Method for Propagating and Cultivating Vegetatively Propagated Plants

Abstract

To provide a method for propagating vegetative-reproduction plants, and a method for cultivating them, with which it is possible to efficiently achieve a high yield.SOLUTION: This method for propagating vegetative-reproduction plants includes: a placement step for placing a virus-free plant body of a vegetative-reproduction plant and a medium including an inorganic component in a light-transmitting container; and a cultivation step for cultivating the plant body placed in the light-transmitting container in a field environment to obtain a seedling of the vegetative-reproduction plant.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for propagating and cultivating a vegetatively propagated plant, and more particularly to a method for propagating and cultivating a vegetatively propagated plant, the method comprising a step of culturing a virus-free plant body in a medium provided in a light-transmitting container. [Background technology]

[0002] Vegetatively propagated plants, such as potatoes, have become increasingly important as food crops in recent years, along with wheat, barley, and rice. Seed-propagated plants such as wheat, barley, and rice can produce 100 to 1,000 seeds from a single seed. On the other hand, vegetatively propagated plants can only produce around 4 to 15 new individuals from a single vegetative body. Therefore, research has been conducted to increase the yield or improve the efficiency of cultivation.

[0003] Non-Patent Document 1 describes a mass propagation technique for potatoes using microtubers. However, in such cultivation techniques using microtubers, artificial light irradiation and appropriate temperature control are required for the propagation of the plant body. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Terttu Kamarainen-Karppinen et al., Plant Cell, Tissue and Organ Culture (PCTOC), May 2010, Volume 101, Issue 2, pp245-249 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the present invention provides a method for propagating and cultivating a vegetatively propagated plant, which can efficiently achieve a high yield. [Means for solving the problem]

[0006] The present inventors have conducted intensive research to solve the above problems and have found that vegetatively propagated plants can be harvested efficiently and in high yields by culturing virus-free plants together with a medium containing inorganic components in a light-transmitting container. [1] A step of placing a virus-free plant body of a vegetatively propagated plant and a medium containing inorganic components in a light-transmitting container; a culturing step of culturing the plant body placed in the light-transmitting container under a field environment to obtain a seedling of the vegetatively propagated plant; A method for propagating vegetatively propagated plants comprising: [2] The molar concentration of calcium ions in the medium is 1.0 to 10.5 mmol / L; The molar concentration of phosphate ions in the medium is 0.4 to 4.4 mmol / L; The method according to [1], wherein the molar concentration of magnesium ions in the medium is 0.5 to 5.3 mmol / L; [3] The method according to [1] or [2], wherein the molar concentration ratio of calcium ions:phosphate ions:magnesium ions in the medium is 30:12:15; [4] The inorganic component is Calcium chloride, a dihydrogen phosphate salt selected from potassium dihydrogen phosphate and sodium dihydrogen phosphate, and Magnesium sulfate The method for propagating a vegetatively propagated plant according to any one of [1] to [3], [5] The method for propagating a vegetatively propagated plant according to any one of [1] to [4], wherein the inorganic components are calcium chloride dihydrate, potassium dihydrogen phosphate, and magnesium sulfate heptahydrate; [6] The method according to [5], wherein the weight ratio of the calcium chloride dihydrate:potassium dihydrogen phosphate:magnesium sulfate heptahydrate is 44:17:37; [7] The method for propagating a vegetatively propagated plant according to any one of [1] to [6], wherein the light-transmitting container is a glass container or a resin container; [8] The proliferation method according to any one of [1] to [7], wherein the resin container contains at least one selected from a polyethylene-based resin, a polypropylene-based resin, and a polyvinyl chloride-based resin, and is a bag-shaped container; [9] The method for proliferation according to any one of [1] to [8], wherein the plant body is cultured in a field environment for 1 to 250 days;

[10] A method for cultivating a vegetatively propagated plant, comprising a step of planting and cultivating a seedling of the vegetatively propagated plant obtained by the propagation method according to any one of [1] to [9] in a field environment without acclimatization;

[11] The method according to

[10] , wherein the vegetatively propagated plant is a plant derived from an underground stem;

[12] The method according to

[10] or

[11] , wherein the vegetatively propagated plant is potato or sweet potato. Regarding. Effect of the Invention

[0007] INDUSTRIAL APPLICABILITY The present invention provides a method for propagating and cultivating a vegetatively propagated plant that can efficiently achieve a high yield. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiment of the propagation method and cultivation method of the present invention will be described in detail. However, the embodiment is an example for explaining the present invention, and it is not intended to limit the present invention to only the embodiment.

[0009] The propagation and cultivation of vegetatively propagated plants according to this embodiment relates to the vegetatively propagated plants exemplified below.

[0010] In this specification, a "vegetatively propagated plant" is a plant that propagates the next generation of plants by vegetative propagation from a vegetative organ, and propagates individuals. Examples of vegetative organs include bulbs, tubers, corms, rhizomes, and liners derived from underground stems, and root tubers and stalks derived from roots. The vegetatively propagated plant used in the present invention is preferably a plant derived from an underground stem such as a bulb, tuber, corm, or rhizome, and more preferably a plant derived from a tuber. Examples of vegetatively propagated plants include potato, taro, garlic, and sweet potato. In this specification, the vegetatively propagated plant is preferably potato or sweet potato, and most preferably potato. The propagation method and cultivation method according to the present invention are preferably applied to the cultivation of crops cultivated for food or feed among the vegetatively propagated plants exemplified above.

[0011] One aspect of the present invention relates to a method for propagating a vegetatively propagated plant, the method comprising the steps of: (i) a step of placing a virus-free plant body of a vegetatively propagated plant and a medium containing inorganic components in a light-transmitting container; (ii) a culturing step of culturing the plant body placed in the light-transmitting container under a field environment to obtain a seedling of the vegetatively propagated plant.

[0012] 1. Placement process 1.1.Plant In this step, the vegetatively propagated plant is used as a virus-free plant. Here, the term "virus-free" in relation to the vegetatively propagated plant refers to a state in which the plant is not infected with a virus, and the plant can be confirmed to be virus-free by means known in the art, for example, by antigen-antibody reaction and PCR. The method for obtaining the virus-free plant is not particularly limited, and the virus-free plant can be obtained, for example, by artificially growing the growing point of the plant using a known growing point culture technique.

[0013] In meristem culture, a tissue called the meristem, where cell division is actively taking place in a plant, is taken out and cultured in a medium for meristem culture. For example, when the vegetatively propagated plant is a potato, the shoot tip is mainly used for the culture. By carrying out this meristem culture, it is possible to produce a virus-free plant body.

[0014] For example, MS (Murashige and Koog) medium is used for meristem culture. The medium contains water, major inorganic components, trace inorganic components, vitamins, organic compounds, agar, and a buffer for adjusting the pH to a range suitable for culture. Specifically, MS medium contains at least one of calcium chloride dihydrate (440 mg / L), potassium dihydrogen phosphate (170 mg / L), magnesium sulfate heptahydrate (370 mg / L), ammonium nitrate (1650 mg / L), and potassium nitrate (1900 mg / L) as major inorganic components. The MS medium also contains at least one of the following trace inorganic components: manganese sulfate pentahydrate (24.1 mg / L), zinc sulfate heptahydrate (8.6 mg / L), copper sulfate pentahydrate (0.025 mg / L), boric acid (6.2 mg / L), potassium iodide (0.83 mg / L), sodium molybdate dihydrate (0.25 mg / L), cobalt (II) chloride hexahydrate (0.025 mg / L), iron sulfate heptahydrate (27.8 mg / L), and sodium ethylenediaminetetraacetate (37.3 mg / L). The above components are merely examples, and other components may or may not be added depending on the application.

[0015] The MS medium used in the meristem culture is preferably a solid medium from the viewpoint of facilitating the intake of oxygen necessary for the growth of the plant body. When the MS medium is used as a solid medium, it contains, for example, 8 g / L to 15 g / L of agar. The MS medium may be used as a liquid medium as long as it can maintain a stationary state in which the nodal slices can sufficiently take in oxygen without impeding the growth of the plant body. As an example of the form of the liquid medium, the nodal slices are placed on a stand so that a part of the nodal slices is always in contact with the liquid medium so that the nodal slices are not completely buried in the liquid medium.

[0016] Typically, meristem culture is carried out as follows. First, a tissue piece containing the shoot apex, which is the meristem, is aseptically removed from a vegetatively propagated plant whose surface has been sterilized with ethyl alcohol or a sodium hypochlorite solution. Next, the removed tissue piece is placed on the above-mentioned medium dispensed into a culture vessel and cultured for a predetermined period of time to grow the plant. In the grown plant, the part of the stem and leaf derived from one shoot apex meristem is called a "shoot," and a plant composed of multiple shoots is called a "multiple shoot" or "multiple shoot."

[0017] If shoots or multiple shoots are cultured for an appropriate period until each shoot reaches a size of about 5 to 10 cm, the work of placing them in a light-transmitting container becomes easy, and work efficiency and yield can be improved. However, if the culture period for meristem culture is too long, the amount of nutrients in the medium necessary for the growth of the multiple shoots will be insufficient and the multiple shoots will wither, so it is necessary to end the culture and place them in a light-transmitting container before the period when the multiple shoots will not wither.

[0018] In meristem culture, it is desirable to seal the culture vessel to prevent contamination by unwanted bacteria that may hinder the culture. However, it is not always necessary to seal the culture vessel if measures to prevent contamination by unwanted bacteria are taken, such as adding pesticides to suppress the growth of unwanted bacteria.

[0019] A virus-free plant body (i.e., shoot) can be obtained by cutting, plucking, or cutting with scissors a shoot containing one or more buds from the shoot or multiple shoot obtained by performing meristem culture as described above. In this manner, the virus-free plant body of a vegetatively propagated plant used in the mounting step is obtained from the shoot or multiple shoot of a vegetatively propagated plant cultured using MS medium.

[0020] Next, the virus-free plant body of the vegetatively propagated plant and the medium containing inorganic components are placed in a light-transmitting container. Here, the light-transmitting container is used as a growth chamber. Specifically, the virus-free plant body is placed on the medium dispensed in the light-transmitting container. The plant body placed on the medium is then allowed to grow for a predetermined period of time. In this step, the shoots are placed at a density of 1 to 40, preferably 5 to 20, and more preferably 10 to 15 shoots per container. The shoots are placed at a density of, for example, 0.02 to 0.67 shoots / cm in the container. 2 , preferably 0.08 to 0.34 lines / cm 2 , and more preferably 0.17 to 0.25 fibers / cm 2 The container used in this step is, for example, a Magenta box (Magenta (trademark) vessel GA-7, manufactured by Merck).

[0021] 1.2. Culture medium The medium placed in the light-transmitting container in the placing step is, for example, an improved MS medium. The improved MS medium contains the same components as the MS medium, specifically, water, major inorganic components, trace inorganic components, vitamins, organic compounds, and a buffer for adjusting the pH to a range suitable for culture. As with the MS medium, other components may be added to the improved MS medium depending on the application, and it is not necessary to add all of the components contained in the MS medium.

[0022] The improved MS medium contains inorganic components selected from the group consisting of calcium ions, phosphate ions, and magnesium ions. The improved MS medium preferably contains all of calcium ions, phosphate ions, and magnesium ions. By containing such ions, cultivation can be carried out without acclimatization prior to cultivation, thereby shortening the cultivation period, increasing efficiency, and increasing yield.

[0023] The inorganic components are selected from the group consisting of calcium chloride, phosphates (e.g., potassium dihydrogen phosphate and sodium dihydrogen phosphate), magnesium sulfate, ammonium nitrate, and potassium nitrate. The inorganic components are preferably calcium chloride, dihydrogen phosphates (selected from potassium dihydrogen phosphate and sodium dihydrogen phosphate), and magnesium sulfate. In one embodiment, the medium contains all of calcium chloride, potassium dihydrogen phosphate, and magnesium sulfate as inorganic components.

[0024] The calcium ion concentration in the improved MS medium is: For example, 1.0mmol / L~10.5mmol / L, -Preferably more than 3.0mmol / L and less than or equal to 10.5mmol / L, More preferably, 3.3mmol / L to 9.0mmol / L. Even more preferably 4.5mmol / L~9.0mmol / L It is.

[0025] The improved MS medium preferably contains calcium chloride as an inorganic component. The calcium chloride is preferably contained in the medium as calcium chloride dihydrate. The concentration of calcium chloride dihydrate in the medium is: For example, 146mg / L~1540mg / L, - preferably more than 440 mg / L and less than 1540 mg / L; More preferably, 484mg / L to 1320mg / L. Even more preferably 660mg / L to 1320mg / L It is.

[0026] The phosphate ion concentration in the improved MS medium is: For example, 0.4mmol / L~4.4mmol / L, - preferably greater than 1.2 mmol / L and less than or equal to 4.4 mmol / L; More preferably, 1.4 mmol / L to 3.7 mmol / L or less. Even more preferably 1.9mmol / L~3.7mmol / L It is.

[0027] The improved MS medium preferably contains phosphate as an inorganic component. The phosphate is preferably contained in the medium as potassium dihydrogen phosphate or sodium dihydrogen phosphate. The concentration of potassium dihydrogen phosphate or sodium dihydrogen phosphate in the medium is: For example, 56mg / L~595mg / L, -Preferably more than 170 mg / L and less than 595 mg / L More preferably, 187mg / L to 510mg / L. Even more preferably 255mg / L to 510mg / L It is.

[0028] The magnesium ion concentration in the improved MS medium is: For example, 0.5mmol / L~5.3mmol / L, - preferably greater than 1.5mmol / L and less than or equal to 5.3mmol / L; More preferably, 1.7 mmol / L to 4.5 mmol / L. Even more preferably 2.3mmol / L~4.5mmol / L It is.

[0029] The modified MS medium preferably contains magnesium sulfate as an inorganic component. The magnesium sulfate is preferably contained in the medium as magnesium sulfate heptahydrate. The concentration of magnesium sulfate in the medium is: For example, 123mg / L~1295mg / L, -Preferably more than 370 mg / L and less than 1295 mg / L More preferably, 407mg / L to 1110mg / L. Even more preferably 555mg / L to 1110mg / L It is.

[0030] In one embodiment, the components in the modified MS medium other than calcium chloride dihydrate, dihydrogen phosphate, and magnesium sulfate heptahydrate are contained in the same concentrations as in the MS medium.

[0031] By using an improved MS medium containing the above three components in specified amounts, it is possible to more effectively increase the yield of vegetatively propagated plants.

[0032] When the improved MS medium contains at least calcium chloride, potassium phosphate, and magnesium sulfate as major inorganic components, the yield of vegetatively propagated plants can be increased more effectively by keeping the ratio of the three components constant. Specifically, the molar concentration ratio of calcium ions, phosphate ions, and magnesium ions is preferably 30:12:15. Alternatively, the weight ratio of calcium chloride dihydrate, potassium dihydrogen phosphate, and magnesium sulfate heptahydrate is preferably 44:17:37, that is, calcium chloride dihydrate:potassium dihydrogen phosphate:magnesium sulfate. This molar concentration ratio or weight ratio is not strict, and the yield can be increased by roughly maintaining the above ratio.

[0033] When calcium chloride, potassium dihydrogen phosphate, and magnesium sulfate are all contained in the medium, the concentrations of these three components are not limited as long as the molar concentration ratio or weight ratio described above is maintained, and they may be lower or higher than those of conventional MS medium. However, if the concentration is too low, the nutrients required for culture may be insufficient, and the plant body may not grow to a specified size or may wither, so specifically, a concentration of up to about 1 / 3 of that of MS medium is preferable. Also, if the concentration is too high, growth disorders occur and the growth of the plant body slows down, so specifically, a concentration of up to about 3.5 times is preferable. More preferably, the concentrations of the above three components are higher than those of MS medium.

[0034] The medium may contain at least one of boric acid, cobalt chloride, copper sulfate, iron sulfate, manganese sulfate, potassium iodide, sodium molybdate, zinc sulfate, etc. as trace inorganic components. These trace inorganic components can be appropriately adjusted depending on the desired culture environment and the type and variety of the vegetatively propagated plant to be cultured.

[0035] 1.3. Container As described above, the virus-free plant body is placed in a light-transmitting container. The light-transmitting container has a transmittance of 5% or more with respect to natural light, more preferably a transmittance of 60% or more, and even more preferably a transmittance of 70% or more. By using a light-transmitting container having such a transmittance, it is possible to more effectively increase the yield of the vegetatively propagated plant. The transmittance of the container is measured by a method known in the art.

[0036] The material of the light-transmitting container may be any material that allows a sufficient amount of natural light for the growth of the shoots to pass through the container and irradiate the shoots. Examples of materials for the container include glass, resin, and rubber.

[0037] In the case where at least a part of the light-transmitting container is a resin-made container, the resin-made container may be a polyethylene-based resin, a cyclic polyolefin-based resin, a fluorine-based resin, a polystyrene-based resin, a polypropylene-based resin, an acrylonitrile-butadiene-styrene copolymer (ABS resin), an acrylonitrile-styrene copolymer (AS resin), a polyvinyl chloride-based resin, a fluorine-based resin, a poly(meth)acrylic resin, a polycarbonate-based resin, a polyester-based resin, a polysulfone-based resin, a polyphenylene sulfide-based resin, a polyethersulfone-based resin, a polyamide-based resin, a polyimide-based resin, a polyamideimide-based resin, a polyarylphthalate-based resin, a silicone-based resin, a polyurethane-based resin, an acetal-based resin, a cellulose-based resin, or a mixture thereof as a main component. Of these, a container containing a polyethylene-based resin, a polypropylene-based resin, or a polyvinyl chloride-based resin, more preferably a polyethylene-based resin, as a main component, may be used.

[0038] The shape, size and thickness of the resin container may be such that it does not hinder the growth of the shoot and is not physically broken. The resin container is, for example, a bag-shaped container having a size of 50 mm to 2,000 mm square, more preferably 700 mm to 1,000 mm square, and even more preferably 100 mm to 500 mm square, and a thickness of, for example, 1 μm to 2,000 μm, more preferably 5 μm to 500 μm, and even more preferably 10 μm to 100 μm. As the bag-shaped container, a so-called plastic bag is typically used. By using such a light-transmitting container for propagation, it is possible to efficiently increase the yield of vegetatively propagated plants.

[0039] As described below, the culture process includes a plurality of culture steps, that is, the growth can be divided into a plurality of steps. For example, when the culture is divided into two steps, in the first culture step, a glass container or a hard resin container that is easy to keep sealed can be used as the light-transmitting container from the viewpoint of preventing contamination by bacteria, and in the second culture step, a soft resin container can be used from the viewpoint of cost.

[0040] If the cultivation process is carried out in one step rather than divided into multiple steps, it is possible to further reduce costs and obtain multiple shoots by growing virus-free shoots in soft plastic containers.

[0041] Into the light-transmitting container, 10 mL to 5,000 mL, more preferably 50 mL to 1,000 mL, and even more preferably 100 mL to 500 mL of the improved MS medium is dispensed. A virus-free plant body is placed on the dispensed medium.

[0042] 2.Culture process In this process, the virus-free plant body placed in the light-transmitting container is cultured in a field environment. The "field environment" refers to an environment similar to a natural environment, in which the temperature and amount of solar radiation are not artificially controlled. Examples of the field include a greenhouse and an open field, and therefore the field environment is, for example, a greenhouse environment and an open field environment.

[0043] The culture process may include multiple stages. By dividing the propagation into multiple stages, it is possible to efficiently culture and propagate the plant by using appropriate light-transmitting containers according to the growth condition, such as the number and size of the shoots. Specifically, a container that is too large for the size of the plant body (specifically the shoot) will use more medium than necessary and will also be difficult to work with. On the other hand, the plant body will stop growing when it reaches the size of the container. Therefore, it is possible to efficiently culture and propagate the plant body by selecting a container of an appropriate size according to the growth condition of the plant body for each stage.

[0044] The culture is carried out for a period of 1 to 250 days, preferably 3 to 180 days, more preferably 7 to 100 days. Here, the culture period is the total period of each process when the culture process is divided into a plurality of processes. By culturing the plant body for the above-mentioned period, it is possible to obtain a seedling that has grown sufficiently to be used in the subsequent cultivation process. The culture is carried out in a field environment with the plant body placed in a light-transmitting container. If the plant body is cultured in a field environment for an appropriate period, the transition to the cultivation process becomes easy, and the work efficiency and yield can be improved. If the period of the culture process is too short, the plant body that has undergone a large environmental change when transferred to the cultivation process may not adapt to the natural environment and may wither. If the period of the culture process is too long, the plant body may wither due to a lack of the components in the medium necessary for the growth of the plant body.

[0045] During the cultivation period, it is desirable to seal the light-transmitting container to prevent contamination by various bacteria that may hinder cultivation and proliferation. However, if measures to prevent contamination by various bacteria are taken, such as adding a pesticide that inhibits the proliferation of various bacteria, it is not necessary to seal the light-transmitting container.

[0046] In this embodiment, particularly in a field environment where the temperature and amount of solar radiation are the same as in nature, it is possible to culture the plant in a field environment such as normal greenhouse cultivation or open-field cultivation without requiring any temperature control equipment such as a heater or air conditioner, or sunshine duration control equipment such as an LED light.

[0047] In this embodiment, as described above, a virus-free plant body (specifically, a shoot) obtained by the above-mentioned meristem culture is placed in a light-transmitting container containing a medium of a predetermined composition and cultured for a predetermined period of time under a field environment to obtain a seedling of a vegetatively propagated plant. The seedling of the vegetatively propagated plant thus obtained can be directly planted in a field for cultivation without the usual acclimatization process.

[0048] Another aspect of the present invention relates to a method for cultivating a vegetatively propagated plant, comprising a cultivation step of cultivating a plant body propagated by the above-mentioned propagation method, i.e., a seedling of a vegetatively propagated plant, in which, as described above, the seedling of the vegetatively propagated plant can be directly planted and cultivated without an acclimation step.

[0049] 3.Cultivation process In the cultivation step, the seedlings of the vegetatively propagated plant are cultivated in a field environment such as an open field or greenhouse environment. In this step, specifically, the seedlings of the vegetatively propagated plant obtained by the above-mentioned cultivation step are planted and cultivated in a field environment such as an open field or greenhouse cultivation environment. More specifically, in this step, one or more seedlings obtained by the cultivation step are harvested and planted in a field. The cultivation environment and cultivation period can be a normal cultivation period in a known cultivation environment such as an open field or greenhouse cultivation. When the cultivation period is reached, the harvested product is appropriately harvested using a harvesting method according to the type and variety of the vegetatively propagated plant.

[0050] When a plant is grown in an in vitro environment using microtubers or minitubers, it is essential to acclimate the seedlings in advance for cultivation in a normal field environment. Here, "acclimation" refers to adapting the plant to a different environment for a certain period of time when the plant is transferred to a different environment. This is done to reduce the stress of the seedling from a large environmental change when transferring the seedling from an in vitro environment to a field environment. For example, acclimatization is usually performed by covering the plant (specifically, the shoot) with a light-transmitting vinyl or plastic container to maintain humidity. At this time, water is sprayed into the container using a sprayer or the like to maintain humidity. When acclimatization is completed, water is supplied to the plant. On the other hand, in the present invention, a medium containing a predetermined component is used, and the plant is cultured in a light-transmitting container under a field environment, so that such an acclimatization step does not need to be performed. Specifically, in the present invention, the plant can be grown without withering by directly placing the plant in a new environment without performing "acclimation". It should be noted that although watering the plant body in the new environment is not essential, it is known that watering increases the establishment rate and watering causes the plant to grow twice as fast as not watering. Therefore, according to the propagation method or cultivation method of the present invention, it is possible to increase the yield of vegetatively propagated plants in a short period of time, and a high yield can be efficiently achieved.

[0051] As described above, in the propagation method or cultivation method according to the present invention, virus-free plants are propagated in a field environment using a light-transmitting container into which a medium having a specific ion composition or component composition is dispensed, thereby making it possible to increase the yield more efficiently than conventional cultivation that requires culture equipment such as microtubers or minitubers. Furthermore, by using a medium containing a certain proportion of specific inorganic components in the culture process, it becomes possible to increase the yield even more efficiently.

[0052] In this specification, a numerical range indicated using "~" indicates a range including the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper limit or lower limit of a numerical range of a certain stage can be arbitrarily combined with the upper limit or lower limit of a numerical range of another stage. EXAMPLES

[0053] <1> Obtaining plants by meristem culture To obtain virus-free plants (specifically shoots), meristem culture was first performed.

[0054] Potato (Solanum tuberosum) was used as a vegetatively propagated plant. A tissue piece from the tip (shoot apex) of a sprout that had germinated from the potato tuber was aseptically cut and harvested. The harvested tissue piece was then placed on MS solid medium dispensed in a test tube (15 mL) and cultured for 21 days to obtain virus-free shoots. The composition of the MS solid medium used is shown in Table 1 below. Among the components of this MS solid medium, the concentrations of the three main ions, calcium ions, phosphate ions, and magnesium ions, are shown in Table 2.

[0055] [Table 1]

[0056] [Table 2]

[0057] <2> Placement and cultivation in a light-transmitting container [Comparative Examples, Examples 1 to 6] The following materials and methods were used for the comparative example and Examples 1 to 6. As described below, the culture was divided into two steps, the first culture and the second culture, for proliferation.

[0058] the above <1> The virus-free shoots obtained by meristem culture in the above were placed on 40 mL of medium dispensed into a light-transmitting container and cultured for 21 days (first culture).

[0059] As the medium, an MS solid medium was used in the comparative example, and an improved MS solid medium was used in Examples 1 to 6.

[0060] In the comparative example, virus-free shoots were cultured using a medium having the same composition as the MS solid medium shown in Table 1 to obtain shoots to be used in the second culture.

[0061] In Examples 1 to 6, virus-free shoots were cultured using improved MS solid medium having concentrations of calcium chloride dihydrate, potassium dihydrogen phosphate, and magnesium sulfate heptahydrate as shown in Table 3 and concentrations of other components as shown in Table 1 to obtain shoots to be used in the second culture.

[0062] In Examples 1 to 4, a magenta box (Merck, Magenta (trademark) vessel GA-7) made of hard resin and measuring 77 mm×77 mm×97 mm was used as the light-transmitting vessel during the first culture, and after placing the chute, the vessel was sealed.

[0063] A glass container was used as the light-transmitting container during the first culture in Examples 5 and 6. Of these, in Example 5, after placing the shoot, the first culture was performed in an open system without sealing the container, while in Example 6, after placing the shoot, the first culture was performed with the container sealed.

[0064] In the first culture, in all of the comparative example and examples 1 to 6, a light-transmitting container containing the shoot in contact with the medium was placed in a greenhouse set up for greenhouse cultivation of potatoes. At this time, no heater or air conditioner was used in the greenhouse, and no adjustment of illuminance and time using LED lighting or the like was performed.

[0065] In the second culture stage of the culture process, in all of the comparative example and Examples 1 to 6, the shoot, which is a mass of the plant body (multiple shoots) obtained in the first culture, was placed in a polyethylene bag (colorless and transparent) with a size of 150 mm x 260 mm and a thickness of 30 μm, containing 100 mL of culture medium. At this time, a polystyrene container with a size of 60 mm x 40 mm was used inside the polyethylene bag to support the shoot. In all of the comparative example and Examples 1 to 6, the same culture medium was used as in the first culture.

[0066] In the second culture, in all of the comparative example and examples 1 to 6, the polyethylene bag containing the shoot in contact with the medium was placed in a greenhouse set up for greenhouse cultivation of potatoes, and the shoots were grown and cultured for 30 to 90 days. During this time, no heater or air conditioner was used in the greenhouse, and no adjustment of the illuminance and duration using LED lighting or the like was performed.

[0067] As a result of the second culture, although there were differences in the degree of shoot proliferation, seedlings could be cultured in all of the examples and comparative examples.

[0068] Table 3 shows the molar concentrations of each substance and each ion corresponding to the medium concentrations in the comparative example and Examples 1 to 6.

[0069] [Table 3]

[0070] <3> Seedling cultivation Among the seedlings obtained by the above propagation, the seedlings obtained in the Comparative Example, Example 1, and Example 3 were planted in a field in a greenhouse cultivation environment with the surface covered with 0.05 mesh mulch. At this time, Examples 1 and 3 were performed without an acclimatization process from the culture process to the cultivation process. Then, the potato tubers were harvested after cultivation in a natural environment for 60 days, and the yield was measured (Table 4). In addition, the Comparative Example was cultivated in a natural environment for 60 days after a 7-day acclimatization process.

[0071] [Table 4]

[0072] As shown in Table 4, in comparison with the conventional cultivation method shown in the comparative example, in Examples 1 and 3 cultivated according to the cultivation method of the present invention, a large amount of tubers could be harvested.

[0073] In the cultivation of Examples 1 and 3, the shoots obtained by meristem culture were finally placed in bag-shaped resin containers and propagated under a field environment. Therefore, the cultivation methods of Examples 1 to 6 do not require the conventional propagation using microtubers or minitubers or the equipment therefor, and furthermore, unlike the conventional method and the cultivation method of the comparative example, do not require acclimatization or the equipment therefor, and it was possible to harvest a large amount of tubers extremely efficiently and inexpensively.

Claims

1. A step of placing a virus-free plant body of a vegetatively propagated plant and a medium containing inorganic components in a light-transmitting container; a cultivation step of culturing the plant body placed in the light-transmitting container in a sealed state under a field environment to obtain a seedling of the vegetatively propagated plant; Including, the molar concentration of calcium ions in the medium is 4.5 mmol / L to 9.0 mmol / L; the molar concentration of phosphate ions in the medium is 1.9 mmol / L to 3.7 mmol / L; The molar concentration of magnesium ions in the medium is 2.3 mmol / L to 4.5 mmol / L; A method for propagating vegetatively propagated plants.

2. A method for producing a culture medium comprising the steps of: a first culture step; and a second culture step, In the first culture step, the shoot obtained by the meristem culture is placed in a light-transmitting container and cultured in a field environment with or without sealing; The shoot that has been subjected to the first culture step is subjected to the second culture step as the plant body. The method of claim 1.

3. 3. The method according to claim 1, wherein the molar concentration ratio of calcium ions:phosphate ions:magnesium ions in the medium is 30:12:

15.

4. The inorganic component is Calcium chloride, a dihydrogen phosphate salt selected from potassium dihydrogen phosphate and sodium dihydrogen phosphate, and Magnesium sulfate The method for propagating a vegetatively propagated plant according to any one of claims 1 to 3,

5. 5. The method for propagating a vegetatively propagated plant according to claim 1, wherein the inorganic components are calcium chloride dihydrate, potassium dihydrogen phosphate and magnesium sulfate heptahydrate.

6. 6. The method of claim 5, wherein the weight ratio of calcium chloride dihydrate:potassium dihydrogen phosphate:magnesium sulfate heptahydrate is 44:17:

37.

7. 7. The method for propagating a vegetatively propagated plant according to claim 1, wherein the light-transmitting container is a glass container or a resin container.

8. The light-transmitting container is a resin container at least a part of which is made of resin, The proliferation method according to any one of claims 1 to 7, wherein the resin container contains at least one selected from a polyethylene resin, a polypropylene resin, and a polyvinyl chloride resin, and is a bag-shaped container.

9. The plant body is cultured under a field environment for 1 to 250 days, including the culture step, wherein the culture period starts from the time of the shoot obtained by meristem culture. The method for proliferation according to any one of claims 1 to 8.

10. Obtaining seedlings of the vegetatively propagated plant by the method according to any one of claims 1 to 9; and A method for cultivating a vegetatively propagated plant, comprising a step of planting and cultivating the obtained seedling of the vegetatively propagated plant in a field environment without acclimatization.

11. The method according to claim 10, wherein the vegetatively propagated plant is a plant derived from an underground stem.

12. The cultivation method according to claim 10, wherein the vegetatively propagated plant is potato or sweet potato.

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