Method for improving propagation coefficient of virus-free seedlings of sweet potatoes

Abstract

The invention discloses a method for increasing the propagation coefficient of virus-free seedlings of sweet potatoes, and belongs to the technical field of crop propagation. According to the method, in the cultivation process of the sweet potato virus-free seedlings, the sweet potato virus-free seedlings are alternately treated by blue light and darkness. Wherein the wavelength of the blue light is 460 nm. According to the method, blue light (peak wavelength is 460 nm) is creatively adopted to cultivate the sweet potato virus-free seedlings, so that the propagation coefficient of the sweet potato virus-free seedlings is remarkably improved, and the propagation speed of the sweet potato virus-free seedlings is increased in a geometric progression manner, so that the virus-free seedlings are rapidly and massively propagated, and the agricultural production efficiency is further improved. Therefore, the method shows excellent application prospect and economic value in the technical field of crop propagation.

Description

Technical Field

[0001] The invention belongs to the technical field of crop propagation, and in particular relates to a method for improving the propagation coefficient of virus-free sweet potato seedlings. Background Art

[0002] Sweet potatoes (Ipomoea batatas (L.) Lam.) have significant applications, including food, feed, and industrial raw materials. However, their production process relies on vegetative reproduction, making them susceptible to viral infection. The primary method for combating viral diseases is to produce virus-free seedlings through shoot tip culture. However, the current low reproduction coefficient of virus-free sweet potato seedlings hinders the development of the sweet potato industry. Therefore, improving the reproduction coefficient of virus-free sweet potato seedlings is crucial for sweet potato production and utilization. Summary of the Invention

[0003] The invention provides a method for improving the reproduction coefficient of the virus-free sweet potato seedlings. During the cultivation process of the virus-free sweet potato seedlings, the virus-free sweet potato seedlings are subjected to alternating light and dark treatments to improve the reproduction coefficient of the virus-free sweet potato seedlings.

[0004] In the above method, the conditions for the alternating light and dark treatments are: alternating light treatments of 12 hours and dark treatments of 12 hours; that is, light treatments of 12 hours and dark treatments of 12 hours.

[0005] In the above method, the conditions of the light treatment are selected from: the light quality is blue light, and the light intensity is 500~1500 lx.

[0006] In the above method, the wavelength of the blue light is selected from 400 to 480 nm, preferably 460 nm.

[0007] In the above method, the light intensity is 1000 lx.

[0008] In the above method, the cultivation of the virus-free sweet potato seedlings is selected from conventional cultivation methods; preferably, the following method can be used to cultivate the virus-free sweet potato seedlings: take the stem tip of the virus-free sweet potato seedlings as material, cut it into the matrix soil in the seedling box, and then place it in the seedling box, close the vents, maintain the temperature at 24°C and the humidity at 40%.

[0009] In the above method, the selection criteria for the stem tip of the virus-free sweet potato seedlings are: taking the top of the stem tip with two leaves and one heart, 1.5-2 cm long, and a stem thickness of ≥0.15 cm.

[0010] In the above method, the matrix soil consists of perlite, vermiculite and nutrient soil; the proportions thereof can be adjusted according to different sweet potato varieties.

[0011] The present invention provides application of blue light in improving the reproduction coefficient of virus-free sweet potato seedlings.

[0012] The present invention provides a method for rapid propagation of virus-free sweet potato seedlings, comprising the following steps: Take the stem tips of the virus-free seedlings as the propagation material, cut them into the substrate soil, seal it, maintain the temperature at 24℃ and the humidity at 40%, and then give them alternating treatments of 12 hours of blue light and 12 hours of darkness; ventilate the seedlings after they have grown, and obtain complete virus-free seedlings after 7 to 10 days of growth; cut off the 1.5-2 cm stem segments with the terminal buds, and continue to repeat the above stem segment breeding process, continue cutting the seedlings and cuttings to achieve rapid propagation of the virus-free sweet potato seedlings.

[0013] The beneficial effects of the present invention are: This invention pioneered the use of blue light (peak wavelength 460 nm) to cultivate virus-free sweet potato seedlings, significantly increasing their reproduction coefficient and geometrically increasing their propagation rate. This allows for rapid and large-scale propagation of virus-free seedlings, further improving agricultural production efficiency. This technology demonstrates excellent application prospects and economic value in the field of crop propagation technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The effects of light quality and illumination time on the growth performance of virus-free seedlings; A is a statistical graph of the measurement data of aboveground traits; B is a phenotypic diagram of virus-free seedlings treated with different light qualities and illumination times.

[0015] Figure 2 The effect of light intensity on the growth performance of virus-free seedlings; A is the statistical diagram of representative trait measurement data of the aboveground part; B is the phenotypic diagram of the virus-free seedlings treated with different light intensities.

[0016] Figure 3 This is a diagram of three-dimensional rapid propagation; among them, A is a three-dimensional culture rack, B is the blue light culture effect, and C is the sweet potato virus-free seedlings under blue light culture. DETAILED DESCRIPTION

[0017] In the present invention, the sweet potato varieties used in the following examples are "Meixiu" and "Hami." The experiments used plastic seedling boxes (54 × 28 × 24 cm) consisting of a base, a seedling cover, and a 32-hole tray. The substrate materials used included Pinstop compressed nutrient soil imported from Denmark, vermiculite (2-4 cm), and perlite (3-6 cm), all purchased from Yongtu Trading. The experiments were conducted in an artificial climate chamber in the Science and Technology Building of Qingdao Agricultural University, equipped with built-in racks and light tubes above them. The chamber temperature was set at 24°C and the humidity was 40%.

[0018] In the present invention, the agronomic traits of the virus-free sweet potato seedlings are determined as follows: Leaf area, leaf length and leaf width: Select the third leaf of sweet potato plants and use LI-3000C portable leaf area meter to read the values ​​in cm 2, cm, cm. Plant Height: Use a tape measure to measure the vertical distance from the base of the potato seedling to the top growth point, in cm. Number of Leaves: Count the number of expanded leaves on each potato seedling, in pieces. Stem Diameter: Use a vernier caliper to measure the stem diameter of the plant 1 cm below the root, in cm.

[0019] The other materials used in the present invention, unless otherwise stated, can be obtained through commercial channels. Unless otherwise specified, other terms used in the present invention generally have the meanings commonly understood by those of ordinary skill in the art. The present invention will be further described in detail below with reference to specific examples and data. The following examples are merely for illustration of the present invention and are not intended to limit the scope of the present invention in any way.

[0020] Example 1 Effects of light quality and illumination time on the growth performance of virus-free seedlings: The stem tips of the virus-free "Hami" seedlings (the top of the stem tip with two leaves and one heart, 1.5-2 cm long, and a stem thickness of ≥0.15 cm) were used as materials and were cut into the substrate soil in the seedling box.

[0021] The peak wavelengths of red, blue, and white light used in the experiment were 620 nm, 460 nm, and 450 nm, respectively. Two treatments were used: 12 h light-12 h dark (hereafter referred to as 12 h light) and 24 h light. The light intensity was set at 1000 lx.

[0022] The light quality and treatment time combinations are as follows: (1) B1: red light, 12 h; (2) B2: red light, 24 h; (3) B3: blue light, 12 h; (4) B4: blue light, 24 h; (5) B5: red and blue 3:1 light, 12 h; (6) B6: red and blue 3:1 light, 24 h; (7) B7: white light, 12 h; (8) B8: white light, 24 h.

[0023] Each combination included three replicates, with 20 plants in each replicate. After 30 days, the appropriate light quality and duration were determined based on indicators such as leaf area, stem diameter, plant height, and root length of the sweet potato seedlings.

[0024] The test results are as follows Figure 1 As shown: Compared with 12-hour light exposure, plants exposed to 24-hour light exposure are more likely to experience leaf yellowing, whitening, and shedding, and their overall growth is inferior to that of virus-free seedlings treated with 12-hour light exposure. Compared with red light, white light, and red-blue light, blue light promotes plant height and stem diameter in virus-free seedlings. Therefore, alternating blue light and darkness, with 12 hours of blue light and 12 hours of darkness each, is the optimal treatment for rapid growth in virus-free seedlings.

[0025] Example 2 Effect of light intensity on the growth performance of virus-free seedlings: In order to determine the suitable light intensity for rapid propagation of virus-free sweet potato seedlings, the stem tips of "Hami" virus-free seedlings (the top of the stem tip with two leaves and one heart, 1.5-2 cm long, and stem thickness ≥0.15 cm) were selected as materials and cut into substrate soil (light quality and lighting time: 12 h of blue light + 12 h of darkness).

[0026] Set the following light intensities: (1) G1: 500 lx; ​​(2) G2: 1000 lx; ​​(3) G3: 1500 lx.

[0027] Each combination included three replicates, with 20 plants in each replicate. After 30 days, the effects of light intensity on the growth performance of virus-free sweet potato seedlings were analyzed based on leaf area, plant height, and root length.

[0028] The test results are as follows Figure 2 As shown: After 30 days, the 1000 lx treatment group outperformed the 500 lx and 1500 lx treatments in leaf area, leaf length, leaf width, plant height, leaf number, and stem diameter. However, the 500 lx treatment exhibited symptoms such as leaf yellowing and leaf drop, significantly impacting the growth of virus-free seedlings. Therefore, 1000 lx was selected as the optimal light intensity for sweet potato.

[0029] Example 2 Rapid propagation of virus-free seedlings: Stem tips of robust "Meixiu" and "Hami" virus-free seedlings (the top of the stem tip with two leaves and one heart, 1.5-2 cm long, with a stem diameter ≥0.15 cm) were used as cuttings and planted into the substrate soil in seedling boxes. The initial number of seedlings of each variety was 10. The seedlings were then placed in the seedling box with the air vents closed and maintained at a temperature of 24°C, a humidity of 40%, and light conditions. After acclimatization (2-3 days), the air vents were opened. After 7-10 days of growth, complete virus-free seedlings (meeting the standard for cutting) were obtained. A 1.5-2 cm stem segment with a terminal bud was cut and the stem segment propagation process was repeated in this step. After 30 days, the total number of cuttings was counted and the propagation coefficient was calculated. Each treatment included three replicates.

[0030] Reproduction coefficient = total number of cuttings / initial number of seedlings.

[0031] Cultivation conditions of the variety "Meixiu": Lighting conditions: alternating light-dark cycles (12 h light-12 h dark), light intensity of 1000 lx, with light qualities of blue (460 nm), red (620 nm), red-blue (3:1), and white (450 nm) light, respectively. The substrate soil ratio was 10% perlite + 10% vermiculite + 80% nutrient soil. The fertilizer ratio was N:P:K = 10:30:20. Fertilizer was added to the substrate soil every 7 days at a concentration of 1 g / L, with 10 mL added per plant.

[0032] Cultivation conditions of the "Hami" variety: Light conditions: alternating light-dark cycles (12 h light-12 h dark), light intensity of 1000 lx, light qualities of blue (460 nm), red (620 nm), red-blue (3:1), and white (450 nm) light. The substrate soil ratio was 10% perlite + 10% vermiculite + 80% nutrient soil. The fertilizer ratio was N:P:K = 25:10:20. Fertilizer was added to the substrate soil every 7 days at a concentration of 1 g / L, with 10 mL added per plant.

[0033] During the entire breeding process, the virus-free seedlings whose terminal buds have been cut off can grow a large number of axillary buds in a short period of time. After growing for 7 to 10 days, each axillary bud grows up, and the stem segments with terminal buds are cut off, and the stem segment breeding process described in this embodiment is repeated to increase the breeding speed exponentially, thereby allowing the virus-free original seedlings to be rapidly and massively propagated.

[0034] Within 30 days of virus-free seedling propagation, the seedlings were pruned three times, and the number of pruned seedlings was counted each time. Three sets of experiments were repeated for each variety, and the total number of pruned seedlings at 30 days was recorded.

[0035] The test results are shown in Table 1: Table 1 Reproduction coefficients of various varieties after treatment with blue light, red light, red-blue light, and white light As shown in Table 1, among the four light quality treatments, the blue light treatment produced the most cuttings and the highest reproduction coefficient. The total number of cuttings for Meixiu (65), 71, and 62 for Meixiu (71), and 53, 51, and 59 for Hami (59), respectively, was 65 for Meixiu and 71 for Hami. The reproduction coefficients calculated using the above formula were 6.60 for Meixiu and 5.43 for Hami, respectively.

[0036] Based on the above culture conditions, the present invention integrates a three-dimensional high-efficiency virus-free seedling soilless cultivation rapid propagation technology, such as Figure 3 This technology can be used to achieve rapid propagation of virus-free sweet potato seedlings.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A method for increasing the reproduction coefficient of virus-free sweet potato seedlings, characterized in that: During the cultivation process of the virus-free sweet potato seedlings, the virus-free sweet potato seedlings are given alternating light and darkness treatments to improve the reproduction coefficient of the virus-free sweet potato seedlings.

2. The method according to claim 1, characterized in that The conditions for the alternating light and dark treatment are: alternating light for 12 hours and dark for 12 hours.

3. The method according to claim 2, characterized in that The conditions of the light treatment are selected from: the light quality is blue light, and the light intensity is 500-1500 lx.

4. The method according to claim 3, characterized in that The wavelength of the blue light is selected from 400 to 480 nm.

5. The method according to claim 3, characterized in that The light intensity is 1000 lx.

6. The method according to claim 1, characterized in that The cultivation of the virus-free sweet potato seedlings is selected from the following cultivation method: taking the stem tips of the virus-free sweet potato seedlings as materials, cutting them into the matrix soil in the seedling box, and then placing them in the seedling box, closing the vents, and maintaining the temperature at 24°C and the humidity at 40%.

7. The method according to claim 6, characterized in that The selection criteria for the stem tip of the virus-free sweet potato seedlings are: taking the top of the stem tip with two leaves and one heart, 1.5-2 cm long, and a stem thickness of ≥0.15 cm.

8. The method according to claim 6, characterized in that The matrix soil consists of perlite, vermiculite and nutrient soil; the proportions of the soil can be adjusted according to different sweet potato varieties.

9. Application of blue light in improving the reproduction coefficient of virus-free sweet potato seedlings.

10. A method for rapid propagation of virus-free sweet potato seedlings, characterized in that: The steps include: Take the stem tips of the virus-free seedlings as the propagation material, cut them into the substrate soil, seal it, maintain the temperature at 24℃ and the humidity at 40%, and then give them alternating treatments of 12 hours of blue light and 12 hours of darkness; ventilate the seedlings after they have grown, and obtain complete virus-free seedlings after 7 to 10 days of growth; cut off the 1.5-2 cm stem segments with the terminal buds, and continue to repeat the above stem segment breeding process, continue cutting the seedlings and cuttings to achieve rapid propagation of the virus-free sweet potato seedlings.

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