Method for grafting and rejuvenating endangered varieties of sweet potato germplasm resources

Abstract

The invention relates to the technical field of sweet potato rejuvenation, in particular to a sweet potato germplasm resource endangered variety grafting rejuvenation method. Cutting the tree morning glory with the height of 40cm, and taking the tree morning glory as a stock after survival; grafting the sweet potato germplasm resource endangered variety to the rootstock in a scion form, and removing all leaves and lateral buds of the rootstock after the scion grows leaves; the length of the scion is 5.5 cm, and two leaves of a stem tip are reserved; the scions are soaked in a naphthylacetic acid solution with the concentration of 15 mg / L for 30 s before grafting. By adopting the rejuvenation method provided by the invention, the total survival rate of weak seedlings is 76.7% in 14 days, 61.7% in 21 days and 46.7% in 28 days, the survival rates of the variety 12, the variety 22 and the variety 24 in the whole observation period (14 days, 21 days and 28 days) are 100.0%, and the variety 7 and the variety 4 show remarkable growth rates.

Description

Technical Field

[0001] The invention relates to the technical field of sweet potato rejuvenation, in particular to a method for grafting and rejuvenation of endangered varieties of sweet potato germplasm resources. Background Art

[0002] For endangered sweet potato germplasm resources, there are two conventional methods: preservation in loose soil pots and preservation by virus-free methods. Preservation in soil pots cannot achieve the effect of rejuvenation, and it is easy to die, which cannot guarantee germplasm preservation; the virus-free method of endangered germplasm resources has the problems of small seedling quantity, few growth points of branches that can be used for virus-free, and virus-free seedlings cannot guarantee all success, and the virus-free cycle is long.

[0003] The present invention aims to solve the problems of small amount of seedlings and long detoxification period in detoxification preservation. By grafting, the endangered seedlings are expanded and rejuvenated, the available growth points are increased, the detoxification success rate is improved, and another way to preserve endangered resources is provided. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for grafting and rejuvenation of endangered varieties of sweet potato germplasm resources, which can achieve the rejuvenation of weak seedling varieties.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for grafting and rejuvenation of endangered varieties of sweet potato germplasm resources, comprising the following steps:

[0007] 1) Take cuttings of 40 cm tall morning glory and use them as rootstocks after they survive;

[0008] 2) grafting the endangered variety of sweet potato germplasm resources onto the rootstock obtained in step 1) in the form of a scion, and after the scion grows leaves, removing all leaves and side buds of the rootstock;

[0009] The length of the scion is 5.5 cm, and two leaves are retained on the stem tip; the scion is soaked in a 15 mg / L naphthaleneacetic acid solution for 30 seconds before grafting.

[0010] Preferably, the grafting method in step 2) comprises: processing the stem node of the rootstock into a flat end, opening a vertical end perpendicular to the stem node, processing the lower 1 cm of the scion into a flat state, inserting it into the vertical end, and wrapping the grafting site tightly with a grafting film.

[0011] Preferably, a sunshade net is covered after the grafting, and the sunshade net is removed after the scion survives.

[0012] Preferably, the endangered varieties of sweet potato germplasm resources include one or more of Guangshu 87-21, Ningyinshu, Sumor, Guangshu 97-40, Xu 98-22-23, Tebianshu, Dayezhizi, Heigui, Shuangshenghuang, AIS35-2, 440185L0-323, Sushu 22 and Zhongbao red-skinned white-hearted potato.

[0013] Beneficial effects of the present invention:

[0014] By using the rejuvenation method provided by the present invention, the total survival rate of weak seedlings was 76.7% in 14 days, 61.7% in 21 days, and 46.7% in 28 days, while the survival rates of varieties 12, 22, and 24 were all 100.0% in the entire observation period (14 days, 21 days, and 28 days), and varieties 7 and 4 showed significant growth rates. All 4 control varieties survived, proving the high feasibility of the grafting technology; among the 20 embodiments, 3 varieties of seedlings died, 17 varieties were preserved, and the variety preservation rate reached 85%, which could play a greater time buffering role for weak seedlings and win preparation time for the detoxification of endangered resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0016] Figure 1 is the survival rate of grafted seedlings at different stages;

[0017] Figure 2 The height of grafted seedlings at different stages;

[0018] Figure 3 It is the weak seedling state of the endangered varieties of sweet potato germplasm resources;

[0019] Figure 4 Planting for wild species of morning glory rootstock;

[0020] Figure 5 For the grafting process and status;

[0021] Figure 6 This is the state 21 days after grafting. DETAILED DESCRIPTION

[0022] The present invention provides a method for grafting and rejuvenation of endangered varieties of sweet potato germplasm resources, comprising the following steps:

[0023] 1) Take cuttings of 40 cm tall morning glory and use them as rootstocks after they survive;

[0024] 2) grafting the endangered variety of sweet potato germplasm resources onto the rootstock obtained in step 1) in the form of a scion, and after the scion grows leaves, removing all leaves and side buds of the rootstock;

[0025] The length of the scion is 5.5 cm, and two leaves are retained on the stem tip; the scion is soaked in a 15 mg / L naphthaleneacetic acid solution for 30 seconds before grafting.

[0026] In the present invention, the tree morning glory with a height of 40 cm is cut and used as a rootstock after it survives. In the present invention, the tree morning glory is preferably cut into 40 cm seedlings, and the tree morning glory with a height of 40 cm is cut and cultured by conventional methods, and used as a rootstock after it survives.

[0027] The present invention grafts the endangered varieties of sweet potato germplasm resources onto the stock in the form of a scion, and after the scion grows leaves, all the leaves and lateral buds of the stock are removed; the length of the scion is 5.5 cm, and two leaves at the stem tip are retained; the scion is soaked in a naphthaleneacetic acid solution with a concentration of 15 mg / L for 30 seconds before grafting. In the present invention, the grafting method preferably includes: processing the stem node of the stock into a flat mouth, opening a vertical mouth vertical to the stem node, processing the lower 1 cm of the scion into a flat state, inserting it into the vertical mouth, and wrapping the grafting with a grafting film. In the present invention, the tree morning glory only retains one stem node after survival. In the present invention, it is preferred to cover the sunshade net after the grafting, and remove the sunshade net after the scion survives. The present invention has no special restrictions on the culture conditions for rejuvenation of the endangered varieties of sweet potato germplasm resources, and conventional operations by those skilled in the art are sufficient. In the present invention, the endangered preferred varieties of sweet potato germplasm resources include one or more of Guangshu 87-21, Ningyinshu, Sumor, Guangshu 97-40, Xu 98-22-23, Tebishu, Dayezhi, Heigui, Shuangshenghuang, AIS35-2, 440185L0-323, Sushu 22 and Zhongbao red skin white heart potato. The present invention has no special restrictions on the sources of the above varieties.

[0028] In order to further illustrate the present invention, the present invention is described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0029] Example 1

[0030] 20 weak seedling varieties and 4 normal seedling varieties were selected from the field germplasm resource bank as test subjects. Six seedlings of each variety were grafted. All grafting activities were carried out in a greenhouse to provide stable environmental control and simulate ideal growth conditions. Tree morning glory was used as the rootstock, which is a wild variety with wide adaptability. The grafting operation was carried out on October 26, 2023, and all grafting work must be completed on the same day to ensure that all samples are at the same grafting time point.

[0031] Grafting steps: First, cut the seedlings of the special wild variety of morning glory to 40cm, and cut them into a flower pot as the rootstock. After about 25 days, the rootstock has taken root and survived. Select the weak seedlings in the resources, cut the scion for grafting, the scion length is 5.5cm, and the scion only retains 2 leaves at the stem tip. The lower leaves are cut off with a blade. The scion needs to be soaked in the grafting solution (15mg / LNAA solution) for 30s to improve the grafting survival rate; the lower 1cm of the scion is cut into a nearly flat state with a grafting blade, and at the rootstock stem node, it is cut into a flat mouth, and a vertical mouth is opened at the vertical stem node so that the cut scion can be inserted into the vertical mouth, and then the grafting film is used to wrap the grafting place tightly and tie it up. After grafting, cover the shade net for shade, the shade net has a light transmittance of 20%, and the transpiration of the scion is weakened. The rootstock only retains 2 leaves to ensure the supply of photosynthesis. After the scion grows leaves, remove all the leaves and side buds of the rootstock. When the grafted seedlings have grown a large number of new leaves (about 21 days after grafting), the scion has survived and adapted to the external environment, remove the shade net to enhance photosynthesis. When the scion stretches longer or has more branches, it meets the rejuvenation requirements, and then remove the virus or cut the seedlings for transplanting, which can ensure the success rate of virus removal or field transplanting.

[0032] On the 7th, 14th, 21st and 28th day after grafting, the plant height is accurately measured and the growth of each seedling is recorded. In addition to plant height, the survival rate of each variety needs to be observed and recorded at the same time point to evaluate the effect of grafting.

[0033] Normal seedling varieties: varieties 1, 2, 3, 4;

[0034] Weak seedling varieties: varieties 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.

[0035] Table 1 Variety name

[0036]

[0037] Results Analysis

[0038] Survival rate and rejuvenation of weak seedlings grafted

[0039] like Figure 1 It can be seen that among the normal seedling varieties, 4 varieties had a 100.0% survival rate on day 14. 4 varieties had a 100.0% survival rate on day 21. One variety had a 66.7% survival rate on day 28, and three varieties had a 100.0% survival rate. The continued high survival rate of the normal seedling varieties at all observation time points indicated strong stability and good grafting adaptability.

[0040] Among the weak seedling varieties, the survival rate of 14 days was 0 for 2 varieties, 33.3% for 2 varieties, 66.7% for 4 varieties, and 100.0% for 12 varieties. Among the 21-day survival rates, 0.0% for 2 varieties, 33.3% for 2 varieties, 66.7% for 4 varieties, and 100.0% for 8 varieties. Among the 28-day survival rates, 0.0% for 3 varieties, 33.3% for 9 varieties, 66.7% for 5 varieties, and 100.0% for 3 varieties. Among them, the survival rates of varieties 8 and 11 were all 0.0% at 14 days, 21 days, and 28 days. The total number of weak seedlings that survived was 46 in 14 days, 37 in 21 days, and 28 in 28 days. The total survival rate of weak seedlings was 76.7% in 14 days, 61.7% in 21 days, and 46.7% in 28 days.

[0041] The survival rates of weak seedling varieties showed diversity, with some varieties maintaining a high survival rate after grafting and others showing a significant decline in survival rate. At 14 days, the survival rates of these varieties showed obvious distribution differences: among them, there were 2 varieties that failed to survive at all (accounting for 10%), 2 varieties with a survival rate of 33.3% (accounting for 10%), 4 varieties with a survival rate of 66.7% (accounting for 20%), and the number of varieties that fully survived reached 12 (accounting for 60%). Further observation of the survival rates at 21 days and 28 days showed that the number of surviving varieties gradually decreased: at 21 days, the number of fully surviving varieties dropped to 8 (accounting for 40%); and at 28 days, there were only 3 varieties that fully survived (accounting for 15%). This trend shows that the survival status of some varieties began to deteriorate over time. The survival rates of varieties 8 and 11 were both 0.0% during the entire observation period (14 days, 21 days, and 28 days), indicating that the survival ability of these two varieties after grafting is extremely poor, and their applicability in actual planting may need to be reconsidered. The survival rates of varieties 12, 22, and 24 were all 100.0% during the entire observation period (14 days, 21 days, and 28 days). This shows that these two varieties have excellent survival ability after grafting and can be cultivated as a priority. The difference in survival rate also reflects the biodiversity in sweet potato germplasm resources. The differences in the responses of different varieties to grafting may be due to different genetic backgrounds.

[0042] Table 1 Survival rate of grafted seedlings at different stages

[0043] serial number 14-day survival rate 21-day survival rate 28-day survival rate Variety 1 100.0％ 100.0％ 100.0％ Variety 2 100.0％ 100.0％ 66.7％ Variety 3 100.0％ 100.0％ 100.0％ Variety 4 100.0％ 100.0％ 100.0％ Variety 5 66.7％ 33.3％ 33.3％ Variety 6 33.3％ 33.3％ 33.3％ Variety 7 100.0％ 100.0％ 66.7％ Variety 8 0.0％ 0.0％ Not alive Variety 9 100.0％ 100.0％ 33.3％ Variety 10 33.3％ 33.3％ 33.3％ Variety 11 0.0％ 0.0％ Not alive Variety 12 100.0％ 100.0％ 100.0％ Variety 13 66.7％ 66.7％ 66.7％ Variety 14 100.0％ 100.0％ 66.7％ Variety 15 100.0％ 100.0％ 66.7％ Variety 16 100.0％ 33.3％ 33.3％ Variety 17 100.0％ 66.7％ 33.3％ Variety 18 100.0％ 100.0％ Not alive Variety 19 66.7％ 33.3％ 33.3％ Variety 20 100.0％ 100.0％ 66.7％ Variety 21 66.7％ 33.3％ 33.3％ Variety 22 100.0％ 100.0％ 100.0％ Variety 23 100.0％ 33.3％ 33.3％ Variety 24 100.0％ 100.0％ 100.0％

[0044] like Figure 2It can be seen that the average plant height of sweet potato varieties, the normal seedling varieties as the control group, showed a relatively uniform growth pattern, while the weak seedling varieties showed significant diversity. In the control group, varieties 1, 2, 3, and 4 all showed a consistent growth trend during the 28-day observation period. The plant height of these varieties experienced continuous growth from the initial measurement, and the final plant height was higher than the initial plant height. However, the weak seedling varieties showed complex survival and growth patterns throughout the grafting process. Some varieties, such as varieties 7 and 4, showed significant growth rates, while the plant heights of other varieties, such as varieties 8 and 11, dropped directly to 0 after the first measurement, indicating that these varieties did not survive the grafting process. In addition, the plant heights of varieties 9 and 21 regressed after the initial growth, and the remaining varieties, such as variety 16, showed abnormally high growth, which may reflect specific biological responses or experimental errors under specific conditions. The widely different responses of weak seedling varieties reveal the huge differences in their responses to grafting technology, which highlights the need to deeply understand the characteristics of each variety before promoting grafting technology.

[0045] Table 2 Plant height of grafted seedlings at different stages (cm)

[0046]

[0047] All 4 control varieties survived; among the 20 examples, 3 varieties of seedlings died, 17 varieties were preserved, and the variety preservation rate reached 85%.

[0048] Through the exploration and application of grafting technology, this study provides powerful insights into how to use these genetic resources more efficiently. The total survival rate of weak seedlings was 76.7% in 14 days, 61.7% in 21 days, and 46.7% in 28 days, while the survival rates of varieties 12, 22, and 24 were all 100.0% during the entire observation period (14 days, 21 days, and 28 days). Varieties 7 and 4 showed significant growth rates. All 4 control varieties survived, proving the high feasibility of grafting technology; among the 20 examples, 3 varieties of seedlings died, and 17 varieties were preserved, with a variety preservation rate of 85%, which can play a greater time buffering role for weak seedlings and gain preparation time for the detoxification of endangered resources.

[0049] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for grafting and rejuvenation of endangered varieties of sweet potato germplasm resources, characterized in that: The following steps are involved: 1) Take cuttings of 40 cm tall morning glory and use them as rootstocks after they survive; 2) grafting the endangered variety of sweet potato germplasm resources onto the rootstock obtained in step 1) in the form of a scion, and after the scion grows leaves, removing all leaves and side buds of the rootstock; The length of the scion is 5.5 cm, and two leaves are retained on the stem tip; the scion is soaked in a 15 mg / L naphthaleneacetic acid solution for 30 seconds before grafting.

2. The method according to claim 1, characterized in that The grafting method of step 2) comprises: processing the stem node of the rootstock into a flat end, opening a vertical end perpendicular to the stem node, processing the lower 1 cm of the scion into a flat state, inserting it into the vertical end, and wrapping the grafting site tightly with a grafting film.

3. The method according to claim 1 or 2, characterized in that: After the grafting, a sunshade net is covered, and when the scion survives, the sunshade net is removed.

4. The method according to claim 1, characterized in that The endangered varieties of sweet potato germplasm resources include one or more of Guangshu 87-21, Ningyinshu, Sumor, Guangshu 97-40, Xu 98-22-23, Tebieshu, Dayezhiyou, Heigui, Shuangshenghuang, AIS35-2, 440185L0-323, Sushu 22 and Zhongbao red-skinned white-hearted potato.

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