Method for indoor resistance identification of amaranthus retroflexus in soybean field

Abstract

The present application relates to the technical field of soybean field amaranth resistance identification, and discloses a soybean field amaranth indoor resistance identification method.The method comprises the following steps: performing composite time sequence breaking sleep pretreatment on amaranth seeds collected from a soybean field; cultivating the pretreated seeds to the 2-4 leaf stage according to standardized parameters and screening uniform seedlings; performing gradient dose herbicide treatment on the seedlings and setting a sensitive control; calculating GR 50 values by combining images with NDVI chlorophyll spectrum, and synchronously detecting resistance related indexes; calculating corrected resistance indexes by combining correction coefficients, and outputting identification results and resistance types according to customized standards.The present application is standard in operation, lossless and efficient, can accurately determine the resistance grade and type of amaranth, and provides technical support for soybean field amaranth resistance prevention and control.

Description

Technical Field

[0001] This invention relates to the field of resistance identification technology for amaranth in soybean fields, specifically a method for indoor resistance identification of amaranth in soybean fields. Background Technology

[0002] Amaranthus retroflexus is a common and noxious broadleaf weed in leguminous crop fields, especially prevalent and rapidly spreading in soybean fields. Its highly adaptable plants and vigorous reproductive capacity compete with soybeans for sunlight, water, nutrients, and growing space, significantly reducing soybean yield and quality, increasing field management costs, and severely hindering the high-quality development of the soybean industry. With the long-term and singular use of herbicides in soybean fields, amaranthus retroflexus has developed increasing resistance to many commonly used herbicides, and the distribution range of resistant populations has continued to expand, further exacerbating the difficulty of control. Therefore, accurate and rapid identification of the resistance level and type of amaranthus retroflexus in soybean fields has become a crucial prerequisite for scientifically formulating control strategies, delaying the development of resistance, and ensuring safe soybean production.

[0003] Currently, methods for identifying resistance to amaranth in soybean fields are mainly divided into two categories: field identification and laboratory identification. While field identification can reflect resistance performance in natural habitats, it is affected by various external factors such as climate, soil, cultivation management, and weed community structure. This results in a long identification cycle, poor repeatability, and susceptibility to environmental interference leading to biased results, making rapid and accurate identification of large batches of samples difficult. Laboratory identification, due to its controllable environment, ease of operation, and good repeatability, has become the mainstream method for weed resistance identification. However, existing laboratory identification techniques still have many shortcomings, limiting identification efficiency and accuracy.

[0004] Specifically, existing indoor identification methods for Amaranthus retroflexus seeds often employ single soaking, low-temperature treatment, or hormone therapy for dormancy breaking, lacking a sequential and comprehensive treatment approach. This results in low germination rates, uneven germination, and significant differences in seedling growth, affecting the stability of identification results. During seedling cultivation, parameters such as seedling substrate, watering frequency, light, and temperature are not standardized and controlled, leading to significant variations in operation between different batches and personnel, further reducing the comparability of identification results. Furthermore, the concentration gradient settings for herbicide treatments are unreasonable, with some methods failing to cover key concentration nodes, making it impossible to accurately fit the GR (Growth Rate). 50The current resistance index is difficult to accurately reflect the level of resistance. The detection of growth inhibition indicators often relies on single morphological observations or spectral detections, failing to combine image acquisition with NDVI chlorophyll spectral detection. This results in low detection accuracy, high subjectivity, or the use of a single indicator, making it impossible to comprehensively quantify seedling growth status. Furthermore, existing methods do not consider the influence of actual soybean field habitat factors (such as soil moisture, co-occurring competition, diurnal temperature variation, and light intensity) when calculating resistance indices, lacking a scientific correction mechanism. This leads to discrepancies between the identification results and actual resistance performance in the field, making it difficult to directly guide field control practices. In addition, the lack of unified resistance grading standards and unclear resistance type determination also prevents comparison of identification results from different studies and regions, hindering the integration and application of resistance monitoring data.

[0005] To address the shortcomings of existing technologies, there is an urgent need to develop a standardized, non-destructive, efficient, accurate, and reliable indoor resistance identification method for amaranth in soybean fields. This method would solve problems such as uneven seed dormancy breaking, non-standard cultivation parameters, single detection methods, lack of correction for resistance indices, and unclear grading standards. It would enable accurate determination of the resistance level and type of amaranth, providing scientific and reliable technical support for the prevention and control of amaranth resistance in soybean fields and filling the gap in existing technologies. Summary of the Invention

[0006] This invention addresses the aforementioned problems in the prior art by providing an indoor resistance identification method for amaranth in soybean fields. It effectively solves the problems of uneven seed dormancy breaking, non-standard cultivation parameters, single detection method, lack of correction for resistance index, and unclear grading standards, thereby achieving accurate determination of the resistance level and type of amaranth.

[0007] To achieve the above objectives, this invention proposes a method for indoor resistance identification of amaranth offshoots in soybean fields, comprising the following steps: S1. A compound time-sequential dormancy-breaking pretreatment was carried out on seeds of Amaranthus retroflexus collected from soybean fields; S2. After the seeds have been pretreated in step S1, cultivate them according to standardized parameters until they reach the 2-4 leaf stage, and select seedlings with uniform growth. S3. The seedlings screened in step S2 were treated with gradient doses of herbicides, and a known sensitive Amaranthus retroflexus population was set up as a control. S4. Using a combination of image acquisition and NDVI chlorophyll spectroscopy detection, the growth inhibition index of seedlings is quantified non-destructively, and the growth inhibition rate (GR) is calculated using a fitting formula. 50 value; S5. Simultaneously, resistance-related indicators were tested on the seedlings treated in step S3 and the control seedlings. S6. GR calculated according to step S4 50The resistance index is calculated by combining the value and the test results of step S5 with the correction formula, and then the resistance identification results and resistance type of Amaranthus retroflexus are output according to the customized grading standard.

[0008] Preferably, in step S1, the composite time-sequential sleep-breaking preprocessing specifically includes the following sub-steps, and the order of each step cannot be reversed: S11. After removing impurities from the seeds of *Amaranthus retroflexus*, place them in a weak alkaline solution with a pH of 8.0-8.5 and soak them at a constant temperature of 25-28℃ with shaking for 2-3 hours at a shaking rate of 120-150 r / min. S12. Rinse the seeds treated with S11 with deionized water 3-5 times, each rinse lasting 30-60 seconds. Then place them in a plant growth regulator solution and immerse them in the dark at 22-25°C for 12-16 hours. S13. Evenly spread the seeds treated in S12 onto petri dishes lined with 2-3 layers of moist filter paper with a saturated moisture content of 80%-90%. Place the dishes in a constant temperature incubator at 25-28℃, 70%-80% relative humidity, and in complete darkness to promote germination. Turn the seeds every 6 hours until the germination potential reaches 85% or higher. The germination potential is calculated using the following formula: ; In the formula, For germination potential, This refers to the number of seeds that germinate within 3 days of germination. This represents the total number of seeds tested.

[0009] Preferably, in step S2, the cultivation according to standardized parameters specifically includes: sterilizing the seedling substrate; watering with deionized water every 36 hours; controlling substrate moisture using a weighing method to maintain substrate moisture at 60%–70% of field capacity; maintaining a cultivation environment with a 14-hour light / 10-hour dark cycle, light intensity of 3000–3500 lx, and temperature of 23–27°C; ensuring no pests or diseases during the cultivation period; and calculating substrate moisture using the following formula: ; In the formula, For substrate moisture, This represents the actual moisture content of the substrate. This refers to the field water holding capacity of the substrate.

[0010] Preferably, in S2, the seedlings with uniform growth are selected based on the following criteria: plant height 3-5cm, cotyledons fully expanded, 2-4 true leaves, free from pests and diseases and mechanical damage, with a single plant fresh weight variation coefficient ≤7% and a plant height variation coefficient ≤8%. After screening, each treatment group should have at least 30 seedlings. The formula for calculating the variation coefficient is: ; In the formula, Here, denoted as coefficient of variation, and SD as standard deviation. This is the average value.

[0011] Preferably, in step S3, the gradient dosage herbicide treatment specifically involves setting 5 to 7 concentration gradients, including 0.25 times, 0.5 times, 1 times, 2 times, and 4 times the recommended dosage, with deionized water as a blank control; spraying is performed using a small spray tower with a spray pressure of 0.2 to 0.3 MPa and a spray volume of 15 to 20 mL per plant, ensuring that the seedling leaves are evenly covered with droplets without dripping during spraying; and allowing the seedlings to stand for 30 minutes after spraying before transferring them to a standardized cultivation environment.

[0012] Preferably, in S4, the growth inhibition indicators include plant height inhibition rate, canopy width inhibition rate, fresh weight inhibition rate, and wilting grade; the NDVI chlorophyll spectrum detection wavelengths are 660nm and 850nm, and image acquisition uses a high-definition camera with at least 12 megapixels, collecting data twice a week for four consecutive weeks; GR 50 The value is calculated by fitting the logistic equation, and the fitting formula is: ; In the formula, Growth inhibition rate, denoted as herbicide concentration, and a and b are fitting parameters.

[0013] Preferably, in step S5, the resistance-related index detection adopts a combination of spectral detection and morphological observation. The spectral detection wavelength range is 600~900nm, and the detection is carried out once a week for 4 consecutive weeks. The morphological changes of seedlings are recorded simultaneously to form complete detection data.

[0014] Preferably, in step S6, the resistance index RI is calculated as follows: first, the GR of the resistant population and the control sensitive population of the *Amaranthus retroflexus* population to be identified are calculated using the fitting formula in step S4. 50 The value is then substituted into the formula for calculating the resistance index RI: ; In the formula, GR for the resistant population of the Amaranthus retroflexus population to be identified 50 value, GR for control sensitive population 50 .

[0015] Preferably, in step S5, a soybean field habitat correction coefficient K is introduced when calculating the resistance index, and the corrected resistance index formula is: ; The formula for calculating the correction coefficient K is as follows: ; In the formula, This is a soil moisture correction factor, with values ​​ranging from 0.8 to 1.2. The accompanying competitive pressure correction factor has a value ranging from 0.9 to 1.1. This is a diurnal temperature range correction factor, with values ​​ranging from 0.85 to 1.15. This is the light intensity correction factor, with a value ranging from 0.9 to 1.1.

[0016] Preferably, in step S6, a customized grading standard is used to correct the resistance index. Based on, specifically: <2.0 indicates a sensitive type, 2.0≤ <5.0 indicates low resistance; 5.0≤ <10.0 indicates moderate resistance; 10.0≤ <20.0 indicates a high-resistance type. ≥20.0 indicates extremely high resistance; combined with the detection results of step S5, the resistance type is determined: abnormal morphological indicators alone indicate morphological resistance, abnormal spectral indicators alone indicate physiological resistance, and abnormal spectral indicators alone indicate complex resistance.

[0017] Therefore, this invention proposes a method for indoor resistance identification of amaranth in soybean fields, the beneficial effects of which are as follows: (1) Effectively solves the problems of low seed germination rate and uneven germination in existing methods. Combines standardized seedling cultivation parameters and strict screening standards to ensure uniform seedling growth, reduce the impact of operational differences, and significantly improve the stability of identification results and the comparability between different batches.

[0018] (2) Achieve non-destructive and accurate quantification of seedling growth inhibition indicators, and fit GR with a reasonable herbicide concentration gradient. 50 The resistance index is calculated by combining the value with the habitat correction coefficient, clarifying the resistance classification and type, solving the problems of single detection, large result deviation and inconsistent classification in the existing methods, and providing precise guidance for field prevention and control.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is an overall flowchart of the method for indoor resistance identification of amaranth offshoot in soybean fields according to the present invention; Figure 2 This is a schematic diagram of the composite time-sequential dormancy-breaking pretreatment in the indoor resistance identification method for soybean field reverse-branch amaranth of the present invention; Figure 3 This is a schematic diagram of the standardized seedling cultivation and screening process for the indoor resistance identification method of amaranth offshoot in soybean fields according to the present invention. Detailed Implementation

[0021] To make the technical solutions, advantages, and objectives of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the protection scope of this application.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] like Figures 1-3 As shown, the method for indoor resistance identification of soybean field reverse-branch amaranth provided by the present invention includes: S1. A compound time-sequential dormancy-breaking pretreatment was carried out on seeds of Amaranthus retroflexus collected from soybean fields; The composite time-sequential sleep-breaking preprocessing specifically includes the following sub-steps, and the order of each step cannot be reversed: S11. After removing impurities from the seeds of *Amaranthus retroflexus*, place them in a weak alkaline solution with a pH of 8.0-8.5 and soak them at a constant temperature of 25-28℃ with shaking for 2-3 hours at a shaking rate of 120-150 r / min. S12. Rinse the seeds treated with S11 with deionized water 3-5 times, each rinse lasting 30-60 seconds. Then place them in a plant growth regulator solution and immerse them in the dark at 22-25°C for 12-16 hours. S13. Evenly spread the seeds treated in S12 onto petri dishes lined with 2-3 layers of moist filter paper with a saturated moisture content of 80%-90%. Place the dishes in a constant temperature incubator at 25-28℃, 70%-80% relative humidity, and in complete darkness to promote germination. Turn the seeds every 6 hours until the germination potential reaches 85% or higher. The germination potential is calculated using the following formula: ; In the formula, For germination potential, This refers to the number of seeds that germinate within 3 days of germination. This represents the total number of seeds tested.

[0024] S2. After the seeds have been pretreated in step S1, cultivate them according to standardized parameters until they reach the 2-4 leaf stage, and select seedlings with uniform growth. The standardized cultivation parameters are as follows: the seedling substrate is sterilized; deionized water is applied every 36 hours, and substrate moisture is controlled by weighing to maintain 60%–70% of field capacity; the cultivation environment is a 14-hour light / 10-hour dark cycle, with a light intensity of 3000–3500 lx and a temperature of 23–27℃. There are no pests or diseases during the cultivation period. The substrate moisture calculation formula is: ; In the formula, For substrate moisture, This represents the actual moisture content of the substrate. This refers to the field water holding capacity of the substrate.

[0025] Seedlings with uniform growth were selected based on the following criteria: plant height 3-5cm, fully expanded cotyledons, 2-4 true leaves, free from pests, diseases, and mechanical damage, with a coefficient of variation of ≤7% for fresh weight per plant and ≤8% for plant height. Each treatment group should have at least 30 seedlings after screening. The coefficient of variation was calculated using the following formula: ; In the formula, Here, denoted as coefficient of variation, and SD as standard deviation. This is the average value.

[0026] S3. The seedlings screened in step S2 were treated with gradient doses of herbicides, and a known sensitive Amaranthus retroflexus population was set up as a control. Gradual dosage herbicide treatment was conducted as follows: 5-7 concentration gradients were set up, including 0.25 times, 0.5 times, 1 times, 2 times, and 4 times the recommended dosage, with deionized water as a blank control; spraying was carried out using a small spray tower with a spray pressure of 0.2-0.3 MPa and a spray volume of 15-20 mL / plant. During spraying, the seedling leaves were evenly covered with droplets without dripping. After spraying, the seedlings were allowed to stand for 30 minutes before being transferred to a standardized cultivation environment.

[0027] S4. Using a combination of image acquisition and NDVI chlorophyll spectroscopy detection, the growth inhibition index of seedlings is quantified non-destructively, and the growth inhibition rate (GR) is calculated using a fitting formula. 50 value; Growth inhibition indicators include plant height inhibition rate, canopy width inhibition rate, fresh weight inhibition rate, and wilting grade; the NDVI chlorophyll spectrum detection wavelengths are 660nm and 850nm, and image acquisition is performed using a high-definition camera with at least 12 megapixels, collecting data twice a week for four consecutive weeks; GR 50 The value is calculated by fitting the logistic equation, and the fitting formula is: ; In the formula, Growth inhibition rate, denoted as herbicide concentration, and a and b are fitting parameters.

[0028] S5. Simultaneously, resistance-related indicators were tested on the seedlings treated in step S3 and the control seedlings. Resistance-related indicators were detected by combining spectral detection and morphological observation. The spectral detection wavelength range was 600~900nm, and the detection was carried out once a week for 4 consecutive weeks. The morphological changes of seedlings were recorded simultaneously to form complete detection data.

[0029] S6. GR calculated according to step S4 50 The resistance index is calculated by combining the value and the test results of step S5 with the correction formula, and then the resistance identification results and resistance type of Amaranthus retroflexus are output according to the customized grading standard.

[0030] The resistance index RI is calculated as follows: First, the GR of the resistant population and the control sensitive population of *Amaranthus retroflexus* to be identified are calculated using the fitting formula in step S4. 50 The value is then substituted into the formula for calculating the resistance index RI: ; In the formula, GR for the resistant population of the Amaranthus retroflexus population to be identified 50 value, GR for control sensitive population 50 .

[0031] When calculating the resistance index, a soybean field habitat correction coefficient K is introduced. The corrected resistance index formula is as follows: ; The formula for calculating the correction coefficient K is as follows: ; In the formula, This is a soil moisture correction factor, with values ​​ranging from 0.8 to 1.2. The accompanying competitive pressure correction factor has a value ranging from 0.9 to 1.1. This is a diurnal temperature range correction factor, with values ​​ranging from 0.85 to 1.15. This is the light intensity correction factor, with a value ranging from 0.9 to 1.1.

[0032] Customized grading standards to correct the resistance index Based on, specifically: <2.0 indicates a sensitive type, 2.0≤ <5.0 indicates low resistance; 5.0≤ <10.0 indicates moderate resistance; 10.0≤ <20.0 indicates a high-resistance type. ≥20.0 indicates extremely high resistance; combined with the detection results of step S5, the resistance type is determined: abnormal morphological indicators alone indicate morphological resistance, abnormal spectral indicators alone indicate physiological resistance, and abnormal spectral indicators alone indicate complex resistance.

[0033] This invention uses the common soybean plant species *Amaranthus retroflexus* as the identification target and acetochlor, a commonly used herbicide in soybean fields, as the treatment agent. Combining the aforementioned technical solutions, the specific implementation process is as follows: Seed collection and pretreatment: Mature amaranth seeds were collected from soybean fields. After removing impurities, they underwent a compound sequential dormancy-breaking pretreatment according to step S1. First, the seeds were placed in a weak alkaline solution with a pH of 8.2 and soaked at a constant temperature of 26°C with shaking for 2.5 hours at a shaking rate of 130 r / min. They were then rinsed four times with deionized water for 45 seconds each time, and then placed in a plant growth regulator solution and statically soaked at 23°C in the dark for 14 hours. Finally, the seeds were evenly spread on petri dishes lined with two layers of moist filter paper with a saturated moisture content of 85%. Germination was carried out at 26°C, 75% relative humidity, and in the dark throughout the process, with the seeds being turned over every 6 hours until the germination potential reached more than 85%.

[0034] Seedling cultivation and selection: Pretreated seeds were sown in sterilized seedling substrate and cultivated according to standardized parameters. Deionized water was applied every 36 hours. The substrate moisture was controlled to 65% of field capacity by weighing. The cultivation environment was a 14-hour light / 10-hour dark cycle with a light intensity of 3200 lx and a temperature of 25℃. When the seedlings reached the 3-leaf stage, seedlings with a height of 3-5 cm, fully expanded cotyledons, no diseases, pests, or mechanical damage, and a single plant fresh weight variation coefficient ≤7% and a plant height variation coefficient ≤8% were selected. 35 seedlings with uniform growth were retained in each treatment group.

[0035] Herbicide gradient treatment: Six herbicide concentration gradients were set up according to step S3, namely 0.25 times, 0.5 times, 1 times, 2 times, 4 times and 8 times the recommended dose of acetochlor. Deionized water was used as a blank control. Spraying was carried out using a small spray tower at a spray pressure of 0.25 MPa and a spray volume of 18 mL / plant. After spraying, the plants were allowed to stand for 30 min and then transferred to the above-mentioned standardized cultivation environment for continued cultivation.

[0036] GR 50 Value Calculation: Seedling images were acquired using a 12-megapixel high-definition camera, and chlorophyll content was simultaneously detected using an NDVI chlorophyll spectrometer (detection wavelengths 660nm and 850nm). Data were collected twice a week for four consecutive weeks. Plant height inhibition rate, crown width inhibition rate, fresh weight inhibition rate, and wilting grade were quantified. The growth coefficients (GR) of the target population and the control sensitive population were calculated using a Logistic regression equation. 50 value.

[0037] Resistance-related index detection: The resistance-related indexes were detected once a week for four consecutive weeks using a combination of a spectrometer (detection wavelength range of 600~900nm) and morphological observation. Simultaneously, morphological changes such as seedling leaf color and wilting degree were recorded to form complete detection data.

[0038] Resistance identification and result output: Calculate the resistance index RI of the population to be identified and the control sensitive population, introduce the soybean field habitat correction coefficient K (where the soil moisture correction factor is 1.0, the associated competition pressure correction factor is 1.0, the diurnal temperature difference correction factor is 1.0, and the light intensity correction factor is 1.0, K=1.0), calculate the corrected resistance index, and combine it with the customized grading standard to determine the resistance level and type of Amaranthus retroflexus, and output the identification results.

[0039] Example Results: Through the above specific implementation process, three sets of parallel repeated experiments were completed, and the experimental results are as follows: Seed pretreatment and seedling cultivation results: After compound sequential dormancy-breaking pretreatment, the germination rate of Amaranthus retroflexus seeds reached 92.3%±1.2%, and the uniformity of germination (coefficient of variation) was 5.8%, which was significantly higher than the existing single dormancy-breaking method (germination rate 78.5%±2.1%, coefficient of variation 11.3%). The seedlings cultivated to the 3-leaf stage had plant height and fresh weight coefficients of variation controlled within the required range. The seedlings in the three parallel treatment groups had uniform growth, which met the requirements of the identification experiment and showed good repeatability.

[0040] GR 50 Results of resistance index calculation: Seedlings in the blank control group showed no wilting and grew normally, with chlorophyll content maintained at 3.2~3.5 mg / g; after acetochlor gradient treatment, the GR of the control sensitive population... 50 The value was 0.32 ± 0.04 times the recommended dose, indicating the GR of the *Amaranthus retroflexus* population to be identified. 50 The value is 2.56 ± 0.11 times the recommended dose; the calculated resistance index RI is 8.0. After introducing the habitat correction coefficient K = 1.0, the corrected resistance index is still 8.0.

[0041] Resistance level and type determination results: According to the customized grading standard (RI < 2.0 is sensitive, 2.0 ≤ RI < 5.0 is low resistance, 5.0 ≤ RI < 10.0 is moderate resistance, and RI ≥ 10.0 is high resistance), the population of *Amaranthus retroflexus* to be identified is determined to be a moderately resistant population to acetochlor; combined with the test results of resistance-related indicators, the rate of decrease in chlorophyll content of seedlings is 38.6% slower than that of sensitive populations, and the degree of wilting is mild, so its resistance type is determined to be mainly metabolic resistance.

[0042] Experimental repeatability verification results: GR of 3 parallel experiments 50The coefficient of variation for the resistance index was 3.7% and the coefficient of variation for the resistance index was 4.1%, both less than 5%, indicating that the method of the present invention has good repeatability and stable identification results. Compared with the actual identification results in the field, the consistency reached 96.8%, proving that the identification method of the present invention is accurate and reliable and can effectively reflect the actual resistance level of Amaranthus retroflexus in the field.

[0043] Therefore, this invention provides an indoor resistance identification method for amaranth retroflexus in soybean fields. It integrates image acquisition and NDVI chlorophyll spectroscopy to achieve non-destructive and accurate quantification, accurately fits GR50 values ​​with reasonable gradient herbicide treatment, introduces a soybean field habitat correction coefficient to optimize the resistance index calculation, and clarifies the resistance level and type by combining customized grading standards. The method is standardized and efficient, providing accurate and reliable technical support for the prevention and control of amaranth retroflexus resistance in soybean fields. It effectively improves the seed germination rate and uniformity of amaranth retroflexus, reduces the impact of operational differences, and enhances the stability and comparability of identification results. It solves the problems of existing methods such as single detection, large result deviation, uneven seedling growth, and poor repeatability.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for indoor resistance identification of amaranth offshoot in soybean fields, characterized in that, Includes the following steps: S1. A compound time-sequential dormancy-breaking pretreatment was carried out on seeds of Amaranthus retroflexus collected from soybean fields; S2. After the seeds have been pretreated in step S1, cultivate them according to standardized parameters until they reach the 2-4 leaf stage, and select seedlings with uniform growth. S3. The seedlings screened in step S2 were treated with gradient doses of herbicides, and a known sensitive Amaranthus retroflexus population was set up as a control. S4. Using a combination of image acquisition and NDVI chlorophyll spectroscopy detection, the growth inhibition index of seedlings is quantified non-destructively, and the growth inhibition rate (GR) is calculated using a fitting formula. 50 value; S5. Simultaneously, resistance-related indicators were tested on the seedlings treated in step S3 and the control seedlings. S6. GR calculated according to step S4 50 The resistance index is calculated by combining the value and the test results of step S5 with the correction formula, and then the resistance identification results and resistance type of Amaranthus retroflexus are output according to the customized grading standard.

2. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 1, characterized in that, In step S1, the composite time-sequential sleep-breaking preprocessing specifically includes the following sub-steps, and the order of each step cannot be reversed: S11. After removing impurities from the seeds of *Amaranthus retroflexus*, place them in a weak alkaline solution with a pH of 8.0-8.5 and soak them at a constant temperature of 25-28℃ with shaking for 2-3 hours at a shaking rate of 120-150 r / min. S12. Rinse the seeds treated with S11 with deionized water 3-5 times, each rinse lasting 30-60 seconds. Then place them in a plant growth regulator solution and immerse them in the dark at 22-25°C for 12-16 hours. S13. Evenly spread the seeds treated in S12 onto petri dishes lined with 2-3 layers of moist filter paper with a saturated moisture content of 80%-90%. Place the dishes in a constant temperature incubator at 25-28℃, 70%-80% relative humidity, and in complete darkness to promote germination. Turn the seeds every 6 hours until the germination potential reaches 85% or higher. The germination potential is calculated using the following formula: ； In the formula, For germination potential, This refers to the number of seeds that germinate within 3 days of germination. This represents the total number of seeds tested.

3. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 2, characterized in that, In S2, the cultivation according to standardized parameters specifically includes: sterilizing the seedling substrate; watering with deionized water every 36 hours; controlling substrate moisture using a weighing method to maintain a moisture content of 60%–70% of field capacity; maintaining a cultivation environment with a 14-hour light / 10-hour dark cycle, a light intensity of 3000–3500 lx, and a temperature of 23–27°C; ensuring no pests or diseases during the cultivation period; and calculating substrate moisture using the following formula: ； In the formula, For substrate moisture, This represents the actual moisture content of the substrate. This refers to the field water holding capacity of the substrate.

4. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 3, characterized in that, In S2, the seedlings with uniform growth were selected based on the following criteria: plant height 3-5cm, cotyledons fully expanded, 2-4 true leaves, free from pests and diseases and mechanical damage, with a single plant fresh weight variation coefficient ≤7% and a plant height variation coefficient ≤8%. Each treatment group had at least 30 seedlings after screening. The formula for calculating the variation coefficient was: ； In the formula, Here, denoted as coefficient of variation, and SD as standard deviation. This is the average value.

5. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 4, characterized in that, In S3, the gradient dosage herbicide treatment is specifically as follows: 5 to 7 concentration gradients are set, including 0.25 times, 0.5 times, 1 times, 2 times, and 4 times the recommended dosage, with deionized water as a blank control; spraying is carried out using a small spray tower, with a spray pressure of 0.2 to 0.3 MPa and a spray volume of 15 to 20 mL / plant. During spraying, the seedling leaf surface is evenly covered with droplets without dripping. After spraying, the seedlings are left to stand for 30 minutes before being transferred to a standardized cultivation environment.

6. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 5, characterized in that, In S4, the growth inhibition indicators include plant height inhibition rate, canopy width inhibition rate, fresh weight inhibition rate, and wilting grade; the NDVI chlorophyll spectrum detection wavelengths are 660nm and 850nm, and image acquisition uses a high-definition camera with at least 12 megapixels, collecting data twice a week for four consecutive weeks; GR 50 The value is calculated by fitting the logistic equation, and the fitting formula is: ； In the formula, Growth inhibition rate, denoted as herbicide concentration, and a and b are fitting parameters.

7. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 6, characterized in that, In S5, the resistance-related index detection adopts a combination of spectral detection and morphological observation. The spectral detection wavelength range is 600~900nm, and the detection is carried out once a week for 4 consecutive weeks. The morphological changes of seedlings are recorded simultaneously to form complete detection data.

8. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 7, characterized in that, In step S6, the resistance index RI is calculated as follows: first, the GR of the resistant population and the control sensitive population of *Amaranthus retroflexus* to be identified are calculated using the fitting formula in step S4. 50 The value is then substituted into the formula for calculating the resistance index RI: ； In the formula, GR for the resistant population of the Amaranthus retroflexus population to be identified 50 value, GR for control sensitive population 50 .

9. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 8, characterized in that, In step S5, a soybean field habitat correction coefficient K is introduced when calculating the resistance index. The corrected resistance index formula is as follows: ； The formula for calculating the correction coefficient K is as follows: ; In the formula, This is a soil moisture correction factor, with values ​​ranging from 0.8 to 1.

2. The accompanying competitive pressure correction factor has a value ranging from 0.9 to 1.

1. This is a diurnal temperature range correction factor, with values ​​ranging from 0.85 to 1.

15. This is the light intensity correction factor, with a value ranging from 0.9 to 1.

1.

10. The method for indoor resistance identification of amaranth offshoots in soybean fields according to claim 1, characterized in that, In S6, a customized grading standard is used to correct the resistance index. Based on, specifically: <2.0 indicates a sensitive type, 2.0≤ <5.0 indicates low resistance; 5.0≤ <10.0 indicates moderate resistance; 10.0≤ <20.0 indicates a high-resistance type. ≥20.0 indicates extremely high resistance; combined with the detection results of step S5, the resistance type is determined: abnormal morphological indicators alone indicate morphological resistance, abnormal spectral indicators alone indicate physiological resistance, and abnormal spectral indicators alone indicate complex resistance.

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