A method of treating kidney bean seeds against a continuous cropping obstacle

Abstract

The application relates to the technical field of seed treatment, and particularly discloses a kidney bean seed treatment method for resisting continuous cropping obstacles. The method comprises the following steps: applying an aqueous pre-coating pretreatment liquid containing benzothiadiazole-S-methyl ester and hydroxypropyl-beta-cyclodextrin to the surface of kidney bean seeds at a dosage of 15-25 g / kg of seeds and uniformly mixing; placing the treated kidney bean seeds at 15-25 DEG C for 2-4 hours; ventilating or airing until no visible liquid drops exist on the surface of the seeds, and no obvious adhesion exists between the seeds; and then applying a seed coating agent containing a fungicidal active ingredient and drying. The concentration of the benzothiadiazole-S-methyl ester in the pre-coating pretreatment liquid is 20-55 mg / L, and the mass ratio of the hydroxypropyl-beta-cyclodextrin to the benzothiadiazole-S-methyl ester is 6:1-12:1. The method can help reduce the seedling stage root rot disease index of kidney beans under the condition of continuous cropping soil and improve the seedling emergence rate.

Description

Technical Field

[0001] This invention relates to the field of seed treatment technology, and more specifically to a method for treating kidney bean seeds to resist continuous cropping obstacles. Background Technology

[0002] Seed treatment is a common method of disease control in agricultural production. It usually involves applying fungicides, plant growth regulators, plant activators, and adjuvants to the seed surface to reduce the impact of seed-borne pathogens and soil-borne pathogens during the seedling stage on seeds and seedlings, or to improve the adaptability of seeds and seedlings to adverse environments.

[0003] Continuous planting of kidney beans in the same plot can lead to problems such as root rot, seed rot, pre-emergence mortality, and uneven emergence. After seed germination, the radicle and young roots gradually come into contact with the soil, making them susceptible to factors such as soil temperature, moisture content, and pathogens. Therefore, pre-sowing seed treatment is a crucial step in controlling diseases in kidney bean seedlings. We generally treat kidney bean seeds with seed coating agents containing fungicidal active ingredients, allowing these active ingredients to adhere to the seed surface along with the coating layer, providing some pathogen protection to the seeds and seedlings after sowing. Plant activators such as benzothiadiazole-S-methyl ester can also be used to treat seeds to induce a defensive response in the seeds or seedlings. In some seed treatment methods, plant activators can be added together with fungicidal active ingredients, film-forming agents, and other adjuvants to the seed coating agent and applied to the seed surface in one application.

[0004] Plant activators and fungicidal active ingredients act differently. When both are co-contained in the seed coating layer, the contact between the plant activator and the seed, and its release process, may be affected by the coating material and other components in the seed coating agent. Treating seeds with an aqueous solution of the plant activator alone requires consideration of both the water-based application properties of the treatment solution and the uniformity of application on the seed surface. For plant activators with limited water solubility, such as benzothiadiazole-S-methyl ester, these issues may be more pronounced when the treatment solution volume is small. Summary of the Invention

[0005] The purpose of this invention is to provide a method for treating kidney bean seeds to resist continuous cropping obstacles, so as to take into account the water-based application performance of plant activators, seed treatment uniformity, and the coordination between plant resistance induction treatment and subsequent sterilization and coating.

[0006] The specific technical solution of the present invention is as follows.

[0007] This invention provides a method for treating kidney bean seeds to resist continuous cropping obstacles, comprising the following steps: S1. Apply the pre-coating solution to the surface of kidney bean seeds at a rate of 15-25 g / kg of seeds and mix evenly. The pre-coating solution includes benzothiadiazole-S-methyl ester (ASM), hydroxypropyl-β-cyclodextrin and water. The concentration of ASM is 20-55 mg / L, and the mass ratio of hydroxypropyl-β-cyclodextrin to ASM is 6:1-12:1. S2. Place the kidney bean seeds treated in step S1 at 15-25℃ for 2-4 hours; S3. Ventilate or spread out the kidney bean seeds treated in step S2 until there are no visible droplets on the seed surface and no obvious adhesion between the seeds. S4. Apply a seed coating agent containing bactericidal active ingredients to the surface of the kidney bean seeds treated in step S3, and then dry them.

[0008] The common English name for benzothiadiazole-S-methyl ester is acibenzolar-S-methyl, abbreviated as ASM, and it belongs to the category of plant activators.

[0009] In this invention, a pretreatment solution containing ASM and hydroxypropyl-β-cyclodextrin is first applied to kidney bean seeds. After being placed and ventilated or spread out to dry, a seed coating agent containing bactericidal active ingredients is then applied, thereby implementing the plant activator pretreatment and bactericidal coating in separate steps.

[0010] In some embodiments, the concentration of ASM in the pretreatment solution before coating is 20-55 mg / L, preferably 28-42 mg / L; the mass ratio of hydroxypropyl-β-cyclodextrin to ASM is 6:1-12:1, preferably 7:1-10:1.

[0011] In some embodiments, the pretreatment solution for coating is prepared by a method comprising the following steps: Hydroxypropyl-β-cyclodextrin was added to water and stirred at 35–45°C to dissolve it, thus obtaining an aqueous solution of hydroxypropyl-β-cyclodextrin. ASM is dissolved in ethanol to obtain an ASM ethanol solution; Under stirring conditions at 35–45°C, the feeding time is controlled at 10–30 min. The ASM ethanol solution is gradually added to the hydroxypropyl-β-cyclodextrin aqueous solution. After the addition is completed, stirring is continued for 1–3 h. Ethanol is removed under reduced pressure, with the system temperature at 45°C or less during the removal process, and water is added to a predetermined volume to obtain the pretreatment solution before coating.

[0012] In the above preparation process, ASM ethanol solution is gradually added to hydroxypropyl-β-cyclodextrin aqueous solution, and ethanol is removed under reduced pressure after constant temperature stirring to improve the dispersion state of the obtained pretreated solution.

[0013] In some embodiments, under conditions of 38–42°C, the feeding time is controlled to be 15–25 min, and the ASM ethanol solution is gradually added to the hydroxypropyl-β-cyclodextrin aqueous solution. After the feeding is completed, stirring is continued for 1.5–2.5 h.

[0014] In some embodiments, ethanol is removed under reduced pressure at a system temperature of less than or equal to 45°C until the ethanol content in the resulting pre-coating solution is less than or equal to 0.5 wt%, preferably less than or equal to 0.3 wt%. The ethanol content can be determined by headspace gas chromatography.

[0015] In some embodiments, the amount of the pretreatment solution used before coating is 15-25 g / kg relative to the kidney bean seeds.

[0016] In some embodiments, step S1 uses a rotary drum seed treatment device to turn the kidney bean seeds at a speed of 20-35 rpm and spray the pre-treatment solution before coating within 1-3 minutes; after spraying, continue mixing for 3-6 minutes to distribute the pre-treatment solution on the surface of the kidney bean seeds.

[0017] In some embodiments, in step S2, the kidney bean seeds treated with the pre-coating solution are placed at 15–25°C for 2–4 hours and turned over at least once during the placement period.

[0018] In some embodiments, in step S3, the kidney bean seeds are ventilated at 20–30°C for 10–60 minutes. The ventilation treatment ends when there are no visible droplets on the seed surface and no obvious adhesion between the seeds.

[0019] In some embodiments, in step S4, the amount of seed coating agent used relative to kidney bean seeds is 8-15 g / kg.

[0020] In some embodiments, the fungicidal active ingredient in the seed dressing agent is selected from one or more of metalaxyl, fludioxonil, tebuconazole, and thiamethoxam. The fungicidal active ingredient may be a combination of metalaxyl and fludioxonil, tebuconazole, or a combination of thiamethoxam and fludioxonil.

[0021] The term "resistance to continuous cropping obstacles" in this invention refers to reducing the incidence of root rot disease in seedlings and increasing the emergence rate of kidney beans under continuous cropping soil conditions.

[0022] Compared with existing technologies, the present invention has at least the following beneficial effects: Under the experimental conditions of this application, the pretreatment solution before coating has a high 7-day filterable ASM retention rate, and the ASM load variation among different seed samples after treatment is small. Compared with treatments such as only performing fungicide coating, applying the pretreatment solution and seed coating agent in one step, and not placing the seedlings after pretreatment, the method of the present invention has higher early defense-related enzyme activity, higher seedling emergence rate in continuously cropped soils, and lower seedling root rot disease index; the subsequent fungicide actual loading rate, loading coefficient of variation, and coating shedding rate are close to those of the fungicide-only coating group. Detailed Implementation

[0023] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] Example 1: Preparation of pretreatment solution before coating Weigh 0.252 g of hydroxypropyl-β-cyclodextrin and add it to 700 mL of deionized water. Stir at 40 °C until dissolved to obtain an aqueous cyclodextrin solution. Weigh 31.5 mg of ASM and add it to 10 mL of ethanol. Stir until dissolved to obtain an ASM ethanol solution.

[0025] The cyclodextrin aqueous solution was kept at 40°C with continuous stirring. An ASM ethanol solution was uniformly added to the cyclodextrin aqueous solution over 20 minutes. After addition, stirring was continued at 40°C for 2 hours. Ethanol was then removed under reduced pressure at 40°C, cooled to room temperature, and diluted to 1 L with deionized water to obtain the pretreatment solution before coating. Headspace gas chromatography analysis showed that the ethanol content in the pretreatment solution was 0.28 wt%. The theoretical concentration of ASM in the pretreatment solution was 31.5 mg / L, and the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 8:1.

[0026] In addition to the bactericidal active ingredients listed in Table 1, each bactericidal seed coating agent comprises 2.0 wt% polyvinyl alcohol, 0.5 wt% sodium carboxymethyl cellulose, 0.8 wt% sodium lignosulfonate, 0.2 wt% nonionic wetting agent (Tween 80), 0.1 wt% organosilicon defoamer (polydimethylsiloxane emulsion), and the balance water, which are prepared by shear dispersion.

[0027] Table 1. Composition and dosage of active ingredients in fungicide seed coating agents

[0028] Example 2: Pretreatment before coating with fungicide seed coating agent A and subsequent fungicide coating Place 1000g of kidney bean seeds in a rotary drum seed treatment device and agitate them at 25 rpm. While the seeds are continuously agitated, spray 20g of the pre-treatment solution prepared in Example 1 evenly over 1 minute. After spraying, continue mixing for 4 minutes.

[0029] The pretreated seeds were placed at 20℃ for 3 hours, and turned over once after 1.5 hours. After the initial placement, the seeds were treated at 25℃ under ventilation for 30 minutes until no visible droplets remained on the seed surface and the seeds did not stick together significantly. Subsequently, fungicide seed coating agent A was applied at a dosage of 10 g / kg of seeds, rolled and coated for 3 minutes, and then dried at 25℃ under ventilation for 4 hours.

[0030] Examples 3-11 investigated the effects of ASM concentration, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM, the amount of pretreatment solution used before coating, and the standing time on the treatment effect. Except for the parameters listed in each example, the preparation method of the pretreatment solution was the same as in Example 1, and the treatment method of the kidney bean seeds was the same as in Example 2. Factors and levels are shown in Table 2.

[0031] Table 2 Experimental Factors and Levels

[0032] Example 3 The concentration of ASM was 20 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 6:1, the amount of pretreatment solution used before coating was 15 g / kg of seeds, and the standing time was 2 h.

[0033] Example 4

[0034] The concentration of ASM was 20 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 8:1, the amount of pretreatment solution used before coating was 20 g / kg of seeds, and the standing time was 3 h.

[0035] Example 5

[0036] The concentration of ASM was 20 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 12:1, the amount of pretreatment solution used before coating was 25 g / kg of seeds, and the standing time was 4 h.

[0037] Example 6

[0038] The ASM concentration was 31.5 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 6:1, the amount of pretreatment solution used before coating was 20 g / kg of seeds, and the standing time was 4 h.

[0039] Example 7

[0040] The ASM concentration was 31.5 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 8:1, the amount of pretreatment solution used before coating was 25 g / kg of seeds, and the standing time was 2 h.

[0041] Example 8

[0042] The ASM concentration was 31.5 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 12:1, the amount of pretreatment solution used before coating was 15 g / kg of seeds, and the standing time was 3 h.

[0043] Example 9

[0044] The ASM concentration was 55 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 6:1, the amount of pretreatment solution used before coating was 25 g / kg of seeds, and the standing time was 3 h.

[0045] Example 10

[0046] The concentration of ASM was 55 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 8:1, the amount of pretreatment solution used before coating was 15 g / kg of seeds, and the standing time was 4 h.

[0047] Example 11

[0048] The concentration of ASM was 55 mg / L, the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 12:1, the amount of pretreatment solution used before coating was 20 g / kg of seeds, and the standing time was 2 h.

[0049] Example 12

[0050] The kidney bean seeds were treated according to the method of Example 2, except that the concentration of ASM in the pretreatment solution before coating was 28 mg / L, and the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 8:1; the other conditions were the same as in Example 2.

[0051] Example 13

[0052] The kidney bean seeds were treated according to the method of Example 2, except that the concentration of ASM in the pretreatment solution before coating was 55 mg / L and the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 8:1; the other conditions were the same as in Example 2.

[0053] Example 14

[0054] Kidney bean seeds were treated according to the method of Example 2, except that the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 6:1; the other conditions were the same as in Example 2.

[0055] Example 15

[0056] The kidney bean seeds were treated according to the method of Example 2, except that the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 12:1; the other conditions were the same as in Example 2.

[0057] Example 16

[0058] The kidney bean seeds were treated according to the method in Example 2, except that fungicide seed coating agent A was replaced with fungicide seed coating agent B.

[0059] Example 17

[0060] The kidney bean seeds were treated according to the method in Example 2, except that fungicide seed coating agent A was replaced with fungicide seed coating agent C.

[0061] Comparative Example To investigate the effects of pretreatment solution composition and preparation method, treatment sequence, and type of fungicide seed coating agent on the treatment results, the following comparative examples were set up. Unless otherwise specified, comparative examples 1-7 and 9-11 used fungicide seed coating agent A, while comparative example 8 did not apply any fungicide seed coating agent. Except for comparative examples 7, 9, and 11, the theoretical application rate of ASM relative to seeds in each ASM-containing treatment group was the same as in Example 2.

[0062] Comparative Example 1: Sterilization and coating were performed using only 10g / kg of seeds, without any pretreatment before coating.

[0063] Comparative Example 2, without the addition of hydroxypropyl-β-cyclodextrin. 31.5 mg ASM was dissolved in 10 mL of ethanol, and added to 700 mL of water over 20 min. The ethanol was then removed under reduced pressure according to the conditions of Example 1, and the volume was brought to 1 L. The resulting treatment solution was used for seed pretreatment, storage, and sterilization coating according to Example 2.

[0064] Comparative Example 3 used the same amounts of ASM and hydroxypropyl-β-cyclodextrin as in Example 1, but without the stepwise addition and constant-temperature stirring. The ASM ethanol solution, hydroxypropyl-β-cyclodextrin, and water were mixed at room temperature for 10 min, and the ethanol was removed under reduced pressure according to the conditions of Example 1 and the volume was brought to 1 L. The resulting treatment solution was used for seed treatment according to Example 2.

[0065] Comparative Example 4: The pretreatment solution for coating of Example 1 was sprayed and mixed, but not left to stand. The mixture was immediately ventilated for 30 minutes, followed by sterilization and coating.

[0066] Comparative Example 5: 20g of pre-coating solution per kilogram of seeds in Example 2 was mixed with 10g of fungicide seed coating agent and applied to the surface of kidney bean seeds in one go, without setting separate pre-coating treatment and placement steps.

[0067] Comparative Example 6: First, the kidney bean seeds were sterilized, coated, and dried. Then, an equal amount of pre-coating solution as in Example 2 was applied, and the seeds were ventilated and dried.

[0068] Comparative Example 7 was processed according to Example 2, except that the pretreatment solution before coating did not contain ASM, and the amount of hydroxypropyl-β-cyclodextrin was the same as in Example 2.

[0069] Comparative Example 8 was pretreated and placed according to Example 2, but without subsequent sterilization coating.

[0070] Comparative Example 9 was treated according to Example 2, except that the concentration of ASM in the pretreatment solution before coating was 80 mg / L and the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 8:1.

[0071] Comparative Example 10 was processed according to Example 2, except that the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 3:1.

[0072] Comparative Example 11 was treated according to Example 2, except that the concentration of ASM in the pretreatment solution before coating was 10 mg / L and the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was 8:1.

[0073] Comparative Example 12: fungicide seed coating agent B was applied at a dosage of 10 g / kg of seeds, without any pretreatment before coating.

[0074] Comparative Example 13: fungicide seed coating agent C was applied at a dosage of 10 g / kg of seeds, without any pretreatment before coating.

[0075] Test methods Unless otherwise specified, each test was conducted in triplicate. The pot experiments in the rotation soil and continuous cropping soil were conducted in triplicate, with 5 pots per replicate and 20 seeds sown in each pot. The germination rate and root rot disease index were calculated for each replicate. The results in the table are the average of the 3 triplicates.

[0076] Test Method 1: ASM retention rate after 7 days of storage of the pretreated solution. After thoroughly mixing the pretreatment solution, the initial ASM concentration C0 was determined, and the solution was then placed in a sealed brown glass bottle and stored at 25°C for 7 days. After storage, the sample was slowly inverted and mixed 10 times, filtered through a 0.45 μm polyethersulfone microporous membrane pre-washed with the sample, and the ASM concentration C7 in the filtrate was determined. The ASM concentration was determined by high-performance liquid chromatography (HPLC). The ASM retention rate after 7 days of storage was calculated as the percentage of C7 to C0.

[0077] Test Method 2: ASM loading and its coefficient of variation can be extracted from small samples within a batch. Each treatment was performed independently three times. Before each coating, and after pretreatment and placement but before sterilization coating, 30 seed samples (10.0 g each) were randomly selected from different locations on the treated seeds. ASM was extracted using acetonitrile-water mixed solvent with shaking, and determined by high-performance liquid chromatography (HPLC). The actual ASM loading rate of the sample was the ratio of the measured ASM mass to the theoretical ASM mass applied to that sample; the theoretical ASM mass was calculated based on the actual amount of pretreatment solution applied relative to the seeds, the measured density of the pretreatment solution, the initial measured ASM concentration C0, and the seed sample mass. The coefficient of variation of ASM loading within each batch was calculated for each treatment; the results in the table are the average of the three independent treatments.

[0078] Test Method 3: Early Defense-Related Enzyme Activity Seeds from each treatment were collected and germinated at 25℃ after absorbing water. Thirty seeds were collected from each replicate, and after 24 hours of water absorption, the embryo and adjacent hypocotyl tissue were excised, mixed, and 0.5g was weighed for enzyme extraction. Phenylalanine ammonia-lyase activity was measured using L-phenylalanine as a substrate, and the trans-cinnamic acid produced was determined. β-1,3-glucanase activity was measured using laminarin as a substrate, and the amount of reducing sugar produced was determined. Enzyme activities were normalized to soluble protein content. The relative enzyme activity of each treatment was calculated with the absolute enzyme activity of the same batch of untreated seeds as 1.00.

[0079] Test Method 4: Low Temperature Germination Experiment Each treatment was performed in triplicate, with 100 seeds per replicate. The seeds were placed on a moist filter paper germination bed and germinated at 10°C. Germination potential was assessed on day 7, and germination rate was assessed on day 14. At least 10 normal seedlings were randomly selected from each replicate, and the length from the base of the radicle to the root tip was measured and the average value was calculated.

[0080] Test Method 5: Coating Quality and Storage Stability The content of active ingredients in seed samples was determined using high-performance liquid chromatography (HPLC) methods suitable for the corresponding fungicidal active ingredients. The actual fungicide loading rate was the ratio of the sum of the measured application amounts of each fungicide active ingredient to the sum of the theoretical application amounts; the coefficient of variation of fungicide loading was calculated from the results of 30 randomly selected samples.

[0081] The coating shedding rate was determined by the change in mass of the coated seeds before and after shaking. The mass of uncoated seeds was recorded as m0, and the mass of coated and dried seeds was recorded as m1. The coated seeds were shaken at 150 rpm for 30 min, and the mass of the seeds after removing the shed material was recorded as m2. The coating shedding rate was calculated as (m1 - m2) / (m1 - m0) × 100%.

[0082] The treated seeds were stored at 20℃ and 50% relative humidity for 60 days. After storage, each treatment was replicated three times, with 100 seeds taken each time, and the germination rate was determined according to GB / T 3543.4—1995 "Specifications for Seed Inspection of Agricultural Crops - Germination Test".

[0083] Test Method 6: Pot Experiments in Rotation Soil and Continuous Crop Soil Soils from both crop rotation and continuous cropping were collected from the same experimental area. Continuous cropping soil consisted of topsoil from areas where kidney beans had been planted for three consecutive seasons, while crop rotation soil consisted of adjacent topsoil from areas where no legumes had been previously grown. Soil samples with similar pH, organic matter, and electrical conductivity were selected, sieved through a 5mm sieve, and mixed thoroughly. Each pot contained 5 kg of soil, with five pots per replicate, and 20 seeds were sown in each pot. Germination rate was recorded 14 days after sowing. On day 28, the root rot disease index was assessed on germinated plants. Seeds that had not yet germinated were only counted in the germination rate and not in the root rot disease index.

[0084] Root rot disease is classified into four grades: Grade 0: no obvious browning on the roots; Grade 1: browning area not exceeding 1 / 4 of the total root area; Grade 2: browning area exceeding 1 / 4 but not exceeding 1 / 2; Grade 3: browning area exceeding 1 / 2 but not exceeding 3 / 4; Grade 4: browning area exceeding 3 / 4, with plant wilting or death. The disease index is calculated by multiplying the sum of the products of the number of plants at each disease grade and the corresponding representative value, divided by the product of the total number of plants surveyed and the highest representative value of the disease grade, and then multiplying by 100. The germination rate is calculated using the total number of seeds sown as the denominator, while the root rot disease index is calculated using the number of plants that have emerged and been surveyed as the denominator.

[0085] Test case Test Example 1: Determination of Experimental Results and Optimal Conditions Examples 3-11 were tested according to test methods 1-4 and test method 6. The experimental design and results are shown in Table 3. For screening, the basic conditions were that the ASM retention rate after 7 days of storage in the pretreated solution was not less than 90%, and the germination rate after 14 days at 10℃ was not less than 85%. Among combinations meeting these basic conditions, the coefficient of variation of ASM loading, relative enzyme activity of phenylalanine ammonia-lyase, and root rot disease index in continuously cropped soil were compared among the samples within the batch.

[0086] Table 3 Experimental Design and Results

[0087] Table 3 shows that as the mass ratio of hydroxypropyl-β-cyclodextrin to ASM (factor B) increases, the overall retention rate of filterable ASM in the pretreatment solution after 7 days of storage increases, and the overall coefficient of variation of ASM loading in the batch decreases. The increases in the mass ratio, ASM concentration, and pretreatment solution dosage did not lead to a sustained improvement in the activity of early defense-related enzymes or the root rot disease index in continuously cropped soils. The pretreatment solution in Example 11 showed a high retention rate of filterable ASM after 7 days of storage and a low coefficient of variation of ASM loading in the batch, but the germination rate at 10℃ for 14 days was lower than the screening conditions. Based on the comprehensive performance of each factor at different levels, A2, B2, C2, and D2 were selected for combined verification, and this parameter combination was used in Example 2. Test Example 2: The influence of pretreatment solution composition and preparation method.

[0088] According to test methods 1-3 and test method 6, the results of Example 2, Comparative Example 2, Comparative Example 3 and Comparative Example 10 are shown in Table 4.

[0089] Table 4. Effects of Pretreatment Solution Composition and Preparation Method on Performance

[0090] As shown in Table 4: Compared with Comparative Examples 2, 3 and 10, Example 2 showed a higher 7-day filterable ASM retention rate and a lower coefficient of variation for ASM loading in the batch, indicating that the use of hydroxypropyl-β-cyclodextrin and the preparation of the pretreatment solution through stepwise feeding and constant temperature stirring are beneficial to improving the filterable ASM retention rate after storage and the uniformity of ASM loading during seed treatment.

[0091] Test Example 3: The Impact of Processing Order and Placement According to test methods 3 and 4, the untreated seeds, Example 2, Comparative Examples 1, and Comparative Examples 4-8 were tested, and the results are shown in Table 5.

[0092] Table 5. Results of different processing orders and placement conditions

[0093] As shown in Table 5, compared with Comparative Examples 1, 4 and 5, the relative enzyme activity of PAL and the relative enzyme activity of β-1,3-glucanase in Example 2 were higher, and the germination rate at 10℃ for 14 days was also higher. This indicates that implementing the pretreatment, placement and sterilization coating in steps is beneficial to improving the early defense response of kidney bean seeds and improving the low-temperature germination performance.

[0094] Test Example 4: Coating Quality and Storage Stability According to test method 5, the actual loading rate of fungicide, the coefficient of variation of fungicide loading, the coating shedding rate, and the germination rate after 60 days of storage were tested for Comparative Example 1, Comparative Example 5, and Example 2. The results are shown in Table 6.

[0095] Table 6. Subsequent coating quality and storage stability under different treatment methods

[0096] As shown in Table 6, compared with Comparative Example 1, the actual fungicide loading rate, loading coefficient of variation, coating shedding rate, and germination rate after 60 days of storage in Example 2 were all quite similar. This indicates that pretreatment before coating and subsequent sterilization and coating did not have a significant adverse effect on the quality of subsequent sterilization and coating or the germination performance of seeds after storage. Compared with Comparative Example 5, the fungicide loading coefficient of variation and coating shedding rate in Example 2 were lower.

[0097] Test Example 5: Compatibility of different fungicide seed coating agents According to test methods 4 to 6, the tests were performed on Examples 2, 16, 17, and Comparative Examples 1, 12, and 13, and the results are shown in Table 7.

[0098] Table 7. Treatment results under different fungicide seed coating conditions

[0099] As shown in Table 7: (1) When using fungicide seed coating agent A (a combination of metalaxyl and fludioxonil), fungicide seed coating agent B (tebuconazole seed coating agent), or fungicide seed coating agent C (a combination of thiabendazole and fludioxonil seed coating agent), the actual loading rate, loading variation coefficient, and coating shedding rate of the pre-treatment group before coating are close to those of the corresponding fungicide-only coating group.

[0100] (2) Under the conditions of using the above three fungicides, the pre-treatment groups before coating all showed a high germination rate at low temperature and a low disease index of root rot in continuous cropping soil.

[0101] Test Example 6: Verification of Pretreatment Fluid Parameters Tests were performed on Examples 2, 12-15, and Comparative Examples 9-11 according to Test Methods 1, 3, 4, and 6. The results are shown in Table 8.

[0102] Table 8. Treatment results with different pretreatment liquid parameters

[0103] As shown in Table 8, Examples 2 and 12-15 generally performed well in terms of the retention rate of filterable ASM in the pretreated solution after 7 days, the activity of early defense-related enzymes, the low-temperature germination rate, and the disease index of root rot in continuously cropped soil. When the ASM concentration was too low, the improvement in the activity of early defense-related enzymes and the disease index was limited; when the ASM concentration was too high, the low-temperature germination rate decreased; and when the mass ratio of hydroxypropyl-β-cyclodextrin to ASM was too low, the retention rate of filterable ASM in the pretreated solution after storage decreased.

[0104] The above results indicate that controlling the ASM concentration and the mass ratio of hydroxypropyl-β-cyclodextrin to ASM within the range described in this application is beneficial to taking into account the storage performance of the pretreatment solution, the early defense response of kidney bean seeds, low-temperature germination performance, and the control effect of root rot in continuously cropped soil.

[0105] Test Example 7: Potted Plant Effects in Crop Rotation and Continuous Crop Rotation Soils According to test method 6, pot experiments were conducted on untreated seeds, Comparative Example 1, Comparative Example 4, Comparative Example 5, Example 2 and Comparative Example 8, respectively, using rotation soil and continuous cropping soil. The results are shown in Table 9.

[0106] Table 9. Pot results of different seed treatments in crop rotation and continuous cropping soils.

[0107] Table 9 shows that the germination rates of different treatments were relatively similar in the rotation soil. In the continuous cropping soil, compared with the untreated, sterilized and coated only, pretreated without placement, pretreated solution and seed coating agent applied in one step, and ASM pretreated only treatment, the germination rate of Example 2 was higher and the root rot disease index was lower. The above results indicate that using a pretreatment solution containing ASM and hydroxypropyl-β-cyclodextrin for pre-coating of kidney bean seeds, followed by placement and ventilation or drying before sterilization and coating, is beneficial to improving the germination rate of kidney beans in continuously cropped soil and reducing the root rot disease index during the seedling stage.

[0108] Based on the above experimental results, this invention utilizes cyclodextrin-assisted dispersion to prepare an aqueous pretreatment solution containing ASM and hydroxypropyl-β-cyclodextrin. This improves the retention rate of filterable ASM after storage and the uniformity of ASM loading during seed treatment. Using this pretreatment solution for pre-coating of kidney bean seeds, followed by placement and ventilation or air-drying, before sterilization and coating, enhances the early defense response of kidney bean seeds and improves germination rate in continuously cropped soils, reduces the seedling root rot disease index, and does not significantly affect the subsequent sterilization and coating quality. This treatment method can be used in conjunction with different tested fungicides for seed coating.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. All equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for treating kidney bean seeds to resist continuous cropping obstacles, characterized in that, Includes the following steps: S1. Apply the pre-treatment solution (15-25 g / kg of seeds) to the surface of the kidney bean seeds and mix thoroughly. The pretreatment solution before coating comprises benzothiadiazole-S-methyl ester, hydroxypropyl-β-cyclodextrin, and water. The concentration of benzothiadiazole-S-methyl ester is 20-55 mg / L, and the mass ratio of hydroxypropyl-β-cyclodextrin to benzothiadiazole-S-methyl ester is 6:1-12:

1. S2. Place the kidney bean seeds treated in step S1 at 15-25℃ for 2-4 hours; S3. Ventilate or dry the kidney bean seeds treated in step S2. S4. Apply a seed coating agent containing bactericidal active ingredients to the surface of the kidney bean seeds treated in step S3, and then dry them.

2. The method for treating kidney bean seeds to resist continuous cropping obstacles according to claim 1, characterized in that, The concentration of benzothiadiazole-S-methyl ester is 28–42 mg / L, and the mass ratio of hydroxypropyl-β-cyclodextrin to benzothiadiazole-S-methyl ester is 7:1–10:

1.

3. The method for treating kidney bean seeds to resist continuous cropping obstacles according to claim 1 or 2, characterized in that, The pretreatment solution for coating is prepared by a method comprising the following steps: Hydroxypropyl-β-cyclodextrin was dissolved in water to obtain an aqueous solution of hydroxypropyl-β-cyclodextrin; benzothiadiazole-S-methyl ester was dissolved in ethanol to obtain an ethanol solution of benzothiadiazole-S-methyl ester. Under stirring conditions at 35–45°C, the feeding time is controlled at 10–30 min. The benzothiadiazole-S-methyl ester ethanol solution is gradually added to the hydroxypropyl-β-cyclodextrin aqueous solution. After the addition is completed, stirring is continued for 1–3 h. Ethanol is removed under reduced pressure, with the system temperature at 45°C or less during the removal process, and water is added to a predetermined volume to obtain the pretreatment solution before coating.

4. The method for treating kidney bean seeds to resist continuous cropping obstacles according to claim 3, characterized in that, Under conditions of 38–42°C, the feeding time is controlled at 15–25 min, and the benzothiadiazole-S-methyl ester ethanol solution is gradually added to the hydroxypropyl-β-cyclodextrin aqueous solution. After the feeding is completed, stirring is continued for 1.5–2.5 h.

5. The method for treating kidney bean seeds to resist continuous cropping obstacles according to claim 3, characterized in that, After ethanol removal under reduced pressure, the ethanol content in the pretreatment solution before coating is less than or equal to 0.5 wt%.

6. The method for treating kidney bean seeds to resist continuous cropping obstacles according to claim 1, characterized in that, In step S1, the kidney bean seeds are turned over at a speed of 20-35 rpm, and the pretreatment solution before coating is sprayed within 1-3 minutes. After spraying, continue mixing for 3-6 minutes.

7. The method for treating kidney bean seeds to resist continuous cropping obstacles according to claim 1, characterized in that, In step S3, the kidney bean seeds are ventilated at 20–30℃ for 10–60 minutes; In step S4, the amount of seed coating agent used relative to the kidney bean seeds is 8-15 g / kg.

8. The method for treating kidney bean seeds to resist continuous cropping obstacles according to claim 1, characterized in that, The bactericidal active ingredient is selected from one or more of metalaxyl, fludioxonil, tebuconazole and thiamethoxam.

9. The method for treating kidney bean seeds to resist continuous cropping obstacles according to claim 8, characterized in that, The bactericidal active ingredient is any one of the following: a combination of metalaxyl and fludioxonil, tebuconazole, or a combination of thiabendazole and fludioxonil.

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