Method for rejuvenating old pomegranate trees

Abstract

The application discloses a method for rejuvenation of old pomegranate trees, comprising: 1) preparing scion; 2) selecting and pretreating grafting site; 3) drilling and cleaning rootstock; 4) cutting scion and pretreating scion; 5) grafting; 6) managing after grafting; wherein, steps 3), 4) and 5) all use grafting healing agent, the grafting healing agent comprises callus inducer, antioxidant and fungicide. The drilling grafting in the application can be directly performed on the trunk of the old pomegranate tree, and is simple and feasible; the use of the grafting healing agent effectively improves the survival rate of grafting. The method has the advantages that callus of the old pomegranate tree is formed fast, the germination time of the scion is shortened by 7-10 days compared with the germination time after conventional grafting, the survival rate of grafting is high, and reaches more than 90%. The method can be used for tree shape reconstruction of the old pomegranate tree, and therefore has good practical application value.

Description

Technical Field

[0001] This invention relates to the field of fruit tree cultivation technology, specifically to a method for rejuvenating old pomegranate trees. Background Technology

[0002] Pomegranates have been cultivated in my country for over 2000 years, resulting in four major traditional production areas: Huaiyuan in Anhui, Lintong in Shaanxi, Huili in Sichuan, and Zaozhuang in Shandong. Pomegranates were among the first fruits recognized by humans as edible. Rich in nutrients and with a unique flavor, they can be eaten fresh or processed into juice, wine, and other nutritional supplements and medicines. In May, pomegranate blossoms are ablaze with color; in June, flowers and fruit appear simultaneously; in autumn, the trees are laden with fruit; and in winter, the branches remain strong and vigorous. Pomegranates are also widely used in leisure agriculture and landscaping, and can be made into bonsai.

[0003] Pomegranate trees, as economic forests, have economic lifespans ranging from decades to centuries. Traditional pomegranate producing areas in my country have numerous old trees, some decades or even centuries old, characterized by bare interiors, outward-shifted fruiting areas, small fruiting areas, and low yields. While horticultural measures such as pruning back and heavy shortening can promote the rejuvenation of the outer branches, addressing the issue of bare interiors remains a challenge. Similarly, increasing new branches when using old pomegranate tree stumps for bonsai is also a problem. Therefore, developing a method for rejuvenating old pomegranate trees is essential.

[0004] Pomegranate fruits and plants are rich in polyphenols. Therefore, how to reduce the adverse effects of polyphenols on wound healing during grafting and promote the healing of grafted sites, especially the grafted sites of old trees, is also an important issue.

[0005] There are currently no reported studies on the use of drilling and grafting to rejuvenate old pomegranate trees. Summary of the Invention

[0006] The purpose of this invention is to provide a method for rejuvenating old pomegranate trees, in order to overcome the shortcomings of the prior art.

[0007] The present invention adopts the following technical solution:

[0008] A method for rejuvenating old pomegranate trees includes the following steps:

[0009] 1) Scion preparation: Select 1-2 year old branches with a diameter of 0.3-0.5 cm and single axis extension from the pomegranate scion variety; the scion branches should be collected in autumn after leaf fall and before sap flow in the following year. They can be grafted immediately after collection or collected and stored in sand at low temperature before grafting.

[0010] 2) Grafting site selection and pretreatment: In spring, before the sap of the old pomegranate tree (rootstock) begins to flow, determine the grafting site based on the tree's growth and shape; the bark of the grafting site should be intact and free of knots, and if there is old peeling bark, it needs to be removed first.

[0011] 3) Drilling and cleaning the rootstock: Select a drill bit with a diameter closest to that of the scion and drill a hole at a 60-90° angle at the selected grafting site. The hole should be deep enough to reach the xylem but not exceed 1 / 2 the diameter of the grafting site. When drilling, be careful not to damage the bark around the hole. Before grafting, use a grafting knife to trim the edges of the hole neatly. After drilling, inject grafting healing agent with a syringe, then suck it out and drain it. Repeat this 2-3 times to flush away sawdust and sap from the hole and prevent browning and pathogen infection.

[0012] 4) Scion preparation and pre-grafting treatment: Before grafting, cut the scion branches into 10-20cm scions, each with at least 2-3 plump leaf buds; remove the outer bark from the lower end of the scion, leaving a portion of the cambium, with the cut length basically consistent with the drilling depth, keeping the cut surface smooth and flat; immerse the cut end of the prepared scion in grafting healing agent for 15-20 minutes to remove pathogens and sap from the branch surface;

[0013] 5) Grafting: Insert the prepared scion into the drilled hole, one scion per hole. Use a tool to tap the scion to ensure it fits tightly against the rootstock, aligning the cambium layer of the scion with that of the rootstock. Apply absorbent paper or cotton cloth soaked in grafting healing agent to the graft union and its vicinity to prevent the continuous seepage of polyphenols from affecting callus formation and to prevent harmful substances, including pathogens, from entering the grafting site. Then, wrap grafting film around the rootstock along the graft union to ensure a tight seal. At the same time, wrap the scion with grafting film to retain moisture and fix the scion in place.

[0014] 6) Post-grafting management: After grafting, perform routine management of the rootstock and pay attention to the budding of the scion. For scions that have not sprouted, replace the grafting site in time and regraft. After the scion sprouts, cut the grafting film wrapped around the scion to avoid the grafting film restricting the growth of the bud. When there is obvious callus tissue forming at the grafting point, cut the grafting film wrapped around the rootstock to avoid the grafting film restricting the growth of the callus tissue or cutting into the tree. When the new shoots on the scion grow to about 20cm, pinch off the tips. Afterwards, depending on the growth space, use thinning or short pruning methods on the scion to promote the formation of main branches or fruiting branches.

[0015] In steps 3), 4), and 5), the grafting healing agent includes a callus inducer, an antioxidant, and a bactericide; the callus inducer includes auxin NAA 0.1–0.2 mg / L and cytokinin 6-BA 0.8–1.0 mg / L; the antioxidant includes glycine 50–100 mg / L, ascorbic acid 50–100 mg / L, and salicylic acid 0.05–0.1 mg / L; the bactericide includes a multi-fold dilution of wettable powder, which includes 800–1000 times dilution of carbendazim or thiophanate-methyl.

[0016] Furthermore, in step 3), drilling is performed using a manual drilling machine or an electric drilling machine.

[0017] Further, in steps 3), 4) and 5), the grafting healing agent is prepared by the following method: according to the component ratio and preparation volume of the grafting healing agent, each component is weighed, each component is first dissolved in a small amount of water, and then added to the water one by one and mixed evenly to obtain the grafting healing agent.

[0018] The beneficial effects of this invention are:

[0019] Old pomegranate trees have weak regeneration capabilities and poor wound healing, and their high phenolic content is particularly detrimental to wound healing. Therefore, reducing phenolic content, promoting healing at the grafting site, and enhancing regeneration capabilities during grafting can significantly improve the grafting survival rate and accelerate rejuvenation of old pomegranate trees. This invention addresses the urgent need for rejuvenation of old pomegranate trees due to issues such as bare interiors, outward shift of fruiting sites, small fruiting area, and low yield, as well as the need to increase new branches when creating bonsai from old pomegranate stumps. It proposes a method of hole-drilling grafting in the trunk of old pomegranate trees, utilizing a grafting healing agent to improve the grafting survival rate. The hole-drilling grafting method used in this invention can be performed directly on the trunk of old pomegranate trees, making the operation simple and feasible. The use of the grafting healing agent effectively improves the grafting survival rate. The method of this invention results in rapid callus formation in old pomegranate trees, shortens the scion budding time by 7-10 days compared to conventional grafting, and achieves a high grafting survival rate of over 90%. The method of this invention can be used for the tree shape transformation of old pomegranate trees, and therefore has good practical application value. Attached Figure Description

[0020] Figure 1 The survival rate of the 'Feihong' scion grafted onto the trunk of the 'Hongyushizi' pomegranate tree one month after drilling holes. Detailed Implementation

[0021] The present invention will be further explained below with reference to embodiments and accompanying drawings. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0022] Example 1

[0023] Prepare the following tools: pruning shears, grafting knife, drill (electric or manual drill), hammer, toilet paper or gauze, and grafting film.

[0024] The specific steps are as follows:

[0025] Before the sap begins to flow in early March, collect one-year-old branches (approximately 0.5cm in diameter) of the 'Fei Hong' variety to be grafted and keep them moist at 4℃ for later use. Prepare 10L of grafting healing agent, which includes NAA 0.15mg / L, 6-BA 1.0mg / L, glycine 100mg / L, ascorbic acid 100mg / L, salicylic acid 0.05mg / L, and carbendazim at an 800-fold dilution. Select the old 'Hong Yu Shi Zi' pomegranate tree (rootstock) to be grafted and the grafting site. Using a 0.5cm drill bit, begin drilling, maintaining an angle of approximately 60° between the drill bit and the rootstock trunk. Drill to about 3cm, then remove the drill bit, clean off any sawdust, and continue drilling. Complete the drilling in three stages, reaching a depth of approximately 4-5cm (the rootstock grafting site should be approximately 10cm in diameter). After drilling, use a grafting knife to trim the edges of the drilled holes neatly. Inject grafting healing agent with a syringe, then aspirate and drain it, repeating 2-3 times to flush away sawdust and sap from the drill hole, preventing browning and pathogen infection. Before grafting, cut the prepared 'Fei Hong' branches into 10-20cm scions, each with at least 2-3 plump leaf buds. Use a grafting knife to remove the outer bark of the lower end of the scion, retaining a portion of the cambium layer. The cut should be 4-5cm long, ensuring the cut length is roughly the same as the drill hole depth, keeping the cut surface smooth and flat. Immerse the cut end of the scion in grafting healing agent for 15-20 minutes to remove pathogens and sap from the branch surface. Then insert the treated scion into the drill hole, one scion per hole, gently tapping the scion several times with a hammer to ensure close contact between the scion and rootstock, aligning the cambium layer of the scion cut end with that of the rootstock. Soak clean tissue paper or gauze in grafting healing agent and apply it to the graft union and surrounding area. This prevents the continuously seeping polyphenols from affecting callus formation and prevents harmful substances, including pathogens, from entering the grafting site. Then, wrap grafting film tightly around the rootstock along the graft union. Simultaneously, wrap the scion with grafting film to retain moisture and secure it. Check the scion's budding status 15-20 days after grafting. Replace any scions that haven't sprouted and regraft them. Once the scion sprouts, cut the grafting film around it to prevent it from restricting bud growth. When obvious callus formation is visible at the graft union, cut the grafting film around the rootstock to prevent it from restricting callus growth or digging into the tree. Figure 1 This is the survival rate of the 'Feihong' scion grafted onto the trunk of the 'Hongyushizi' pomegranate tree one month after the graft was performed.

[0026] When the new shoots on the scion grow to about 20cm, pinch off the tips; then, depending on the growing space, use thinning or short pruning methods on the scion to promote the formation of main branches or fruiting branch groups.

Claims

1. A method for rejuvenating old pomegranate trees, characterized in that, Includes the following steps: 1) Scion preparation: Select 1-2 year old branches with a diameter of 0.3-0.5 cm and single axis extension from the pomegranate scion variety; the scion branches should be collected in autumn after leaf fall and before sap flow in the following year. They can be grafted immediately after collection or collected and stored in sand at low temperature before grafting. 2) Grafting site selection and pretreatment: In spring, before the sap of the old pomegranate tree (rootstock) begins to flow, determine the grafting site based on the tree's growth and shape; the bark of the grafting site should be intact and free of knots, and if there is old peeling bark, it needs to be removed first. 3) Drilling and cleaning the rootstock: Select a drill bit with a diameter closest to that of the scion and drill a hole at a 60-90° angle at the selected grafting site. The hole should be deep enough to reach the xylem but not exceed 1 / 2 the diameter of the grafting site. When drilling, be careful not to damage the bark around the hole. Before grafting, use a grafting knife to trim the edges of the hole neatly. After drilling, inject the grafting healing agent with a syringe, then suck it out and drain it. Repeat this process 2-3 times. 4) Scion preparation and pre-grafting treatment: Before grafting, cut the scion branches into 10-20cm scions, each with at least 2-3 plump leaf buds; remove the outer bark from the lower end of the scion, leaving part of the cambium, with the cut length basically consistent with the drilling depth, keeping the cut surface smooth and flat; immerse the cut of the prepared scion in grafting healing agent for 15-20 minutes. 5) Grafting: Insert the prepared scion into the drilled hole, one scion per hole. Use a tool to tap the scion to make it fit tightly against the rootstock, aligning the cambium layer of the scion cut with that of the rootstock. Apply absorbent paper or cotton cloth soaked in grafting healing agent to the graft union and its vicinity. Then wrap the grafting film around the rootstock along the graft union to make the graft union tightly covered. At the same time, wrap the scion with the grafting film. 6) Post-grafting management: After grafting, perform routine management of the rootstock and pay attention to the budding of the scion. For scions that have not sprouted, replace the grafting site in time and regraft. After the scion sprouts, cut the grafting film wrapped around the scion. When there is obvious callus tissue forming at the grafting point, cut the grafting film wrapped around the rootstock. When the new shoots on the scion grow to about 20cm, pinch off the tips. Afterwards, depending on the growth space, use thinning or short pruning methods on the scion to promote the formation of main branches or fruiting branches. In steps 3), 4), and 5), the grafting healing agent includes a callus inducer, an antioxidant, and a bactericide; the callus inducer includes auxin NAA 0.1–0.2 mg / L and cytokinin 6-BA 0.8–1.0 mg / L; the antioxidant includes glycine 50–100 mg / L, ascorbic acid 50–100 mg / L, and salicylic acid 0.05–0.1 mg / L; the bactericide includes a multi-fold dilution of wettable powder, which includes 800–1000 times dilution of carbendazim or thiophanate-methyl.

2. The method for rejuvenating old pomegranate trees according to claim 1, characterized in that, In step 3), drilling is performed using a manual drilling machine or an electric drilling machine.

3. The method for rejuvenating old pomegranate trees according to claim 1, characterized in that, In steps 3), 4), and 5), the grafting healing agent is prepared by the following method: according to the component ratio and preparation volume of the grafting healing agent, weigh each component, dissolve each component separately in a small amount of water, and then add them one by one to the water and mix evenly to obtain the grafting healing agent.

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