Ground strawberry high-density seedling breeding method

Abstract

The invention relates to the technical field of seedling raising methods, and discloses a ground strawberry high-density seedling breeding method which comprises the steps of seedling breeding site preparation and matrix tank system construction, mother plant high-density field planting and management, staged nutrition regulation and control, stolon directional pressure guiding and seedling off-ground cultivation, and seedling quantitative management and harvesting. The planting method is limited, so that the effective seedling yield of stock plants is remarkably increased. By means of a three-level isolation system composed of ground isolation (gardening ground cloth), matrix groove cultivation and seedling planting cup off-ground rooting, the propagation path of soil-borne diseases is thoroughly cut off, a rain-sheltering and insect-preventing physical barrier is combined, the produced seedlings are healthy and non-toxic, and the quality of the seedlings is remarkably superior to that of traditional field planting seedlings.

Description

Technical Field

[0001] This invention relates to the field of seedling cultivation methods, and more specifically, to a method for high-density propagation of strawberry seedlings on the ground. Background Technology

[0002] Strawberry seedling propagation is the foundation of the strawberry industry, and its core lies in obtaining daughter seedlings through the growth of runners from the mother plant. Traditional strawberry seedling propagation mostly uses open-field seedbed planting, which has the following significant drawbacks: Low land utilization: The spacing between mother plants is large (usually ≥0.8m×1.0m), resulting in limited seedling production per unit area.

[0003] High incidence of diseases and pests: Seedlings are in direct contact with the soil and are easily infected with soil-borne diseases (such as anthracnose, Verticillium wilt, etc.), resulting in a high rate of disease-carrying seedlings and a low survival rate after transplanting.

[0004] Uneven seedling quality: The seedlings are greatly affected by the natural environment (rainfall, drought, high temperature) and the water and fertilizer management is extensive, resulting in uneven growth of stolons and inconsistent quality of seedlings.

[0005] Low management efficiency: Agricultural operations such as weeding, seedling pressing, and pest and disease control are cumbersome and labor costs are high.

[0006] To address these issues, existing technologies have developed soilless cultivation methods such as elevated seedling raising and plug seedling raising. While these methods effectively control diseases, they also present challenges such as high facility investment costs, high technical barriers, and easy root entanglement, making it difficult to promote them on a large scale among ordinary farmers.

[0007] Therefore, it is of great practical significance to provide a ground-based high-density strawberry propagation method that can significantly improve the propagation coefficient, ensure healthy and uniform seedlings, and is low-cost, easy to operate, and suitable for large-scale promotion. Summary of the Invention

[0008] In view of this, the present invention proposes a method for high-density ground strawberry seedling propagation, aiming to solve at least one of the aforementioned background technical problems.

[0009] This invention proposes a method for high-density propagation of strawberry seedlings on the ground, comprising the following steps: 1) Preparation of seedling propagation site and construction of substrate trough system: Select a flat site with good drainage, build a rain shelter with a transparent plastic film on the top, and install 50-60 mesh insect-proof netting around the shelter; A horticultural ground cover is laid on the ground, and several cultivation troughs are arranged in parallel on the horticultural ground cover. The cultivation troughs are bottomless open troughs and are filled with mixed seedling substrate. A movable micro-sprinkler irrigation system is installed directly above the cultivation trough, with a nozzle spacing of 1.0-1.2 meters; 2) High-density planting and management of mother plants: Select virus-free and healthy strawberry seedlings as mother plants. Plant them when the average daily temperature is stable above 12℃. The planting adopts the double-row staggered high-density planting method. Plant two rows of mother plants in a 40cm wide cultivation trough with a row spacing of 20cm and a plant spacing of 15cm. The adjacent two rows of mother plants are arranged in a triangular staggered arrangement. 3) Stage-based nutrient regulation: Immediately after transplanting, water thoroughly to help the roots establish. After the seedling establishment period, stage-based nutrient regulation is carried out. The stage-based nutrient regulation includes the vegetative growth period and the reproductive growth initiation period. During the vegetative growth period, a high-nitrogen balanced nutrient solution is applied through a micro-sprinkler irrigation system. During the reproductive growth initiation period, switch to a nutrient solution specifically for promoting runners, and at the same time, spray the leaves with a 60 mg / L gibberellin solution once. 4) Oriented pressing of stolons and off-ground cultivation of seedlings: When the stolons grow to 15-20cm, directional pressing is carried out; the directional pressing adopts the U-shaped wire fixing method, specifically: use a 2mm diameter U-shaped wire to gently press the front of the stolon growing point into the substrate surface, so that the seedling node is in full contact with the substrate, but without damaging the stem; pre-bury small planting cups at the seedling node, fill the cups with the same seedling substrate, and let the stolons pass through the side holes of the cups, and the seedlings take root in the cups; 5) Quantitative management and harvesting of seedlings: Retain 8-10 strong runners for each mother plant, and retain 3-4 seedlings for each runner. Remove excess runners and seedlings in a timely manner. When the seedlings have grown 3-4 unfolded leaves and their roots have filled the planting cup, they can be cut off from the side of the runner closest to the mother plant with sterilized scissors to achieve single-plant harvesting. After harvesting, the seedlings can be directly transferred to the temporary planting or sales stage with the planting cup to form standardized commercial seedlings.

[0010] Preferably, the mixed seedling substrate is obtained by mixing peat moss, coconut coir, vermiculite and perlite in a mass ratio of 3:3:2:1.

[0011] Preferably, the high-nitrogen balanced nutrient solution includes ammonium nitrate, urea, potassium dihydrogen phosphate, potassium sulfate, calcium nitrate, magnesium sulfate, chelated iron, chelated zinc, chelated calcium, and ammonium molybdate. Preferably, the nutrient solution for promoting stolon growth includes potassium nitrate, ammonium dihydrogen phosphate, potassium sulfate, calcium nitrate, magnesium sulfate, chelated iron, chelated zinc, chelated copper, and humic acid.

[0012] Preferably, the vegetative growth period is from the time of transplanting until the first batch of stolons emerges; the reproductive growth initiation period is when the first batch of stolons grows to 2-3 cm.

[0013] Preferably, during steps 1) to 5) of the seedling propagation method, environmental factors are regulated and managed, specifically including temperature management, light management, and water management.

[0014] Preferably, the temperature management is achieved by using the roll-up ventilation system of the rain shelter to control the daytime temperature at 20-28℃ and the nighttime temperature at 12-18℃.

[0015] Preferably, the light management is as follows: during periods of strong sunlight in summer, a 30%-50% shade net is placed outside the greenhouse film to ensure an average daily light duration of 6-7 hours.

[0016] Preferably, the moisture management involves: real-time detection of the surface humidity of the seedling substrate, and implementation of pulsed mist irrigation based on the real-time detection results to maintain the surface humidity of the substrate at 60%-70%.

[0017] This invention also provides the application of the above-described high-density ground strawberry seedling propagation method in strawberry seedling breeding.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Extremely high propagation density and efficiency: The present invention uses the "double row staggered high density planting method" to plant mother plants at a density more than 3 times that of the traditional method. Combined with scientific nutrition and hormone regulation, the effective seedling yield of each mother plant is increased to 30-40 plants, while the land utilization rate is significantly improved.

[0019] (2) Excellent pest and disease control capabilities: This invention uses a three-level isolation system consisting of ground isolation (horticultural ground cover), substrate trough cultivation and seedling planting cups for off-ground rooting to completely cut off the transmission route of soil-borne diseases. Combined with the physical barrier of rain protection and insect prevention, the seedlings produced are healthy and non-toxic, and their quality is significantly better than that of traditional ground-planted seedlings.

[0020] (3) Uniform and controllable seedling quality: The present invention also regulates and manages environmental factors throughout the seedling propagation process. Through precise regulation of the microenvironment (temperature, light, water, air) and phased nutrient management, the optimal and consistent conditions are created for the growth of stolons and seedlings, ensuring the uniformity and robustness of batches of seedlings.

[0021] (4) Simplified and standardized management: The present invention realizes the automatic management of integrated water and fertilizer through micro-sprinkler irrigation / atomization system; the application of U-shaped iron wire and planting cup makes the seedling pressing operation standardized and labor-saving, and the off-ground design facilitates observation and management. Detailed Implementation

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0023] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0025] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0026] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0027] This invention proposes a method for high-density propagation of strawberry seedlings on the ground, comprising the following steps: 1) Preparation of seedling propagation site and construction of substrate trough system: Select a flat site with good drainage, build a rain shelter with a transparent plastic film on the top, and install 50-60 mesh insect-proof netting around the shelter; A horticultural ground cover is laid on the ground, and several cultivation troughs are arranged in parallel on the horticultural ground cover. The cultivation troughs are bottomless open troughs and are filled with mixed seedling substrate. A movable micro-sprinkler irrigation system is installed directly above the cultivation trough, with a nozzle spacing of 1.0-1.2 meters; 2) High-density planting and management of mother plants: Select virus-free and healthy strawberry seedlings as mother plants. Plant them when the average daily temperature is stable above 12℃. The planting adopts the double-row staggered high-density planting method. Plant two rows of mother plants in a 40cm wide cultivation trough with a row spacing of 20cm and a plant spacing of 15cm. The adjacent two rows of mother plants are arranged in a triangular staggered arrangement. 3) Stage-based nutrient regulation: Immediately after transplanting, water thoroughly to help the roots establish. After the seedling establishment period, stage-based nutrient regulation is carried out. The stage-based nutrient regulation includes the vegetative growth period and the reproductive growth initiation period. During the vegetative growth period, a high-nitrogen balanced nutrient solution is applied through a micro-sprinkler irrigation system. During the reproductive growth initiation period, switch to a nutrient solution specifically for promoting runners, and at the same time, spray the leaves with a 60 mg / L gibberellin solution once. 4) Oriented pressing of stolons and off-ground cultivation of seedlings: When the stolons grow to 15-20cm, directional pressing is carried out; the directional pressing adopts the U-shaped wire fixing method, specifically: use a 2mm diameter U-shaped wire to gently press the front of the stolon growing point into the substrate surface, so that the seedling node is in full contact with the substrate, but without damaging the stem; pre-bury small planting cups at the seedling node, fill the cups with the same seedling substrate, and let the stolons pass through the side holes of the cups, and the seedlings take root in the cups; 5) Quantitative management and harvesting of seedlings: Retain 8-10 strong runners for each mother plant, and retain 3-4 seedlings for each runner. Remove excess runners and seedlings in a timely manner. When the seedlings have grown 3-4 unfolded leaves and their roots have filled the planting cup, they can be cut off from the side of the runner closest to the mother plant with sterilized scissors to achieve single-plant harvesting. After harvesting, the seedlings can be directly transferred to the temporary planting or sales stage with the planting cup to form standardized commercial seedlings.

[0028] The high-density ground strawberry seedling propagation method of this invention first involves preparing the propagation site and constructing the substrate trough system, specifically as follows: Choose a flat, well-drained site to avoid waterlogging in low-lying areas. In actual production, drainage ditches can be dug around the site to assist drainage and prevent rainwater backflow. Then, build a rain shelter with a transparent plastic film covering the top. The size of the rain shelter can be selected according to actual needs. The material of the rain shelter can be transparent polyethylene film. Install 50-60 mesh insect netting around the shelter to further reduce the spread of viruses. The lower edge of the insect netting should be buried 10cm underground to prevent pests from burrowing in from the ground.

[0029] Then, lay horticultural ground cover on the ground. The horticultural ground cover can be made of PP material to prevent weeds from coming into direct contact with the substrate and reduce the risk of soil-borne diseases (such as root rot). The ground cover is laid along the length of the shed, with an overlap width of ≥15cm between adjacent ground covers. It is fixed with U-shaped ground nails (1m apart, 10cm deep in the soil) to ensure that the ground cover is flat and wrinkle-free, and the edges extend to the drainage ditch outside the shed to prevent rainwater from seeping into the substrate along the inside of the ground cover.

[0030] Then, several cultivation troughs are arranged in parallel on the horticultural ground cover. The cultivation troughs are bottomless open troughs filled with mixed seedling substrate. The present invention uses bottomless open troughs, and the specific dimensions can be selected as follows: length 5m / section, width 40cm, height 15cm, wall thickness 3mm). The bottomless design can ensure that the bottom of the substrate is breathable and avoid water accumulation. When arranged in parallel, the troughs are spaced 50cm apart to reserve an operation channel for easy manual management of the stolons. Each row of cultivation troughs is raised by 5cm with bricks to further improve drainage.

[0031] Next, the seedling substrate is prepared and filled. Specifically, peat moss, coconut coir, vermiculite, and perlite are mixed in a mass ratio of 3:3:2:1. Before mixing, each raw material is treated. The peat moss needs to have a fiber length of 5-10mm, the coconut coir needs to have a mesh size of 10-20 after crushing and be soaked in clean water for 24 hours in advance, the vermiculite needs to have a particle size of 3-5mm, and the perlite needs to have a particle size of 2-4mm. Before mixing, the peat moss and coconut coir need to be crushed and sieved (sieve hole 1cm) to remove large impurities. When filling, the substrate needs to be compacted in layers to avoid substrate settling later. The filling height is 80% of the height of the trough, leaving 3cm space to prevent substrate from overflowing when watering.

[0032] A movable micro-irrigation system is installed directly above the cultivation trough, with nozzles spaced 1.0-1.2 meters apart. The micro-irrigation system specifically includes: a main pipe (PE pipe), branch pipes (PE pipes), movable nozzles (atomizing nozzles), solenoid valves, and a timer (for setting irrigation time and frequency). The main pipe is laid along the length of the greenhouse on one side, and the branch pipes are perpendicular to the main pipe and installed directly above the cultivation trough. Nozzles are installed at 1.0-1.2m intervals to ensure comprehensive spray coverage and prevent localized substrate drought. The nozzle flow rate is controlled at 80-100mL / min to ensure atomization and prevent water flow from impacting the substrate, causing nutrient loss or seedling lodging.

[0033] Step (2) High-density planting and management of mother plants: Select virus-free and healthy strawberry seedlings as mother plants. Plant them when the average daily temperature is stable above 12℃. The planting adopts the double-row staggered high-density planting method. Plant two rows of mother plants in a cultivation trough with a width of 40cm, with a row spacing of 20cm and a plant spacing of 15cm. The adjacent two rows of mother plants are arranged in a triangular staggered arrangement. Specifically: The optimal method for high-density planting and management of mother plants is as follows: First, select seedlings, using virus-free strawberry seedlings (virus-free through shoot tip culture, tested free of common viruses such as strawberry mottle virus and strawberry mild yellow edge virus) to avoid the transmission of viral diseases from the mother plant to the daughter seedlings, which would result in weak growth and low yield. Select robust seedlings with 3-4 leaves and 1 bud, 15-20cm in height, with well-developed root systems (≥15 fibrous roots, ≥5cm in length, free of black or rotten roots), dark green leaves, and no disease or pest spots. One day before planting, soak the roots of the mother plant in a 500-fold dilution of carbendazim solution for 15 minutes for sterilization. At the same time, prune old roots and weak or diseased leaves to reduce water evaporation and nutrient consumption, thereby improving the survival rate of the planted seedlings.

[0034] Secondly, transplanting should be done when the average daily temperature is consistently above 12℃ (monitoring for 7 consecutive days, with a minimum temperature ≥8℃). At this time, strawberry root activity is enhanced, and seedlings recover quickly after transplanting. Avoid transplanting when the temperature is below 10℃ or above 30℃, as low temperatures can easily cause root damage, and high temperatures can easily cause plant dehydration and wilting. Specifically, a double-row staggered high-density planting method should be used. The planting details are as follows: Planting Layout: In a 40cm wide cultivation trough, divide the trough into two rows along its length, with a row spacing of 20cm (the center line of the two rows is 20cm apart, and each row is 10cm away from the edge of the trough to ensure space for root growth); plant spacing is 15cm (6-7 mother plants are planted per meter of trough length, and 30-35 plants can be planted per 5m long trough, which is a significantly higher density than traditional single-row planting (plant spacing of 25cm).

[0035] Staggered arrangement: Adjacent rows of mother plants are arranged in a triangular staggered pattern. This method can make the leaves of the mother plants more evenly distributed, avoid the overlapping and shading caused by single-row arrangement, and improve photosynthetic efficiency. At the same time, the growth space of the stolons is more reasonable, reducing the cross-entanglement of stolons in the later stage.

[0036] In addition, when planting, use a small shovel to dig a hole 8-10cm deep in the substrate, place the mother plant in the hole, and spread out the roots (to avoid root curling). Cover the substrate up to the junction of the root and stem (i.e., the "green head" position; if it is higher than the substrate, the stem will easily dry out, and if it is lower than the substrate, the root and stem will easily rot). After planting, gently press the substrate to make the roots and substrate in close contact and reduce air gaps.

[0037] Step 3 of this invention is staged nutrient regulation. Immediately after transplanting, the roots are thoroughly watered. After the seedling establishment period, staged nutrient regulation is carried out. The staged nutrient regulation includes the vegetative growth period and the reproductive growth initiation period. During the vegetative growth period, a high-nitrogen balanced nutrient solution is applied through a micro-sprinkler irrigation system. During the reproductive growth initiation period, the solution is switched to a nutrient solution for promoting runners, and at the same time, a 60 mg / L gibberellin solution is sprayed on the leaves once. The preferred method is as follows: Immediately after transplanting, thoroughly water the plant using a micro-irrigation system, adding a 500-fold dilution of rooting agent (such as naphthaleneacetic acid) to the water to promote rapid root recovery. For the next three days, irrigate once daily (for 15 minutes each time), keeping the substrate moist to aid in seedling establishment. The 7-10 day period after transplanting is the seedling establishment period. Observe the leaves of the mother plant daily; if the leaves wilt, increase the frequency of spraying and lower the temperature inside the greenhouse. After the seedling establishment period, when the leaves regain their upright position and new leaves begin to grow, it indicates that the mother plant has entered a normal growth stage. Afterwards, implement phased nutrient regulation. Based on the different nutrient requirements of the strawberry mother plant at different growth stages, switch nutrient solution types and supplement with foliar fertilizer to achieve "on-demand fertilization," avoiding nutrient waste or deficiency, ensuring robust mother plants during the vegetative growth period and numerous, strong runners during the reproductive growth initiation period.

[0038] During the vegetative growth period, the mother plants primarily focus on vegetative growth, requiring a large amount of nitrogen to promote leaf and stem growth. Simultaneously, a balanced intake of phosphorus, potassium, and micronutrients is necessary to build a robust plant body and reserve nutrients for subsequent runner development. The specific application method is as follows: apply fertigation via a micro-sprinkler system every 3-5 days, using 8-10L per square meter of cultivation trough each time (ensuring the substrate surface is moist but not waterlogged). The application time is between 9-10 am (when transpiration is weak and nutrient absorption efficiency is high, avoiding nutrient evaporation due to midday heat or substrate waterlogging due to evening low temperatures). Sample the substrate EC value every 7 days, controlling it between 1.8-2.2 mS / cm. If the EC value is too high (>2.5 mS / cm), irrigate once with clean water (to wash away salt) to prevent nutrient accumulation and root burn. If the EC value is too low (<1.5 mS / cm), shorten the nutrient solution application interval (to once every 2 days).

[0039] During the reproductive growth initiation phase, the mother plant transitions from vegetative to reproductive growth. This requires reducing nitrogen and increasing phosphorus and potassium, while also supplementing with gibberellin (to break dormancy and induce runner growth). Specifically, the preferred method is to immediately stop using high-nitrogen nutrient solution and switch to a runner-promoting nutrient solution when the first batch of runners reaches 2-3 cm in length. During the switch, first irrigate with clean water to wash away any residual high-nitrogen nutrients before applying the special nutrient solution to avoid nutrient imbalance caused by mixing the two solutions. Apply every 4-6 days, using 10-12 L per square meter of cultivation trough each time, focusing on spraying the runner growth area. The EC value should be controlled at 2.0-2.5 mS / cm to ensure sufficient but not excessive phosphorus and potassium nutrients.

[0040] During the reproductive growth initiation period, spray the leaves once with gibberellin solution. Choose a sunny day before 10:00 am to spray evenly on the back of the mother plant's leaves and the growth point of the stolons, ensuring that the leaves are moist but not dripping. If it rains within 6 hours after spraying, re-spray (with half the concentration) to avoid rain washing away the efficacy. The method for preparing the gibberellin solution is as follows: dissolve the gibberellin powder in a small amount of alcohol, then add water to dilute to a concentration of 60 mg / L. Avoid excessively high concentrations (>80 mg / L) which can cause excessive and weak stolons, and excessively low concentrations (<40 mg / L) which will result in poor induction effects.

[0041] It is important to note that during the transition from the vegetative growth period to the reproductive growth initiation period (approximately 20 days after transplanting), the amount of high-nitrogen nutrient solution should be halved 3 days in advance. At the same time, observe the growth status of the mother plant. If the leaves of the mother plant are too thick or too dark in color, the interval between water irrigation can be extended to promote nutrient consumption. If the mother plant is growing weakly and the leaves are yellowing, a 500-fold diluted amino acid foliar fertilizer should be added once to improve the plant's growth before switching to a different nutrient solution.

[0042] Step 4 of this invention involves directional pressing of the stolons and cultivation of seedlings off the ground. When the stolons grow to 15-20cm, directional pressing is performed. The directional pressing adopts the U-shaped wire fixing method, specifically: a U-shaped wire with a diameter of 2mm is used to gently press the front of the stolon's growth point into the substrate surface, so that the seedling node is in full contact with the substrate without damaging the stem; a small planting cup is pre-buried at the seedling node, and the cup is filled with the same seedling substrate, so that the stolons pass through the side holes of the cup, and the seedlings take root in the cup; Step 4 is preferably performed as follows: When the stolon reaches 15-20cm in length, directional pressing is carried out. At this time, the stem nodes have been formed (the first and second nodes are the seedling nodes). Pressing at this time can make the seedling nodes contact the substrate and induce rooting. Pressing too early (<15cm) will result in thinner stolons that are easy to break. Pressing too late (>20cm) will result in stolons that are easy to entangle themselves, increasing the difficulty of management.

[0043] The directional pressing method uses a U-shaped wire fixing method. The fixing details are as follows: Select 2mm diameter galvanized iron wire (rust-proof, long service life), cut it into 10cm long sections, and bend it into a U-shape with pliers (opening width 3cm, bottom arc radius 1cm). Avoid openings that are too narrow (<2cm) to prevent damage to the runners, and openings that are too wide (>4cm) to ensure a secure fixation. Then, along the length of the cultivation trough, with the U-shaped wire opening downwards, gently press it 2cm in front of the runner's growth point (above the node of the seedling), ensuring close contact between the seedling node and the substrate surface (the pressure should be such that the wire is embedded 1cm into the substrate without damaging the stem epidermis). Press each runner in a straight line, with a 10cm spacing between adjacent runners to avoid crossing (e.g., the runners of the first row of mother plants are directed towards the outside of the trough, and the runners of the second row of mother plants are directed towards the inside of the trough).

[0044] After pressing, observe the status of the runners daily. If the wire becomes loose (due to substrate settling), it needs to be pressed firmly again. If the runners deviate from the direction of growth (not growing in the direction of pressing), use small stones to gently press the middle of the runners to adjust the growth direction.

[0045] Then, small planting cups are pre-buried at the nodes of the seedlings, and the same seedling substrate is filled into the cups so that the stolons pass through the side holes of the cups and the seedlings take root in the cups; The optimal parameters for planting cups are as follows: Use plastic planting cups with a diameter of 5cm and a height of 8cm (with 3 holes of 0.5cm diameter each on the bottom and side; the bottom hole is for drainage, and the side hole is for the runners to pass through). The edge of the cup should be wavy (for easy handling during harvesting). Prepare 8-10 planting cups for each mother plant (corresponding to the number of runners to be retained). Fill the planting cups with the same mixed seedling substrate as the cultivation trough (pre-moistened to 60% moisture content, i.e., it can be formed into a ball when squeezed but does not crumble when released). Fill the cups to 70% (5.6cm) of the cup height, leaving 30% (2.4cm) of space for the daughter seedlings to grow, avoiding overfilling which would result in insufficient space for the daughter seedlings to grow.

[0046] The pre-buried location is in the substrate below the node of the stolon seedling (1cm away from the node). Dig a hole 5cm deep and place the planting cup in the hole, making the rim of the cup level with the substrate surface (avoid the rim being higher than the substrate, preventing the seedling node from contacting the substrate; if it's lower, water will easily accumulate). Insert the stolon through the hole on the side of the planting cup, so that the seedling node (the node with small leaves) is above the substrate in the center of the planting cup. Gently press the substrate to make the seedling node contact the substrate inside the cup. Guide each stolon to one seedling per cup, that is, place the first seedling node of each stolon in the first planting cup, the second seedling node in the second planting cup (15cm apart), to avoid multiple seedlings sharing one cup and causing nutrient competition.

[0047] After pressing and pre-burying, spray the substrate in the planting cup 1-2 times a day (5 minutes each time) using a micro-irrigation system to maintain a substrate moisture content of 60%-70% (the substrate should feel moist but not sticky to the touch). Avoid excessive dryness (<50%), which will slow down the rooting of the seedlings, and excessive moisture (>80%), which will cause the nodes of the seedlings to rot. Every 10 days, spray the planting cup and the surrounding substrate with a 300-fold dilution of chlorothalonil solution, focusing on spraying the nodes of the seedlings to prevent anthracnose and root rot. If brown spots are found on the leaves of the seedlings, the diseased seedlings and corresponding runners should be removed in time to prevent the spread of the disease.

[0048] During the pressing and cultivation process, the runners need to be tidied up once a week, removing excess runners (retain 8-10 runners per mother plant, selecting healthy runners free from pests and diseases), and cutting them off at the base with scissors (avoid pulling and injuring the mother plant); at the same time, remove ineffective nodes (nodes without leaves) on the runners to reduce nutrient consumption; if the runners grow too vigorously (length > 30cm), the apical growing point can be pinched off to promote the growth of seedlings.

[0049] Step 5 of this invention involves the quantitative management and harvesting of seedlings. Each mother plant retains 8-10 robust runners, and each runner retains 3-4 seedlings. Excess runners and seedlings are removed promptly. When the seedlings have grown 3-4 unfolded leaves and their roots have filled the planting cup, they can be cut off from the side of the runner closest to the mother plant with sterilized scissors to achieve single-plant harvesting. The harvested seedlings can be directly transplanted or sold with their planting cups to form standardized commercial seedlings.

[0050] The preferred method is as follows: Retain 8-10 healthy runners per mother plant (choose runners with thick stems and green leaves), and remove weak or diseased runners (such as those with aphids on the stem or spots on the leaves) to avoid wasting nutrients. If the mother plant is weak (less than 5 leaves), reduce the number of runners (6-7) to prioritize the growth of the mother plant. On each runner, retain 3-4 daughter plants (counting from the mother plant outwards, the 1st to 4th nodes), and remove daughter plants from the 5th node onwards (those that are weak and have underdeveloped root systems). If any daughter plant on a runner is diseased or infested, remove the entire runner to prevent infection of other daughter plants.

[0051] Use different colored plastic tags (e.g., red tags to mark retained runners, blue tags to mark runners to be removed) to attach to the base of the mother plant for easy identification; on each retained runner, mark the fourth seedling with a white tag outside as the "maximum number of seedlings to retain" to avoid mistakenly retaining them later. Check every 5 days, removing any newly grown excess runners (lateral runners sprouting from the base of the mother plant) and seedlings to ensure the number of seedlings retained meets the standard; at the same time, observe the growth status of the seedlings, and remove any seedlings with yellowing leaves or few roots in time to avoid taking up space.

[0052] Seedlings can be harvested when they meet the following two conditions: First, the number of leaves, with 3-4 unfolded leaves; second, the root system, with roots covering the planting cup, white fibrous roots visible from the outside of the cup, and roots intertwined but not tangled inside the cup. At this time, the seedlings have the ability to grow independently and have a high survival rate after transplanting.

[0053] In this invention, the mixed seedling substrate is preferably obtained by mixing peat moss, coconut coir, vermiculite and perlite in a mass ratio of 3:3:2:1.

[0054] In this invention, the high-nitrogen balanced nutrient solution preferably includes ammonium nitrate, urea, potassium dihydrogen phosphate, potassium sulfate, calcium nitrate, magnesium sulfate, chelated iron, chelated zinc, chelated calcium, and ammonium molybdate. This invention does not impose specific limitations on the dosage of each component in the high-nitrogen balanced nutrient solution; adjustments can be made as needed.

[0055] In this invention, the nutrient solution specifically for promoting runner growth preferably includes potassium nitrate, ammonium dihydrogen phosphate, potassium sulfate, calcium nitrate, magnesium sulfate, chelated iron, chelated zinc, chelated copper, and humic acid. This invention does not impose specific limitations on the dosage of each component in the nutrient solution for promoting runner growth; adjustments can be made as needed.

[0056] In this invention, the vegetative growth period is preferably from the time of transplanting until the first batch of stolons emerges; the reproductive growth initiation period is preferably when the first batch of stolons grows to 2-3 cm.

[0057] In this invention, during steps 1) to 5) of the seedling propagation method, it is preferable to regulate and manage environmental factors, specifically including temperature management, light management, and water management.

[0058] In this invention, the temperature management is preferably achieved by using the roll-up ventilation system of the rain shelter to control the daytime temperature at 20-28°C and the nighttime temperature at 12-18°C.

[0059] In this invention, the preferred method of light management is to cover the outside of the greenhouse film with 30%-50% shade netting during periods of strong sunlight in summer to ensure an average daily light duration of 6-7 hours.

[0060] In this invention, the preferred method of water management is to monitor the surface humidity of the seedling substrate in real time and implement pulsed atomized irrigation based on the real-time monitoring results to maintain the surface humidity of the substrate at 60%-70%.

[0061] The technical means for real-time detection of the surface humidity of the seedling substrate can be any technical method known to those skilled in the art, without special limitation, and preferably can be a humidity sensor, etc.

[0062] This invention also provides the application of the above-described high-density ground strawberry seedling propagation method in strawberry seedling breeding.

[0063] Example 1 (1) Preparation of seedling propagation site and construction of substrate trough system Select a flat plot of land, remove gravel, weed roots, and other debris, and construct a 30m long and 8m wide steel pipe rain shelter. Cover the top with an 8-filament PO film and install 60-mesh insect netting around the perimeter. The entire floor inside the shelter is covered with black PP horticultural ground cover. On the ground cover, set up seven bottomless, brick-built cultivation troughs, each 28m long, 0.4m wide, and 0.15m high, spaced 0.8m apart as walkways. Fill the cultivation troughs with a seedling substrate composed of peat moss, coconut coir, vermiculite, and perlite in a 3:3:2:1 mass ratio. Fill to a height of 12cm (80% of the trough height). Install micro-irrigation branch pipes 1.2m directly above the cultivation troughs, install atomizing nozzles at 1.1m intervals, connect the main pipe, solenoid valve, and timer, and bury the substrate humidity sensor in the substrate (5cm deep). Test the system to ensure even spraying.

[0064] (2) High-density planting of mother plants Select virus-free 'Hongyan' seedlings (3 leaves and 1 bud, with well-developed root system). One day before transplanting, soak the mother plant's root system in a 500-fold dilution of carbendazim solution for 15 minutes. After removing them, trim old roots and diseased or weak leaves, and place them in a cool, shady place to dry for 30 minutes. Transplant when the average daily temperature is consistently 15℃, using a double-row staggered method: plant two rows in a 0.4m wide trench, with a row spacing of 0.2m and a plant spacing of 0.15m, arranged in a triangular staggered pattern.

[0065] (3) Stage-based nutritional regulation Seedling establishment period (7 days after transplanting): Immediately after transplanting, thoroughly water the plants using a micro-sprinkler irrigation system, adding a 500-fold dilution of naphthaleneacetic acid rooting agent to the water; for the next 3 days, irrigate for 15 minutes at 10:00 AM each day to keep the substrate moist; during the seedling establishment period, observe the condition of the mother plants daily. If the leaves wilt, increase the frequency of spraying and control the temperature inside the greenhouse at 22-26℃ through ventilation by rolling up the film; once normal management begins, irrigate for 15 minutes daily using a micro-sprinkler irrigation system to keep the substrate moist.

[0066] During the vegetative growth period (April): Apply a high-nitrogen balanced nutrient solution (EC value 1.8 mS / cm) every 4 days.

[0067] Reproductive growth initiation period (early May): When 50% of the mother plants have produced 2-3cm runners, switch to a special nutrient solution for promoting runner growth (EC value 2.2 mS / cm) and spray the leaves once with a 60mg / L gibberellin solution.

[0068] (4) Orientation and pressing of stolons and off-ground cultivation of seedlings Starting in mid-May, when the runners reach 15-20cm in length, straighten them. Use a 2mm diameter U-shaped galvanized iron wire to gently press and fix the runner's growing point to the substrate surface. Pre-bury 5cm diameter plastic planting cups at the nodes of the seedlings, filling the cups with the same substrate to allow the seedlings to root within the cups.

[0069] (5) Environmental regulation (6) Temperature, light and moisture are monitored and controlled throughout steps (1) to (4). Specifically, temperature is controlled at 22-26℃ during the day and 14-16℃ at night through ventilation of the roll film; light is covered with 50% shade netting during sunny days in July and August from 10:00 to 16:00; moisture is sprayed for 30 seconds every 20 minutes on hot days from 10:00 to 16:00 based on observation.

[0070] (6) Quantitative management and harvesting of seedlings Retain 8-10 strong runners per mother plant, and keep the first 3-4 strong daughter plants on each runner. Begin harvesting in batches starting from July 20th. When the daughter plants have 3-4 unfolded leaves and their roots have filled the planting cup, cut them off the runners with sterilized scissors.

[0071] The entire process of Example 1 was recorded, and the recording results are as follows: (1) Survival rate of mother plants: 20 days after transplanting, the survival rate of mother plants reached 98.5%, which is significantly higher than that of traditional open-field transplanting (survival rate of about 85%).

[0072] (2) Number of stolons produced: Each mother plant produces an average of 12.3 stolons, of which 9 are kept. The effective utilization rate of stolons is 73.2%, while the effective utilization rate of stolons using traditional methods is about 50%.

[0073] (3) Produced seedlings: Each retained stolon produces an average of 3.6 qualified seedlings, and each mother plant produces an average of 32.4 qualified seedlings. The total yield per greenhouse (40m×7m) is 66,096 seedlings, which is equivalent to 254,000 seedlings per mu (the yield of traditional open-field seedling propagation is about 80,000 seedlings per mu), significantly improving land utilization.

[0074] (4) Seedling quality Appearance and growth indicators: The average height of the harvested seedlings is 12cm, the number of unfolded leaves is 3.4, the number of fibrous roots is ≥22, the root length is ≥7cm, the uniformity of the seedlings is 92% (the difference in plant height is ≤2cm), and there are no diseases or pests (the disease rate is 0%, while the disease rate of traditional open-field seedlings is about 15%).

[0075] Transplant survival rate: The harvested seedlings were used for field planting. The survival rate was 97.2% 30 days after transplanting. The survival rate of traditional open-field seedling transplanting is about 80%, which is 21.5% higher.

[0076] Based on this, it can be seen that the present invention verifies the feasibility of the ground strawberry high-density seedling propagation method and achieves the production goals of high yield, high quality and high efficiency.

[0077] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for high-density propagation of strawberry seedlings on the ground, characterized in that, Includes the following steps: 1) Preparation of seedling propagation site and construction of substrate trough system: Select a flat site with good drainage, build a rain shelter with a transparent plastic film on the top, and install 50-60 mesh insect-proof netting around the shelter; A horticultural ground cover is laid on the ground, and several cultivation troughs are arranged in parallel on the horticultural ground cover. The cultivation troughs are bottomless open troughs and are filled with mixed seedling substrate. A movable micro-sprinkler irrigation system is installed directly above the cultivation trough, with a nozzle spacing of 1.0-1.2 meters; 2) High-density planting and management of mother plants: Select virus-free and healthy strawberry seedlings as mother plants. Plant them when the average daily temperature is stable above 12℃. The planting adopts the double-row staggered high-density planting method. Plant two rows of mother plants in a 40cm wide cultivation trough with a row spacing of 20cm and a plant spacing of 15cm. The adjacent two rows of mother plants are arranged in a triangular staggered arrangement. 3) Stage-based nutrient regulation: Immediately after transplanting, water thoroughly to help the roots establish. After the seedling establishment period, stage-based nutrient regulation is carried out. The stage-based nutrient regulation includes the vegetative growth period and the reproductive growth initiation period. During the vegetative growth period, a high-nitrogen balanced nutrient solution is applied through a micro-sprinkler irrigation system. During the reproductive growth initiation period, switch to a nutrient solution specifically for promoting runners, and at the same time, spray the leaves with a 60 mg / L gibberellin solution once. 4) Oriented pressing of stolons and off-ground cultivation of seedlings: When the stolons grow to 15-20cm, directional pressing is carried out; the directional pressing adopts the U-shaped wire fixing method, specifically: use a 2mm diameter U-shaped wire to gently press the front of the stolon growing point into the substrate surface, so that the seedling node is in full contact with the substrate, but without damaging the stem; pre-bury small planting cups at the seedling node, fill the cups with the same seedling substrate, and let the stolons pass through the side holes of the cups, and the seedlings take root in the cups; 5) Quantitative management and harvesting of seedlings: Retain 8-10 strong runners for each mother plant, and retain 3-4 seedlings for each runner. Remove excess runners and seedlings in a timely manner. When the seedlings have grown 3-4 unfolded leaves and their roots have filled the planting cup, they can be cut off from the side of the runner closest to the mother plant with sterilized scissors to achieve single-plant harvesting. After harvesting, the seedlings can be directly transferred to the temporary planting or sales stage with the planting cup to form standardized commercial seedlings.

2. The method for high-density propagation of strawberry seedlings on the ground according to claim 1, characterized in that, The mixed seedling substrate is obtained by mixing peat moss, coconut coir, vermiculite and perlite in a mass ratio of 3:3:2:

1.

3. The method for high-density propagation of strawberry seedlings on the ground according to claim 1, characterized in that, The high-nitrogen balanced nutrient solution includes ammonium nitrate, urea, potassium dihydrogen phosphate, potassium sulfate, calcium nitrate, magnesium sulfate, chelated iron, chelated zinc, chelated calcium, and ammonium molybdate.

4. The method for high-density propagation of strawberry seedlings on the ground according to claim 1, characterized in that, The nutrient solution specifically for promoting stolon growth includes potassium nitrate, ammonium dihydrogen phosphate, potassium sulfate, calcium nitrate, magnesium sulfate, chelated iron, chelated zinc, chelated copper, and humic acid.

5. The method for high-density propagation of strawberry seedlings on the ground according to claim 1, characterized in that, The vegetative growth period is from the time of planting until the first batch of stolons emerges; the reproductive growth initiation period is when the first batch of stolons grows to 2-3 cm.

6. The method for high-density propagation of strawberry seedlings on the ground according to claim 1, characterized in that, During steps 1) to 5) of the seedling propagation method, environmental factors are regulated and managed, specifically including temperature management, light management, and water management.

7. The method for high-density propagation of strawberry seedlings on the ground according to claim 6, characterized in that, The temperature management is achieved by using the roll-up ventilation system of the rain shelter to control the daytime temperature at 20-28℃ and the nighttime temperature at 12-18℃.

8. The method for high-density propagation of strawberry seedlings on the ground according to claim 6, characterized in that, The light management is as follows: during periods of strong sunlight in summer, cover the outside of the greenhouse film with 30%-50% shade netting to ensure an average daily light duration of 6-7 hours.

9. The method for high-density propagation of strawberry seedlings on the ground according to claim 6, characterized in that, The moisture management involves real-time monitoring of the surface humidity of the seedling substrate, and pulsed mist irrigation based on the real-time monitoring results to maintain the surface humidity of the substrate at 60%-70%.

10. The application of the ground-based high-density strawberry seedling propagation method according to any one of claims 1 to 9 in strawberry seedling breeding.