Durian rootstock propagation method based on infinite cuttage

Abstract

The invention belongs to the technical field of plant asexual propagation engineering, and discloses a durian rootstock propagation method based on infinite cuttage, and the durian rootstock propagation method comprises the following steps: step 1, seed optimization and disinfection; step 2, preparing a sowing substrate; step 3, precise sowing; step 4, seedling cultivation; step 5; step 6, performing cuttage treatment; step 7, intelligent environment regulation and control; step 8, circularly propagating; step 9, quality monitoring; and step 10, outplanting standard. According to the method, a large-scale and standardized durian stock production system is successfully constructed through breakthrough technology integration and innovation, and the method shows five core advantages that the annual propagation coefficient reaches the industry leading level of 20.5 and is improved by 4-6 times compared with a traditional propagation mode, and powerful power is injected for industrial large-scale development; an SSR molecular marker monitoring system is established, the genetic stability is accurately controlled, the genetic similarity of continuous five-generation breeding materials is kept to be 99% or above, and the consistency of variety characteristics is fundamentally guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of plant asexual propagation engineering, and in particular relates to a durian rootstock propagation method based on unlimited cuttings. Background Art

[0002] As the "king of fruits" among tropical fruits, the global market value of durian continues to rise, and the industry scale has exceeded the 10 billion mark. However, the severe shortage of high-quality rootstock resources is becoming a core bottleneck restricting the sustainable development of the industry. In the field of improved seed breeding, traditional breeding technology faces three technical barriers:

[0003] In terms of seed propagation, the genetic variation rate of durian is as high as 30%-45%, resulting in a large number of trait separation phenomena in the seedling population. This genetic instability not only causes uneven fruit quality (single fruit weight fluctuations can reach 500-5000 grams), but also leads to extreme fluctuations in yield of 30%-60%, seriously weakening the establishment of a standardized production system.

[0004] Although grafting can maintain the characteristics of the mother tree, its development is constrained by the severe shortage of scion resources. The current grafting technology is highly dependent on scarce mother tree resources. The annual supply of scions per mother tree is less than 200, and the reproduction coefficient has long hovered between 3-5. This inefficient expansion model is difficult to meet the industry demand with an average annual growth of more than 20%, resulting in a slow promotion of excellent varieties.

[0005] Conventional cutting technology faces rooting problems. Even under hormone treatment and temperature control conditions, the rooting rate is still difficult to break the 60% threshold. What is more difficult is that cutting seedlings generally have problems such as underdeveloped root systems (the number of taproots is less than 40% of that of seedlings), few absorbing roots and shallow distribution, which leads to a 35%-50% decrease in plant stress resistance, becoming a major obstacle to large-scale application.

[0006] This triple technical dilemma has formed a vicious cycle: insufficient high-quality germplasm resources → low breeding efficiency → limited industry expansion → reduced R&D investment → slow technological breakthroughs. To solve this dilemma, a revolutionary breakthrough in innovative breeding technology is urgently needed. Summary of the invention

[0007] The object of the present invention is to provide a method for propagating durian rootstock based on unlimited cuttings to solve the problems raised in the above background technology.

[0008] In order to achieve the above object, the present invention provides the following technical scheme: a method for propagating durian rootstock based on unlimited cuttings, through the technical path of mother parent cultivation, truncation cuttings and then cyclic propagation, to obtain unlimited reproduction of durian rootstock, the steps of the durian rootstock propagation method include:

[0009] Step 1: Seed selection and disinfection: Select D197 seeds, and disinfect the seeds by soaking them in warm water combined with potassium permanganate-sodium hypochlorite double-stage disinfection;

[0010] Step 2: Preparation of sowing matrix and precise sowing, according to the matrix ratio of red soil: coconut bran: vermiculite: perlite = 2:6:1:1, after sterilization, 50-52 hole trays are used for sowing, the germination end of the seeds faces down, and the thickness of the covering matrix is ​​0-1cm; Step 3: seedling cultivation, seedling cultivation adopts tidal irrigation and LED light control system and nutrient solution EC value control, when the seedling plant height reaches 30-35cm, the first truncation treatment of step 5 is performed;

[0011] Step 4: First cutting treatment: use a sterile blade to cut at 45° and apply callus paste. The cut materials are graded according to A / B standards and transferred to the cutting treatment in step 5;

[0012] Step 5: Cutting treatment: IBA hormone treatment and standardized grading before cutting;

[0013] Step 6: Intelligent environment control. The intelligent environment control system adopts fuzzy PID control algorithm, equipped with temperature and humidity sensors and UPS power supply. The rooting environment is maintained at RH90%-95% and 26±1℃ through the intelligent control system;

[0014] Step 7: Circular propagation, establishing a three-level propagation system of mother-offspring-grandchildren;

[0015] Step 8: Quality control: SSR molecular marker genetic stability test is carried out every 5 generations; unqualified products are subject to the whole batch destruction system;

[0016] Step 9: Standards for nursery seedlings: the nursery seedlings shall be based on the dual index system of morphology and physiology, with plant height of 25-30cm, stem diameter ≥4mm, root system fibrous roots ≥12 and length ≥5cm, photosynthetic rate ≥12μmol / (m 2 ·s).

[0017] Preferably, the two-stage disinfection includes: first soaking in 0.3% potassium permanganate solution for 30 minutes to effectively kill pathogens on the surface of seeds and activate enzyme activity; second soaking in 2% sodium hypochlorite solution for 15 minutes to deeply remove internal microbial contamination.

[0018] Preferably, the preparation of the sowing matrix also includes: sterilization using saturated steam at 70°C for 60 minutes to completely kill fungal spores and nematode eggs in the matrix; after sterilization, evenly mixing 100 grams of carbendazim wettable powder per cubic meter of matrix to form a long-term antibacterial mechanism to ensure the sterile state of the sowing environment.

[0019] Preferably, the tidal irrigation system performs 5 minutes of cyclic irrigation every 2 hours to accurately control the moisture content of the substrate; the EC value of the nutrient solution increases gradually from 0.8 to 1.2 mS / cm at a gradient of 0.1 mS / cm per week, which avoids salt stress and meets nutrient requirements at different stages.

[0020] Preferably, the cutting material is standardized and graded into two levels:

[0021] Grade A: 14-16cm in length, with 2-3 full buds;

[0022] Grade B: 12-14cm in length, with 1-2 healthy buds;

[0023] The grading standard is positively correlated with the rooting rate, and the rooting rate of grade A material can reach over 99.5%.

[0024] Preferably, the intelligent environmental control system adopts a fuzzy PID control algorithm to achieve precise control of temperature and humidity within ±0.5°C and light intensity within ±100lux; it is equipped with a UPS power supply and a backup spray system to ensure that environmental parameters remain stable for more than 30 minutes in the event of a sudden power outage.

[0025] Preferably, the SSR molecular marker detection uses fluorescent labeled primers and capillary electrophoresis analysis technology, which can detect pg-level DNA differences; the whole genome scan is performed on every 5 generations of propagation materials, and the genetic similarity is controlled at above 99.2% through the SSR molecular marker monitoring system.

[0026] Preferably, the cutting treatment uses 1000mg / LIBA solution to soak the base for 15 seconds to promote callus formation; combined with the "U"-shaped plug fixing technology, the "U"-shaped plug fixing technology is used to make the contact area between the cuttings and the substrate reach more than 80%, thereby improving the uniformity of rooting.

[0027] Preferably, the genetic stability monitoring is carried out in a 5-generation detection cycle, genomic DNA is extracted by the CTAB method, and genetic drift is detected by SSR marker analysis; 3% of samples are randomly selected for re-inspection in each generation to ensure the genetic stability of the propagation system.

[0028] Preferably, the three-level propagation system comprises three functional modules: a mother parent preservation area, a rapid propagation area and a production application area. The mother parent area adopts in vitro preservation technology, the propagation area applies aeroponic cultivation, and the production area implements standardized transplanting.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. Through breakthrough technology integrated innovation, the present invention has successfully constructed a large-scale and standardized production system for durian rootstocks, showing five core advantages: First, the breeding efficiency has achieved a qualitative leap, with the annual expansion coefficient reaching an industry-leading level of 20.5, which is 4-6 times higher than the traditional breeding method, injecting strong impetus into the large-scale development of the industry; second, an SSR molecular marker monitoring system is established to accurately control genetic stability, ensuring that the genetic similarity of five consecutive generations of breeding materials remains above 99%, fundamentally ensuring the consistency of variety characteristics; third, the innovative use of matrix localization formula and intelligent environmental control technology has reduced the comprehensive production cost by 42%, significantly improving the production economy.

[0031] 2. The present invention not only shortens the production cycle, but also realizes the standardization of quality control. Through process optimization, the rootstock nursery cycle is shortened from the original 90 days to 60 days, effectively improving the annual turnover rate and space utilization rate of the facility. The standardized grading system implemented simultaneously has increased the seedling qualification rate to 99.8%, ensuring the uniformity and reliability of the quality of each batch of products, laying a high-quality foundation for grafting seedlings. This dual improvement in efficiency and quality has formed the core support for the competitiveness of the industry.

[0032] 3. The present invention effectively solves the bottleneck of rootstock resource shortage that the durian industry has long faced, and supports industry expansion through stable supply. The promotion of standardized production models will promote the transformation of the industry to intensive and standardized development, and form an industrial ecology with sustainable development. In terms of economic benefits, cost reduction and production capacity improvement form a superimposed effect; in terms of social benefits, technological innovation drives employment upgrades, promotes the optimization of regional agricultural economic structure, opens up new paths for the high-quality development of the tropical fruit industry, and realizes the harmonious coexistence of economic and social benefits. Seed seedling cultivation is restricted by seasons, and seedlings can only be cultivated in summer and autumn, while cuttings can be cultivated all year round, thereby improving efficiency and production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a schematic flow chart of the method for multiplying durian rootstocks;

[0034] Figure 2 It is a schematic flow chart of the grafting of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figure 1 to Figure 2As shown, the embodiment of the present invention provides a method for propagating durian rootstock based on unlimited cuttings, through the technical path of mother parent cultivation, truncation cuttings and then cyclic propagation, the unlimited reproduction of durian rootstock is obtained, and the steps of the durian rootstock propagation method include:

[0037] Step 1: Seed selection and disinfection: Select D197 seeds, and disinfect the seeds by soaking them in warm water combined with potassium permanganate-sodium hypochlorite double-stage disinfection;

[0038] Purpose: To eliminate pathogenic microorganisms on the surface of seeds and activate the physiological activity of seeds;

[0039] Operation process:

[0040] Selection criteria: Select D197 seeds with 1000-grain weight ≥ 125g and no cracks in the seed shell;

[0041] Pretreatment: Soak the seeds in 55℃ warm water for 20 minutes, stirring 3 times during the process;

[0042] Disinfection process:

[0043] Initial disinfection: soak in 0.3% potassium permanganate solution for 30 minutes;

[0044] Cleaning: Use 40kHz distilled water ultrasonic cleaning for 10 minutes;

[0045] Secondary disinfection: soak in 2% sodium hypochlorite solution for 15 minutes;

[0046] Germination preparation: After disinfection, the seeds were placed on moist filter paper containing 1 mg / L GA3 and cultured in the dark at 28°C.

[0047] Table 1: Effects of different disinfection treatments on seed germination:

[0048] Processing Contamination rate (%) Germination rate (%) Control group (unsterilized) 42.3 78.5 Potassium permanganate single dose 12.5 89.2 Two-stage disinfection 0.3 98.7

[0049] Step 2: Preparation of sowing matrix and precise sowing: red soil: coconut bran: vermiculite: perlite = 2:6:1:1 matrix, sterilized and sown in a 50-52 hole tray, with the budding end of the seeds facing downwards, and covered with a matrix thickness of 0-1 cm;

[0050] Objective: To construct a microenvironment suitable for seed germination;

[0051] Matrix formula:

[0052] Basic matrix: volume ratio: red soil: coconut bran: vermiculite: perlite = 2:6:1:1;

[0053] Nutritional addition: Mix 15kg of decomposed chicken manure and 3kg of superphosphate into every cubic meter of substrate;

[0054] Physical properties: Bulk density 0.35g / cm3 , total porosity 70%-75%;

[0055] Disinfection:

[0056] First sterilization: After sieving through a 40-mesh sieve, sterilize with steam at 70°C for 60 minutes;

[0057] Secondary disinfection: 100g / m 3 Mix carbendazim wettable powder into the mixture.

[0058] Table 2: Effects of different substrate formulations on root development

[0059] Matrix formula Total root length (cm) Root fresh weight (g) Control substrate (garden soil) 12.4 0.85 Matrix of the present invention 18.7 1.32

[0060] Purpose: To ensure uniform seed germination;

[0061] Operation Specifications:

[0062] Sowing depth: The germination end of the seeds faces downward, and the thickness of the substrate is 0cm-1cm;

[0063] Sowing density: Use a 50-52 hole tray, 1 seed per hole;

[0064] Suppression treatment: Use a wooden pressing board to gently press the substrate surface to a compaction degree of 75%;

[0065] Irrigation system: Install micro-sprinkler belt, water outlet diameter 0.8mm, working pressure 0.2MPa.

[0066] Step 3: Seedling cultivation: seedling cultivation uses tidal irrigation and LED light control system and nutrient solution EC value control. When the seedling height reaches 30-35 cm, the first truncation treatment of step 5 is performed;

[0067] Purpose: To cultivate strong rootstock mother plants;

[0068] Water and fertilizer management:

[0069] Irrigation strategy: Tidal irrigation is used, with a 5-minute cycle every 2 hours;

[0070] Nutrient solution formula: modified Hoagland solution, the ratio is: NO 3 - -N:4mmol / L, P:1mmol / L, K:6mmol / L;

[0071] EC value control: 0.8mS / cm during sowing period; 1.2mS / cm before transplanting;

[0072] Growth regulation:

[0073] Light management: LED plant light, red to blue ratio 7:3, providing 12000 lux light;

[0074] Plant type control: spray 25mg / L paclobutrazol when the seedling height is 15cm;

[0075] Transplanting standards: seedling age 45 days, plant height 30-35cm, stem thickness ≥3.5mm.

[0076] Step 4: First cutting treatment: use a sterile blade to cut at 45° and apply callus paste. The cut materials are graded according to A / B standards and transferred to the cutting treatment in step 5;

[0077] Purpose: To obtain standardized cutting materials;

[0078] Operation details:

[0079] Cutting position: 45° oblique cut 10cm from the ground;

[0080] Tool requirements: Use a sterile blade and soak it in 75% alcohol for 30 minutes in advance;

[0081] Wound treatment: Immediately apply medical healing ointment containing 0.5% indoleacetic acid;

[0082] Grading Standard:

[0083] Grade A cuttings: 14-16cm in length, with 2-3 full buds;

[0084] Grade B cuttings: 12-14cm in length, with 1-2 buds;

[0085] Recovery mechanism: retain the base 5cm stem segment as secondary propagation material.

[0086] Step 5: Cutting treatment: IBA hormone treatment and standardized grading before cutting;

[0087] Purpose: To induce adventitious root formation;

[0088] Processing flow:

[0089] Hormone treatment: 2 cm from the base was soaked in 1000 mg / LIBA solution for 15 seconds;

[0090] Substrate preparation: Pre-wet the substrate to 65% moisture content and place in a 72-hole tray;

[0091] Cutting depth: The cuttings should be planted 4-5cm deep into the soil, with 1 / 3 of the leaves left;

[0092] Fixing method: Use "U"-shaped rods to fix and keep the cuttings upright;

[0093] Environmental Control:

[0094] Rooting period: temperature 26±1℃, RH90%-95%, light 1000-2000lux;

[0095] Seedling hardening period: the temperature difference between day and night is 28 / 22℃, RH 65%-70%.

[0096] Step 6: Intelligent environmental control: the rooting environment is maintained at RH 90%-95% and 26±1℃ through an intelligent control system;

[0097] Purpose: To create the best rooting environment;

[0098] Control system:

[0099] Hardware composition: temperature and humidity sensor, light intensity meter, CO2 controller;

[0100] Software algorithm: adopts fuzzy PID control strategy, response speed ≤ 5 seconds;

[0101] Emergency plan: equipped with UPS power supply + backup sprinkler system;

[0102] Parameter threshold:

[0103] Temperature over-limit alarm: greater than 30℃ or less than 24℃;

[0104] Humidity compensation mechanism: Automatically start ultrasonic atomization when RH is less than 85%.

[0105] Step 7: Circular propagation, establishing a three-level propagation system of mother-offspring-grandchildren;

[0106] Purpose: To achieve exponential growth in the reproduction coefficient;

[0107] Operational Model:

[0108] Expansion cycle: one cycle is completed every 30 days;

[0109] Generation management: adopt the three-level propagation system of "mother-offspring-grandchildren";

[0110] Genetic monitoring: SSR molecular marker detection every 5 generations;

[0111] Efficiency indicators:

[0112] Theoretical annual expansion coefficient: 2 n (n = number of multiplications);

[0113] Actual observed value: 20.5±1.2 (n=5);

[0114] Table 3: Comparison of propagation efficiency

[0115]

[0116]

[0117] Step 8: Quality control: SSR molecular marker genetic stability test is carried out every 5 generations; unqualified products are subject to the whole batch destruction system;

[0118] Purpose: To ensure the stable quality of propagation materials;

[0119] Testing system:

[0120] Rooting rate test: statistics 15 days after cutting, required to be ≥98%;

[0121] Root activity: determined by TTC method, reduction strength>0.35mg / (g·h);

[0122] Pest and disease detection: PCR method is used to detect viruses, and microscopic examination of insect eggs;

[0123] Disposal of defective products:

[0124] Rooting rate <95%: adjust hormone concentration ±200mg / L;

[0125] Positive for pests and diseases: destroy the entire batch and disinfect the environment;

[0126] Step 9: Standards for nursery seedlings: the nursery seedlings shall be based on the dual index system of morphology and physiology, with plant height of 25-30cm, stem diameter ≥4mm, root system fibrous roots ≥12 and length ≥5cm, photosynthetic rate ≥12μmol / (m 2 ·s).

[0127] Purpose: To ensure the quality of commercial seedlings;

[0128] Morphological indicators:

[0129] Plant height: 25-30cm (error ±2cm);

[0130] Stem diameter: greater than or equal to 4 mm (measured 2 cm above the ground);

[0131] Root system: 12 or more white fibrous roots, longer than 5 cm;

[0132] Physiological indicators:

[0133] Photosynthetic rate: Pn greater than or equal to 12μmol / (m 2 s);

[0134] Water condition: leaf water potential Ψw greater than or equal to -0.8MPa;

[0135] Packaging and transportation:

[0136] Matrix wrapping: Use moisturizing non-woven fabric to wrap the root system;

[0137] Transportation conditions: temperature 15-25℃, humidity 60%-70%.

[0138] Among them, the two-stage disinfection includes: the first time using 0.3% potassium permanganate solution to soak for 30 minutes, which effectively kills pathogens on the surface of seeds and activates enzyme activity; the second time using 2% sodium hypochlorite solution to soak for 15 minutes, deeply removes internal microbial contamination and ensures thorough seed disinfection.

[0139] Among them, the preparation of the sowing matrix also includes: sterilization using 70°C saturated steam for 60 minutes to completely kill fungal spores and nematode eggs in the matrix; after sterilization, evenly mix in 100 grams of carbendazim wettable powder per cubic meter of matrix to form a long-term antibacterial mechanism to ensure the sterile state of the sowing environment.

[0140] Among them, the tidal irrigation system performs 5 minutes of cyclic irrigation every 2 hours to accurately control the moisture content of the substrate; the EC value of the nutrient solution increases gradually from 0.8 to 1.2mS / cm at a gradient of 0.1mS / cm per week, which not only avoids salt stress but also meets the nutrient needs at different stages.

[0141] Among them, the standardized classification of cutting materials is divided into two levels:

[0142] Grade A: 14-16cm in length, with 2-3 full buds;

[0143] Grade B: 12-14cm in length, with 1-2 healthy buds;

[0144] The grading standard is positively correlated with the rooting rate, and the rooting rate of grade A material can reach over 99.5%.

[0145] Among them, the intelligent environmental control system adopts fuzzy PID control algorithm to achieve precise control of temperature and humidity ±0.5℃ and light intensity ±100lux; it is equipped with UPS power supply and backup spray system to ensure that environmental parameters remain stable for more than 30 minutes in the event of a sudden power outage.

[0146] Among them, SSR molecular marker detection uses fluorescent labeled primers and capillary electrophoresis analysis technology, which can detect pg-level DNA differences; the whole genome is scanned every 5 generations of propagation materials, and the genetic similarity is controlled at above 99.2% through the SSR molecular marker monitoring system.

[0147] Among them, the cutting treatment uses 1000mg / LIBA solution to soak the base for 15 seconds to promote callus formation; combined with the "U"-shaped plug fixing technology, the "U"-shaped plug fixing technology is used to make the contact area between the cuttings and the substrate reach more than 80%, thereby improving the uniformity of rooting.

[0148] Among them, genetic stability monitoring implements a 5-generation detection cycle, uses the CTAB method to extract genomic DNA, and detects genetic drift through SSR marker analysis; 3% of samples are randomly selected for re-inspection in each generation to ensure the genetic stability of the propagation system.

[0149] Among them, the three-level propagation system includes three functional modules: mother parent preservation area, rapid propagation area and production application area. The mother parent area adopts in vitro preservation technology, the propagation area uses aeroponic cultivation, and the production area implements standardized transplanting.

[0150] Infinite cuttings refer to the continuous proliferation of mother-offspring-grandchildren through a circular propagation system.

[0151] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0152] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for propagating durian rootstock based on unlimited cuttings, characterized in that: Through the technical path of mother parent cultivation, cutting and cutting, and then cyclic propagation, the unlimited reproduction of durian rootstock is obtained. The durian rootstock propagation method includes the following steps: Step 1: Seed selection and disinfection: Select D197 seed varieties, and disinfect the seeds by soaking in warm water combined with potassium permanganate-sodium hypochlorite double-stage disinfection; Step 2: Preparation of sowing matrix and precise sowing: red soil: coconut bran: vermiculite: perlite = 2:6:1:1 matrix, sterilized and sown in a 50-52 hole tray, with the budding end of the seeds facing downwards, and covered with a matrix thickness of 0-1 cm; Step 3: Seedling cultivation: seedling cultivation uses tidal irrigation and LED light control system and nutrient solution EC value control. When the seedling height reaches 30-35 cm, the first truncation treatment of step 5 is performed; Step 4: First cutting treatment: use a sterile blade to cut at 45° and apply callus paste. The cut materials are graded according to A / B standards and transferred to the cutting treatment in step 5; Step 5: Cutting treatment: IBA hormone treatment and standardized grading before cutting; Step 6: Intelligent environment control. The intelligent environment control system adopts fuzzy PID control algorithm, equipped with temperature and humidity sensors and UPS power supply. The rooting environment is maintained at RH90%-95% and 26±1℃ through the intelligent control system; Step 7: Circular propagation, establishing a three-level propagation system of mother-offspring-grandchildren; Step 8: Quality control: SSR molecular marker genetic stability test is carried out every 5 generations; unqualified products are subject to the whole batch destruction system; Step 9: Standards for nursery seedlings: the nursery seedlings shall be based on the dual index system of morphology and physiology, with plant height of 25-30cm, stem diameter ≥4mm, root system fibrous roots ≥12 and length ≥5cm, photosynthetic rate ≥12μmol / (m 2 ·s).

2. A method for multiplying durian stock based on unlimited cuttings according to claim 1, characterized in that: The double-stage disinfection includes: firstly soaking in 0.3% potassium permanganate solution for 30 minutes to effectively kill pathogens on the surface of seeds and activate enzyme activity; and secondly soaking in 2% sodium hypochlorite solution for 15 minutes to deeply remove internal microbial contamination.

3. A method for multiplying durian stock based on unlimited cuttings according to claim 1, characterized in that: The preparation of the sowing matrix also includes: sterilization using saturated steam at 70° C. for 60 minutes to completely kill fungal spores and nematode eggs in the matrix; after sterilization, 100 grams of carbendazim wettable powder is evenly mixed into each cubic meter of the matrix to form a long-term antibacterial mechanism to ensure a sterile sowing environment.

4. A method for multiplying durian stock based on unlimited cuttings according to claim 1, characterized in that: The tidal irrigation system performs 5 minutes of cyclic irrigation every 2 hours to accurately control the moisture content of the substrate; the EC value of the nutrient solution increases from 0.8 to 1.2 mS / cm in a gradient of 0.1 mS / cm per week, which not only avoids salt stress but also meets the nutrient requirements at different stages.

5. A method for multiplying durian stock based on unlimited cuttings according to claim 1, characterized in that: In the cutting process, the cutting materials are standardized and classified into two levels: Grade A: 14-16cm in length, with 2-3 full buds; Grade B: 12-14cm in length, with 1-2 healthy buds; The grading standard is positively correlated with the rooting rate, and the rooting rate of grade A material can reach over 99.5%.

6. A method for multiplying durian stock based on unlimited cuttings according to claim 1, characterized in that: The intelligent environmental control system adopts fuzzy PID control algorithm to achieve precise control of temperature and humidity within ±0.5°C and light intensity within ±100lux; it is equipped with UPS power supply and backup spray system to ensure that environmental parameters remain stable for more than 30 minutes in the event of sudden power outage.

7. A method for multiplying durian stock based on unlimited cuttings according to claim 1, characterized in that: In the quality control, SSR molecular marker detection uses fluorescent labeled primers and capillary electrophoresis analysis technology, which can detect pg-level DNA differences; the whole genome is scanned every 5 generations of propagation materials, and the genetic similarity is controlled at above 99.2% through the SSR molecular marker monitoring system.

8. A method for multiplying durian stock based on unlimited cuttings according to claim 1, characterized in that: The cutting treatment uses 1000mg / LIBA solution to soak the base for 15 seconds to promote callus formation; uses 'U'-shaped plug fixing technology to make the contact area between the cutting and the substrate reach more than 80%, thereby improving rooting uniformity.

9. A method for multiplying durian stock based on unlimited cuttings according to claim 1, characterized in that: The genetic stability monitoring is carried out in a 5-generation detection cycle, using the CTAB method to extract genomic DNA and detecting genetic drift through SSR marker analysis; 3% of the samples are randomly selected for re-inspection in each generation to promote the genetic stability of the propagation system.

10. A method for propagating durian rootstock based on unlimited cuttings according to claim 1, characterized in that: The three-level propagation system of circular propagation specifically includes three functional modules: mother parent preservation area, rapid propagation area and production application area. The mother parent area adopts in vitro preservation technology, the propagation area applies aeroponic cultivation, and the production area implements standardized transplanting.

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