JP7373852B2 - How to grow cherry tomato seedlings - Google Patents

Description

The present invention relates to a method for cultivating tomato seedlings.

As a prior art, Patent Document 1 discloses a seedling-raising method for cultivating plant seedlings by irradiating them with artificial light. In this seedling-raising method, fruit and vegetable seedlings are alternately irradiated with red illumination light and blue illumination light, which are artificial lights, and the daily cumulative photosynthetic effective photon amount of red illumination light and blue illumination light is adjusted to a specific range. This improves the survival of seedlings after planting.

Japanese Patent Application Publication No. 2017-169509

By the way, in tomatoes such as cherry tomatoes, so-called double inflorescences may occur in which the peduncles constituting the inflorescences branch, depending on the cultivation conditions of the seedlings. In order to increase the yield of tomatoes, it is preferable to increase the incidence of double inflorescences.
An object of the present invention is to provide a method for cultivating tomato seedlings with a high incidence of double inflorescences.

For this purpose, the method for cultivating cherry tomato seedlings to which the present invention is applied involves continuously irradiating cherry tomato seedlings with blue light for a predetermined first period following a dark period in which no light is irradiated. irradiate,
The seedlings are continuously irradiated with blue light and red light for a predetermined second period following the first period , and the daily cumulative photosynthetically effective photon amount of the blue light is 4 mol·m- ^2. ・day- ¹ or more and 11 mol·m- ² ·day- ¹ or less, and the daily integrated photosynthetically effective photon quantity of the red light is 4 mol·m- ² ·day - ¹ or more and 11 mol·m- ² ·day- ¹ or less It is characterized by
Here, the first period may be 4 hours or more and 10 hours or less.
Furthermore, the first period may be shorter than the second period.
Furthermore, the total period of the dark period, the first period, and the second period may be one day.

According to the present invention, it is possible to provide a method for cultivating cherry tomato seedlings with a high incidence of double inflorescences.

(a) to (c) are diagrams showing the state of an inflorescence of a cherry tomato, and are diagrams showing a state in which fruit has formed in the inflorescence. 3 is a graph showing the number of fruits or flower buds formed in the double inflorescences of the first inflorescence, the second inflorescence, and the third inflorescence for each of Examples 2 to 4.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First, an overview of the method of cultivating tomatoes will be explained. The method for cultivating tomatoes proceeds in the order of, for example, a sowing and germination process, a primary seedling raising process, a secondary seedling raising process, and a planting and harvesting process. Here, tomatoes include varieties of large tomatoes, medium tomatoes (midi tomatoes), and cherry tomatoes. Hereinafter, cherry tomatoes will be described as an example of tomatoes.

In the sowing and germination process, cherry tomato seeds are sown in culture soil. For example, each cell of a cell tray having a plurality of cells is filled with culture soil, and a depression is formed on the upper surface of the culture soil filled in each cell. Then, after sowing cherry tomato seeds one by one in this depression, the seeds are covered with potting soil. Note that in the description of this embodiment, the above procedure may be referred to as seeding.
Next, the cell tray in which the seeds have been sown is housed in a germinator that is adjusted to a predetermined temperature and humidity. Cultivation is then carried out using a sprout generator until a few sprouts appear from the seeds sown in each cell of the cell tray. "Slightly sprouting from the seed" means, for example, in the case of cherry tomatoes, the bud (the stem that supports the cotyledons) is visible between the cultivation soil, but the stem that supports the cotyledons is not fully erect. means. In the description of this embodiment, "slight sprouting from a seed" may be referred to as germination. Cherry tomato seeds will germinate in about 72 hours (3 days) after being placed in a germinator.

Once the seeds sown in each cell of the cell tray germinate, the cell tray is transferred to a plant cultivation device and a primary seedling raising process is performed. Here, the plant cultivation device is a device (seedling raising device) for growing seedlings germinated in a cell tray until they reach a predetermined size. The plant cultivation device includes, for example, a cultivation shelf on which the cell tray is placed, a light irradiation unit that irradiates artificial light to seedlings growing on the cell tray, a water supply unit that supplies nutrient solution to the culture soil of the cell tray, and various parts of the plant cultivation device. It is equipped with a control section etc. that control the. In the plant cultivation device used in this embodiment, the light irradiation unit includes a red light irradiation unit that irradiates red light to the seedlings in the cell tray, and a blue light control unit that irradiates blue light to the seedlings in the cell tray. ing. Then, in the light irradiation section, the irradiation conditions of the red light and blue light irradiated to the seedlings in the cell tray are adjusted based on the control by the control section.
In the primary seedling-raising step, a plant cultivation device irradiates the germinated seedlings with artificial light, supplies a nutrient solution, etc., and grows the seedlings until they reach a predetermined size. In the case of cherry tomatoes, for example, seedlings are grown for about 14 to 30 days until four to five true leaves develop. In addition, the irradiation conditions of artificial light in the primary seedling raising process will be explained in detail later.

When the seedlings reach a predetermined size in the primary seedling raising process, the seedlings in each cell are potted up on a support such as rock wool, coconut shell, urethane resin, soil, etc., and a secondary seedling raising process is performed.
In the secondary seedling raising process, the potted seedlings are irradiated with artificial light or natural light, and a nutrient solution is supplied, and the seedlings are grown until they reach a predetermined size. In the case of cherry tomatoes, for example, seedlings are grown for about 7 to 10 days until flower buds are formed in the first inflorescence (first inflorescence, hereinafter the same), in other words, until the orientation of the flowers in the first inflorescence is known. We will develop the following.
Note that, depending on the growth state of the seedlings in the primary seedling raising process, the type of cherry tomatoes, etc., the secondary seedling raising process may not necessarily be performed.

When the seedlings reach a predetermined size through the secondary seedling raising process, the seedlings on each support are transferred to a field such as a greenhouse or soil, and a planting and harvesting process is performed.
In the planting and harvesting process, the seedlings are grown by irradiating them with natural light and supplying them with nutrient solution. In the planting and harvesting process, as the seedlings grow, the first inflorescence, second inflorescence, etc. bloom and fruit in order from the lower inflorescence. After that, once the fruits formed in each flower cluster have colored, the fruits are harvested in order of color.
In addition, in the planting and harvesting process, operations such as removal of side buds, fruit thinning, core thinning, and top dressing are performed as necessary.

By the way, when cultivating tomatoes such as cherry tomatoes by the above-mentioned process, so-called double flower clusters may occur in the seedlings in the planting and harvesting process depending on the light irradiation conditions in the primary seedling raising process. Double inflorescence is a phenomenon in which the flower peduncles that make up each flower cluster branch on the way from the base to the tip of the flower cluster, and flower buds are formed on each of the branched flower peduncles. In addition, in the description of this embodiment, a normal inflorescence in which the flower stalk does not branch is referred to as a single inflorescence, as opposed to a double inflorescence.
FIGS. 1(a) to 1(c) are diagrams showing the state of inflorescences of cherry tomatoes, and are diagrams showing the state in which fruits have formed in the inflorescences. FIGS. 1(a) and 1(b) show a double inflorescence, and FIG. 1(c) shows a single inflorescence.

As shown in FIGS. 1(a) and 1(b), in a seedling with a double inflorescence, the inflorescence 10 constituting the inflorescence has a branch part 13, and the first inflorescence part extends from the branch part 13 toward the tip side of the inflorescence. 11 and a second peduncle part 12. In the double flower cluster seedling, flower buds are formed in both the first flower stalk part 11 and the second flower stalk part 12, and fruits 20 are formed in both the first flower stalk part 11 and the second flower stalk part 12. Here, in the double inflorescence, as shown in FIG. 1(a), the branching part 13 is formed at the base of the flower stem 10, and as shown in FIG. 1(b), the branching part 13 is formed at the base of the flower stem 10. There are cases where it is formed between the base and the tip. In the double flower cluster shown in FIG. 1(a), fruits 20 are formed in both the first flower stalk part 11 and the second flower stalk part 12. In addition, in the double inflorescence shown in FIG. 1(b), in addition to the first inflorescence part 11 and the second inflorescence part 12, the fruit 20 is also formed in the inflorescence 10 from the base of the inflorescence to the branch part 13. .
On the other hand, as shown in FIG. 1(c), a single flower cluster seedling does not have a branch 13 (see FIGS. 1(a) and 1(b)).

In the double-flowered seedlings shown in FIGS. 1(a) to 1(b), the number of fruits 20 formed in the flower tassel is increased compared to the single-flowered seedlings shown in FIG. 1(c). In other words, seedlings with double inflorescences have a higher yield of fruit 20 than seedlings with single inflorescences. In this example, the double inflorescence seedlings shown in FIGS. 1(a) and 1(b) are different from the single inflorescence seedlings shown in FIG. The yield will increase by 20.

As described above, in order to increase the yield of tomatoes such as cherry tomatoes, it is preferable to generate double flower clusters in tomato seedlings in the planting and harvesting process.
Hereinafter, the light irradiation conditions in the primary seedling raising process for generating double flower clusters in tomato seedlings will be explained in detail using cherry tomatoes as an example.

In the cultivation method to which this embodiment is applied, in the primary seedling raising process, cherry tomato seedlings are continuously exposed to blue light for a predetermined first period (A) following a dark period (D) in which no light is irradiated. During a predetermined second period (B) following the first period (A), blue light and red light are continuously irradiated. In other words, in this embodiment, cherry tomato seedlings are continuously irradiated with blue light over the first period (A) and the second period (B). Between the first period (A) and the second period (B) in which blue light is continuously irradiated, red light is continuously irradiated in the latter second period (B).
Note that in this embodiment, "continuously irradiating light" basically means continuously irradiating light without any break, but if it is a short period, there may be a period in which no light is irradiated. may have. A short period usually means a period of 30 minutes or less, preferably 5 minutes or less, more preferably 1 minute or less.

In the method for cultivating cherry tomato seedlings according to the present embodiment, the dark period (D), the first period (A), and the second period (B) are set as one cycle, and are repeated according to the growth situation of the seedlings. conduct. The length of one cycle including the dark period (D), the first period (A), and the second period (B) can be, for example, one day (24 hours). In addition, in the primary seedling raising process of cherry tomatoes, if the dark period (D), the first period (A), and the second period (B) are one cycle (one day), this cycle is, for example, 14 to 30 cycles. Repeat the cycle (14 days to 30 days).

It is preferable that the first period (A) lasts for at least 4 hours and at most 10 hours. By setting the length of the first period (A) within this range, double flower clusters are likely to occur in cherry tomato seedlings.
Moreover, it is preferable that the second period (B) is in the range of 4 hours or more and 10 hours or less per time. By setting the length of the second period (B) within this range, double flower clusters are likely to occur in cherry tomato seedlings.
Furthermore, it is preferable that the length of the first period (A) is equal to or less than the length of the second period (B).
Furthermore, the dark period (D) varies depending on the length of the first period (A) and the length of the second period (B), but for example, the period of time per period is 4 hours or more and 12 hours or less. is within the range of

In this embodiment, the blue light irradiated during the first period (A) and the second period (B) has a peak wavelength in a range of 400 nm or more and 515 nm or less. From the viewpoint of the photosynthetic reaction efficiency of cherry tomato seedlings and the suppression of the growth of seedlings, the center wavelength of the blue light is preferably in the range of 430 nm or more and 470 nm or less, and more preferably in the range of 440 nm or more and 460 nm or less.
Further, the red light irradiated during the second period (B) has a peak wavelength in a range of 570 nm or more and 730 nm or less. From the viewpoint of the photosynthetic reaction efficiency of cherry tomato seedlings and the growth rate of seedlings, the center wavelength of the red light is preferably in the range of 640 nm or more and 680 nm or less.

In this embodiment, a conventionally known artificial light source can be used for the irradiation of blue light in the first period (A) and the second period (B) and the irradiation of red light in the second period (B). can. Artificial light sources used for irradiation with blue light and red light include LEDs (Light Emitting Diodes), LDs (Laser Diodes), organic ELs (Electro Luminescence), and the like, and among these, it is preferable to use LEDs.
As the LED that emits blue light, for example, a blue LED that has an InGaN light emitting layer that emits light with a peak wavelength of 400 nm to 515 nm can be used. Further, as the LED that emits red light, for example, a red LED that has an AlGaInP light emitting layer that emits light with a peak wavelength of 570 nm to 730 nm can be used.

In this embodiment, the amount of blue light is 4 mol·m- ² ·day ^-1 or more and 15 mol·m- ² ·day in daily light integral (DLI) on the cultivation surface of the seedling. - Can be in the range ¹ or less. If the DLI of blue light is less than 4 mol·m- ² ·day- ¹ , seedling growth may be impaired. Furthermore, when the DLI of blue light exceeds 15 mol·m- ² ·day- ¹ , energy consumption tends to increase, although the growth of plant seedlings etc. is not affected.
The DLI of blue light is preferably in the range of 4 mol·m- ² ·day ^-1 or more and 11 mol·m- ² ·day- ¹ or less. By setting the DLI of blue light to 11 mol/m- ² /day- ¹ or less, seedling growth is suppressed compared to when the DLI exceeds 11 mol/m- ² /day- ¹ , but cherry tomatoes Double inflorescences are more likely to occur in seedlings, increasing yield.

Further, the amount of red light can be in the range of 4 mol·m ^-2 ·day ^-1 or more and 15 mol·m- ² ·day- ^{1 or} less in terms of DLI on the cultivation surface of the seedling. If the DLI of red light is less than 4 mol·m- ² ·day- ¹ , seedling growth may be impaired. Furthermore, when the DLI of red light exceeds 15 mol·m- ² ·day- ¹ , the growth of plant seedlings etc. is not affected, but energy consumption tends to increase.
The DLI of red light is preferably in the range of 4 mol·m- ² ·day ^-1 or more and 11 mol·m- ² ·day- ¹ or less. By setting the DLI of red light to 11 mol/m- ² /day- ¹ or less, seedling growth is suppressed compared to when the DLI exceeds 11 mol/m- ² /day- ¹ , but cherry tomatoes Double inflorescences are more likely to occur in seedlings, increasing yield.

In the description of this embodiment, the seedling cultivation surface means the upper surface of the culture soil on which the seedlings grow. The amount of light on the cultivation surface of the seedlings can be measured by placing a sensor on the cultivation surface. Furthermore, when cultivating seedlings by hydroponics or the like without using culture soil, the cultivation surface means the upper surface of the panel on which the seedlings are planted.

Furthermore, in the present embodiment, the temperature during cultivation in the primary seedling raising step may be any temperature that is generally used for cultivating cherry tomato seedlings, and may be in the range of 16°C or higher and 28°C or lower, for example. , preferably in the range of 17°C or higher and 26°C or lower.
In addition, the humidity (relative humidity) during cultivation in the primary seedling raising process may be any humidity at which cherry tomato seedlings are generally cultivated, for example, it can be in the range of 39% or more and 90% or less, and 50% or more. It is preferable to set it as the range of % or more and 80% or less.
By keeping the temperature and humidity during cultivation within this range, it is possible to suppress the elongation of the seedlings and promote the growth of the seedlings.

Further, in the primary seedling raising step, the carbon dioxide concentration may be set to the concentration in the atmosphere, or carbon dioxide may be added to increase the carbon dioxide concentration compared to the atmosphere. When adding carbon dioxide gas, the carbon dioxide concentration can be, for example, in the range of 400 ppm or more and 1200 ppm or less, and preferably in the range of 700 ppm or more and 1000 ppm or less.

As described above, the cultivation method of the present embodiment can be applied to tomatoes of the Solanaceae family, such as large tomatoes, medium tomatoes (midi tomatoes), and cherry tomatoes, and is preferably applied to cherry tomatoes.

Next, the present invention will be explained in more detail using Examples. Note that the present invention is not limited to the following examples.
(Example 1)
Cherry tomato seedlings were cultivated as follows using the cultivation method to which the present invention is applied.
First, seed culture soil No. 1 (manufactured by Sumirin Nosan Kogyo Co., Ltd.) and Fuyolite No. 2 (manufactured by Fuyo Perlite Co., Ltd.) were added to each cell of a cell tray in which 72 cells were formed in a lattice shape at a ratio of 1:1. It was filled with mixed culture soil. Then, a depression was formed on the top surface of the culture soil filled in each cell, and one seed of cherry tomato "Petit Puyo" was sown in each of the depressions, and the seeds were then covered with culture soil.

Next, the cell tray in which the seeds were sown in the culture soil of each cell was placed in a germinator kept at 27° C. for 3 days (seeding and germination step).
Thereafter, the cell tray was transferred to a closed plant cultivation device (day 0 of cultivation), and the primary seedling raising process was performed under the following cultivation conditions until day 21 of cultivation.

The culture solution was prepared by dissolving 2.93 mL of Hi Tempo Cu (manufactured by Sumitomo Chemical Co., Ltd.) and 0.98 mL of Hi Tempo Ar (manufactured by Sumitomo Chemical Co., Ltd.) per liter, and the electrical conductivity (EC) of the solution was 1. .6 dS/m and pH 5.9. Further, the content ratio of nitrogen (N), phosphorus (P), and potassium (K) was set to N:P:K=5.9:1.1:2.4.
Irrigation (supply of culture soil) was performed once a day for 10 minutes (from 8:40 to 8:50), and after irrigation was completed, the culture solution was filled to a height of about 30 mm from the bottom of the cell tray. state.

Furthermore, the environment of the seedling growing device during the primary seedling growing process was set so that the average temperature was 23°C. Specifically, the temperature was set at 18°C between 0:00 and 8:00, and the temperature was set at 25°C between 8:00 and 14:00. Further, although humidity was not controlled, the actual relative humidity values during the primary seedling growing process were 39% to 60%. Moreover, the carbon dioxide concentration in the plant cultivation apparatus was set to 1000 ppm.

The light source is a light that emits blue light and red light (RRB, product number: UL0005#01-0R, LED chips: 160 red + 80 blue, wavelength: red 640 nm to 680 nm, blue 425 nm to 475 nm, center wavelength : A straight tube type LED lighting equipped with red 660 nm and blue 450 nm (manufactured by Showa Denko Co., Ltd.) was used. Then, this straight tube type LED lighting was independently controlled into blue light and red light using a dimmer with a timer, and the irradiation time, irradiation light amount, etc. of the blue light and red light were controlled.
Furthermore, a photon sensor (LI-190, LI-COR) and a light meter (LI-250, LI-COR) were used to measure the amount of blue light and red light.

The light irradiation was carried out for 10 hours from 8:00 to 18:00 as the first period (A) on each day from the 0th day of cultivation to the 21st day of cultivation when the primary seedling raising process was carried out. PPFD (Photosynthetic Photon Flux Density): 145 μmol·m ⁻² ·s ⁻¹ ) was irradiated. In addition, as a second period (B) following the first period (A), for 10 hours from 18:00 to 4:00, blue light (PPFD: 145 μmol・m ⁻²・s ⁻¹ ) and red light (PPFD: 290 μmol·m ⁻² ·s ⁻¹ ) was irradiated. Furthermore, no light was irradiated for 4 hours from 4:00 to 8:00 as a dark period (D) following the second period (B). In addition, by irradiating light as described above during the primary seedling raising process from day 0 of cultivation to day 21 of cultivation, the first period (A), the second period (B), and the dark period (D), the first period (A), the second period (B), and so on, each period is repeated.
The DLI of blue light was 10.4 mol·m- ² ·day- ¹ , and the DLI of red light was 10.4 mol·m ^-2 ·day ^-1 .

(Comparative example 1)
A primary light source was prepared in the same manner as in Example 2, except that a fluorescent lamp (Hitachi Hf fluorescent lamp, Heilmic FHF32EX-NK, 32-watt three-wavelength daylight white fluorescent lamp) was used as the light source, and the light was irradiated under the following conditions. The seedling raising process was carried out.
Light irradiation was carried out using white light (PPFD: 363 μmol m ^-2 -s ^-1 ) for 16 hours from 8:00 to 0:00 on each day from the 0th day of cultivation to the 21st day of cultivation during the primary seedling raising process. Light was not irradiated for 8 hours from 0:00 to 8:00.
The DLI of white light was 20.9 mol·m- ² ·day ^-1 .

(evaluation)
Regarding Example 1 and Comparative Example 1, the seedlings that had completed the primary seedling raising process were taken out of the plant cultivation device and planted in Rockwool for plant cultivation "Vegetable Flower Pot 75 x 75 x 75 mm" (manufactured by Nippon Rockwool Co., Ltd.). The secondary seedling growing process was carried out using natural light in the secondary seedling growing room inside the greenhouse. Then, on the 30th day of cultivation counting from the start of primary seedling raising (10th day after starting secondary seedling raising), the seedlings that have completed the secondary seedling raising process are placed in a 1000 mm long slab "Grotop Expert" ( (manufactured by Grodan) and planted in the field.
Then, on the 101st day of cultivation counting from the start of primary seedling raising (69th day after planting), it was visually observed whether double inflorescences had developed in the third and fourth inflorescences of the seedlings. Additionally, for the third and fourth inflorescences, it was observed whether the pedicels constituting the inflorescences were branched. Observations were made by selecting 10 seedlings for each of Example 1 and Comparative Example 1.

In the seedlings of Example 1, the incidence of double inflorescences in the third inflorescence was 30% (that is, it was observed that double inflorescences occurred in 3 out of 10 seedlings. The same applies hereafter. ), the incidence of double inflorescences in the fourth inflorescence was 70%.
On the other hand, in Comparative Example 1, the incidence of double inflorescences in the third inflorescence was 0%, and the incidence of double inflorescences in the fourth inflorescence was 30%.

(Example 2)
A primary seedling-raising process was carried out in the same manner as in Example 1, except that seeds of cherry tomato "Chika" were used and light was irradiated under the following conditions.
The light irradiation was carried out for 4 hours and 12 minutes from 8:00 to 12:12 as the first period (A) on each day from the 0th day of cultivation to the 21st day of cultivation when the primary seedling raising process was carried out, using blue light (PPFD). :181 μmol·m ⁻² ·s ⁻¹ ). In addition, as a second period (B) following the first period (A), for 7 hours and 48 minutes from 12:12 to 20:00, blue light (PPFD: 181 μmol・m ^-2・s ^-1 ) and red light were (PPFD: 279 μmol·m ⁻² ·s ⁻¹ ) was irradiated. Furthermore, no light was irradiated for 12 hours from 20:00 to 8:00 as a dark period (D) following the second period (B).
The DLI of blue light was 7.8 mol·m- ² ·day- ¹ , and the DLI of red light was 7.8 mol·m ^-2 ·day ^-1 .

(Example 3)
The primary seedling raising process was carried out in the same manner as in Example 2, except that light was irradiated under the following conditions.
The light irradiation was carried out for 4 hours and 12 minutes from 8:00 to 12:12 as the first period (A) on each day from the 0th day of cultivation to the 21st day of cultivation when the primary seedling raising process was carried out, using blue light (PPFD). :241 μmol·m ⁻² ·s ⁻¹ ). In addition, as a second period (B) following the first period (A), for 7 hours and 48 minutes from 12:12 to 20:00, blue light (PPFD: 241 μmol・m ^-2・s ^-1 ) and red light (PPFD: 372 μmol·m ⁻² ·s ⁻¹ ) was irradiated. Furthermore, no light was irradiated for 12 hours from 20:00 to 8:00 as a dark period (D) following the second period (B).
The DLI of blue light was 10.4 mol·m- ² ·day- ¹ , and the DLI of red light was 10.4 mol·m ^-2 ·day ^-1 .

(Example 4)
The primary seedling raising process was carried out in the same manner as in Example 2, except that light was irradiated under the following conditions.
The light irradiation was carried out for 4 hours and 12 minutes from 8:00 to 12:12 as the first period (A) on each day from the 0th day of cultivation to the 21st day of cultivation when the primary seedling raising process was carried out, using blue light (PPFD). :301 μmol·m ⁻² ·s ⁻¹ ). In addition, as a second period (B) following the first period (A), for 7 hours and 48 minutes from 12:12 to 20:00, blue light (PPFD: 301 μmol・m ^-2・s ^-1 ) and red light were (PPFD: 465 μmol·m ⁻² ·s ⁻¹ ) was irradiated. Furthermore, no light was irradiated for 12 hours from 20:00 to 8:00 as a dark period (D) following the second period (B).
The DLI of blue light was 13.0 mol·m- ² ·day- ¹ , and the DLI of red light was 13.1 mol·m ^-2 ·day ^-1 .

(Comparative example 2)
The primary seedling raising process was carried out in the same manner as in Example 2, except that light was irradiated under the following conditions.
The light irradiation was carried out for 6 hours and 48 minutes from 8:00 to 14:48 on each day from the 0th day of cultivation to the 21st day of cultivation during the primary seedling raising process, using blue light (PPFD: 210 μmol m ^-2 s). ^-1 ) and red light (PPFD: 360 μmol·m ⁻² ·s ⁻¹ ). Next, blue light (PPFD: 210 μmol·m ⁻² ·s ⁻¹ ) was irradiated for 5 hours and 12 minutes from 14:48 to 20:00. Next, no light was irradiated for 12 hours from 8:00 pm to 8:00 am.
The DLI of blue light was 9.1 mol·m- ² ·day- ¹ , and the DLI of red light was 8.8 mol·m ^-2 ·day ^-1 .

(evaluation)
For Examples 2 to 4 and Comparative Example 2, the seedlings that had completed the primary seedling raising process were taken out of the seedling raising device and planted in Rockwool for plant cultivation "Vegetable Pot 75 x 75 x 75 mm" (manufactured by Nippon Rockwool Co., Ltd.). Then, a secondary seedling growing process was carried out using natural light in a secondary seedling growing room inside the greenhouse. Then, on the 30th day of cultivation counting from the start of primary seedling raising (10th day after starting secondary seedling raising), the seedlings that have completed the secondary seedling raising process are placed in a 1000 mm long slab "Grotop Expert" ( (manufactured by Grodan) and planted in the field.
Then, on the 46th day of cultivation counting from the start of primary seedling raising (14th day after planting), it was visually observed whether double inflorescences had developed in the first, second, and third inflorescences. . In addition, the first inflorescence, the second inflorescence, and the third inflorescence were observed to see whether the pedicels constituting the inflorescences were branched. Observations were made by selecting 10 seedlings for each of Examples 2 to 4 and Comparative Example 2. Note that on the 46th day of cultivation, the third inflorescence had not fully expanded and was in the middle of expansion.

In the seedlings of Examples 2 to 4, double inflorescences were observed in the first, second, and third inflorescences. On the other hand, in Comparative Example 2, no seedlings with double inflorescences in the first, second, and third inflorescences were observed.

Regarding the seedlings of Examples 2 to 4, the number of fruits or flower buds formed in the double inflorescences of the first inflorescence, second inflorescence, and third inflorescence was counted. Here, the number of fruits or flower buds formed in a double inflorescence is the number of fruits or flower buds increased due to the formation of a double inflorescence, and is indicated by the reference numeral 15 in FIGS. 1(a) and (b). This is the number of fruits or flower buds in the flower pedicle that has fewer fruits or flower buds formed among the two flower pedicels extending from the branching part 13 of the double inflorescence.
FIG. 2 is a graph showing the number of fruits or flower buds formed in the double inflorescences of the first inflorescence, second inflorescence, and third inflorescence for each of Examples 2 to 4. FIG. 2 shows the average number of fruit or flower buds measured for 10 seedlings for each of Examples 2 to 4.

As shown in FIG. 2, in Examples 2 to 4, the daily integrated photosynthetically effective light quantum amount DLI of blue light irradiated during the first period (A), blue light and red light irradiated during the second period (B) It was confirmed that the smaller the number of flowers, the more fruits or flower buds are formed by the double inflorescence, and the higher the yield.

10...Flower stem, 11...First flower stem, 12...Second flower stem, 13...Branch, 20... Fruit

Claims (4)

Cherry tomato seedlings are continuously irradiated with blue light for a predetermined first period following a dark period in which no light is irradiated,
Continuously irradiating the seedling with blue light and red light for a predetermined second period following the first period ,
The daily integrated effective photosynthetic photon amount of the blue light is 4 mol·m- ² ·day- ¹ or more and 11 mol·m- ² ·day- ¹ or less, and the daily integrated photosynthetic effective photon amount of the red light is 4 mol·m-2·day-1 or less. - A method for cultivating cherry tomato seedlings, characterized in that the amount is ^2.day - ¹ or more and 11 mol.m- ^2.day - ¹ or less. The method for cultivating cherry tomato seedlings according to claim 1, wherein the first period is 4 hours or more and 10 hours or less. The method for cultivating cherry tomato seedlings according to claim 1 or 2 , wherein the first period is shorter than the second period. The method for cultivating cherry tomato seedlings according to any one of claims 1 to 3, wherein the total period of the dark period, the first period, and the second period is one day.

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