Method for improving grafting survival rate of matrix potted blueberries by regulating stock EC value

Abstract

The invention discloses a method for improving the grafting survival rate of matrix potted blueberries by regulating and controlling the stock EC value, and relates to the field of blueberry grafting. According to the method, by creatively dynamically, scientifically and reasonably regulating and controlling the EC values of liquid feeding and liquid discharging of the rootstock before and after grafting, environmental stress in the grafting process is reduced, the best condition is created for healing of the rootstock and the scion, rapid and high-quality callus formation is promoted, and the grafting survival rate is increased. Results show that the operation method is simple, the investment cost is low, the grafting survival rate is high, the obtained new plant tree body is high in tree vigor and adaptability, grafting and fruit bearing in the same year can be achieved, economic benefits are remarkable, and the method is suitable for being popularized in production by adjusting and controlling the stock liquid inlet and liquid outlet EC values before and after grafting.

Description

Technical Field

[0001] This invention belongs to the field of blueberry grafting, specifically relating to a method for improving the survival rate of grafted blueberries in substrate pots by adjusting the EC value of the rootstock. Background Technology

[0002] Blueberries (Vaccinium uliginosum L.), also known as bilberries, are shrubs belonging to the Vaccinium genus of the Ericaceae family. Blueberry fruits are rich in phenolic substances, ascorbic acid, anthocyanins, and flavonoids, among other nutrients. They have strong antioxidant capabilities and extremely high nutritional and health value, earning them the reputation of "Queen of Fruits" and "Fruit for Beautiful Eyes." They are listed by the Food and Agriculture Organization of the United Nations as one of the five major healthy foods for humans and are highly favored by consumers. The market prospects for blueberry cultivation are broad.

[0003] In recent years, the blueberry industry has developed rapidly, with substrate cultivation gradually replacing soil cultivation. Furthermore, as consumers' demands for blueberry quality continue to increase and the market price of fresh blueberries varies significantly due to different varieties, growers are considering planting high-yield varieties. The replacement of old varieties is inevitable, so the grafting improvement work of blueberries has gradually shifted from soil cultivation grafting improvement model to substrate pot grafting improvement model.

[0004] Grafting is one of the most efficient methods of vegetative propagation for fruit trees. Grafting can maintain the superior traits of the scion variety while utilizing the beneficial characteristics of the rootstock, enhancing the fruit tree's adaptability to adverse environmental conditions and its resistance to diseases and pests. This can lead to earlier fruiting, increased fruit yield and quality, a shorter payback period, and reduced investment costs.

[0005] Currently, most existing blueberry grafting improvement techniques are studied in soil cultivation models, with very few researching substrate cultivation models. However, in actual production, many growers often fail to introduce new blueberry varieties due to a lack of experience, leading to the need for grafting improvement of blueberry varieties in substrate-grown pots. During the grafting improvement process, improper mastery of grafting techniques results in problems such as low survival rates, poor fruit production after successful grafting, low yields, and low economic benefits. Therefore, exploring methods to improve the grafting survival rate of substrate-grown potted blueberries is an urgent technical problem to be solved in the development of the blueberry industry.

[0006] In the grafting improvement of blueberry in substrate-grown pots, the growth environment of the rootstock directly affects the grafting survival rate. Besides pH, EC (electrical conductivity) is also a key factor in the growth of blueberry rootstock. As an indicator of the soluble salt content of the substrate, EC significantly impacts its growth. Excessively high EC values ​​reduce substrate water potential, causing physiological drought, making it difficult for blueberry roots to absorb water, resulting in poor plant water status, reduced root hair development or even root damage, and decreased growth vitality. High-salt environments inhibit cell division and elongation, directly hindering callus formation. Conversely, excessively low EC values ​​lead to a lack of nutrients in the substrate, resulting in weak blueberry rootstock plants with insufficient energy and nutrients to provide enough energy for callus formation and new bud sprouting, causing the scion to "starve" or heal poorly. Therefore, properly controlling the EC values ​​of rootstock sap inflow and outflow before and after grafting is crucial for improving grafting survival rates. Summary of the Invention

[0007] To address the above problems, this invention provides a method for improving the grafting survival rate of substrate-grown blueberries by regulating the EC value of the rootstock. The method involves scientifically and dynamically regulating the EC values ​​of the rootstock before and after grafting to reduce environmental stress during the grafting process, create optimal conditions for the healing of the rootstock and scion, promote rapid and high-quality callus formation, and improve the grafting survival rate.

[0008] The technical solution adopted in this invention is:

[0009] A method for improving the grafting survival rate of potted blueberries in substrate by adjusting the EC value of the rootstock includes the following steps:

[0010] (1) Selecting rootstock: Select healthy blueberry varieties that are 2 to 4 years old, free from pests and diseases, and need improvement as rootstock.

[0011] (2) Adjusting the EC values ​​of the rootstock's sap inlet and outlet before grafting: Before grafting, test the EC values ​​of the rootstock's sap inlet and outlet. If the EC value of the sap inlet is greater than 380 μS / cm and the EC value of the outlet is greater than 600 μS / cm, adjust the EC value of the rootstock's sap inlet to 380 μS / cm and water for 10-15 days. Grafting can then be carried out when the EC value of the outlet drops to 600 μS / cm. At this time, the substrate water potential is high, and water can be more easily absorbed by the rootstock and supplied to the scion through intercellular osmosis.

[0012] (3) Collection of scion branches: Collect well-developed, plump, vigorous, disease-free, and undamaged one-year-old semi-lignified vegetative branches as scion branches. Use the scion branches immediately after collection. If they are not to be used after collection, wrap them with a damp towel to keep them moist. Select Southern Highbush blueberry varieties that mature early, have good taste, excellent quality, and are popular in the market.

[0013] (4) Grafting.

[0014] A. Grafting season: The grafting season should be at the end of winter, specifically 5 to 10 days before the beginning of spring (January 25 to January 30).

[0015] B. Grafting time: Choose a sunny day between 9:30 and 11:30 in the morning and between 15:00 and 18:30 in the afternoon to carry out grafting, avoiding the low temperature in the morning and the scorching sun at noon.

[0016] C. Grafting method: Cleft grafting.

[0017] a. Rootstock preparation: Retain 3-4 original main trunks of the rootstock mother tree, cut and fix the trunks to a height of 25-30cm, and make a flat and smooth cut. On the smooth part, use a knife to make a vertical cut 4-6cm deep from the cut surface. Remove all other main branches from the base without leaving any stumps.

[0018] b. Preparing the scion: Remove the unlignified young shoots and the underdeveloped, slightly lignified parts of the basal leaf buds from the collected scion branches. Cut the scion branches into 5-8cm long pieces with 2-3 buds each. Then, using a sterilized, sharp grafting knife, make 2-3cm long wedge-shaped cuts on both sides of the lower end of the scion, about 3cm below the bud. Ensure the cut surfaces are smooth and even, with one side slightly thicker and the other slightly thinner. This allows the cut surfaces to adhere closely to the rootstock cut, facilitating healing of the cambium layers. After preparing the scion, keep it moist and complete the grafting quickly to prevent moisture evaporation.

[0019] c. Inserting and binding the scion: Quickly insert the prepared scion into the cut of the rootstock, keeping it close to the cut surface of the rootstock, aligning the cambium layers on both sides, leaving a 0.3-0.5cm gap. Then, use grafting film to bind the scion from bottom to top in a counterclockwise direction. When binding, pull the film strip tight to prevent the scion from moving and rainwater from entering. At the same time, seal the upper cut of the scion with a waterproofing agent.

[0020] (5) Post-grafting management:

[0021] A. Adjust the EC value and the amount of liquid entering and leaving the rootstock after grafting.

[0022] a. After grafting and before budding and branching, adjust the EC value of the rootstock's influent to 450 μS / cm, maintain the EC value of the outfluent to 700–800 μS / cm, the influent volume to 800–1000 ml, and the outfluent volume to 10–15% of the influent volume, keeping the substrate moist.

[0023] b. After the grafted seedlings have survived and sprouted, when the branches grow to 15-20cm, adjust the EC value of the sap in the rootstock to 800-1000us / cm and maintain the EC value of the sap outflow at 1200-1400us / cm. Control the sap inflow to 1200-1500ml and the outflow to 15-20% of the sap inflow to continuously provide nutrition for the grafted seedlings after they have survived.

[0024] B. Remove sprouts: Remove any sprouts on the rootstock in a timely manner to prevent nutrient consumption and create favorable conditions for the rapid growth of the scion.

[0025] C. Unbinding: When the new shoots of the scion have grown to 30-40cm after the scion has sprouted and the graft union has healed firmly, the wrapping film can be loosened or removed to prevent it from affecting thickening and growth.

[0026] D. Other management: After the seedlings have survived, timely topping and pest and disease control should be carried out.

[0027] The beneficial effects of this invention are:

[0028] 1. The grafting method provided by this invention is simple to operate, easy to implement, and low in cost.

[0029] 2. This invention applies innovative grafting technology, which reduces environmental stress during grafting by scientifically and rationally and dynamically controlling the EC values ​​of sap ingress and egress of the rootstock before and after grafting. This creates optimal conditions for the healing of the rootstock and scion, enhances the root vigor of the rootstock, and ensures smooth transport of water and nutrients, thereby promoting the rapid formation of callus tissue and significantly improving the grafting survival rate and survival rate.

[0030] 3. The grafting technology provided by this invention results in vigorous plant growth, with significantly better grafting base thickness, branch number, and tree crown width compared to existing grafting techniques. It enables grafting and fruiting in the same year, resulting in significant economic benefits. Attached Figure Description

[0031] Figure 1 This is a rendering of the broken anvil.

[0032] Figure 2 This is a diagram showing the effect of shaving the ears of grain.

[0033] Figure 3 This is a rendering of the scion cuttings.

[0034] Figure 4 This is a diagram showing the effect of the binding.

[0035] Figure 5 The above figures show a comparison of germination and growth two months after grafting in the example and comparative cases.

[0036] Figure 6 This is a comparison chart showing the growth effect of grafted plants 4 months after the implementation example and the comparative example.

[0037] Figure 7 The above figures show a comparison of the flowering and fruit setting effects 10 months after grafting in the example and comparative examples.

[0038] Figure 8 This is a comparison chart of wound healing 8 months after grafting in the example and the comparative example. Detailed Implementation

[0039] To make the innovative technical solutions and effects of the present invention clearer, the present invention will be further described in detail below with reference to specific examples and accompanying drawings. It should be understood that the specific examples described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0040] Example 1

[0041] A method for improving the grafting survival rate of potted blueberries in substrate by adjusting the EC value of the rootstock includes the following steps:

[0042] Location of implementation: Blueberry experimental base of Yuxi Academy of Agricultural Sciences.

[0043] (1) Selecting rootstock: Select a healthy, disease-free, and improved Southern Highbush blueberry variety, Jewel, that is 3 years old and needs improvement.

[0044] (2) Adjusting the EC values ​​of the rootstock's sap inlet and outlet before grafting: Before grafting, test the EC values ​​of the rootstock's sap inlet and outlet. If the EC value of the sap inlet is greater than 380 μS / cm and the EC value of the outlet is greater than 600 μS / cm, adjust the EC value of the rootstock's sap inlet to 380 μS / cm and water for 10-15 days. Grafting can then be carried out when the EC value of the outlet drops to 600 μS / cm. At this time, the substrate water potential is high, and water can be more easily absorbed by the rootstock and supplied to the scion through intercellular osmosis.

[0045] (3) Collection of scion branches: Collect well-developed, plump, vigorous, disease-free, and undamaged one-year-old semi-lignified vegetative branches as scion branches. Use the scion branches immediately after collection. If they are not to be used after collection, wrap them with a damp towel to keep them moist. Select the Spanish 42 Southern Highbush blueberry variety, which is early-maturing, has a good taste, excellent quality, and is popular in the market.

[0046] (4) Grafting:

[0047] A. Grafting season: The grafting season should be at the end of winter, specifically 5 to 10 days before the beginning of spring (January 25 to January 30).

[0048] B. Grafting time: Choose a sunny day between 9:30 and 11:30 in the morning and between 15:00 and 18:30 in the afternoon to carry out grafting, avoiding the low temperature in the morning and the scorching sun at noon.

[0049] C. Grafting method: Cleft grafting.

[0050] a. Rootstock preparation: Retain 3 original main trunks of the rootstock mother tree, cut and fix the trunks to a height of 25-30cm, and make a flat and smooth cut. On the smooth part, use a knife to make a vertical cut 4-6cm deep from the cut. Remove all other main branches from the base without leaving any stumps.

[0051] b. Preparing the scion: Remove the unlignified young shoots and the underdeveloped, slightly lignified parts of the basal leaf buds from the collected scion branches. Cut the scion branches into 5-8cm long pieces with 3 buds each. Then, using a sterilized, sharp grafting knife, make 2-3cm long wedge-shaped cuts on both sides of the lower end of the scion, about 3cm below the bud. Ensure the cut surfaces are smooth and even, with one side slightly thicker and the other slightly thinner. This allows the cut surfaces to adhere closely to the rootstock cut, facilitating healing of the cambium layers. After preparing the scion, keep it moist and complete the grafting quickly to prevent moisture evaporation.

[0052] c. Inserting and binding the scion: Quickly insert the prepared scion into the cut of the rootstock, keeping it close to the cut surface of the rootstock, aligning the cambium layers on both sides, leaving a gap of 0.3-0.5cm. Then, use grafting film to bind the scion from bottom to top in a counterclockwise direction. When binding, pull the film strip tight to prevent the scion from moving and rainwater from entering. At the same time, seal the upper cut of the scion with a waterproofing agent.

[0053] (5) Post-grafting management:

[0054] A. Adjust the EC value and the amount of liquid entering and leaving the rootstock after grafting.

[0055] a. After grafting and before budding and branching, adjust the EC value of the rootstock's influent to 450 μS / cm, maintain the EC value of the outfluent at 700 μS / cm, the influent volume is 800-1000 ml, and the outfluent volume is 10-15% of the influent volume, keeping the substrate moist.

[0056] b. After the grafted seedlings have survived and sprouted, when the branches grow to 15-20cm, adjust the EC value of the sap in the rootstock to 800us / cm and maintain the EC value of the sap outflow at 1200us / cm. Control the sap inflow to 1200-1500ml and the outflow to 15-20% of the sap inflow to continuously provide nutrition for the grafted seedlings after they have survived.

[0057] B. Remove sprouts: Remove any sprouts on the rootstock in a timely manner to prevent nutrient consumption and create favorable conditions for the rapid growth of the scion.

[0058] C. Unbinding: When the new shoots of the scion have grown to 30-40cm after the scion has sprouted and the graft union has completely healed and become firm, the wrapping film can be loosened or removed to prevent it from affecting thickening and growth.

[0059] D. Other management: After the seedlings have survived, timely topping and pest and disease control should be carried out.

[0060] Example 2

[0061] Similar to Example 1, the difference is that in step (5), after grafting until the buds sprout and branches grow, the EC value of the drainage is kept at 800us / cm. After the buds survive and sprout, when the branches grow to 15-20cm, the EC value of the rootstock is adjusted to 1000us / cm, and the EC value of the drainage is kept at 1400us / cm.

[0062] Comparative Example

[0063] Similar to Examples 1-2, the difference is that in step (1), the EC value of the liquid inlet is 1200 μS / cm and the EC value of the liquid outlet is 1600 μS / cm. In step (5), the EC values ​​of the liquid inlet and outlet of the rootstock are not adjusted after grafting.

[0064] The effects of the above embodiments and comparative examples are as follows:

[0065] In 2024, at the experimental base of the Yunnan Academy of Agricultural Sciences in Yuxi City, Yunnan Province, five treatment groups were set up with three replicates. Each treatment group was grafted with 15 plants, and the grafting was carried out according to the methods of Examples 1-2 and the comparative example. To avoid errors in the experimental results due to differences in rootstock and scion, three-year-old Jewel cultivars were uniformly selected as rootstocks, and the blueberry variety Spain 42 was selected as scions, with three buds left on each scion.

[0066] Grafting survival rate: The proportion of plants that, after grafting, have callus formation, maintain the viability of the scion and continue to grow (new shoots elongate ≥2cm), and have leaves that are fully expanded and of normal color.

[0067] Number of branches: The number of branches 4 months after grafting is the sum of primary and secondary branches; the number of branches 10 months after grafting is the sum of primary, secondary and tertiary branches.

[0068] Table 1: Comparison of Different Grafting Methods for Blueberries

[0069] Table 2: Comparison of growth and yield of blueberries using different grafting methods

[0070] As shown in Table 1, when blueberry grafting variety improvement was carried out by two grafting methods, one with reasonable control of the EC values ​​of rootstock sap ingress and egress before and after grafting and the other without reasonable control of the EC values ​​of rootstock sap ingress and egress before and after grafting, the grafting survival rate with reasonable control of EC values ​​could reach 98.60%, which is 102.88% higher than the grafting survival rate without reasonable control of EC values.

[0071] As shown in Table 2, four months after grafting, the grafting method with properly controlled EC values ​​increased the branch base thickness, number of branches, and crown width by 106.46%–109.68%, 133.29%–138.15%, and 135.30–147.06%, respectively, compared to the grafting method without properly controlled EC values. Ten months after grafting, the grafting method with properly controlled EC values ​​increased the branch base thickness, number of branches, and crown width by 224.36%–225.65%, 109.21%–118.48%, and 215.22%–217.40%, respectively, compared to the grafting method without properly controlled EC values. In the first year after grafting, the fruit yield of the grafting method with properly controlled EC values ​​increased by 126.82%–127.21% compared to the grafting method without properly controlled EC values. Therefore, it can be seen that properly controlling the EC value of rootstock sap inflow and outflow before and after grafting can not only improve the grafting survival rate, but also has the advantages of rapid growth and strong branching ability, enabling fruiting in the same year of grafting, resulting in significant economic benefits and making it suitable for promotion in production.

[0072] The above description is merely some implementations and comparative examples of the present invention, and is not intended to limit the present invention in any way. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to obtain equivalent embodiments without departing from the scope of the technical solution of the present invention. Any simple modifications, equivalent changes and alterations made to the above implementations and comparative examples based on the technical essence of the present invention without departing from the content of the technical solution of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for improving the grafting survival rate of substrate-grown blueberries by adjusting the EC value of the rootstock, the specific steps of which are as follows: (1) Selecting rootstock: Select healthy blueberry varieties that are 2 to 4 years old, free from pests and diseases, and in need of improvement as rootstock; (2) Adjusting the EC values ​​of the rootstock's sap inlet and outlet before grafting: Before grafting, test the EC values ​​of the rootstock's sap inlet and outlet. If the EC value of the sap inlet is greater than 380 μS / cm and the EC value of the outlet is greater than 600 μS / cm, adjust the EC value of the rootstock's sap inlet to 380 μS / cm and water for 10-15 days. Grafting can then be carried out when the EC value of the outlet drops to 600 μS / cm. At this time, the substrate water potential is high, and water can be more easily absorbed by the rootstock and supplied to the scion through intercellular osmosis. (3) Collecting scion branches: Collect one-year-old semi-lignified branches that are well-developed, have plump buds, grow vigorously, are free from pests and diseases, and are undamaged as scion branches. The scion branches should be used immediately after collection. If they are not to be used after collection, wrap them with a damp towel to keep them moist. (4) Grafting: A. Grafting season: Grafting should be carried out at the end of winter, specifically 5 to 10 days before the beginning of spring (January 25 to January 30). B. Grafting time: Choose a sunny day between 9:30 and 11:30 in the morning and between 15:00 and 18:30 in the afternoon to carry out grafting, avoiding the low temperature in the morning and the scorching sun at noon; C. Grafting method: Cleft grafting a. Cutting the rootstock: Retain 3-4 of the original main trunks of the rootstock mother tree, cut and fix the trunks to a height of 25-30cm, and make the cut surface flat and smooth. On the smooth part, use a knife to make a vertical cut 4-6cm deep from the cut surface. Remove all other main branches from the base without leaving any stumps. b. Preparing the scion: Remove the unlignified young shoots and the parts of the basal leaf buds that are not fully developed and have a slightly higher degree of lignification from the collected scion branches. Cut the scion branches into 5-8cm long scions with 2-3 buds. Then, use a sharp, sterilized grafting knife to make 2-3cm long wedge-shaped bevels on both sides of the lower end of the scion 3cm below the bud. One side should be slightly thicker and the other slightly thinner. This way, the cut surface can easily come into close contact with the cleft of the rootstock, and the cambium layers on both sides can easily heal. c. Inserting and binding the scion: Quickly insert the prepared scion into the cut of the rootstock, close to the cut surface of the rootstock, align the cambium layers on both sides, leaving a gap of 0.3-0.5cm. Then, use grafting film to bind the scion from bottom to top in a counterclockwise direction. When binding, pull the film strip tight to prevent the scion from moving and rainwater from entering. At the same time, use a waterproofing agent to seal the upper cut of the scion. (5) Post-grafting management: A. Adjust the EC value and the amount of liquid entering and exiting the rootstock after grafting; a. After grafting and before budding and branching, adjust the EC value of the rootstock's slurry infusion to 450 μS / cm, maintain the EC value of the drainage slurry at 700–800 μS / cm, the infusion volume at 800–1000 ml, and the drainage volume at 15–20% of the infusion volume to keep the substrate moist. b. After the grafted seedlings have survived and sprouted, when the branches grow to 15-20cm, adjust the EC value of the sap in the rootstock to 800-1000us / cm and maintain the EC value of the sap outflow at 1200-1400us / cm. Control the sap inflow to 1200-1500ml and the outflow to 15-20% of the sap inflow to continuously provide nutrition for the grafted seedlings after they have survived. B. Remove sprouts: Remove any sprouts on the rootstock in a timely manner to prevent nutrient consumption and create favorable conditions for the rapid growth of the scion; C. Unbinding: When the new shoots of the scion have grown to 30-40cm after the scion sprouts and the graft union has healed firmly, the wrapping film can be loosened or removed to prevent it from affecting thickening growth; D. Other management: After the seedlings have survived, timely topping and pest and disease control should be carried out.

2. The grafting method according to claim 1, characterized in that, The variety to be improved is the Southern Highbush blueberry, and the cultivation conditions are open-field substrate pot cultivation.

3. The grafting method according to claim 1, characterized in that, In step (1), the rootstock varieties can be selected from Southern Highbush varieties such as Jewel, Spring Highbush, Sharpland, Misty, Emerald, and O'Neill, or varieties from the Rabbiteye series such as Brilliant, Sapphire, and Pink Blue.

4. The grafting method according to claim 1, characterized in that, In step (2), the pH value of the influent is adjusted to 4.5 to 5.5 before grafting. The number of days for watering after adjusting the influent to 380 μS / cm depends on the EC values ​​of the influent and the drain before grafting.

5. The grafting method according to claim 1, characterized in that, In step (3), the selection of scion varieties should adhere to the principle of strong affinity and similar physiological traits. Choose blueberry varieties that mature early, taste good, have good quality, and are popular in the market, such as L11, Spanish 42, Eurica, F6, etc.

6. The grafting method according to claim 1, characterized in that, In step (4), when cutting the scion, ensure that the cut surface is flat and smooth without burrs. After cutting, keep it moist and complete the grafting quickly to prevent moisture evaporation.

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