is about 29 cm, the number of primary stalks is about 64, the primary stalks are uniform and consistent, the stalks are yellow-green, it is a new early-maturing dwarf sorghum variety with anti-broom properties, good branch quality, moderate resistance to head smut, relatively mild leaf diseases, resistance to borers, and no diseases and insect pests have been found in the production fields.

[0054] Step 2: Hybrid breeding and screening of dwarf plants

[0055] This embodiment adopts artificial pollination operation for hybridization, and the operation steps are as follows: before pollination, the stamens of the female parent are cleaned to prevent self-pollination, and then pollination is carried out with pollen from the male parent, and isolation measures are taken to ensure that the purity of the hybrid seeds is not disturbed by external pollen.

[0056] After harvesting the F1 hybrid seeds, dwarf plants are screened, and detailed records are taken of traits such as leaf morphology, stem toughness, and branch number. Due to heterosis, the F1 generation may exhibit super-parental vigor, where plant height and other traits surpass those of both parents. Therefore, the present invention conducts a rigorous screening process for dwarf plants at this stage to select high-quality F1 plants that meet the desired traits.

[0057] Among them, the method for screening dwarf plants is as follows:

[0058] (1) F1 hybrid seeds were soaked in a screening agent for 10 hours, removed, drained, dried, and stored for future use. The formulation of the screening agent per liter was as follows: 2 mg zinc sulfate, 2 mg copper sulfate, 1 μg streptomycin, and diluted to 1 L with tap water. The streptomycin was 500,000 units of streptomycin sulfate injection.

[0059] (2) 100 dry seeds were sown in the seedbed, and the plant height was measured at the two-leaf and one-heart stage. The plants were sorted from low to high according to plant height. Among them, the top 30% and 30% of the plants were dwarf plants, that is, excellent F1 generation plants.

[0060] Step three: self-pollination purification.

[0061] The excellent F1 generation plants were self-pollinated for three generations, so that the dwarfing traits and other excellent traits could be stably inherited, and finally a dwarf broom sorghum variety was obtained.

[0062] It should be noted that field management, such as weeding, pest control, disease control, irrigation, and fertilization, should be carried out during the growth period of sorghum. The same field management methods were used in the examples and the control group, with the only difference being in Table 1.

[0063] Table 1 Differences between Examples and Control Groups

[0064]

[0065] Note: “ / ” in Table 1 means no operation of screening dwarf plants was performed.

[0066] The mutagenesis treatment of Example 11 in Table 1 is chemical mutagenesis breeding, and the related dwarfing breeding method for broom sorghum is as follows:

[0067] Step 1: Parent selection

[0068] The parent is the broom sorghum variety Chituo 102, which has strong stem toughness and a good number of branches.

[0069] Step 2: Chemical mutagenesis and screening of dwarf plants

[0070] The parent seeds were soaked in EMS (ethyl methanesulfonate) mutagen for 20 hours for mutagenesis, and then the seeds were taken out and the residual EMS was washed off with tap water to obtain chemically mutagenized seeds, wherein the EMS mutagen was obtained by dissolving 0.8 mL of EMS in 70% by volume ethanol and mixing them evenly.

[0071] Dwarf plants are screened using seeds that have undergone chemical mutagenesis. Detailed records are kept of traits such as leaf morphology, stem toughness, and number of branches to select sorghum dwarf strains that meet the target traits.

[0072] Among them, the method for screening dwarf plants is as follows:

[0073] (1) After chemical mutagenesis, the seeds were soaked in a screening agent for 10 hours, removed, drained, dried, and stored for future use. The formulation of the screening agent per liter was as follows: 2 mg zinc sulfate, 2 mg copper sulfate, 1 μg streptomycin, and diluted to 1 L with tap water. The streptomycin was 500,000 units of streptomycin sulfate injection.

[0074] (2) 100 dry seeds were sown in the seedbed, and the plant height was measured at the two-leaf and one-heart stage. The plants were ranked from low to high according to plant height. Among them, the top 30% and 30% of the ranked plants were dwarf plants, that is, dwarf sorghum strains for broom.

[0075] Step three: self-pollination purification.

[0076] The dwarf broom sorghum line was self-pollinated for three generations, so that the dwarfing trait and other excellent traits could be stably inherited, and finally a dwarf broom sorghum variety was obtained.

[0077] The present invention has also carried out the following application experiment:

[0078] According to the grouping in Table 1, 100 seeds were selected for each grouping to conduct a dwarf plant screening test and field planting verification. 100 dried F1 generation seeds (i.e., seeds after breeding treatment) were screened for dwarf plants at the two-leaf, one-heart stage. The specific operation of screening dwarf plants at the two-leaf, one-heart stage was as follows: the seeds were soaked in a screening treatment agent for 10 hours, removed, drained, and dried; wherein, the formula of the screening treatment agent per liter was as follows: 2 mg zinc sulfate, 2 mg copper sulfate, 1 μg streptomycin, and diluted to 1 L with tap water; the streptomycin was 500,000 units of streptomycin sulfate injection; the dried seeds were sown in a seedbed, and the plant height was measured at the two-leaf, one-heart stage. The plants were ranked from low to high according to plant height. The top 30% and above were dwarf plants. Before ranking, seeds that did not germinate on the sixth day after sowing were removed, as such seeds germinated too late and had poor quality. The number of dwarf plants screened out and the number of plants with mature plant heights below 150 cm were recorded, and the statistical results are shown in Table 2.

[0079] Among them, the control group did not screen for dwarf plants, but directly sowed the F1 generation seeds in the seedbed, measured the plant height at the two-leaf and one-heart stage, and sorted them from low to high according to plant height. The top 30% and including 30% were dwarf plants. Before sorting, the seeds that did not germinate on the 6th day after sowing were removed.

[0080] The results in Table 2 show that the method of the present invention has a high accuracy rate in screening out dwarf plants. After three generations of self-pollination, the rate of stable inheritance of dwarf traits is 29.4% to 47.1% higher than that of the control group.

[0081] Table 2 Screened dwarf plants

[0082]

[0083] Table 3 Comprehensive quality of dwarf plants obtained by self-pollination purification (measured three times and averaged)

[0084]

[0085]

[0086] The results in Table 3 show that the quality of the dwarf sorghum plants screened for broom use according to the embodiment of the present invention is also better than that of the control group.

[0087] Primary stalk thickness, a key ear trait of sorghum, impacts its quality in many ways. For example, it increases the number of grains per ear. Increased primary stalk thickness means a more robust ear structure, capable of supporting more grains. It also improves lodging resistance. Sorghum plants with robust stalks have greater support and lodging resistance. This improved lodging resistance helps ensure better photosynthesis in the later stages of sorghum growth, reducing grain loss and quality degradation caused by lodging, thereby indirectly increasing yield.

[0088] Sorghum plants with more primary branches can carry more spikelets, thereby increasing the number of grains per spike, which is one of the key factors in increasing yield. The dominant structure of the primary branches can also improve the ventilation and light conditions of the spike and increase the fruit set rate.

[0089] The length of primary branches is also one of the important traits of sorghum, and is highly correlated with the number of grains per ear and yield.

[0090] When the thickness of the first-level branches, the number of the first-level branches and the length of the first-level branches are all advantageous, the yield of branches per mu is high, and the brooms made from the corresponding sorghum plants have good commercial value, because brooms made from sorghum are made from the first-level branches.

[0091] Therefore, the dwarf sorghum plants with good primary stalk length, primary stalk number, and primary stalk thickness have at least the following comprehensive advantages:

[0092] (1) Enhanced adaptability: Dwarf plants are more compact in structure and can better adapt to dense planting conditions, thereby increasing yield per unit area.

[0093] (2) Quality improvement: Optimization of the ear structure helps improve the quality of broom sorghum, such as reducing grain shedding and increasing thousand-grain weight.

[0094] (3) Lodging resistance: Dwarf plants have a lower center of gravity, which, combined with thick spike necks and stalks, can significantly reduce the risk of lodging.

[0095] It should be noted that after the excellent F1 generation plants grow to the appropriate stage, they are self-pollinated to obtain the F2 generation population. In the F2 generation population, due to the separation and recombination of genes, extremely rich trait separation will appear. At this time, the screening and dwarfing plant treatment operation can be continued. For example, the F2 generation seeds are soaked in the screening treatment agent for 10 hours or 12 hours, taken out, drained, and after the seeds are dried, 50, 100 or 200 dry seeds are taken and sown in the seedbed. The plant height is measured at the two-leaf and one-heart stage, and the plants are ranked from low to high according to plant height. Among them, the top 30% of the plants are dwarf plants, and the dwarf sorghum strains that better meet the target traits are selected; the formula of the screening treatment agent per liter is as follows: 2mg~4mg zinc sulfate, 2mg~4mg copper sulfate, 1μg~3μg streptomycin, and the volume is adjusted to 1L with water.

[0096] It should be noted that when numerical ranges are involved in the present invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the inventive concept of the present invention, and such changes and modifications fall within the scope of the present invention.

[0097] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. If these modifications and variations of the present invention fall within the scope of the equivalent technology of the present invention, the present invention is intended to include these modifications and variations.

Claims

1. A dwarfing breeding method for broom sorghum, characterized in that: The following steps are involved: Step 1, parent selection; Step 2: Perform breeding treatment on the parents to obtain treated seeds, and then screen for dwarf plants; The method for selecting dwarf plants is as follows: After treatment, the seeds are soaked in the screening treatment agent for 10 to 12 hours, taken out, drained, and sown after drying. Dwarf plants are selected based on plant height at the two-leaf and one-heart stage. The formula of the screening treatment agent per liter is as follows: 2mg~4mg zinc sulfate, 2mg~4mg copper sulfate, 1μg~3μg streptomycin, and water to 1L; Step three, the selected dwarf plants are self-pollinated for purification.

2. The dwarfing breeding method for broom sorghum according to claim 1, characterized in that: The formula of the screening treatment agent per liter is as follows: 3 mg of zinc sulfate, 3 mg of copper sulfate, 3 μg of streptomycin, and dilute to 1 L with water.

3. The dwarfing breeding method for broom sorghum according to claim 1, characterized in that: The streptomycin is 500,000 units of streptomycin sulfate injection.

4. The dwarfing breeding method for broom sorghum according to claim 1, characterized in that: The criteria for sowing and selecting dwarf plants based on plant height at the two-leaf, one-heart stage are as follows: 50 to 200 dry seeds are sown in a seedbed, plant heights are measured at the two-leaf and one-heart stage, and the plants are ranked from low to high according to their heights. The top 30% of the plants are dwarf plants.

5. The dwarfing breeding method for broom sorghum according to claim 1, characterized in that: Remove the seeds that do not germinate on the 6th day after sowing.

6. The dwarfing breeding method for broom sorghum according to claim 1, characterized in that: After sowing, control the ambient temperature to 20℃~30℃.

7. The dwarfing breeding method for broom sorghum according to claim 1, characterized in that: Breeding treatments on parents refer to cross breeding or mutagenesis treatments.

8. The dwarfing breeding method for broom sorghum according to claim 7, characterized in that: The male parent selected for hybrid breeding is American Long Fiber No. 1, and the female parent is Chituo 102; The parent subjected to the mutagenesis treatment is Chituo 102.

9. The dwarfing breeding method for broom sorghum according to claim 7, characterized in that: The mutagenesis treatment is chemical mutagenesis breeding.

10. The dwarfing breeding method for broom sorghum according to claim 9, characterized in that: The chemical mutagenesis breeding utilizes ethyl methanesulfonate for mutagenesis breeding. The specific method of the mutagenesis breeding is as follows: soaking the seeds of the parent in an ethyl methanesulfonate solution with a mass concentration of 0.1 mg / 100 mL to 0.3 mg / 100 mL for 1 hour to 24 hours.

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