Method for suppressing development of bullous disease, seedling raising method and seedling raising system

Abstract

To provide a method for suppressing the development of bullous disease in Solanaceae plants.SOLUTION: The present invention provides a method including the step for applying leaf watering to Solanaceae plants, thereby suppressing the development of bullous disease.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for inhibiting the occurrence of blister disease, a seedling raising method, and a seedling raising system. [Background technology]

[0002] For some time now, an increasing number of flower and vegetable producers have been purchasing seedlings from seedling production companies. Many seedling production companies have introduced closed seedling production systems, and the use of these systems has enabled stable and efficient seedling production.

[0003] On the other hand, in recent years, cases of blister disease occurring in seedlings in closed seedling production systems have been frequently reported and become a problem. Blister disease is a physiological disorder that is also called leaf knot disease, blister disease, blister disease, or intumescence, and causes bump-like convex deformations on the leaf surface. As the condition progresses, the leaves turn brown and then fall off. For this reason, if blister disease occurs and progresses during seedling raising, the seedlings lose their commercial value.

[0004] Blister disease has been reported in plants such as tomatoes, eggplants, peppers, potatoes, petunias, and geraniums, with the incidence of the disease being particularly high in tomatoes. Blister disease can occur during seedling cultivation in a so-called natural environment using sunlight, and during cultivation after the seedlings are planted in a field, but to date, the most notable reports of the occurrence of blister disease have been in seedling cultivation using closed seedling production systems.

[0005] On the other hand, as a suppression technique for blister disease that has been publicly known, for example, Patent Documents 1 and 2 disclose a suppression technique using specific light irradiation conditions. Specifically, Patent Document 1 discloses a method including a step of irradiating light including blue light, green light, and red light having a photon flux density in a specific range. Patent Document 2 discloses a cultivation device equipped with a semiconductor lighting device that has a specific UV intensity and irradiates light in a wavelength range of at least 450 to 660 nm. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-145975 A [Patent Document 2] Patent Publication No. 2022-022299 Summary of the Invention [Problem to be solved by the invention]

[0007] Although the occurrence of blister disease has been reported frequently in many plant species, especially tomatoes, in recent years, the mechanism behind this disease remains unclear. For this reason, there is a need to develop various approaches to suppress blister disease in addition to the above-mentioned light-based suppression technique.

[0008] One aspect of the present invention has been made in consideration of the above-mentioned problems, and aims to provide a method for suppressing the occurrence of physiological disorders such as blister disease in plants. [Means for solving the problem]

[0009] As a result of extensive research, the inventors of the present application have found that spraying water on the leaves of a plant is an effective measure for suppressing the occurrence of blister disease.

[0010] That is, in order to solve the above-mentioned problems, one aspect of the present invention provides a method for suppressing the occurrence of blister disease in a solanaceous plant, the method including a step of applying water to the leaves of the solanaceous plant.

[0011] Another aspect of the present invention provides a method for raising tomato seedlings, the method comprising the step of spraying water on the leaves of tomatoes 0.5 to 4 hours before the onset of the dark period of the light-dark cycle.

[0012] Another aspect of the present invention provides a seedling raising system comprising a chamber for housing seedlings and a leaf watering means for watering the leaves, the leaf watering means performing leaf watering at a predetermined timing before the start of the dark period of the light-dark cycle. Effect of the Invention

[0013] According to one aspect of the present invention, the occurrence of physiological disorders such as blister disease in plants can be suppressed. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram showing an outline of a configuration example of a seedling raising system according to an embodiment of the present invention. [Diagram 2] FIG. 13 is a diagram showing the measurement results of the incidence of blister disease depending on the type of light source and the presence or absence of leaf water in an embodiment of the present invention. [Diagram 3] This figure shows the state of seedlings 15 days after sowing when grown under an LED light source in an embodiment of the present invention, with or without leaf watering (left: no leaf watering, right: leaf watering from 8 days after sowing). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Definition] In this specification, "leaf watering" refers to artificially watering the leaf surface of a plant body under cultivation. Leaf watering may be in the form of a film of water applied to the leaf surface, but is preferably in the form of water applied to the leaf surface to the extent that water droplets form on the leaf surface. The means for watering the leaves (leaf watering means) is not particularly limited, but examples of water supply means that can apply water to the leaf surface to the extent that water droplets form on the leaf surface include sprayers (mist generators, misters), watering cans, humidifiers, and the like. However, it is preferable to use a sprayer because 1) excessive watering can be prevented, 2) water can be easily applied selectively to the leaf surface, and 3) operation control in the form of an electrical circuit is also possible. The water used for leaf watering may contain pesticide components such as fungicides and insecticides, fertilizer components, etc., but it is preferable to use pure water, tap water, or well water that does not contain pesticide components, fertilizer components, etc.

[0016] In this specification, when a range is indicated in the format of "A to B," this notation is used to mean that both ends of the range, A and B, are included, unless otherwise specified.

[0017] [1. How to cultivate Solanaceae plants] A method according to one embodiment of the present invention is a method for cultivating a solanaceous plant, comprising a step of applying water to the leaves of the plant. The type of solanaceous plant is not particularly limited, but specific examples include tomato, eggplant, capsicum (Capsicum plants including green peppers, shishito peppers, paprika, etc.), potato, petunia, etc., and in particular tomato.

[0018] The cultivation period for spraying water on the leaves of the plants is not particularly limited as long as the plants have leaves after sowing, but it is preferable to spray water on the leaves during the cultivation period after seedling raising or transplanting, and more preferably during the cultivation period after seedling raising. In the section [2. Seedling raising method] described later, a method for raising tomato seedlings will be described in particular.

[0019] During the cultivation period of a plant after the seedling is raised, the plant body can be irradiated with light in a cycle of light and dark periods (hereinafter also referred to as a "light-dark cycle"). The light period is a period during which the plant body is irradiated with light, and the dark period is a period during which the plant body is not irradiated with light. In the light-dark cycle, the light period and the dark period are repeated alternately.

[0020] Here, the light irradiation includes natural light (sunlight) and artificial light. Examples of the light irradiation using artificial light include LED lighting and fluorescent lighting. Examples of the cultivation of plants under natural light irradiation include outdoor cultivation, greenhouse cultivation, and cultivation in a sunlight-based plant factory. Examples of the cultivation of plants under artificial light irradiation include cultivation in a closed facility that does not capture sunlight (e.g., a closed seedling system or a closed plant factory). The method according to one embodiment of the present invention is preferably applied to the cultivation of plants under artificial light irradiation, and more preferably applied to the cultivation of plants under LED light irradiation.

[0021] It is preferable to water the leaves at a predetermined timing before the start of the dark period of the light-dark cycle described above. Specifically, the timing of watering the leaves is, for example, 0.5 to 4 hours before the start of the dark period, preferably 1 to 4 hours before the start of the dark period, more preferably 1 to 3 hours before the start of the dark period, and particularly preferably 1.5 to 2.5 hours before the start of the dark period.

[0022] The amount of water applied to the leaves each time varies depending on the cultivation season of the plant (i.e., the size of the plant body), but is, for example, within the range of 0.001 ml to 100 ml per plant, and preferably within the range of 0.01 ml to 5 ml or 0.01 ml to 1 ml per plant. It may be preferable to set the timing of watering the leaves and the amount of watering so that substantially no water remains on the leaf surface at the start of the dark period.

[0023] The frequency of leaf watering depends on the plant's cultivation period (i.e., the size of the plant body), but is, for example, once every 1 to 7 days, once every 1 to 3 days, or once a day, and is preferably once a day. However, for example, when blister disease begins to occur after planting, leaf watering may be performed multiple times a day as necessary. When leaf watering is performed multiple times a day, it is preferable to perform the final leaf watering at a predetermined timing before the start of the dark period of the above-mentioned light-dark cycle. The period for spraying water on the leaves may be set appropriately depending on the plant's growing season and the plant's condition, but is preferably at least one day, at least two days, or at least three days, and more preferably at least one week.

[0024] The leaves to be watered may be all the leaves of the plant or only some of the leaves. When only some of the leaves are to be watered, it is preferable to water the younger leaves. That is, water may be applied only to the vicinity of the growing point (terminal bud), or water may be applied to the growing point (terminal bud) and the young expanded leaves below it. During seedling cultivation, the number of expanded leaves is relatively small, so it may be preferable to water all the leaves.

[0025] The number of plants grown simultaneously as targets for leaf watering is not particularly limited, and may be, for example, 5 or more, 10 or more, 20 or more, 30 or more, 40 or more, 50 or more, 100 or more, 200 or more, 300 or more, 400 or more, 500 or more, or 1000 or more. The upper limit of the number of plants grown simultaneously is not particularly limited, and may be, for example, 100,000 or less, 10,000 or less, or 9,000 or less.

[0026] By adopting the method according to the embodiment described above, it is possible to perform leaf watering under conditions suitable for solanaceous plants, particularly tomato plants, and thus the occurrence of blister disease in solanaceous plants, particularly tomatoes, can be suppressed compared to the case where leaf watering is not performed. Note that by applying the method according to the embodiment to plants other than the solanaceous family, the occurrence of blister disease in plants other than the solanaceous family can also be suppressed.

[0027] [2. Seedling raising method] One example of the cultivation method shown in the above section [1. Cultivation method of a solanaceae plant] is a method for raising tomato seedlings using leaf water. That is, a method according to one embodiment of the present invention is a method for raising tomato seedlings, which includes a step of applying leaf water to tomato seedlings 0.5 to 4 hours before the start of the dark period of the light-dark cycle.

[0028] The seedlings may be grown under any cultivation conditions suitable for tomato seedlings, such as temperature, humidity, light / dark cycle, nutrient supply, carbon dioxide gas supply, and water supply, and may be appropriately changed depending on the seedling cultivation season. Specifically, for example, seedlings may be grown under sunlight or in a closed seedling production environment, but seedlings are preferably grown in a closed seedling production environment. Here, the closed seedling production environment refers to a closed environment partitioned from the outside, in which any cultivation conditions suitable for tomato seedlings, such as temperature, light irradiation conditions, humidity, nutrient supply, carbon dioxide gas supply, and water supply, can be artificially set and controlled, and the environment can be formed, for example, by a commercially available closed seedling production system.

[0029] More specifically, the light irradiation conditions during seedling cultivation can be performed with any light / dark cycle after germination. The light irradiation can be performed using LED lighting or fluorescent lighting. When one cycle is 24 hours, the light / dark cycle after germination is preferably 4 to 20 hours light / 4 to 20 hours dark (however, it is desirable that the total of the light and dark periods is 24 hours).

[0030] During seedling cultivation, any amount of carbon dioxide, water, and nutrients can be supplied to the seedlings by any method. Here, nutrients refer to nitrogen, phosphorus, potassium, etc., and may be supplied simultaneously with water by using liquid fertilizer containing these as ingredients. A preferred example of a method for supplying water and nutrients includes bottom irrigation with liquid fertilizer at any frequency, and the frequency can be once every 2 to 3 days, or once to three times a day. In a typical example, both bottom irrigation and leaf watering are performed during the light period, but bottom irrigation is preferably performed before leaf watering. The timing of bottom irrigation is, for example, simultaneously to within 4 or 5 hours from the start of the light period, and simultaneously to within 2 hours from the start of the light period.

[0031] More specifically, the process of watering the leaves may be performed manually using a sprayer or the like at a predetermined timing before the onset of the dark period, or the leaves may be automatically watered at a predetermined timing before the onset of the dark period, for example by utilizing the closed seedling production system described above and linking it to a sprayer.

[0032] The tomato seedlings to be grown may be seedlings, grafted seedlings, or cuttings, but are preferably seedlings or grafted seedlings. Leaf watering may be started immediately after germination, before the true leaves unfold, when the first true leaves unfold, or after the second true leaves unfold. Leaf watering may be continued throughout the seedling period, or a break from leaf watering may be provided during the seedling period. Other cultivation conditions may be appropriately selected from those shown in the above section [1. Cultivation method for Solanaceae plants].

[0033] After the seedling raising period, the seedlings are shipped, for example, as plug seedlings, pot seedlings, or seedlings for hydroponic cultivation (seedlings supported by urethane or rock wool), etc. After shipping, the seedlings may continue to be irrigated even after they are planted in a main field or a hydroponic cultivation facility, or the irrigation of the leaves may be stopped at the same time as the seedlings are planted in a main field or a hydroponic cultivation facility, etc.

[0034] There are no particular limitations on the tomato varieties to which this seedling raising method can be applied, but preferred examples include varieties such as Rinka 409 (Sakata Seed Co., Ltd.), Momotaro Peace (Takii Seed Co., Ltd.), Reika (Sakata Seed Co., Ltd.), Reigetsu (Sakata Seed Co., Ltd.), Momotaro Haruka (Takii Seed Co., Ltd., registered trademark), Frutica (Takii Seed Co., Ltd., registered trademark), House Momotaro (Takii Seed Co., Ltd.), CF House Momotaro (Takii Seed Co., Ltd.), CF Momotaro Haruka (Takii Seed Co., Ltd.), Momotaro Hope (Takii Seed Co., Ltd.), Sunroad (Sakata Seed Co., Ltd.), Reishun (Sakata Seed Co., Ltd.), and TY Misora ​​86 (Vilmorant Mikado).

[0035] By adopting the method according to the above-described embodiment, it is possible to suppress physiological disorders such as blister disease that may occur in tomato seedlings, thereby maintaining good growth of the tomato seedlings and maintaining their commercial value.

[0036] [3. Seedling raising system] With reference to the above-mentioned embodiment, a seedling raising system utilizing leaf water is provided. That is, the seedling raising system according to one embodiment of the present invention includes a chamber for accommodating seedlings and a leaf watering means for performing leaf watering. Here, the leaf watering means performs leaf watering at a predetermined timing before the start of the dark period of the light-dark cycle. Hereinafter, the seedling raising system according to one embodiment of the present invention will be described in more detail with reference to FIG. 1.

[0037] 1 is a diagram showing an outline of a configuration example of a seedling raising system 1. The seedling raising system 1 is configured to include a chamber 11 for accommodating seedlings and a leaf watering means 12.

[0038] The chamber 11 has a space therein capable of accommodating a sufficient number of seedlings 101, and the space may be large enough to accommodate, for example, a plurality of seedling-raising cell trays 100 arranged in parallel. There are no particular limitations on the shape and number of seedling-raising cell trays 100 that can be accommodated, and the number of seedlings 101 that can be accommodated, as long as leaf watering by the leaf watering means 12 and other steps necessary for seedling raising can be carried out efficiently. The seedlings 101 accommodated in the chamber 11 may be, for example, those cultivated on seedling-raising cell trays 100, but are not limited to this.

[0039] The leaf watering means 12 may be in the form of a sprayer, etc. The leaf watering means 12 is installed in a position and shape that allows it to evenly supply water to the leaves of the seedlings 101 housed in the chamber 11 and does not block the light that is irradiated to the seedlings 101 by the light irradiating means 13 described below.

[0040] The seedling raising system 1 further includes a light irradiation means 13 for irradiating the seedlings 101 with light, and a control unit 14. The light irradiation means 13 may include an LED light source, a fluorescent lamp, or the like as a light source, but an LED light source is preferable in terms of power consumption and lifespan. The timing of turning on and off the light irradiation means 13 is controlled by the control unit 14, and the light irradiation means 13 is repeatedly turned on and off in an arbitrary cycle. In other words, the light-dark cycle in the seedling raising system according to one embodiment of the present invention may be a cycle of turning on and off the light irradiation means 13, with the light period corresponding to the time when the light is on and the dark period corresponding to the time when the light is off.

[0041] The control unit 14 further controls the leaf watering means 12 to be linked with the on / off cycle of the light irradiating means 13. Specifically, the control unit 14 controls the leaf watering means 12 to supply water (mist) to the leaf surfaces of the seedlings before the light irradiating means 13 is turned off, i.e., at a predetermined timing before the dark period of the light-dark cycle begins. The predetermined timing before the dark period of the light-dark cycle begins is as shown in the above columns [1. Cultivation method of Solanaceae plants] and [2. Seedling raising method]. Other cultivation conditions, etc., as described in these columns can also be adopted.

[0042] In addition, although not shown, the seedling raising system 1 may further include a water supplying means, a nutrient supplying means, a temperature adjusting means, a humidity adjusting means, a carbon dioxide gas supplying means, etc. Furthermore, the water supplying means, the nutrient supplying means, the temperature adjusting means, the humidity adjusting means, the carbon dioxide gas supplying means, etc. may be controlled by the control unit 14, and may be controlled so as to be linked to the on / off cycle of the light irradiating means 13. For example, water and nutrients may be supplied to the seedlings 101 from the water supplying means and the nutrient supplying means at the same time as the light irradiating means 13 is turned on, i.e., the start of the light period.

[0043] The light irradiation means 13, water supply means, nutrient supply means, temperature control means, humidity control means, and carbon dioxide gas supply means of the seedling raising system 1 may be substituted with functions of a commercially available closed-type seedling production system. In this case, the control unit 14 may control the leaf watering means 12 in conjunction with the closed-type seedling production system, or may be substituted by adding a function of controlling the leaf watering means 12 to those of the closed-type seedling production system.

[0044] According to the seedling raising system of the present invention, it is possible to perform leaf watering under conditions suitable for plant seedlings, thereby suppressing physiological disorders such as blister disease, thereby maintaining good growth of the seedlings and maintaining their commercial value.

[0045] (summary) To summarise the above embodiments, the present invention can also be summarised as follows. (1) A method for suppressing the occurrence of blister disease in a Solanaceae plant, the method comprising a step of applying water to the leaves of the Solanaceae plant. (2) The method described in (1), wherein the leaf watering is carried out during seedling cultivation. (3) The method according to (1) or (2), wherein the leaf watering is performed at a predetermined timing before the onset of the dark period of the light-dark cycle. (4) The method according to (3), wherein the leaf watering is carried out between 0.5 hours and 4 hours before the onset of the dark period of the light-dark cycle. (5) The method according to (3), wherein the solanaceae plant is grown under an LED light source. (6) The method according to any one of (1) to (5), wherein the solanaceae plant is tomato. (7) A method for raising tomato seedlings, comprising the step of spraying water on the leaves of tomatoes between 0.5 hours and 4 hours before the onset of the dark period of a light-dark cycle. (8) A seedling raising system comprising a chamber for accommodating seedlings and a leaf watering means for watering the leaves, the leaf watering means performing leaf watering at a predetermined timing before the start of the dark period of a light-dark cycle.

[0046] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. EXAMPLES

[0047] An embodiment of the present invention will now be described.

[0048] Using the tomato variety "Momotaro Peace," the following cultivation test was conducted to compare the incidence of blister disease between a sample group with leaf watering and a sample group without leaf watering, and between a sample group using LED lighting (white light source) and a sample group using fluorescent lighting. "Momotaro Peace" is a tomato variety that has been reported to be prone to blister disease.

[0049] Momotaro Peace seeds were sown one per cell in a 128-well cell tray and cultivated under conditions of 30°C temperature, 90% or higher relative humidity, and 24 hours of darkness. Three days after sowing, almost all seeds were confirmed to have germinated.

[0050] After confirming germination, the cell tray was moved into a closed seedling production system (Naeterrace (registered trademark), Mitsubishi Chemical Aqua Solutions Co., Ltd.) for continued cultivation. When moving to the closed seedling production system, 64 cells from the 128-hole cell tray were placed in a cultivation shelf using LED lighting as a light source, and the remaining 64 cells were placed in a cultivation shelf using fluorescent lighting as a light source. Other common cultivation conditions in the closed seedling production system were set as follows. CO2: 1000ppm Temperature: Light period 28℃ / Dark period 23℃ Light / dark cycle: 16 hours light / 8 hours dark

[0051] During cultivation in the closed seedling production system, subirrigation was performed once a day for 10 minutes at the start of the light period. Liquid fertilizer (OAT Houses 1 and 2, OAT Agrio Co., Ltd.) was used for subirrigation.

[0052] From the 8th day after sowing, when the cotyledons had unfolded and the true leaves had begun to appear, the samples with leaf watering under both LED lighting and fluorescent lighting were sprayed with water once a day, 2 hours before the start of the dark period, using a sprayer (The Spray, Maruhachi Sangyo Co., Ltd.) at a rate of approximately 0.05 ml per plant on the leaves near the growth point.

[0053] The incidence of blistering was measured for four sample groups based on whether leaf watering was applied or not, and whether LED lighting or fluorescent lighting was used, 15 days after sowing. The incidence of blistering for each sample group was calculated by observing the condition of each plant in the sample group, assigning a corresponding "incidence index" as shown below, and adding up the incidence indexes for each plant, dividing the total by (4 x total number of plants measured), and multiplying the total by 100. Incidence index 0: No symptoms observed. Incidence index 1: Symptoms are observed on less than half of the leaf area. Incidence index 2: Symptoms are observed on more than half of the leaf area, and there is no defoliation. Incidence index 3: Incidence is observed on more than half of the leaf area, and less than half of the total leaves have fallen. Incidence index 4: Incidence is observed on more than half of the leaf area, and more than half of all leaves have fallen.

[0054] The number of strains used for measurement of each sample group is as follows: LED lighting / leaf water: 36 plants LED lighting / no leaf water: 36 plants Fluorescent light / leaf water: 21 plants Fluorescent light / no water on leaves: 19 plants

[0055] FIG. 2 shows the measurement results of the incidence of blistering in each sample group.

[0056] When LED lighting was used as the light source, in the sample group that did not receive leaf watering, over 80% of the plants had an incidence index of 3 or 4, and the blister incidence was 76.4, showing a significant incidence of blistering. On the other hand, in the sample group that received leaf watering, all but one plant had an incidence index of 0-2, and the blister incidence was 34.7. In other words, it was confirmed that the incidence of blistering in the plants that received leaf watering was suppressed to less than half of the plants that did not receive leaf watering. Figure 3 shows the condition of seedlings 15 days after sowing with and without leaf watering when grown under an LED light source (left: no leaf watering, right: leaf watering from 8 days after sowing).

[0057] On the other hand, when fluorescent lamps were used as the light source, the incidence of blistering was 14.6 in the sample group that was not sprayed with water on the leaves, and the incidence of blistering was 9.0 in the sample group that was sprayed with water on the leaves. Additionally, whether sprayed with water on the leaves or not, the incidence index for each plant was either 0 or 1. In other words, when fluorescent lamps were used as the light source, the incidence of blistering was milder than when LED lighting was used as the light source, but it was suggested that spraying with water on the leaves could further suppress the occurrence of blistering. [Industrial Applicability]

[0058] The present invention can be used in the agricultural field. In particular, it is expected to contribute to the stable production of seedlings of fruit vegetables. [Explanation of symbols]

[0059] 1 Seedling raising system Room 11 12 Leaf watering method 13 Light irradiation means 14 Control section 100 Seedling Cell Trays 101 Seedlings

Claims

1. A method for suppressing the occurrence of blister disease in a solanaceous plant, comprising: The method includes a step of spraying water onto the leaves of the Solanaceae plant.

2. The method according to claim 1 , wherein the leaf watering is carried out during seedling raising.

3. The method according to claim 1 or 2, wherein the leaf watering is carried out at a predetermined timing before the onset of the dark period of the light-dark cycle.

4. The method according to claim 3, wherein the leaf watering is carried out between 0.5 hours and 4 hours before the onset of the dark period of the light-dark cycle.

5. The method of claim 3 , wherein the solanaceous plant is grown under an LED light source.

6. The method according to claim 1 or 2, wherein the solanaceae plant is tomato.

7. A method for raising tomato seedlings, comprising the step of spraying water on the leaves of the tomato plants between 0.5 hours and 4 hours before the onset of the dark period of a light-dark cycle.

8. A chamber for accommodating seedlings and a leaf watering means for watering leaves, The leaf watering means performs leaf watering at a predetermined timing before the start of the dark period of the light-dark cycle. Seedling raising system.

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