Rapid breeding method for twig cuttage of Huai plum

Abstract

The invention discloses a rapid propagation method for twig cuttage of Huai plum, and solves the problems that the traditional grafting rootstock has many defects and the propagation coefficient of a root tiller seedling is low. Comprising the following steps: selecting current-year semi-lignified branches of varieties such as Kakaanka resurrection lily rhizome and the like, and pruning to obtain cutting slips; turfy soil, perlite and vermiculite are mixed according to the volume ratio to prepare a matrix, and the matrix is put into a cultivation pot; the cutting slips are soaked in rooting agent liquid medicine for treatment after being disinfected, and the rooting agent liquid medicine is selected from naphthylacetic acid or ABT rooting powder; vertically inserting the treated cutting slips into holes in the surface of the substrate; curing is conducted in the environment with the temperature being 20-25 DEG C and the humidity being 70%-80%, and carbendazim and monopotassium phosphate are sprayed in the later period. The survival rate of 90-day cuttage is 78-84%, the root system is developed, breeding is efficient, and the method is suitable for large-scale seedling raising.

Description

Technical Field

[0001] The present invention relates to the technical field of plant cutting, and particularly to a rapid propagation method for softwood cutting of Prunus salicina var. cordata. Background Art

[0002] Prunus salicina Prunus salicina Lindl.) is an important deciduous fruit tree of the genus Prunus in the Rosaceae family. It has a long cultivation history and wide distribution in China, and has good ecological adaptability and economic value. Prunus salicina var. cordata Prunus salicina Lindl. var. cordata J. Y. Zhang et al.), as a variety of Prunus salicina, is native to Fujian Province and is known as the "king of plums". Due to its large fruit, excellent quality, late maturity, and good storage and transportation characteristics, it has become one of the most influential economic fruit trees in southern China.

[0003] In recent years, the Prunus salicina var. cordata industry has developed particularly rapidly in Fujian Province and has ranked first among deciduous fruit trees in the province. According to the latest statistical yearbook data released in 2024, the planting area of Prunus salicina var. cordata in Fujian Province has reached 27,100 hectares, with an annual output of up to 414,100 tons. Its industrial scale significantly exceeds that of traditional deciduous fruit trees such as pears (14,100 hectares, 213,100 tons), peaches (12,500 hectares, 185,900 tons), grapes (11,200 hectares, 254,200 tons), and persimmons (10,000 hectares, 140,800 tons), playing an irreplaceable role in regional agricultural economy and farmers' income increase.

[0004] Currently, Prunus salicina var. cordata is mainly propagated by grafting in production to maintain the excellent traits of the variety. The commonly used rootstock is mainly Prunus persica, but there are problems in production such as susceptibility to root nodules, serious damage by longhorn beetles, easy gum bleeding, easy premature senescence, and poor waterlogging tolerance. The seedling raising cycle is long and the cost is high. At the same time, root suckers formed from the roots of mother trees also play an important role in seedling production, but the number of root suckers is limited, the propagation coefficient is low, and it may cause nutrient depletion of the mother tree and premature senescence of the tree vigor. Therefore, both of these propagation methods have their inherent limitations.

[0005] Therefore, it is imperative to explore a new asexual propagation technology that can overcome the above limitations. Summary of the Invention

[0006] Softwood cutting technology is regarded as a potential solution due to its high propagation coefficient, stable genetic traits, independence from rootstocks, and small damage to mother trees. In view of this, the present invention aims to create a rapid propagation method for softwood cutting of Prunus salicina var. cordata by systematically optimizing cutting treatment, rooting agent formula, and seedling raising environment, providing a reliable technical approach for the efficient and standardized production of its seedlings.[[ID=二十九]] [[ID=三十]]

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A rapid propagation method for Prunus cerasifera by cuttings includes the following steps: (1) Collection and preparation of cuttings: Select healthy and disease-free mature mother trees of Prunus cerasifera. 7-10 days before collecting cuttings, perform ring barking and shading pretreatment on the branches of the mother tree to be collected. At a distance of 1.5-3cm below the planned cutting, use a blade to ring bark a 3-5 mm wide layer of bark, and wrap the ring bark and the upper part with tin foil or black plastic film to shade the light. Collect semi-lignified branches from the upper part of the current year, prune the branches, retain plump buds, make a horizontal cut 0.8-1.2cm from the terminal bud and leave 1-2 half leaves, and make a single oblique cut 0.5-1.0cm from the lowest bud to obtain cuttings; (2) Preparation of cutting substrate: Mix peat moss, perlite and vermiculite in the specified volume ratio to prepare the substrate, fill the cultivation pot, and adjust its moisture content to 60%-70%; (3) Disinfection and hormone treatment of cuttings: The base of the cuttings is disinfected by immersing in a carbendazim solution, and after drying, the base is treated by immersing in a rooting agent solution; the rooting agent solution is selected from naphthaleneacetic acid or ABT rooting powder. When the rooting agent solution is naphthaleneacetic acid, the concentration is 80~140mg / L; when the rooting agent solution is ABT rooting powder, the concentration of ABT rooting powder is 140~160mg / L. (4) Cutting operation: Use a wooden stick to make holes in the substrate surface beforehand, insert the treated cuttings vertically into the holes, and compact the substrate so that the base of the cuttings is in close contact with the substrate; (5) Post-cutting maintenance: From day 1 to 15 after cutting, place the pot in a controlled environment and provide sufficient diffused light; from day 16 to 30 after cutting, implement a wet-dry cycle. Water and spray the leaves when the surface of the substrate turns white and dry; after 30 days after cutting, carry out normal moisture management, keep the substrate moist and the air humidity stable, and avoid water accumulation in the substrate; after 50 to 70 days after cutting, spray with carbendazim solution once. From 50 to 70 days after cutting, spray the leaves with potassium dihydrogen phosphate solution once a week for 3-4 consecutive times.

[0008] Furthermore, in step (1), the bark of the branch is light brown, the diameter of the pith accounts for 1 / 3-1 / 2, the length of the cutting after pruning is 10-15cm, and the number of plump buds is 2-4.

[0009] Furthermore, in step (2), the volume ratio of peat moss, perlite and vermiculite is 3:1:1. The cutting substrate is thoroughly disinfected by watering it thoroughly with a 700-1000 times dilution of 50% carbendazim solution 24 hours before cutting.

[0010] Further, in step (3), the length of the base of the disinfected cutting is 2-4 cm, the carbendazim solution is 700-900 times 50% carbendazim solution, the disinfection time is 8-12 min, the concentration of naphthaleneacetic acid is 100 mg / L, the concentration of ABT rooting powder is 150 mg / L, the solvent of the rooting agent solution is water, and methanol is added at 0.5-1% of the solvent volume.

[0011] Furthermore, in step (4), 3 to 5 cuttings are inserted into each pot, with a plant spacing of 5cm × 5cm and an insertion depth of 1 / 3 to 1 / 2 of the cutting length.

[0012] Furthermore, in step (5), the temperature of the controllable environment is 20-25℃ and the relative humidity of the air is 75%-85%; the dry-wet cycle is as follows: after the surface layer of the substrate is about 1-2 cm slightly white and dry, watering and foliar spraying are carried out; 30 days after cutting, the air humidity is controlled at 60%-75% and the substrate moisture content is maintained at 60%-65%.

[0013] Furthermore, in step (5), the concentration of potassium dihydrogen phosphate solution is 0.05-0.15%.

[0014] Furthermore, the plum varieties mentioned include Shisaka Late Plum, Crown Plum, and Early Hibiscus.

[0015] The present invention also provides the application of any of the above-described methods in the propagation of Prunus armeniaca by cuttings.

[0016] The beneficial effects of this invention include at least the following: (1) Effectively solves the problems of rootstock (peach) being susceptible to root nodules, longhorn beetle damage, premature aging due to gum exudation, and poor waterlogging resistance in grafting propagation, as well as the long seedling cycle and high cost. At the same time, it avoids the defects of limited number of root suckers, low propagation coefficient and loss of mother tree nutrition leading to tree decline, and fills the technical gap of efficient asexual propagation of Prunus cerasifera.

[0017] (2) By optimizing the rooting agent (100mg / L NAA or 150mg / L ABT) and the seedling environment, the survival rate of cuttings after 90 days reached 78%-84%, which was significantly higher than that of the water control (26%-34%). Moreover, it induced the formation of a well-developed root system that combines bark roots and callus roots, with the best key indicators such as total root length and number of root tips, laying the foundation for the vigorous growth of seedlings after planting.

[0018] (3) The cost of single-plant seedling cultivation is low, and only tender branches are collected from the mother tree, resulting in minimal damage. The mother tree resources can be utilized sustainably, making it suitable for industrialized mass production of seedlings. Attached Figure Description

[0019] Figure 1Phenotypic characteristics of softwood cuttings of *Lagerstroemia indica* at different stages of rooting, from left to right: cuttings at 20, 40, 60, and 90 days.

[0020] Figure 2 Phenotypic characteristics of crown plum cuttings at different stages of rooting, from left to right: cuttings at 20, 40, 60, and 90 days.

[0021] Figure 3 The phenotypes of hibiscus cuttings at different stages of rooting are shown from left to right: cuttings at 20, 40, 60, and 90 days.

[0022] Figure 4 The effects of different treatments on the phenotype of *Lagerstroemia indica* cuttings after 90 days.

[0023] Figure 5 The effects of different treatments on the phenotype of Crown Plum softwood cuttings at 90 days.

[0024] Figure 6 The effects of different treatments on the phenotype of early hibiscus softwood cuttings at 90 days.

[0025] Figure 7 This is a field photo of Shisaka Banna grafted onto a peach rootstock in Comparative Example 1.

[0026] Figure 8 This diagram shows a healthy branch with plump one-year-old buds from the comparative example 1, used as a scion. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0029] The following specific embodiments illustrate the solution proposed in this invention: Example 1 1. Materials and Methods 1.1 Plant materials The experimental varieties used in this invention were *Prunus serrulata*, *Prunus crownifolia*, and *Prunus serrulata*, which were selected as leading agricultural varieties in Fujian Province for two consecutive years (2023-2024). Among them, *Prunus serrulata* was selected as a national leading variety by the Ministry of Agriculture and Rural Affairs of the People's Republic of China in 2024, possessing extremely high representativeness and economic value. All experimental cuttings were collected from healthy, disease- and pest-free mature mother plants in the Fruit Tree Germplasm Resource Nursery of the College of Horticulture, Fujian Agriculture and Forestry University.

[0030] 1.2 Hormone Treatment and Experimental Design The hormone reagents used were ABT rooting powder and naphthaleneacetic acid (NAA) (Beijing Solarbio Science & Technology Co., Ltd.). Four concentration gradients of ABT rooting powder were set up: 100 mg / L, 125 mg / L, 150 mg / L, and 175 mg / L. Four concentration gradients of NAA were set up: 50 mg / L, 75 mg / L, 100 mg / L, and 150 mg / L. A water treatment was used as a blank control (CK). A total of 9 treatments were formed (8 hormone treatments + 1 control). Each treatment was replicated 3 times, with 25 cuttings used per replicate, resulting in a total of 75 cuttings per treatment level. The total number of cuttings for the three varieties exceeded 2000 to ensure the statistical power of the experimental results.

[0031] 1.3 Collection and preparation of cuttings Select vigorous, disease-free mother trees and prepare cuttings from the upper, current-year semi-lignified branches. (Morphological characteristics: light brown bark, pith diameter accounting for 1 / 3 to 1 / 2 of the branch). 7-10 days before collection, pre-treat the branches by girdling and shading. About 2 cm below the planned cutting point, girdle approximately 3-5 mm wide of bark (down to the xylem but without damaging it) with a blade. Wrap the girdled area and the upper part with aluminum foil or black plastic film for shading. This aims to block the downward transport of photosynthetic products and rooting inhibitors, allowing them to accumulate at the base of the branch in preparation for subsequent rooting. Process the collected branches on the same day. Cut the branches into 10-15 cm long cuttings, retaining 2-3 plump buds. Make a horizontal cut 1.0 ± 0.2 cm from the terminal bud, leaving 1 to 2 half leaves. Make a single oblique cut 0.5-1.0 cm from the lowest terminal bud.

[0032] 1.4 Preparation of Cutting Matrix The cutting substrate is prepared by mixing peat moss, perlite, and vermiculite in a volume ratio of 3:1:1. The mixed substrate is then placed into a 12 cm diameter, 10 cm high cultivation pot, and the moisture content is adjusted to 60%-70%. 24 hours before cutting, the substrate is thoroughly disinfected by watering it with an 800-fold dilution of 50% carbendazim solution.

[0033] 1.5 Disinfection and treatment of cuttings Immerse the base of the cuttings (approximately 3 cm) in an 800-fold dilution of 50% carbendazim solution for 10 minutes for disinfection. Afterward, remove the cuttings and allow them to air dry in a cool, well-ventilated place. Weigh the required amount of ABT rooting powder or NAA, dissolve it in a small amount of methanol (approximately 0.5%–1% of the total solvent volume), and then dilute to the specified concentration with water, stirring well. Immerse the base of the disinfected and dried cuttings (2–4 cm) in the corresponding hormone solution for 1 hour. Use water treatment as a control (CK).

[0034] 1.6 Cuttings Propagation Use a wooden stick with a diameter of about 3 mm to pre-drill holes in the substrate surface, with the hole depth being 1 / 3 to 1 / 2 of the cutting length. Set the plant spacing to 5 cm × 5 cm. Insert the hormone-treated cuttings vertically into the holes, gently compact the surrounding substrate, and ensure that the base of the cutting is in close contact with the substrate. Plant 4 cuttings per pot.

[0035] 1.7 Post-cutting maintenance and management After planting, place the potted cuttings in a controlled environment at 20-25℃, using a phased water control method. From day 1 to 15 after planting, maintain high humidity in the substrate (75%-85% relative humidity) and provide ample diffused light. From day 16 to 30, implement a "wet-dry cycle," allowing the top 1-2 cm of substrate to slightly dry and whitish before watering and foliar spraying. This allows the substrate to experience mild wet-dry cycles; moderate water stress stimulates the cuttings to seek moisture downwards, inducing a more developed root system. After 30 days, resume regular humidity management (60%-75% air humidity). Keep the substrate moist (60%-65% water content), avoiding waterlogging, to promote root consolidation and robust above-ground growth. 60 days after planting, spray with an 800-fold dilution of carbendazim solution, focusing on the substrate surface and the base of the cuttings to prevent disease. Starting 60 days after cutting, spray the leaves with a 0.1% potassium dihydrogen phosphate solution once a week for 3-4 consecutive times to promote further root development and new shoot growth.

[0036] 1.8 Phenotypic and Physiological Indicator Measurement On days 30, 60, and 90 after cutting, growth status was investigated and samples were taken for measurement. The survival rate of cuttings in each treatment was statistically analyzed, and root dynamics and root morphology were observed and recorded. Five rooted seedlings with uniform growth were randomly selected from each replicate. After carefully washing the root substrate, the following root morphological parameters were accurately measured using a root scanner (Agripheno Expression 12000X2, Hanfino Corporation) and its accompanying analysis software: total root length, root surface area, average root diameter, root volume, total number of root tips, and number of root branches. All data were initially processed using Microsoft Excel 2019, and the mean and standard deviation of each indicator were calculated.

[0037] 2. Results and Analysis 2.1 Morphological observation of the rooting process of tender shoot cuttings of three varieties of Prunus cerasifera Morphological observation of the rooting process showed that the method of this invention successfully induced a typical mixed rooting system in cuttings of three Prunus cerasifera varieties (Shiban Wanna, Crown Prunus, and Zao Furong). Twenty days after cutting, the cuttings entered the rooting initiation stage, with obvious root primordia protrusions (root points) observed on the bark. Simultaneously, callus tissue began to form at the lower cut, exhibiting differentiation potential. Forty days after cutting, the root system entered the morphological formation stage, with healthy, milky-white, dense callus tissue forming at the lower cut. At the same time, the root points on the bark broke through the epidermis and rapidly elongated to form early adventitious roots. Sixty days after cutting, the growth system matured, and the previously formed callus tissue further differentiated into dense adventitious roots, forming a preliminary root cluster together with the adventitious roots emerging from the bark. Ninety days after cutting, a complete and well-developed fibrous root system composed of bark roots and callus roots was finally formed. Figure 1-3 ).

[0038] 2.2 Effects of different treatments on the survival rate of softwood cuttings of three Prunus cerasifera varieties Sixty days after cutting, the survival rate of the three Prunus cerasifera varieties under each treatment was statistically analyzed (as shown in Table 1). The type and concentration of plant growth regulators had a significant impact on the survival rate of softwood cuttings.

[0039] In the NAA treatment group, the 100 mg / L concentration showed the best effect, with survival rates of all three varieties exceeding 80% (82% for *Prunus serrulata*, 86% for *Prunus serrulata* var. *semperflorens*, and 84% for *Prunus serrulata* var. *early bloom*), significantly higher than other treatments (p<0.01). When the NAA concentration increased to 150 mg / L, a slight inhibitory effect appeared, with the survival rate decreasing to 65%-70%, indicating that excessively high concentrations had an inhibitory effect. Lower NAA concentrations (75 mg / L and 50 mg / L) had limited effects on promoting rooting, with survival rates of only 50%-65% and 45%-55%, respectively, significantly lower than the high-concentration treatment group.

[0040] In ABT rooting powder treatment, a concentration of 150 mg / L showed the best effect, with a survival rate comparable to that of NAA 100 mg / L treatment. The survival rates for the three varieties were 82%, 85%, and 85%, respectively. Treatments with ABT 125 mg / L and 175 mg / L were less effective than those with ABT 150 mg / L, indicating that the optimal concentration window for ABT is relatively narrow.

[0041] The survival rate of all hormone treatments was significantly higher than that of the water control (CK) (28%-32%), which fully demonstrates the key role of exogenous growth regulators in overcoming the rooting obstacles of Prunus armeniaca cuttings.

[0042] Table 1. Effects of different hormone treatments on the survival rate of softwood cuttings of three Prunus cerasifera varieties after 60 days.

[0043] Note: Different lowercase letters in each column indicate significant differences at the p<0.05 level. The same applies below.

[0044] 2.3 Effects of different treatments on the survival rate of cuttings Ninety days after cutting, the final seedling survival rate of each treatment was statistically analyzed, and the results are shown in Table 2. Compared with the data at 60 days after cutting, the survival rate of all treatment groups showed a slight natural decrease, which is a normal phenomenon caused by the environmental adaptation process such as hardening off and transplanting in the later stages. However, the optimal treatment group still maintained extremely high stability.

[0045] In the NAA treatment group, the survival rate of the three varieties (Shisaka Late Plum 78%, Crown Plum 84%, and Early Hibiscus 84%) under the 100 mg / L concentration treatment was still significantly higher than that of most other treatments, showing good seedling stability.

[0046] In the ABT treatment group, the 150 mg / L concentration also showed the best and most stable effect, with survival rates of 82%, 84% and 82% for the three varieties, respectively. Its seedling effect was not significantly different from that of the NAA 100 mg / L treatment, and together they became the most effective treatment combination.

[0047] In conclusion, the NAA 100 mg / L and ABT 150 mg / L treatments not only performed excellently in the rooting stage, but also ensured the highest seedling survival rate during the subsequent seedling growth, further verifying their reliability as the most suitable methods for softwood cuttings of Prunus armeniaca.

[0048] Table 2. Effects of different hormone treatments on the survival rate of softwood cuttings of three Prunus cerasifera varieties after 90 days.

[0049] 2.4 Effects of different treatments on root development of cuttings To comprehensively evaluate the quality of the cuttings, root morphology parameters of the surviving seedlings from each treatment were precisely measured 90 days after cutting (Tables 3, 4, and 5). The data showed that the type and concentration of plant growth regulators had a highly significant impact on the root architecture of the three *Prunus cerasifera* varieties.

[0050] The root system of *Lagerstroemia indica* was the most developed. The treatment with 100 mg / L NAA and 150 mg / L ABT was once again the optimal combination. Both treatments showed significant advantages in total root length (946.09 cm vs 936.10 cm), root surface area (108.39 cm² vs 85.34 cm²), number of root tips (3409 vs 4704), and number of branches (3514 vs 3312). The average root diameter of both treatments reached the maximum value (0.39 mm), which together created the largest and best-structured root system.

[0051] Among the *Prunus cerasifera* species, the NAA 100 mg / L treatment showed the best performance in most key indicators, with significantly higher total root length (372.61 cm), root surface area (39.83 cm²), number of root tips (2127), and number of branches (1681) compared to other treatments, indicating that this treatment effectively promoted the quantitative growth and morphogenesis of the root system. The ABT 150 mg / L treatment induced the thickest root system (average diameter 0.38 mm) and also showed good results in total root length and number of root tips.

[0052] The roots of *Hibiscus rosa-sinensis* showed a more sensitive response to ABT treatment. The 150 mg / L ABT treatment achieved the highest values ​​in root volume (572.19 cm³), root tip number (3211), and branch number (1979), demonstrating its superior effect in promoting root biomass accumulation and fine branching. The 100 mg / L NAA treatment led in total root length (585.68 cm) and root surface area (67.34 cm²), while the average root diameter (0.38 mm) was comparable to that of the 150 mg / L ABT treatment (0.35 mm), together constituting a superior root system.

[0053] In summary, NAA 100 mg / L and ABT 150 mg / L showed the best overall performance in the two leading varieties (Shisaka Late-blooming Plum and Crown Plum), and were comparable to or complementary to the other best treatment in Early Hibiscus, further validating that they are the core solutions for inducing high-quality rooting in Plum. Shisaka Late-blooming Plum exhibited the strongest root development potential; Crown Plum responded better to NAA; and Early Hibiscus showed particularly outstanding response to ABT on certain indicators, indicating that the choice of rooting agent can be fine-tuned according to the characteristics of the variety in practical applications.

[0054] The optimal treatments (NAA 100, ABT 150) not only ensured a high survival rate (see Table 2), but also cultivated a well-developed root system that was significantly superior to the control and other treatments in terms of total length, surface area, degree of subdivision (number of root tips, number of branches) and thickness (Tables 3, 4, 5), laying a solid foundation for the robust growth of seedlings in the later stages.

[0055] Table 3. Root system indices of *Lagerstroemia indica* cuttings under different treatment concentrations

[0056] Table 4. Root system indicators of *Prunus crownensis* cuttings under different treatment concentrations

[0057] Table 5. Root system indicators of *Hibiscus rosa-sinensis* cuttings under different treatment concentrations

[0058] To visually demonstrate the ultimate effects of different hormone treatments on the growth of *Prunus cerasifera* cuttings, phenotypic images of representative plants from each treatment group were taken 90 days after cutting. The results are as follows: Figure 4-6 As shown, the cuttings treated with NAA 100 mg / L and ABT 150 mg / L exhibited the best growth. Their aboveground parts produced rapid new shoot growth with numerous, dark green, and large leaf areas; their underground root systems were extremely well-developed, with dense fibrous roots forming plump root masses, a stark contrast to the control (CK). This directly confirms their leading position in survival rate and various root quantitative indicators (total root length, root surface area, number of root tips, etc.). The phenotypic observation results are highly consistent with the survival rate data in Tables 1-2 and the root quantitative data in Tables 3-5, further confirming the excellent effect of NAA 100 mg / L and ABT 150 mg / L treatments in promoting the overall growth and development of *Prunus cerasifera* cuttings from a morphological perspective, achieving synergistic optimization from the root system to the aboveground parts.

[0059] Comparative Example 1: Traditional grafting propagation method This comparative example uses the most widely used conventional grafting propagation method in production, with *Lagerstroemia indica* as the scion variety, and follows a complete seedling cultivation process, including the following steps: 1. Rootstock cultivation (1) Rootstock selection The most commonly used peach in production ( Amygdalus persica L. Batsch) One-year-old seedlings were used as rootstock.

[0060] (2) Seed treatment and sowing Mature peach seeds are collected, and after dormancy is broken by sand stratification (60-90 days, 0-5°C), they are sown in seedbeds in spring.

[0061] (3) Rootstock seedling management After thinning, watering, fertilizing, and pest and disease control, healthy rootstock seedlings that meet grafting standards (approximately 8-10 cm in diameter) are cultivated. This process requires at least one growing season (approximately 8-10 months).

[0062] 2. Grafting procedure (1) Scion collection Healthy, one-year-old branches with plump buds were collected from the mother tree of *Lysimachia christinae* as scions.

[0063] (2) Grafting time and method Grafting should be performed in spring before the rootstock sprouts, using grafting methods such as cleft grafting or whip grafting. Ensure that the cambium layers of the scion and rootstock are aligned and bound with a special film.

[0064] 3. Grafted seedling management (1) Survival management After grafting, meticulous management is required, including removing sprouts, untying, and setting up supports to prevent wind damage.

[0065] (2) Seedling Management After the grafting is successful, continue to cultivate for one growing season until the seedlings reach the standard for leaving the nursery (seedling height ≥ 80 cm, good healing of the graft union).

[0066] 4. Results and Comparison (1) Total seedling raising cycle The entire process, from sowing rootstock seeds to obtaining grafted seedlings ready for transplanting, takes 18-24 months.

[0067] (2) Reproductive efficiency The number of scions that can be provided annually from a single superior mother tree is limited, and the scale of propagation is low due to the time constraints of rootstock cultivation and grafting.

[0068] (3) Characteristics of seedlings The resulting seedlings are grafted seedlings with roots from peach rootstock. This presents problems such as interaction between the rootstock and scion, potential incompatibility at the graft union, and the inability to maintain the plant's own complete root system characteristics.

[0069] This comparative example demonstrates that while traditional grafting methods can maintain varietal traits, they suffer from inherent drawbacks such as long processing times, low efficiency, dependence on rootstock, and seedling uniformity being affected by multiple factors. This contrasts sharply with the present invention (Example 1), which yields genetically stable, well-developed rooted seedlings within 3-4 months, highlighting the advantages of the present invention in rapid, efficient, and high-quality seedling production.

[0070] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0071] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for rapid propagation of Prunus armeniaca by tender branch cuttings, characterized in that, Includes the following steps: (1) Collection and preparation of cuttings: Select healthy and disease-free mature mother trees of Prunus cerasifera. 7-10 days before collecting cuttings, perform ring barking and shading pretreatment on the branches of the mother tree to be collected. At a distance of 1.5-3cm below the planned cutting, use a blade to ring bark a 3-5 mm wide layer of bark, and wrap the ring bark and the upper part with tin foil or black plastic film to shade the light. Collect semi-lignified branches from the upper part of the current year, prune the branches, retain plump buds, make a horizontal cut 0.8-1.2cm from the terminal bud and leave 1-2 half leaves, and make a single oblique cut 0.5-1.0cm from the lowest bud to obtain cuttings; (2) Preparation of cutting substrate: Mix peat moss, perlite and vermiculite in the specified volume ratio to prepare the substrate, fill the cultivation pot, and adjust its moisture content to 60%-70%; (3) Disinfection and hormone treatment of cuttings: The base of the cuttings is disinfected by immersing in a carbendazim solution, and after drying, the base is treated by immersing in a rooting agent solution; the rooting agent solution is selected from naphthaleneacetic acid or ABT rooting powder. When the rooting agent solution is naphthaleneacetic acid, the concentration is 80~140mg / L; when the rooting agent solution is ABT rooting powder, the concentration of ABT rooting powder is 140~160mg / L. (4) Cutting operation: Use a wooden stick to make holes in the substrate surface beforehand, insert the treated cuttings vertically into the holes, and compact the substrate so that the base of the cuttings is in close contact with the substrate; (5) Post-cutting maintenance: From day 1 to 15 after cutting, place the pot in a controlled environment and provide sufficient diffused light; from day 16 to 30 after cutting, implement a wet-dry cycle. Water and spray the leaves when the surface of the substrate turns white and dry; after 30 days after cutting, carry out normal moisture management, keep the substrate moist and the air humidity stable, and avoid water accumulation in the substrate; after 50 to 70 days after cutting, spray with carbendazim solution once. From 50 to 70 days after cutting, spray the leaves with potassium dihydrogen phosphate solution once a week for 3-4 consecutive times.

2. The method according to claim 1, characterized in that, In step (1), the bark of the branch is light brown, the diameter of the pith accounts for 1 / 3-1 / 2, the length of the cutting after pruning is 10-15cm, and the number of plump buds is 2-4.

3. The method according to claim 1, characterized in that, In step (2), the volume ratio of peat moss, perlite and vermiculite is 3:1:

1. The cutting substrate is thoroughly disinfected by watering it with a 700-1000 times dilution of 50% carbendazim solution 24 hours before cutting.

4. The method according to claim 1, characterized in that, In step (3), the length of the base of the disinfected cutting is 2-4 cm, the carbendazim solution is 700-900 times 50% carbendazim solution, the disinfection time is 8-12 min, the concentration of naphthaleneacetic acid is 100 mg / L, the concentration of ABT rooting powder is 150 mg / L, the solvent of the rooting agent solution is water, and methanol is added at 0.5-1% of the solvent volume.

5. The method according to claim 1, characterized in that, In step (4), 3 to 5 cuttings are planted in each pot, with a plant spacing of 5cm×5cm and an insertion depth of 1 / 3 to 1 / 2 of the cutting length.

6. The method according to claim 1, characterized in that, In step (5), the temperature of the controllable environment is 20-25℃ and the relative humidity of the air is 75%-85%; after 30 days of cutting, the air humidity is controlled at 60%~75% and the substrate moisture content is maintained at 60%~65%.

7. The method according to claim 1, characterized in that, In step (5), the concentration of potassium dihydrogen phosphate solution is 0.05-0.15%.

8. The method according to any one of claims 1-7, characterized in that, The plum varieties mentioned include Shisaka Late Plum, Crown Plum, and Early Hibiscus.

9. The application of the method according to any one of claims 1 to 8 in the propagation of Prunus armeniaca by cuttings.

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