Method and device for creating heat-resistant potato germplasm through interspecific grafting

Abstract

The invention discloses a method and a device for creating heat-resistant potato germplasm through interspecific grafting. The method comprises the following steps: (1) cultivating potato seedlings and tomato seedlings; (2) mutual stock-scion grafting; 3, grafted plant treatment, wherein after grafting is conducted for three weeks, grafting openings are pulled to the positions 15 cm below plate holes, and variable temperature treatment is conducted; (4) potato seed management: cutting off all the grown stolons before temperature-changing treatment, leaving the potatoes after temperature-changing treatment, and harvesting the potatoes at proper time; and (5) heat-resistant domestication: after 5-6 compound leaves grow on the seed potato potted plant in the step (4), performing high-temperature domestication at 38 DEG C in the daytime and 30 DEG C at night in an illumination incubator for 9 days, transferring the heat-resistant plant to outdoor culture, and harvesting tubers. And (6) heat-resistant germplasm screening: repeating the step (5) for two generations, and harvesting tubers. According to the method, the potato germplasm with high heat resistance and genetic stability is obtained, the variety breeding process is shortened, and the problems that a heat-resistant potato germplasm creation technology and heat-resistant varieties are lacked, and potato production is affected by high temperature are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of breeding, and in particular relates to a method and a device for creating heat-resistant potato germplasm by interspecific grafting. Background Art

[0002] Potato (Solanum tuberosum L.) is a plant of the genus Solanum in the Solanaceae family. It is a shallow-rooted crop that likes coolness but cannot tolerate high temperatures. Temperature is one of the main factors restricting potato growth. 17-21℃ is the most suitable growth temperature for potatoes, and the daily average temperature of 14-22℃ is the best temperature for tuber accumulation. When the temperature is ≥25℃, tuber formation will be inhibited, so suitable temperature is conducive to potato tuber formation and material accumulation. With the intensification of the greenhouse effect and the continued warming of the global climate, since the 1990s, the temperature in Northwest China, one of the main potato producing areas in my country, has increased by an average of 0.6℃ every 10 years. Rising temperatures will shorten the vegetative growth period of potatoes and delay the reproductive growth period, mainly manifested in internode elongation, leaf contraction, weakened photosynthesis, affecting material accumulation, reducing the number of tubers and reducing the weight of single tubers, resulting in reduced production and quality. Continuously high temperatures will lead to stagnation of plant growth, increased incidence of deformed potatoes, and even death of the entire plant, causing serious economic losses, which is extremely unfavorable to the sustainable and healthy development of potatoes.

[0003] In addition to the evolution of plants to adapt to harsh environments, some external means such as hybridization technology, genetic engineering, grafting technology, various cultivation and management measures, etc. can also be used to strengthen the stress resistance of plants to adapt to changes in the external environment and achieve high yield and high quality. Among them, grafting is one of the effective and commonly used ways to improve the stress resistance of plants. There are also patents that disclose grafting potatoes and tomatoes to improve the stress resistance of grafted plants, such as the patent "A method for mist cultivation of potato grafted tomatoes and breeding potato and tomato seedlings with this method" (CN112690200A). The potato and tomato seedlings bred by this method have strong disease resistance in the current season and good pest control effects. The quality of the potato micro-tubers and tomatoes produced is good, and the economic benefits are high. However, this grafting cultivation method cannot obtain heritable heat-resistant potato germplasm, and cannot solve the problem of high temperature affecting potato production.

[0004] On the other hand, the existing potato aeroponic device generally places a 2-3 cm thick foam board on the top of the aeroponic box, and a planting hole is opened in the board to plant the plants. After the potato and tomato are grafted, the grafting part is generally fixed by a fixing clamp, and then the fixing clamp is set on the planting hole, so that the grafting part is above the foam board and does not fall into the box body and is contaminated by the nutrient solution and rots. However, in the early stage of grafting, the grafting part has not healed yet and has wounds, which is very easy to be contaminated by the nutrient solution directly sprayed from the bottom of the box through the planting hole and become sick and rotten, reducing the survival rate of the grafted seedlings. Summary of the invention

[0005] The purpose of the present invention is to provide a method and device for creating heat-resistant potato germplasm by interspecific grafting, so as to solve the problem that the existing potato varieties have reduced potato yield and quality due to the influence of high temperature due to the lack of heat-resistant potato varieties and heat-resistant potato germplasm creation technology.

[0006] The specific technical solutions are as follows:

[0007] A method for creating heat-resistant potato germplasm by interspecific grafting comprises the following steps:

[0008] (1) Cultivation of potato and tomato seedlings:

[0009] After germination treatment, the tomato seeds were sown in a plug tray filled with a seedling medium. When they grew to 2 compound leaves, they were transferred to a homemade aeroponic device and continued to be cultivated until they grew to 3-4 compound leaves. Conventional aeroponic management was used to cultivate the plants.

[0010] The method comprises the following steps: selecting germinated virus-free potato seed potatoes and planting them in a flower pot covered with a seedling medium, cultivating them under natural light conditions until they have 4-5 compound leaves, cutting them from the connection of the seed potatoes, retaining 2-3 compound leaves, soaking them in a rooting solution for 25-35 minutes, and transplanting them into a self-made aeroponic device, wherein the aeroponic device is provided with a planting plate with planting holes, spraying only a rooting solution with a rooting powder before the roots take root, and spraying a nutrient solution when the roots grow to 1-2 cm in length, and carrying out conventional aeroponic management to cultivate the plants;

[0011] (2) Mutual rootstock-scion grafting: using potato as rootstock and tomato as scion, or using tomato as rootstock and potato as scion;

[0012] The grafting operation includes: the method is a cleft grafting method, that is, the stock stem is cut at the thick part under shading conditions, and a 1-2 cm opening is split from the middle, then the lower end of the scion with similar thickness is cut off, 1-2 functional leaves are retained, the scion stem segment is cut into a gentle slope, the two sides are kept symmetrical and the length is equal to the stock opening, and then the scion is inserted into the stock so that the stock cut surface is closely fitted with the scion cut surface, and fixed with a grafting clamp;

[0013] (3) Treatment of grafted plants: The grafted tomato / potato (scion / stock) grafted seedlings or potato / tomato grafted seedlings are further cultivated in the aeroponic device, wherein the tomato / potato grafted seedlings or potato / tomato grafted seedlings are planted at the planting hole, with the grafting port located above the planting hole and the grafted seedling root system located below the planting hole. The ambient temperature of the aeroponic device is controlled at 20-24° C. and the relative humidity is 60-70% to prevent the grafted seedlings from dehydration and death. In the first week, the grafted seedlings are covered with a sunshade net with a shading rate of 70-80%, and then exposed to natural light. After 3 weeks, the grafting port is pulled to 12-20 cm below the planting hole and the grafted seedlings are subjected to temperature change treatment.

[0014] (4) Seed potato management: Before the temperature change treatment, all the runners are cut off. After the treatment, the runners and the grown potatoes are left, and the tubers are harvested in time to obtain the initially treated seed potatoes;

[0015] (5) Heat-resistance acclimation: After the seed potatoes harvested in step (4) have grown to 4-5 compound leaves, they are subjected to high-temperature acclimation in a light incubator for 9 days, and the plants that show heat resistance are moved outdoors for culturing, and the tubers are harvested to obtain acclimated seed potatoes;

[0016] (6) Screening for heat-resistant germplasm: Repeat step (5) for 1 to 4 generations, and harvest the tubers to obtain the desired heat-resistant potato germplasm.

[0017] Preferably, in step (1), potatoes are cultivated 13-16 days after tomato seedlings emerge.

[0018] Preferably, the grafting time is selected within one week before or after New Year's Day.

[0019] Preferably, in step (1), the aeroponic device comprises: an aeroponic box, a spray system, a planting plate and an annular rubber gasket;

[0020] The spray system is arranged in the mist culture box, the planting plate is arranged on the top of the mist culture box, the planting holes are arranged at intervals on the planting plate, the annular rubber gasket is arranged above the planting plate, and corresponds to the position of the planting holes up and down; the annular rubber gasket includes a stacked first gasket and a second gasket, the first gasket is arranged above the second gasket, the inner diameter of the first gasket is smaller than the inner diameter of the second gasket, and the inner circles of the first gasket and the second gasket are provided with easy-tear openings.

[0021] Preferably, the annular rubber gasket also includes a third gasket, which is stacked between the first gasket and the second gasket. The inner diameter of the third gasket is larger than the inner diameter of the first gasket and smaller than the inner diameter of the second gasket. The inner circle of the third gasket is also provided with an easy-tear notch.

[0022] Preferably, the nozzle of the spray system extends 10-20 cm downward from the joint between the bottom of the planting plate and the box body at an angle of 30-45 degrees for spraying.

[0023] Preferably, a regulating box with an opening at the bottom is arranged above the mist cultivation box, and the regulating box is detachably covered above the mist cultivation device. A temperature control device and a light control device are arranged in the regulating box, and the temperature control device includes a temperature probe, a heating tube and a temperature controller, and the temperature probe and the heating tube are electrically connected to the temperature controller respectively, and the temperature in the mist cultivation device is controlled by the temperature controller; the light control device includes an LED lamp and a time controller, and the LED lamp and the time controller are electrically connected, and the lighting time in the mist cultivation device is controlled by the time controller.

[0024] Preferably, the temperature change treatment in step (3) is to adjust the temperature to 25-30°C and maintain it for 3-5 days, then cool it down to 18-24°C and maintain it for 3-5 days, with an air humidity of 70%, a light intensity of 10,000 Lux, 16 hours of light, and 8 hours of dark culture, and repeat this cycle.

[0025] Preferably, the aeroponics device is placed in a temperature-controllable air-conditioned room for temperature change treatment.

[0026] Preferably, in step (5), the high temperature acclimation refers to: the light in the light incubator is illuminated for 16 hours during the day, with a light intensity of 10,000 Lux and a temperature of 38° C.; dark culture is carried out for 8 hours at night, with a temperature of 30° C.; and the relative humidity of the air is 70% throughout the day.

[0027] Preferably, in step (6), the potato tubers harvested in step (5) are recycled and domesticated for two generations, and the fourth generation selected is the desired heat-resistant potato germplasm.

[0028] Compared with the existing technology, the present invention has the following beneficial effects:

[0029] 1. The present invention grafts tomato seedlings grown to 3-4 compound leaves with potato seedlings grown to 4-5 compound leaves, and after grafting, a self-made aeroponic device is used for aeroponic management, and variable temperature management is performed, which can improve the heat resistance of the potatoes obtained after grafting, and then after high-temperature acclimation, the required heat-resistant potato germplasm is bred, thereby solving the problem that the existing potato varieties have reduced potato yield and quality due to the influence of high temperature due to the lack of heat-resistant potato varieties and heat-resistant potato germplasm creation technology.

[0030] 2. The mist cultivation device of the present invention can reduce the contact between the grafting wound and the water vapor coming out of the box body by providing an annular rubber gasket on the planting plate, reduce the phenomenon of disease and rot, and improve the survival rate of the grafted seedlings; the nutrient solution nozzle extends downward about 15 cm from the joint of the bottom of the planting plate and the box body at an angle of 30-45 degrees. On the one hand, it prevents the nozzle from directly spraying into the planting hole on the planting plate from below and causing contamination of the grafting port. On the other hand, it can spray at a close distance and spray more evenly on the roots, so that the roots can absorb nutrients more efficiently, promote faster healing of the grafting port and plant growth.

[0031] 3. The present invention performs cutting, temperature change and other treatments on the grafted potatoes, which can improve the stress resistance of the potato materials harvested after grafting. At the same time, the harvested potato materials are subjected to high temperature acclimation for 2 generations, so that the heat-resistant genes from tomatoes are fully expressed, and heat-resistant potato germplasm with stable traits can be selected, which is conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0033] Figure 1 It is a schematic diagram of the external structure of the aeroponic device of the present invention.

[0034] Figure 2 Schematic diagram of the internal structure of the aeroponic device of the present invention.

[0035] Figure 3 It is a schematic structural diagram of the annular rubber gasket of the present invention.

[0036] Figure 4 It is a schematic diagram of the disassembled structure of the annular rubber gasket of the present invention.

[0037] Figure 5 This is a graph for evaluating the heat damage grade of potato materials of the present invention.

[0038] Figure 6 The graph is a comparison of the growth differences of potato plants used as rootstocks or scions during grafting after high temperature test of the potato material harvested after the potato and tomato grafting of the present invention has been acclimated to high temperature for 3 generations and completed.

[0039] Figure 7 The figure is a plant growth diagram of the potato material harvested after the potato and tomato grafting of the present invention when the high temperature test is completed.

[0040] Among them, the main reference numerals are described as follows:

[0041] 1. Mist culture box; 2. Spray system; 21. Nozzle; 3. Planting plate; 31. Planting hole; 4. Annular rubber gasket; 41. First gasket; 42. Second gasket; 43. Third gasket; 44. Tear-off; 5. Adjustment box; 6. Temperature control device; 61. Temperature probe; 62. Heating tube; 63. Temperature controller; 7. Light control device; 71. LED light; 72. Time controller; 8. Shade curtain; 9. Collection door. DETAILED DESCRIPTION

[0042] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "top", "bottom", "top surface", "bottom surface", "inside", "outside", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0044] In the description of the present invention, the meaning of "several" is one or more, the meaning of "more" is more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there are terms "first", "second" and "third" in the description, they are only used for the purpose of description and distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following is a description of an embodiment of the present invention based on its overall structure.

[0046] Example 1

[0047] Combination Figure 1-2 A mist cultivation device includes: a mist cultivation box 1, a spray system 2, a planting plate 3, an annular rubber gasket 4, a regulating box 5, a temperature control device 6 and a light control device 7,

[0048] The spray system 2 is disposed in the aerosol box 1 and is used to regularly spray water or nutrient solution to the plants in the aerosol box 1;

[0049] The planting plate 3 is arranged on the top of the aerosol box 1, and planting holes 31 are arranged at intervals on the planting plate 3. The planting plate 3 is used for planting crops, and the stems and leaves of the crops grow toward the top of the planting plate 3, and the roots of the crops grow toward the aerosol box 1 below the planting plate 3;

[0050] The annular rubber gasket 4 is arranged above the planting plate 3 and corresponds to the position of the planting hole 31 in the upper and lower parts; the annular rubber gasket 4 is used to fix the crops on the planting plate 3 and block the water vapor from the mist cultivation box 1;

[0051] The regulating box 5 is detachably arranged above the aeroponic box 1 to regulate the light, temperature and humidity of the plants;

[0052] The temperature control device 6 is disposed in the regulating box 5 and is used to control the temperature in the regulating box 5;

[0053] The light control device 7 is disposed in the adjustment box 5 and is used to control the light in the adjustment box 5 .

[0054] Specific, combined Figure 3-4 The annular rubber gasket 4 includes a stacked first gasket 41, a second gasket 42 and a third gasket 43. The first gasket 41 is arranged above the second gasket 42. The inner diameter of the first gasket 41 is smaller than the inner diameter of the second gasket 42. The inner circles of the first gasket 41 and the second gasket 42 are provided with an easy-tear notch 44. The third gasket 43 is stacked between the first gasket 41 and the second gasket 42. The inner diameter of the third gasket 43 is larger than the inner diameter of the first gasket 41 and smaller than the inner diameter of the second gasket 42. The inner circle of the third gasket 43 is also provided with an easy-tear notch 44. The annular rubber gasket 4 is made of rubber and has a certain elasticity, which can adapt to the growth of crops. The setting of the easy-tear notch 44 allows the gasket to be taken off according to the growth of the stems of the crops. Preferably, the easy-tear notches 44 of the first gasket 41, the second gasket 42 and the third gasket 43 are staggered.

[0055] Combination Figure 2 The nozzle 21 of the spray system 2 extends downward 10-20 cm from the bottom of the planting plate 3 and the junction of the box body at an angle of 30-45 degrees to spray. On the one hand, it is prevented that the nozzle 21 directly sprays into the planting hole 31 on the planting plate 3 from below and causes contamination of the grafting point. On the other hand, it can spray at a close distance and spray more evenly on the roots, so that the roots can absorb nutrients more efficiently, promote faster healing of the grafting point and plant growth.

[0056] Furthermore, the temperature control device 6 includes a temperature probe 61 , a heating tube 62 and a temperature controller 63 . The temperature probe 61 and the heating tube 62 are electrically connected to the temperature controller 63 , respectively, and the temperature in the regulating box 5 is controlled by the temperature controller 63 .

[0057] Furthermore, the light control device 7 includes an LED lamp 71 and a time controller 72 . The LED lamp 71 and the time controller 72 are electrically connected, and the lighting time in the adjustment box 5 is controlled by the time controller 72 .

[0058] In addition, according to the growth requirements of crops, a binding rope can be set on the upper part of the regulating box 5 to provide climbing and fixing for the growth of crops. The mist cultivation box 1 is provided with structures such as a shading curtain 8 and a collection door 9. The regulating box 5 can also be provided with structures such as a door and a curtain.

[0059] The mist culture device of the present invention is used to cultivate grafted potato and tomato seedlings. By providing an annular rubber gasket 4 on the planting plate 3, the water vapor from the mist culture box 1 can be blocked and the grafting wound can be raised, so as to reduce the contact between the grafting wound and the water vapor coming out of the box body, reduce the phenomenon of disease and rot, and improve the survival rate of the grafted seedlings. The nutrient solution nozzle 21 extends downward from the bottom of the planting plate 3 and the junction of the box body at an angle of 30-45 degrees by about 15 cm. On the one hand, it is prevented that the nozzle 21 is directly sprayed from below and easily sprayed into the planting hole 31 on the planting plate 3 to cause contamination of the grafting port. On the other hand, it can spray at a close distance and spray more evenly on the roots, so that the roots can absorb nutrients more efficiently, promote faster healing of the grafting port and plant growth.

[0060] Example 2

[0061] The material cultivation and grafting were carried out in a potato aeroponic room of the Economic Crops Research Institute of Guangxi Academy of Agricultural Sciences, with natural light, a temperature of 20-24° C., and a relative humidity of 60-70%. The potato aeroponic room was provided with a plurality of aeroponic devices described in Example 1.

[0062] A method for creating heat-resistant potato germplasm by interspecific grafting comprises the following steps:

[0063] (1) Cultivation of potato and tomato seedlings:

[0064] A: Cultivation of tomato seedlings: Place tomato seeds in warm water at about 50°C, soak for another 6 hours after the water temperature drops, then pour out the water, keep the seeds moist, and place them in a constant temperature incubator at 28°C for germination. When the seeds turn white, sow them in a 50-hole tray filled with seedling medium. When they grow to 2 compound leaves, transfer them to a homemade aeroponic device and continue to grow to 3-4 compound leaves. Use conventional aeroponic management to cultivate the plants, that is, use nutrient solution for aeroponics, and replace the nutrient solution every 2-3 weeks.

[0065] B: Cultivation of potato seedlings: Select germinated virus-free potato seed potatoes and plant them in pots covered with seedling medium. Cultivate them under natural light conditions until they grow to 4-5 compound leaves. Then cut them from the connection of the seed potatoes, retain 2-3 compound leaves, soak them in rooting solution for 30 minutes, and transplant them into a homemade aeroponic device. Before they take root, only spray the rooting solution with rooting powder. When the roots begin to grow to 1-2 cm in length, start spraying the nutrient solution and carry out conventional aeroponic management and cultivation of the plants as described above.

[0066] (2) Grafting: Use potato as rootstock and tomato as scion, and prepare sterilized blades and grafting clips in advance. The grafting operation includes: cutting off the thick part of the potato stem under light-shielding conditions, and splitting a 1-2 cm opening in the middle, then cutting off the lower end of a tomato of similar thickness, leaving 2-3 functional leaves, and cutting the tomato stem into a gentle slope, keeping the two sides symmetrical and the length equal to the rootstock, and then fitting the potato cut surface tightly with the tomato cut surface and fixing it with a grafting clip.

[0067] In other embodiments, tomatoes can be used as rootstocks and potatoes can be used as scions. The resulting potatoes also have heat resistance. Relatively speaking, tomatoes used as scions are more heat resistant.

[0068] (3) Management of grafted plants: The grafted tomato / potato (scion / stock) seedlings were further cultivated in the aeroponic device for 3 weeks. The ambient temperature of the aeroponic device was controlled at 20-24°C and the relative humidity was controlled at 60-70% to prevent the grafted seedlings from dehydration and death. In the first week, they were covered with a sunshade net with a shading rate of 70-80%, and then exposed to natural light. After 3 weeks, the grafting port was pulled to 15 cm below the plate hole and subjected to temperature change treatment.

[0069] The variable temperature treatment is to adjust the temperature of the conditioning box to 25-30°C for 3-5 days, then lower the temperature to 18-24°C for 3-5 days, with an air humidity of 70%, a light intensity of 10000 Lux, 16 hours of light, and 8 hours of dark culture, and repeat this cycle.

[0070] (4) Seed potato management: Before temperature change treatment, all runners should be cut off. After treatment, the runners and grown potatoes should be retained, and the tubers should be harvested in time.

[0071] (5) Heat resistance acclimation and screening:

[0072] Specifically, the potato seed potatoes harvested in (4) above are cultivated, and when the plants grow to 4-5 compound leaves under natural light and temperature conditions, healthy plants with consistent growth are selected for high temperature acclimation for 9 days in a light incubator, and potato materials with good growth are screened out; this cycle is repeated for 2 generations, and the fourth generation screened out is the required heat-resistant potato germplasm. Furthermore, high temperature acclimation refers to: 38°C during the day, 30°C at night, air humidity of 70%, light intensity of 10,000 Lux, light for 16 hours, and dark culture for 8 hours. On the ninth day, the growth of the potato materials is observed and the heat damage level is evaluated.

[0073] Heat damage level evaluation can refer to Figure 5 Among them, plants at level 0 had no high temperature damage; plants at level 1 had mild water loss, with yellowing edges of the lower old leaves; plants at level 2 had moderate water loss, with curling or yellowing and withering of the middle and upper leaves; plants at level 3 had severe water loss, with curling or yellowing and withering of the upper leaves; and most leaves of plants at level 4 withered and died.

[0074] In this embodiment, a high heat-resistant potato material (such as Figure 6 3 potato material) and heat-resistant potato material obtained by grafting grade 1 potato and tomato (such as Figure 6 1 in the table). Figure 6 No. 2 is a grade 4 heat-intolerant potato material used as rootstock and scion during grafting.

[0075] Comparative Example 1: The method of Comparative Example 1 is similar to that of Example 2, except that the step "(5) heat resistance acclimation and screening" is omitted, i.e. the first batch of potato materials harvested by grafting are propagated for two generations repeatedly, and then potted under natural light and temperature conditions for heat resistance testing. The results show that the growth of the plants is as follows: Figure 7 As shown in Figure 2, the heat resistance of these potato materials can only reach level 2 or 3. Compared with the potato materials obtained after high temperature acclimation ( Figure 6 1 and 3) have a large difference in heat resistance, but they are all better than the potato materials used as rootstocks and scions during grafting ( Figure 6 2) Heat resistance. The heat resistance gene from tomato is fully expressed after high temperature acclimation, so the heat resistance of Example 2 is improved to level 0 and level 1. That is, the potato material obtained after tomato and potato are grafted as stock and scion can be further improved after high temperature acclimation, and the heat resistance of the potato material can be stably inherited, which is conducive to the later promotion and use.

[0076] Comparative Example 2: The method of Comparative Example 2 is similar to that of Example 2, except that: after tuber formation, no temperature change management is performed, and the runners and seed potatoes grown within 3 weeks after grafting are not cut off, but the potatoes are directly harvested after grafting. The heat resistance of potatoes cultivated in this way varies greatly, and more than 90% of the potato materials belong to the heat-intolerant level 3 or 4.

[0077] Comparative Example 3: The method of Comparative Example 3 is similar to that of Example 2, except that: no temperature change management is performed after tuber formation, the runners and seed potatoes grown within two weeks after grafting are cut off, and the potatoes are left and harvested in time. The heat resistance of potatoes cultivated in this way varies greatly, and more than half of the potato materials belong to the heat-intolerant level 3 or 4.

[0078] Comparative Example 4: The method of Comparative Example 4 is similar to that of Example 2, except that a conventional potato aeroponic device is used to manage the aeroponic cultivation of grafted seedlings. That is, the potato aeroponic device is not provided with an annular rubber gasket, and the grafted survival rate is only 60-70%. However, the grafted seedlings cultured by the potato aeroponic device of Example 1 have a survival rate of more than 90%.

[0079] In summary, the present invention grafts tomato seedlings that have grown to 3-4 compound leaves with potato seedlings that have 4-5 compound leaves, and after grafting, a self-made mist culture device is used for mist culture management, and variable temperature seed potato management is performed, which can improve the heat resistance of the potatoes obtained after grafting, and then high temperature acclimation for 2 generations allows the heat-resistant genes from tomatoes to be fully expressed, and heat-resistant potato germplasm with stable heat resistance can be bred. Among them, the mist culture device can reduce the contact between the grafting wound and the water vapor coming out of the box body by providing an annular rubber gasket on the planting plate, reduce the phenomenon of disease and rot, and improve the survival rate of the grafted seedlings; the nutrient solution nozzle extends about 15 cm from the bottom of the planting plate and the junction of the box body at 30-45 degrees. On the one hand, it prevents the nozzle from spraying directly from below into the planting hole on the planting plate to cause contamination of the grafting port, and on the other hand, it can spray at a close distance and spray more evenly on the roots, so that the roots can absorb nutrients more efficiently, promote faster healing of the grafting port and plant growth.

[0080] The foregoing descriptions of specific exemplary embodiments of the present invention are for the purpose of explanation and illustration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is obvious that many changes and variations can be made based on the above teachings. Although an embodiment of the present invention has been shown and described, this specific embodiment is only an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can make modifications, substitutions, variations and various selections and changes to the embodiments without creative contribution as needed without departing from the principles and purpose of the present invention after reading this specification, but they are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for creating heat-resistant potato germplasm by interspecific grafting, characterized in that: The steps include: (1) Cultivation of potato and tomato seedlings: After germination treatment, the tomato seeds were sown in a plug tray filled with a seedling medium. When they grew to 2 compound leaves, they were transferred to a homemade aeroponic device and continued to be cultivated until they grew to 3-4 compound leaves. Conventional aeroponic management was used to cultivate the plants. The method comprises the following steps: selecting germinated virus-free potato seed potatoes and planting them in a flower pot covered with a seedling medium, cultivating them under natural light conditions until they have 4-5 compound leaves, cutting them from the connection of the seed potatoes, retaining 2-3 compound leaves, soaking them in a rooting solution for 25-35 minutes, and transplanting them into a self-made aeroponic device, wherein the aeroponic device is provided with a planting plate with planting holes, spraying only a rooting solution with a rooting powder before the roots take root, and spraying a nutrient solution when the roots grow to 1-2 cm in length, and carrying out conventional aeroponic management to cultivate the plants; (2) Mutual rootstock-scion grafting: using potato as rootstock and tomato as scion, or using tomato as rootstock and potato as scion; The grafting operation includes: the method is a cleft grafting method, that is, the stock stem is cut at the thick part under shading conditions, and a 1-2 cm opening is split from the middle, then the lower end of the scion with similar thickness is cut off, 1-2 functional leaves are retained, the scion stem segment is cut into a gentle slope, the two sides are kept symmetrical and the length is equal to the stock opening, and then the scion is inserted into the stock so that the stock cut surface is closely fitted with the scion cut surface, and fixed with a grafting clamp; (3) Treatment of grafted plants: The grafted tomato / potato grafted seedlings or potato / tomato grafted seedlings are further cultivated in the aeroponic device, wherein the tomato / potato grafted seedlings or potato / tomato grafted seedlings are planted at the planting hole, with the grafting port located above the planting hole and the grafted seedling root system located below the planting hole. The ambient temperature of the aeroponic device is controlled at 20-24° C. and the relative humidity is 60-70% to prevent the grafted seedlings from dehydration and death. In the first week, the grafted seedlings are covered with a sunshade net with a shading rate of 70-80%, and then exposed to natural light. After 3 weeks, the grafting port is pulled to 12-20 cm below the planting hole and the grafted seedlings are subjected to temperature change treatment. (4) Seed potato management: Before the temperature change treatment, all the runners are cut off. After the treatment, the runners and the grown potatoes are left, and the tubers are harvested in time to obtain the initially treated seed potatoes; (5) Heat-resistance acclimation: After the seed potatoes harvested in step (4) have grown to 4-5 compound leaves, they are subjected to high-temperature acclimation in a light incubator for 9 days, and the plants that show heat resistance are moved outdoors for culturing, and the tubers are harvested to obtain acclimated seed potatoes; (6) Screening for heat-resistant germplasm: Repeat step (5) for 1 to 4 generations, and harvest the tubers to obtain the desired heat-resistant potato germplasm.

2. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 1, characterized in that: In step (2), the grafting time is selected within one week before or after New Year's Day.

3. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 1, characterized in that: In step (1), the aeroponic device comprises: an aeroponic box, a spray system, a planting plate and an annular rubber gasket; The spray system is arranged in the mist culture box, the planting plate is arranged on the top of the mist culture box, the planting holes are arranged at intervals on the planting plate, the annular rubber gasket is arranged above the planting plate, and corresponds to the position of the planting holes up and down; the annular rubber gasket includes a stacked first gasket and a second gasket, the first gasket is arranged above the second gasket, the inner diameter of the first gasket is smaller than the inner diameter of the second gasket, and the inner circles of the first gasket and the second gasket are provided with easy-tear openings.

4. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 3, characterized in that: The annular rubber gasket also includes a third gasket, which is stacked between the first gasket and the second gasket. The inner diameter of the third gasket is larger than the inner diameter of the first gasket and smaller than the inner diameter of the second gasket. The inner circle of the third gasket is also provided with an easy-tear notch.

5. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 3, characterized in that: The nozzle of the spray system extends downward 10-20 cm from the joint of the bottom of the planting plate and the box body at an angle of 30-45 degrees for spraying.

6. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 3, characterized in that: A regulating box with an opening at the bottom is arranged above the mist cultivation box, and the regulating box is detachably covered above the mist cultivation device. A temperature control device and a light control device are arranged in the regulating box, and the temperature control device includes a temperature probe, a heating tube and a temperature controller, and the temperature probe and the heating tube are electrically connected to the temperature controller respectively, and the temperature in the mist cultivation device is controlled by the temperature controller; the light control device includes an LED lamp and a time controller, and the LED lamp and the time controller are electrically connected, and the lighting time in the mist cultivation device is controlled by the time controller.

7. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 1, characterized in that: The temperature change treatment in step (3) is to adjust the temperature to 25-30°C for 3-5 days, then lower the temperature to 18-24°C for 3-5 days, with an air humidity of 70%, a light intensity of 10000 Lux, 16 hours of light, and 8 hours of dark culture, and repeat this cycle.

8. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 7, characterized in that: Place the aeroponic device in a temperature-controlled air-conditioned room for temperature change treatment.

9. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 1, characterized in that: In step (5), the high temperature acclimation refers to: the light in the light incubator is illuminated for 16 hours during the day, with a light intensity of 10,000 Lux and a temperature of 38° C.; dark culture is carried out for 8 hours at night, with a temperature of 30° C.; and the relative humidity of the air is 70% throughout the day.

10. The method for creating heat-resistant potato germplasm by interspecific grafting according to claim 1, characterized in that: In step (6), the potato tubers harvested in step (5) are recycled and domesticated for two generations, and the fourth generation selected is the desired heat-resistant potato germplasm.

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