A method to improve the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang'

Abstract

This invention discloses a method for improving the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang', comprising the following steps: (1) selecting a suitable grafting time; (2) selecting a suitable type of grafting rootstock; (3) selecting a suitable scion; and (4) selecting a suitable grafting method. By optimizing relevant process parameters using the method of this invention, the grafting survival rate of the new double-flowered crape myrtle variety 'Yunshang' is extremely high (96.67%), and its growth rate is also relatively fast (i.e., an annual growth of 167.68 cm). This allows for the rapid propagation of a large number of double-flowered crape myrtle 'Yunshang' seedlings, with excellent seedling quality. This method can maintain the superior traits of the new double-flowered crape myrtle variety 'Yunshang', meet the grafting requirements of the new double-flowered crape myrtle variety 'Yunshang', and quickly obtain high-quality seedlings of the new double-flowered crape myrtle variety 'Yunshang', which can be widely promoted and applied.

Description

Technical Field

[0001] This invention relates to the asexual propagation technology of the new double-flowered crape myrtle variety 'Yunshang', and more particularly to a method for improving the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang'. Background Technology

[0002] The double-flowered crape myrtle 'Yunshang' is the first double-flowered, fruitless variety in the crape myrtle genus with petal-like stamens. It has the advantages of bright flower color, long flowering period, good flower shape, and no fruit production, making it an excellent landscape tree species suitable for use in South China.

[0003] New double-flowered crape myrtle variety 'Yunshang' Figure 1 It was granted plant variety authorization by the National Forestry and Grassland Administration in July 2020, certificate number 2508. Figure 2 This new variety is characterized as a semi-erect tree with brown branches, upright stems, long internodes (5-6 cm), deep red color, indistinct four-angled, and hairless. The leaves are large, elliptical, 5-21 cm long and 2.8-9.0 cm wide, an olive green (Green NN137 Greyish Olive Green B), with undulating margins, hairless, thick and leathery, and alternate or opposite. The terminal panicles are 28-48 cm long, with large flower buds 17-18 mm long. 18-20cm wide, spherical, deep red, with prominent sutures and appendages; calyx long, 10-12mm, with distinct ridges, without dense pubescence; flower diameter 7-8cm, petals 5, with ruffled edges, 6-8cm long, flower color violet (RHS N82 Deep purple A); stamens all petaloid, about 1330-180 petals, 2.0-3.5cm long and 1.0-1.2cm wide; flowering period from May to September, does not produce fruit.

[0004] Double-flowered Lagerstroemia indica is a natural mutant of Lagerstroemia indica. In addition to the advantages of Lagerstroemia indica, it also has the characteristics of petaloid stamens and many petals, making it extremely valuable for ornamental purposes. However, the double-flowered Lagerstroemia indica 'Yunshang' does not produce fruit and is difficult to root by cuttings. How to propagate the double-flowered Lagerstroemia indica 'Yunshang' is an urgent problem that the industry needs to solve.

[0005] Currently, only single-petaled large-flowered crape myrtle is available on the market; double-petaled large-flowered crape myrtle is not seen. Public reports on large-flowered crape myrtle are scarce, focusing only on cuttings, seed propagation, and cultivation. Research reports on grafting large-flowered crape myrtle are also limited.

[0006] Chinese patent application document "A Grafting Method for Double-flowered Lagerstroemia indica (Publication No.: CN106888815A)" discloses a grafting method for double-flowered Lagerstroemia indica. The method involves selecting fast-growing, robust, straight-trunked, and disease-free Lagerstroemia indica seedlings as rootstock, and selecting healthy, one-year-old branches with plump buds, free from pests and diseases, and semi-lignified as scions. From April to June, the cut end of the scion is first soaked in 800 times diluted carbendazim for 5 minutes, then dipped in 800 times diluted thiabendazole copper solution for 10 minutes. The scion cut end is then tightly attached to the cambium layer of the rootstock, wrapped with a thin film, tied tightly, and then covered with a plastic bag, securing it below the graft union. This invention can rapidly propagate a large number of double-flowered Lagerstroemia indica seedlings while maintaining excellent traits; however, the grafting survival rate is not high enough to meet the needs of widespread application. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies (such as insufficient grafting survival rate) and to provide a method for improving the asexual reproduction of the new double-flowered crape myrtle variety 'Yunshang', so as to improve the grafting survival rate.

[0008] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0009] A method for improving the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang' includes the following steps:

[0010] (1) Choose an appropriate grafting time;

[0011] (2) Select a suitable type of grafting rootstock;

[0012] (3) Select a suitable scion;

[0013] (4) Choose a suitable grafting method.

[0014] Furthermore, in step (1), the appropriate grafting time is selected as March.

[0015] Furthermore, the grafting time is from 8:00 to 10:00 AM or from 4:00 to 6:00 PM.

[0016] Further, in step (2), a suitable grafting rootstock type is selected as Lagerstroemia speciosa or Lagerstroemia indica.

[0017] Furthermore, the aforementioned Lagerstroemia speciosa or Lagerstroemia indica is a 2-year-old plant.

[0018] Furthermore, the rootstock diameter is selected to be 0.7~1.0cm.

[0019] Further, in step (3), a suitable scion is selected: a 2-year-old branch is used as the scion.

[0020] Furthermore, the scion has two dormant buds, is free from pests and diseases, grows vigorously, and has a length of 3-5 cm.

[0021] Further, in step (4), select a suitable grafting method: graft by cleft grafting or whip grafting, cut the main branch of the rootstock at 50-60cm, do not prune the side branches, trim the scion of the new double-flowered crape myrtle 'Yunshang' into a wedge shape, apply a healing agent to the wound and treat for 3-4 minutes; then graft it onto crape myrtle or crape myrtle, wrap the grafting film at the joint of the rootstock and scion, wrap the top of the grafting film with kraft paper, and tie it tightly with plastic packaging rope to prevent the scion and rootstock joint from losing water due to sun exposure; after three months, prune the sprouting branches of the rootstock, and make a cut on the back of the grafting film with a grafting knife to allow the joint to expand quickly and enhance resistance.

[0022] Furthermore, the healing agent comprises the following components: sodium dioctyl succinate sulfonate, glyceryl monostearate, sodium secondary alkyl sulfate, urethane, 6-BA, NAA, and water.

[0023] Compared with the prior art, the present invention has the following technical advantages:

[0024] (1) In this invention, the addition of sodium dioctyl succinate sulfonate, glyceryl monostearate, sodium secondary alkyl sulfate, and urethane to the healing agent has a synergistic effect, which synergistically improves the grafting survival rate of double-flowered crape myrtle. This is because: sodium dioctyl succinate sulfonate has good surface activity, which can activate sodium secondary alkyl sulfate, 6-BA, and NAA, thereby improving the grafting survival rate; glyceryl monostearate has good dispersibility, and its presence is beneficial to the dispersion of sodium dioctyl succinate sulfonate, sodium secondary alkyl sulfate, 6-BA, and NAA; sodium secondary alkyl sulfate has good permeability, which not only makes glyceryl monostearate more permeable and fully exerts its dispersing effect, but also makes 6-BA and NAA more permeable at the grafting wound, accelerating wound healing and improving the grafting survival rate; urethane has good solubilizing properties, and its addition to the healing agent is beneficial to the solubility of other components and enhances their effect. Therefore, the combined effects of sodium dioctyl succinate sulfonate, glyceryl stearate, sodium secondary alkyl sulfate, and urethane synergistically promote grafting wound healing and improve the grafting survival rate of the new double-flowered crape myrtle variety 'Yunshang'.

[0025] (2) By optimizing the weight ratio of sodium dioctyl succinate sulfonate, glyceryl stearate, sodium secondary alkyl sulfate and urethane within the range of (0.4~0.7):(0.5~0.8):(0.2~0.4):(0.6~1.0), the grafting survival rate of the new double-flowered crape myrtle 'Yunshang' can be significantly improved.

[0026] (3) By optimizing the relevant process parameters using the method of the present invention, the grafting survival rate of double-flowered crape myrtle 'Yunshang' is extremely high, reaching 96.67%. At the same time, the growth rate is relatively fast, and a large number of double-flowered crape myrtle 'Yunshang' seedlings can be quickly propagated. The annual growth of double-flowered crape myrtle 'Yunshang' is 167.68 cm in height. After 3 months, the number of buds sprouting from the scion is 2, and the thickness of the bud is 4.74 mm. Moreover, the seedling quality is excellent, and the excellent traits of the new variety double-flowered crape myrtle 'Yunshang' can be maintained. It can be seen that the present invention can meet the grafting requirements of the new variety double-flowered crape myrtle 'Yunshang', and quickly obtain the new variety double-flowered crape myrtle 'Yunshang' with high seedling quality. It can be vigorously promoted and applied.

[0027] (4) The grafting survival rate of double-flowered crape myrtle obtained by the method of the present invention is higher than that obtained by the prior art “A grafting method of double-flowered crape myrtle (Publication No.: CN106888815A)”, by at least 11.54%, and the cost is low, which can increase the benefits. It can be seen that the technology of the present invention has significant progress compared with the prior art. Attached Figure Description

[0028] Figure 1 A picture of the new double-flowered crape myrtle variety 'Yunshang';

[0029] Figure 2 Image of the certificate for the new double-flowered crape myrtle variety 'Yunshang';

[0030] Figure 3 The top of the graft union area is wrapped with kraft paper and then tied tightly with plastic wrapping rope (see diagram).

[0031] Figure 4 This is a picture showing the growth of the new double-flowered crape myrtle variety 'Yunshang' after grafting. Detailed Implementation

[0032] To facilitate a better understanding of the present invention, the following embodiments are provided. These embodiments are within the scope of protection of the present invention, but do not limit the scope of protection of the present invention.

[0033] In an embodiment of the present invention, a method for improving the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang' includes the following steps:

[0034] (1) Choose a suitable grafting time: March, 8:00-10:00 am or 4:00-6:00 pm;

[0035] (2) Select a suitable type of grafting rootstock: use 2-year-old Lagerstroemia speciosa or Lagerstroemia indica as rootstock, and select rootstock diameter of 0.7~1.0cm;

[0036] (3) Select suitable scions: Use 2-year-old branches as scions. Select branches with 2 dormant buds (3~5cm) and free from pests and diseases, and grow vigorously. Graft the cuttings as soon as they are taken.

[0037] (4) Grafting method: Grafting is done by cleft grafting or whip grafting. The main branch of the rootstock is cut off at 50-60cm. The lateral branches are not pruned. The scion of the new double-flowered crape myrtle 'Yunshang' is pruned into a wedge shape. Apply a healing agent to the wound and treat it for 3-4 minutes. The healing agent is in parts by weight and includes the following components: sodium dioctyl succinate sulfonate 0.4-0.7 parts, glyceryl stearate monoester 0.5-0.8 parts, sodium secondary alkyl sulfate 0.2-0.4 parts, urethane 0.6-1.0 parts, 6-BA 2-4 parts, NAA 4-8 parts, and water 100-230 parts. Then graft the crape myrtle or crape myrtle. The grafting site is wrapped with grafting film. The top of the grafting site is wrapped with kraft paper and tied tightly with plastic packaging rope. Figure 3 The purpose is to prevent the scion and rootstock from losing water due to sun exposure. After three months, the grafting survival rate, scion bud height, number of scion buds, thickness of scion buds, and the sprouting branches of the rootstock are recorded. The grafting film is then pruned, and a cut is made on the back of the scion with a grafting knife to allow the joint to expand quickly and enhance resistance.

[0038] To further illustrate and fully disclose the present invention, more specific details are described below.

[0039] (I) An investigation into the effects of different rootstocks on the grafting survival rate of the new double-flowered crape myrtle variety 'Yunshang'

[0040] Specific research plan: A method to improve the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang', including the following steps:

[0041] (1) Choose the grafting time: March, 9:00 AM;

[0042] (2) Selection of grafting rootstock type: Two-year-old Lagerstroemia speciosa, Lagerstroemia indica and Lagerstroemia indica were used as rootstocks, with a rootstock diameter of 0.8 cm, to explore the effect of different rootstocks on the grafting survival of the new double-flowered Lagerstroemia speciosa 'Yunshang'.

[0043] (3) Select suitable scions: Use 2-year-old branches as scions. Select branches with 2 dormant buds (4cm) and free from pests and diseases, and grow vigorously as scions. Graft the cuttings as soon as they are taken.

[0044] (4) Grafting method: Grafting is performed by cleft grafting. The main branch of the rootstock is cut off at 50cm, and the lateral branches are not pruned. The scion of the new double-flowered crape myrtle 'Yunshang' is pruned into a wedge shape. A healing agent is applied to the wound and treated for 4 minutes. The healing agent is in parts by weight and includes the following components: 0.6 parts sodium dioctyl succinate sulfonate, 0.7 parts glyceryl monostearate, 0.3 parts sodium secondary alkyl sulfate, 0.9 parts urethane, 3 parts 6-BA, and NAA. 6 parts water; then graft Lagerstroemia speciosa, Lagerstroemia indica, or Lagerstroemia hairyensis. Wrap the graft union with grafting film, and wrap the top of the graft union with kraft paper. Tie it tightly with plastic wrap to prevent sun exposure from causing the graft union to lose water. After three months, count the graft survival rate, scion bud height, number of scion buds, scion bud thickness, and prune the sprouting branches of the rootstock. Make a cut on the back of the graft union with a grafting knife to allow the graft union to expand quickly and enhance resistance. The relevant results are shown in Table 1.

[0045]

[0046] The results in Table 1 show that the highest grafting survival rate for the new double-flowered crape myrtle 'Yunshang' was achieved with different rootstocks: *Lagerstroemia indica* (large-flowered crape myrtle) at 96.67%, exhibiting rapid growth (an annual height increase of 167.68 cm), and two buds sprouting from the scion three months after grafting, with a bud diameter of 4.74 mm. *Lagerstroemia indica* was the next highest, with a relatively slower growth rate. The lowest grafting survival rate was with *Lagerstroemia indica* (hairy crape myrtle), at only 10.00%, with buds dying after three months. This may be due to hormones in *Lagerstroemia indica* inhibiting the growth of 'Yunshang'. Therefore, *Lagerstroemia indica* is the optimal rootstock for grafting 'Yunshang'.

[0047] (II) An investigation into the effects of grafting in different months on the survival rate of the new Lagerstroemia speciosa variety 'Yunshang'.

[0048] Specific research plan: A method to improve the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang', including the following steps:

[0049] (1) Grafting time: January to December, 9:00 am, to investigate the effect of grafting in different months on the survival of the new Lagerstroemia speciosa variety 'Yunshang';

[0050] (2) Selection of grafting rootstock type: 2-year-old Lagerstroemia speciosa as rootstock, with a rootstock diameter of 0.8cm;

[0051] (3) Select suitable scions: Use 2-year-old branches as scions. Select branches with 2 dormant buds (4cm) and free from pests and diseases, and grow vigorously as scions. Graft the cuttings as soon as they are taken.

[0052] (4) Grafting method: Grafting is performed by cleft grafting. The main branch of the rootstock is cut off at 50cm, and the lateral branches are not pruned. The scion of the new double-flowered crape myrtle 'Yunshang' is pruned into a wedge shape. A healing agent is applied to the wound and treated for 4 minutes. The healing agent is in parts by weight and includes the following components: 0.6 parts sodium dioctyl succinate sulfonate, 0.7 parts glyceryl monostearate, 0.3 parts sodium secondary alkyl sulfate, 0.9 parts urethane, 3 parts 6-BA, and NAA. 6 parts water; then graft crape myrtle, wrap the graft union with grafting film, wrap the top of the graft union with kraft paper, and tie it tightly with plastic packaging rope to prevent sun exposure from causing the graft union to lose water; after three months, count the graft survival rate and prune the sprouting branches of the rootstock, and use a grafting knife to make a cut on the back of the graft union to allow the joint to expand quickly and enhance resistance. The relevant results are shown in Table 2.

[0053]

[0054] As shown in Table 2, when using Lagerstroemia speciosa as rootstock, the highest survival rate of the new Lagerstroemia speciosa variety 'Yunshang' was in March, with a survival rate as high as 96.67%; followed by April, with a survival rate of 50.00%; and the worst were January, November, and December, with a survival rate of 0.00%. Therefore, March was chosen as the best time for grafting.

[0055] (III) An investigation into the effects of different grafting methods on the new Lagerstroemia speciosa variety 'Yunshang'

[0056] Specific research plan: A method to improve the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang', including the following steps:

[0057] (1) Choose the grafting time: March, 9:00 AM;

[0058] (2) Selection of grafting rootstock type: 2-year-old Lagerstroemia speciosa as rootstock, with a rootstock diameter of 0.8cm;

[0059] (3) Select suitable scions: Use 2-year-old branches as scions. Select branches with 2 dormant buds (4cm) and free from pests and diseases, and grow vigorously as scions. Graft the cuttings as soon as they are taken.

[0060] (4) Grafting methods: Three grafting methods, namely cleft grafting, side grafting, and whip grafting, were used to explore the effects of different grafting methods on the new double-flowered crape myrtle variety 'Yunshang'. The main branch of the rootstock was cut off at 50cm, and the lateral branches were not pruned. The scion of the new double-flowered crape myrtle variety 'Yunshang' was pruned into a wedge shape, and a healing agent was applied to the wound for 4 minutes. The healing agent, in parts by weight, included the following components: 0.6 parts of sodium dioctyl succinate sulfonate, 0.7 parts of glyceryl monostearate, 0.3 parts of sodium secondary alkyl sulfate, 0.9 parts of urethane, 3 parts of 6-BA, and NAA. 6 parts water; then graft crape myrtle, wrap the graft union with grafting film, wrap the top of the graft union with kraft paper, and tie it tightly with plastic packaging rope to prevent sun exposure from causing the graft union to lose water; after three months, count the graft survival rate and prune the sprouting branches of the rootstock, and use a grafting knife to make a cut on the back of the graft union to allow the joint to expand quickly and enhance resistance. The relevant results are shown in Table 3.

[0061]

[0062] As shown in Table 3, the survival rate of cleft grafting is the highest (96.67%), followed by whip grafting with a survival rate of 83.00%, and the lowest is side grafting with a survival rate of only 36.67%. Therefore, cleft grafting is the best grafting method.

[0063] Using the optimal process parameters explored above, the following optimal embodiment was obtained.

[0064] A method for improving the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang' includes the following steps:

[0065] (1) Choose the grafting time: March, 9:00 AM;

[0066] (2) Selection of grafting rootstock type: 2-year-old Lagerstroemia speciosa as rootstock, with a rootstock diameter of 0.8cm;

[0067] (3) Select suitable scions: Use 2-year-old branches as scions. Select branches with 2 dormant buds (4cm) and free from pests and diseases, and grow vigorously as scions. Graft the cuttings as soon as they are taken.

[0068] (4) Grafting method: Grafting is carried out by cleft grafting. The main branch of the rootstock is cut off at 50cm, and the lateral branches are not pruned. The scion of the new double-flowered crape myrtle 'Yunshang' is pruned into a wedge shape. Apply a healing agent to the wound and treat it for 4 minutes. The healing agent is in parts by weight and includes the following components: 0.6 parts of sodium dioctyl succinate sulfonate, 0.7 parts of glyceryl monostearate, 0.3 parts of sodium secondary alkyl sulfate, 0.9 parts of urethane, 3 parts of 6-BA, 6 parts of NAA, and 160 parts of water. Then graft the crape myrtle. The graft union is wrapped with grafting film and the top of the graft union is wrapped with kraft paper and tied tightly with plastic packaging rope. The purpose is to prevent the graft union from losing water due to sun exposure. See the relevant growth conditions after grafting. Figure 4 Three months later, the survival rate of the 90 grafted plants was assessed, and the results are shown in Table 4.

[0069] Comparative Example 1

[0070] The method of asexual propagation of the new double-flowered crape myrtle 'Yunshang' variety is basically the same as that of the best embodiment. The difference is that the healing agent in the asexual propagation method of the new double-flowered crape myrtle 'Yunshang' variety does not contain sodium dioctyl succinate sulfonate, glyceryl stearate monoester, sodium secondary alkyl sulfate, and urethane. The missing four components are supplemented with the same weight of purified water (purified water does not affect the grafting survival rate). Three months after grafting, the survival rate of 90 grafted plants was counted. The relevant results are shown in Table 4.

[0071] Comparative Example 2

[0072] The asexual propagation method for the new double-flowered crape myrtle 'Yunshang' variety was basically the same as that for Comparative Example 1. The difference was that sodium dioctyl succinate was added to the healing agent in the asexual propagation method for the new double-flowered crape myrtle 'Yunshang' variety, and the three missing components were supplemented with the same weight of purified water (purified water does not affect the grafting survival rate). Three months after grafting, the survival rate of 90 grafted plants was counted, and the relevant results are shown in Table 4.

[0073] Comparative Example 3

[0074] The asexual propagation method for the new double-flowered crape myrtle 'Yunshang' variety was basically the same as that for Comparative Example 1. The difference was that the healing agent for the asexual propagation method of the new double-flowered crape myrtle 'Yunshang' variety was supplemented with glyceryl stearate, and the three missing components were supplemented with the same weight of purified water (purified water does not affect the grafting survival rate). Three months after grafting, the survival rate of 90 grafted plants was counted, and the relevant results are shown in Table 4.

[0075] Comparative Example 4

[0076] The asexual propagation method for the new double-flowered crape myrtle 'Yunshang' variety was basically the same as that for Comparative Example 1. The difference was that sodium secondary alkyl sulfate was added to the healing agent in the asexual propagation method of the new double-flowered crape myrtle 'Yunshang' variety, and the three missing components were supplemented with the same weight of purified water (purified water does not affect the grafting survival rate). Three months after grafting, the survival rate of 90 grafted plants was counted, and the relevant results are shown in Table 4.

[0077] Comparative Example 5

[0078] The asexual propagation method of the new double-flowered crape myrtle 'Yunshang' was basically the same as that of Comparative Example 1. The difference was that the healing agent of the new double-flowered crape myrtle 'Yunshang' was supplemented with urethane, and the three missing components were supplemented with the same weight of purified water (purified water does not affect the grafting survival rate). Three months after grafting, the survival of 90 grafted plants was counted. The relevant results are shown in Table 4.

[0079] Comparative Example 6

[0080] The method of asexual propagation of the new double-flowered crape myrtle 'Yunshang' is basically the same as that of the preferred embodiment, except that the raw materials of the healing agent in the asexual propagation method of the new double-flowered crape myrtle 'Yunshang' include 1 part sodium dioctyl succinate sulfonate, 0.3 parts glyceryl monostearate, 0.8 parts sodium secondary alkyl sulfate, and 0.4 parts urethane. Three months after grafting, the survival rate of 90 grafted plants was counted, and the relevant results are shown in Table 4.

[0081] Comparative Example 7

[0082] The method of asexual propagation of the new double-flowered crape myrtle 'Yunshang' is basically the same as that of the preferred embodiment. The difference is that the raw materials of the healing agent in the asexual propagation method of the new double-flowered crape myrtle 'Yunshang' include 1 part sodium dioctyl succinate sulfonate, 1 part glyceryl monostearate, 0.1 part sodium secondary alkyl sulfate, and 0.4 parts urethane. Three months after grafting, the survival rate of 90 grafted plants was counted. The relevant results are shown in Table 4.

[0083] Comparative Example 8

[0084] The method of asexual propagation of the new double-flowered crape myrtle 'Yunshang' is basically the same as that of the preferred embodiment, except that the raw materials of the healing agent in the asexual propagation method of the new double-flowered crape myrtle 'Yunshang' include 0.2 parts of sodium dioctyl succinate sulfonate, 0.3 parts of glyceryl monostearate, 0.8 parts of sodium secondary alkyl sulfate, and 1.2 parts of urethane. Three months after grafting, the survival rate of 90 grafted plants was counted, and the relevant results are shown in Table 4.

[0085] Comparative Example 9

[0086] The grafting of double-flowered crape myrtle was carried out using the method in Example 2 of the Chinese patent application document "A grafting method for double-flowered crape myrtle (Publication No.: CN106888815A)". Three months after grafting, the survival rate of 90 grafted plants was counted. The relevant results are shown in Table 4.

[0087] The grafting survival rates obtained from the best embodiment and comparative examples 1 to 9 were statistically analyzed, and the results are shown in Table 4.

[0088] As shown in Table 4: (1) After optimizing the relevant process parameters, the grafting survival rate of the new double-flowered crape myrtle 'Yunshang' obtained by the method of the present invention is extremely high, reaching 96.67%. It can be seen that the present invention can meet the grafting requirements of the new double-flowered crape myrtle 'Yunshang'.

[0089] (2) The grafting survival rate of the double-flowered crape myrtle 'Yunshang' of the present invention is higher than that of the double-flowered crape myrtle 'Yunshang' obtained in comparative example 9, by at least 11.54%, which shows that the technology of the present invention has made significant progress.

[0090] (3) Based on the grafting survival rate data of the double-flowered crape myrtle 'Yunshang' in the best embodiment and comparative examples 1-5, it can be calculated that the addition of sodium dioctyl succinate sulfonate, glyceryl stearate, sodium secondary alkyl sulfate, and urethane to the healing agent has a synergistic effect, which synergistically improves the grafting survival rate of double-flowered crape myrtle 'Yunshang'. This is because: sodium dioctyl succinate sulfonate has good surface activity, which can activate sodium secondary alkyl sulfate, 6-BA, and NAA, thereby improving the grafting survival rate; glyceryl stearate has good dispersibility, and its presence is beneficial to the dispersion of sodium dioctyl succinate sulfonate, sodium secondary alkyl sulfate, 6-BA, and NAA; sodium secondary alkyl sulfate has good permeability, which not only makes glyceryl stearate more permeable and fully exerts its dispersing effect, but also makes 6-BA and NAA more permeable at the grafting wound, accelerating wound healing and improving the grafting survival rate; urethane has good solubilizing properties, and its addition to the healing agent is beneficial to the solubility of other components and enhances the effect. Therefore, the synergistic effect of sodium dioctyl succinate sulfonate, glyceryl stearate, sodium secondary alkyl sulfate, and urethane promotes grafting wound healing and improves the grafting survival rate of the new double-flowered crape myrtle variety 'Yunshang'. This demonstrates that the combination of sodium dioctyl succinate sulfonate, glyceryl stearate, sodium secondary alkyl sulfate, and urethane has achieved unexpected technical results.

[0091] (4) As can be seen from the grafting survival rates of Comparative Examples 6-8, when the weight ratio of sodium dioctyl succinate sulfonate, glyceryl stearate monoester, sodium secondary alkyl sulfate, and urethane is not within the range of (0.4~0.7):(0.5~0.8):(0.2~0.4):(0.6~1.0), the grafting survival rates of Comparative Examples 6-8 differ significantly from those of the optimal embodiment. The grafting survival rates of the optimal embodiment are 11.54%, 7.41%, and 16.01% higher than those of Comparative Examples 6-8, respectively. The grafting survival rate was similar to that of Comparative Example 9 (existing technology), indicating that the method of improving the asexual propagation of the new double-flowered crape myrtle 'Yunshang' using the present invention, by optimizing and controlling the weight ratio of sodium dioctyl succinate sulfonate, glyceryl stearate, sodium secondary alkyl sulfate, and urethane within the range of (0.4~0.7):(0.5~0.8):(0.2~0.4):(0.6~1.0), can significantly improve the grafting survival rate of the new double-flowered crape myrtle 'Yunshang', demonstrating that the present invention has achieved unexpected technical effects.

[0092] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the asexual propagation of the new double-flowered large-flowered crape myrtle variety 'Yunshang', characterized in that, Includes the following steps: (1) Choose an appropriate grafting time; (2) Select a suitable type of grafting rootstock; (3) Select a suitable scion; (4) Choose a suitable grafting method; In step (1), the appropriate grafting time is selected as March; In step (2), select a suitable grafting rootstock type, such as Lagerstroemia speciosa or Lagerstroemia indica; In step (3), select a suitable scion: use 2-year-old branches as scions; In step (4), choose a suitable grafting method: use cleft grafting or whip grafting. Cut the main branch of the rootstock at 50-60cm, do not prune the side branches, and trim the scion of the new double-flowered crape myrtle 'Yunshang' into a wedge shape. Apply a healing agent to the wound and treat it for 3-4 minutes. Then graft the crape myrtle or crape myrtle. Wrap the grafting film at the junction of the rootstock and scion, and wrap the top of the grafting film with kraft paper. Tie it tightly with plastic packaging rope to prevent the scion and rootstock from losing water due to sun exposure. After three months, prune the sprouting branches of the rootstock and make a cut on the back of the grafting film with a grafting knife to allow the junction to expand quickly and enhance resistance. The healing agent, by weight, comprises the following components: 0.4-0.7 parts sodium dioctyl succinate sulfonate, 0.5-0.8 parts glyceryl monostearate, 0.2-0.4 parts sodium secondary alkyl sulfate, 0.6-1.0 parts urethane, 2-4 parts 6-BA, 4-8 parts NAA, and 100-230 parts water.

2. The method for improving the asexual propagation of the new double-flowered crape myrtle variety 'Yunshang' as described in claim 1, characterized in that, Grafting can be done between 8:00 and 10:00 AM or between 4:00 and 6:00 PM.

3. The method for improving the asexual propagation of the new double-flowered large-flowered crape myrtle variety 'Yunshang' as described in claim 1, characterized in that, The aforementioned Lagerstroemia indica or Lagerstroemia indica is a 2-year-old plant.

4. The method for improving the asexual propagation of the new double-flowered large-flowered crape myrtle variety 'Yunshang' as described in claim 1, characterized in that, The rootstock diameter is selected to be 0.7~1.0cm.

5. The method for improving the asexual propagation of the new double-flowered large-flowered crape myrtle variety 'Yunshang' as described in claim 1, characterized in that, The scion has two dormant buds, is free from pests and diseases, and grows vigorously. The scion length is 3-5 cm.

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