Corn photomorphogenesis induction for rapid breeding in plant factory

Abstract

The application discloses a corn photomorphogenesis establishment induction rapid breeding method for a plant factory, belongs to the technical field of plant factory breeding, and solves the problems of low photomorphogenesis establishment induction efficiency, long cycle caused by delayed flowering and unsuitable reproductive light environment in the existing corn rapid breeding. The method adopts photodormancy temperate corn inbred line seeds, adopts mixed irradiation of red light and far-red light before the growth stage after the induction is switched in, and adopts mixed irradiation of red light and blue light after the growth stage after the induction is switched in; wherein, when the leaf age of more than 80% of the corn plants reaches 5-6 pieces, a 21-day dark interruption treatment is added at the midpoint of each photoperiod dark period, the dark interruption treatment also uses mixed irradiation of red light and far-red light, the time length is 10-30 min, and the photon flux density ratio of the red light and the far-red light gradually decreases in the time length. The method is used for corn rapid breeding in a plant factory, can induce photomorphogenesis establishment and shorten the cycle.

Description

Technical Field

[0001] This invention relates to the field of plant factory breeding technology. More specifically, this invention relates to a rapid breeding method for inducing photomorphogenesis in maize for use in plant factories. Background Technology

[0002] In maize breeding, the long generation cycle is one of the key factors restricting breeding efficiency. Under traditional field planting conditions, temperate maize inbred lines can typically only be planted for 1 to 2 generations per year, requiring approximately 100-120 days from sowing to seed maturity. This makes the homozygosity and trait aggregation process of breeding materials time-consuming. To shorten the breeding cycle, researchers have attempted to conduct maize generation-accumulation breeding in artificially controlled environments, such as using greenhouses or plant factories to achieve year-round planting. However, several technical problems still exist in practical applications.

[0003] First, maize is a crop that is quite sensitive to photoperiod. Most temperate maize inbred lines exhibit delayed flowering under long-day conditions, while flowering is promoted under short-day conditions. Plant factories often use fixed light durations (such as 12 to 14 hours) for cultivation, but simply shortening the light duration is often insufficient to fully induce the reproductive growth transition, resulting in excessive vegetative growth of maize plants, delayed tasseling and silking, and a period from sowing to seed harvest that is still significantly longer than the theoretical minimum generation interval.

[0004] Secondly, existing artificial light environment control methods have limited efficiency in inducing photomorphogenesis in maize. Some methods use continuous red light or red-blue light combinations to promote growth, but neglect the role of far-red light in photoperiod signal perception. Studies have shown that far-red light can regulate flowering time through the phytochrome system, but current technologies lack dynamic light quality control schemes for maize from the seedling stage to the reproductive growth stage. This results in insufficient induction of flowering transition by light signals, and plants often require a long vegetative growth period to initiate flower bud differentiation.

[0005] Third, while intermittent dark-day treatment is an effective means of regulating flowering in short-day plants, its application in rapid maize breeding is still immature. In existing treatment schemes, the light quality ratio during intermittent dark-day treatment is mostly a fixed value, failing to consider the changes in light signal sensitivity of maize plants at different developmental stages. Furthermore, the timing, duration, and frequency of intermittent dark-day treatment lack a basis for determining their correlation with the actual leaf age of the plant. Treatment that is too early or too late may lead to a decrease in induction effect or even cause abnormal morphogenesis, such as excessive internode elongation or loss of apical dominance.

[0006] Fourth, after flowering induction, maize plants require a suitable light environment to support ear differentiation, tasseling, silking, and grain filling. Current plant factories often use the same light parameters as during the vegetative growth stage, or simply increase light intensity and duration, without adjusting the spectral ratio according to the photomorphogenesis requirements of the reproductive growth stage. This practice easily leads to an imbalance in the distribution of photosynthetic products, manifesting as poor ear development, low pollination and seed setting rates, or insufficient grain filling, ultimately affecting seed yield and quality.

[0007] In summary, in the existing rapid breeding technology for corn in plant factories, how to efficiently induce photomorphogenesis, synchronously coordinate vegetative and reproductive growth, and shorten the cycle from sowing to seed harvest by precisely controlling light environment parameters is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] The purpose of this invention is to provide a rapid breeding method for inducing photomorphogenesis in maize for plant factories, so as to at least solve the above-mentioned problems.

[0009] To achieve the objectives and other advantages of this invention, a rapid breeding method for inducing photomorphogenesis in maize for plant factories is provided, comprising: Seeds from a light-insensitive temperate maize inbred line were used as breeding material. These seeds were sown in a plant factory, and basic light environment parameters were set: photoperiod of 12-13 h and photosynthetically active photon flux density of 700-900 μmol / (m²). 2 •s), using a mixture of red and far-red light for irradiation, with red light wavelength of 660±10 nm and far-red light wavelength of 730±10 nm, and the photon flux density ratio of red light to far-red light controlled between 1.5:1 and 2.5:1; The current leaf age of the corn plant is detected, and the trigger point for starting the dark period interruption process is when the number of leaves reaches 5-6. When more than 80% of the corn plants have 5-6 leaves, a 10-30 min dark period interruption is applied at the midpoint of the dark period in each photocycle. The dark period interruption lasts for 21 days. The light source used for the dark period interruption is a mixture of red and far-red light, with a red light wavelength of 660 ±10 nm and a far-red light wavelength of 730 ±10 nm. The ratio of the photon flux density of red light to far-red light is controlled between 1:1 and 2:1, and this ratio decreases step by step during the dark period interruption according to the following pattern: 2:1 for days 1-7, 1.5:1 for days 8-14, and 1:1 for days 15-21. The basic light environment parameters remain unchanged during the dark period interruption. After the dark period interruption treatment, the maize plants were transferred to the post-induction growth stage, and the photoperiod was adjusted to 14-16 hours, reducing the photosynthetically active photon flux density to 400-600 μmol / (m²). 2 •s) Irradiation is carried out using a mixture of red and blue light, with the ratio of the photon flux density of red light to blue light controlled between 3:1 and 7:1, until the corn plants complete tasseling and silking, and the seeds are harvested.

[0010] Preferably, during the first 14 days of the dark period interruption treatment, a dark period interruption treatment is applied only once at the midpoint of each day's dark period; during the first 15 days of the dark period interruption treatment, a dark period interruption treatment is applied once at the midpoint of each day's dark period and once 2 hours before the end of the dark period.

[0011] Preferably, the duration of each dark period interruption is dynamically adjusted according to the real-time plant height growth rate of maize plants: when the plant height growth rate exceeds 5 mm / d for three consecutive days, the duration of a single dark period interruption is extended to 1.2-1.5 times the original duration; when the plant height growth rate is less than 1 mm / d for three consecutive days, the duration of a single dark period interruption is shortened to 0.6-0.8 times the original duration.

[0012] Preferably, after the dark period interruption treatment ends and the induction growth stage begins, a 4-7 day light environment transition period is first implemented. During this transition period, the light source is gradually transitioned from a mixture of red and far-red light to a mixture of red and blue light. Specifically, the illumination time is increased by 0.5-1 hour per day, and the photosynthetically active photon flux density is decreased by 40-80 μmol / (m²) per day. 2 ·s), while increasing the percentage of blue light photon flux density in the mixed light by 2%-5% daily until the percentage of blue light photon flux density reaches 16.7%-25%, which corresponds to a photon flux density ratio of red light to blue light of 3:1 to 5:1.

[0013] Preferably, during the post-induction growth stage, before the corn plant completes tasseling, the photon flux density ratio of red light to blue light is controlled between 3:1 and 4:1; after the corn plant completes tasseling, the photon flux density ratio of red light to blue light is switched to between 4:1 and 5:1.

[0014] Preferably, during the post-induction growth stage, starting from the date the corn plant completes silking, the mass concentration ratio of nitrogen to potassium in the nutrient solution is adjusted from 1:2 to 1:3 to 1:4 to 1:6, and the photon flux density ratio of red light to blue light is adjusted to 5:1 to 7:1, continuing until seed harvest.

[0015] Preferably, a vertical three-dimensional cultivation rack is used for layered planting, with two rows of corn planted on each layer, with a row spacing of 20-30 cm and a plant spacing of 10-15 cm. A movable LED light source module is installed above each layer of the cultivation rack. The distance between the light source module and the corn plant canopy is maintained at 30-40 cm before entering the dark interruption treatment stage, the distance is shortened to 20-30 cm after entering the dark interruption treatment stage, and the distance is restored to 30-40 cm after entering the induction growth stage.

[0016] Preferably, during the post-induction growth stage, the daytime temperature is set to 24°C-26°C, the nighttime temperature to 18°C-20°C, the relative humidity to 50%-60%, and the carbon dioxide concentration to 1200-1500 ppm.

[0017] The present invention has at least the following beneficial effects: First, the method of this invention targets light-insensitive temperate maize inbred lines. In the basic light environment, a mixture of red and far-red light is used for irradiation. When the leaves reach 5-6, a dark interruption treatment is initiated. During the dark interruption treatment, the ratio of red to far-red light is gradually reduced to avoid over-adaptation or desensitization of the photoreceptors, effectively improving the flowering conversion efficiency. After the dark interruption ends, a long light environment with a mixture of red and blue light is introduced to support the accumulation of photosynthetic products required for reproductive growth. Overall, this method significantly shortens the cycle from sowing to tasseling, silking, and seed harvesting, solving the problems of delayed flowering and unsuitable reproductive light environment in the prior art.

[0018] Secondly, by adding an additional light interruption before the end of the dark period in the later stage of the dark period interruption treatment, the cumulative effect on the photoperiodic signal was enhanced. This phased and asymmetric interruption frequency design enabled the maize plants to maintain a high flower signal intensity in the later stage of induction, which promoted the continuous differentiation and development of flower organs, improved the synchronicity of tasseling and silking, reduced the uneven development caused by individual differences, and thus improved the overall breeding efficiency of the breeding population.

[0019] Third, by monitoring the plant height growth rate of maize plants in real time and dynamically adjusting the duration of the dark period interruption treatment, a closed-loop feedback control of vegetative growth potential was achieved: when the plant height growth is too fast, the interruption treatment is extended to moderately inhibit excessive internode elongation and prevent excessive growth; when growth stagnates, the interruption treatment is shortened to avoid excessive inhibition and affect the accumulation of photosynthetic area. This adaptive adjustment method makes the photomorphogenesis induction match the actual physiological state of the plant, ensuring sufficient vegetative body size to support subsequent reproductive growth, and preventing flowering delay caused by excessive vegetative growth.

[0020] Fourth, by setting a light environment transition period before the induced growth stage after the dark period interruption, by gradually increasing the light duration, reducing the photosynthetically active photon flux density, and gradually increasing the proportion of blue light, the photosynthetic system and photoreceptors of maize plants can smoothly adapt to the transition from red / far-red light to red / blue light, effectively avoiding photoinhibition or photomorphogenesis disorder caused by abrupt changes in the light environment, and ensuring the continuous development of floral organs during the transition period.

[0021] Fifth, during the post-induction growth stage, the ratio of photon flux density of red and blue light is controlled in stages according to whether the maize plant has completed tasseling: a relatively high proportion of blue light is used before tasseling is completed, which is conducive to maintaining a compact plant shape and promoting normal tassel emergence. After tasseling is completed, a higher proportion of red light is switched to facilitate the transport and distribution of photosynthetic products to the ear, promoting grain filling. Through this staged spectral regulation, structural development and material production are taken into account, which effectively improves the seed setting rate and seed fullness, while avoiding the problem of poor adaptability that may occur during the reproductive transition period with a single fixed light quality ratio.

[0022] Sixth, by simultaneously adjusting the nitrogen-potassium mass concentration ratio and the red-blue light ratio in the nutrient solution from the date the corn plant completes silking, a synergistic regulation of nutrients and light signals is formed: reducing the nitrogen-potassium ratio helps to inhibit excessive germination of new leaves in the later stage of vegetative growth, directing more photosynthetic products to the grains; increasing the proportion of red light enhances the conversion efficiency of the photosynthetic electron transport chain to photosynthetic assimilation and promotes the transport of sugars from the source organs to the grains. This combined regulation significantly prolongs the effective duration of grain filling, improves the uniformity of seed maturity and thousand-grain weight, and enhances the vigor and genetic stability of harvested seeds.

[0023] Seventh, by adopting vertical three-dimensional cultivation racks and movable LED light source modules, combined with adjusting the distance of the light source at different stages, the space utilization and light energy efficiency of the plant factory are significantly improved. During the dark intermittent treatment stage, the distance of the light source is shortened, enhancing the photon flux density reaching the canopy and the signal intensity of red / far-red light, thus improving the induction effect. In the early vegetative growth stage and the post-induction growth stage, the distance is restored to a greater distance, avoiding photoinhibition or heat load caused by excessive light intensity.

[0024] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0026] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials described are commercially available.

[0027] In all treatments described below, the light-insensitive temperate maize inbred line "Zheng 58" was used as the material. Seeds were surface-sterilized with 0.1% HgCl2 for 10 min and then sown in a composite substrate of peat moss:vermiculite:perlite = 2:1:1, placed on vertical cultivation racks with a row spacing of 25 cm and a plant spacing of 12 cm. Movable LED light source modules were installed above each layer of the vertical cultivation racks. The basic environmental settings within the plant factory were: daytime temperature 28°C, nighttime temperature 23°C, relative humidity 60%, and CO2 concentration 600 ppm. The nutrient solution used was the Hoagland formula. Artificial pollination was performed daily during the silking stage. The remaining procedures for each treatment are as follows.

[0028] Example 1: After sowing, the basic light environment was set as follows: light duration 12.5 h, photosynthetically active photon flux (PPFD) 800 μmol / (m²). 2 The plants were irradiated with a mixture of red (660 nm) and far-red (730 nm) light, with a red to far-red photon flux ratio (R:FR) of 2:1. Leaf age was observed daily, and when over 80% of the plants had 5-6 leaves, a dark interruption treatment was initiated, lasting 21 days. During the dark interruption treatment, the baseline light environment parameters remained constant. The light source used for the dark interruption treatment was a mixture of red and far-red light, with the R:FR ratio decreasing progressively: 2:1 from days 1-7, 1.5:1 from days 8-14, and 1:1 from days 15-21. During days 1-14, the dark interruption treatment was applied only once at the midpoint of each day's dark period; during days 15-21, it was applied once at the midpoint of each day's dark period and again 2 hours before the end of the dark period. The baseline duration of each dark interruption treatment was 20 minutes, dynamically adjusted based on the real-time plant height growth rate of maize plants: when the plant height growth rate exceeded 5 mm / d for three consecutive days, the duration of a single dark interruption treatment was extended to 26 minutes; when the plant height growth rate was less than 1 mm / d for three consecutive days, it was shortened to 14 minutes. After the dark interruption treatment, a 5-day light environment transition period was implemented: the light duration was increased by 0.8 hours daily until it reached 15 hours, and PPFD was reduced by 60 μmol / (m²) daily. 2 ·s) until PPFD drops to 500 μmol / (m 2•s), the percentage of photon flux density of blue light (450 nm) in the mixed light is increased by 4% daily until the blue light proportion reaches 20%, corresponding to a red light to blue light ratio R:B = 4:1. After the transition period, the induction growth stage begins: illumination time 15 h, PPFD 500 μmol / (m 2 •s), using a mixture of red and blue light for irradiation. Before the corn plants complete tasseling, the R:B ratio is 3.5:1; from the date of tasseling completion, the R:B ratio is switched to 4.5:1. From the date the corn plants complete silking, the mass concentration ratio of nitrogen to potassium in the nutrient solution is adjusted from 1:2.5 to 1:5, and the R:B ratio is adjusted to 6:1, continuing until seed harvest. The distance between the LED light source module on the vertical cultivation rack and the corn plant canopy is maintained at 35 cm before entering the dark interruption treatment stage, shortened to 25 cm after entering the dark interruption treatment stage, and restored to 35 cm after entering the post-induction growth stage. The post-induction growth stage is set with a daytime temperature of 25°C, a nighttime temperature of 19°C, a relative humidity of 55%, and a CO2 concentration of 1350 ppm.

[0029] Comparative Example 1: The only difference from Example 1 is that during the entire dark period interruption process, a dark period interruption is always applied only once at the midpoint of the dark period each day, and a second interruption is not added before the end of the dark period. All other processes are exactly the same as in Example 1.

[0030] Comparative Example 2: The only difference from Example 1 is that the duration of each interruption during the dark period is fixed at 20 minutes and is not dynamically adjusted according to the plant height growth rate. All other treatments are exactly the same as in Example 1.

[0031] Comparative Example 3: The only difference from Example 1 is that, during the post-induction growth stage, from the transition to this stage until seed harvest, the R:B ratio remains constant at 4:1. All other treatments are exactly the same as in Example 1.

[0032] Comparative Example 4: The only difference from Example 1 is that during the dark intermittent processing, the R:FR ratio is fixed at 1.5:1 and is not gradually decreased. All other processing steps are exactly the same as in Example 1.

[0033] Example for comparison: Using a traditional red-blue light combination (R:B=3:1), with an illumination time of 14 h, PPFD was 600 μmol / (m 2·s), no far-red light is introduced throughout the process, no dark period interruption is performed, no transition period is set, no segmented light quality adjustment is made, the nutrient solution and light quality are not changed after silking, the temperature, humidity and CO2 are kept constant (28°C during the day / 23°C at night, relative humidity 60%, CO2 concentration 600 ppm, the nutrient solution uses the standard Hoagland formula (N:K=1:2.5), the distance between the light source module and the canopy is fixed at 40 cm, and no distance adjustment is made. The planting density and substrate are the same as in Example 1.

[0034] Experimental example: I. Experimental Methods (1) Breeding cycle: Record the number of days from sowing to 50% of the plants tasseling, the number of days from sowing to 50% of the plants spinning silk, and the number of days from seed maturity for harvest.

[0035] (2) Yield per plant: All grains are harvested from each plant, the number of grains per ear and the weight of 1,000 grains are measured, and the dry weight of grains per plant (grams) is calculated.

[0036] (3) Seed germination rate: 50 seeds were taken from each treatment and placed in a petri dish lined with moist filter paper. The seeds were incubated in the dark at 25°C for 7 days. The number of germinated seeds was counted (radicle length ≥ 2 mm was considered as germination), and the germination rate (%) was calculated.

[0037] (4) Photomorphogenesis effect: At the end of the dark period interruption treatment, the plant height and average internode length were measured, and the shoot tip was dissected to observe the differentiation of tassel primordia under a stereomicroscope. The differentiation time of tassel primordia (number of days after sowing) was recorded.

[0038] All treatments were set up with 3 replicates, with 10 plants per replicate. Data are expressed as mean ± standard deviation. One-way ANOVA was performed using SPSS software, and multiple comparisons were performed using the LSD method (significance level p < 0.05).

[0039] II. Experimental Results The results are shown in the table below.

[0040] Note: Different lowercase letters in the same row indicate significant differences (p<0.05).

[0041] As shown in the table above, compared with Comparative Example 1, Example 1, by adding a second interruption before the end of the dark period, advanced tasseling by 3.2 days, shortened the harvest cycle by 3.9 days, and increased the yield per plant by 7.8%, indicating that increasing the interruption frequency in the later stages can enhance the cumulative effect of photoperiodic signals and improve flowering induction efficiency. Compared with Comparative Example 2, Example 1, by dynamically adjusting the interruption duration, reduced plant height by 7.1 cm and increased the yield per plant by 5.5%, indicating that adjusting the interruption duration based on the plant height growth rate feedback can effectively control vegetative growth potential, prevent excessive vegetative growth, and optimize the allocation of photosynthetic products. Compared with Comparative Example 3, Example 1, by increasing the proportion of red light after tasseling, advanced tasseling by 1.5 days and increased the yield per plant by 4.3%, proving that segmented light quality regulation is beneficial for grain filling in the later stages. Compared with Comparative Example 4, Example 1 advanced tasseling by 7.4 days, shortened the harvest cycle by 9.6 days, and increased the yield per plant by 17.1%, indicating that a progressively decreasing R:FR ratio can avoid over-adaptation of photoreceptors and improve induction efficiency. Compared with the control example, Example 1 shortened the harvest cycle by 32.4 days, increased the yield per plant by 84.1%, increased the germination rate by 22.1%, reduced the plant height by 25.4 cm, and advanced the differentiation of male spikes by 8.8 days, showing significant advantages.

[0042] The above results indicate that this invention, by adding a dark period interruption treatment, employing a step-by-step decrease in the R:FR ratio, phased adjustment of the dark period interruption frequency, and dynamic control of the interruption duration during the dark period interruption treatment, and adding a light environment transition period after the dark period interruption treatment, adopting a segmented red-blue light ratio and synergistic regulation of nitrogen and potassium after silking during the post-induction growth stage, and combining the synergistic effects of multiple measures such as adjustable distance of the three-dimensional cultivation light source, and phased differentiated temperature and humidity and CO2 concentration, has achieved the beneficial effects of shortening the sowing to seed harvest cycle to less than 86 days, with a single plant yield exceeding 160 grams and a seed germination rate higher than 97% in maize rapid breeding.

[0043] The number of devices and processing scale described herein are for simplification of the invention. Applications, modifications, and variations of the present invention's method for rapid breeding of maize using photomorphogenesis in plant factories will be readily apparent to those skilled in the art.

[0044] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A rapid breeding method for inducing photomorphogenesis in maize for use in plant factories, characterized in that, include: Seeds from a light-insensitive temperate maize inbred line were used as breeding material. These seeds were sown in a plant factory, and basic light environment parameters were set: photoperiod of 12-13 h and photosynthetically active photon flux density of 700-900 μmol / (m²). 2 •s), using a mixture of red and far-red light for irradiation, with red light wavelength of 660±10 nm and far-red light wavelength of 730±10 nm, and the photon flux density ratio of red light to far-red light controlled between 1.5:1 and 2.5:1; The current leaf age of the corn plant is detected, and the trigger point for starting the dark period interruption process is when the number of leaves reaches 5-6. When more than 80% of the corn plants have 5-6 leaves, a 10-30 min dark period interruption is applied at the midpoint of the dark period in each photocycle. The dark period interruption lasts for 21 days. The light source used for the dark period interruption is a mixture of red and far-red light, with a red light wavelength of 660 ±10 nm and a far-red light wavelength of 730 ±10 nm. The ratio of the photon flux density of red light to far-red light is controlled between 1:1 and 2:1, and this ratio decreases step by step during the dark period interruption according to the following pattern: 2:1 for days 1-7, 1.5:1 for days 8-14, and 1:1 for days 15-21. The basic light environment parameters remain unchanged during the dark period interruption. After the dark period interruption treatment, the maize plants were transferred to the post-induction growth stage, and the photoperiod was adjusted to 14-16 h, reducing the photosynthetically active photon flux density to 400-600 μmol / (m²). 2 •s) Irradiation is carried out using a mixture of red and blue light, with the ratio of the photon flux density of red light to blue light controlled between 3:1 and 7:1, until the corn plants complete tasseling and silking, and the seeds are harvested.

2. The rapid breeding method for inducing photomorphogenesis in maize for plant factories as described in claim 1, characterized in that, During the first 14 days of the dark period interruption treatment, a dark period interruption treatment was applied only once at the midpoint of each day's dark period; during the first 15 days of the dark period interruption treatment, a dark period interruption treatment was applied once at the midpoint of each day's dark period and once 2 hours before the end of the dark period.

3. The rapid breeding method for inducing photomorphogenesis in maize for plant factories as described in claim 1, characterized in that, The duration of each dark period interruption is dynamically adjusted based on the real-time plant height growth rate of maize plants: when the plant height growth rate exceeds 5 mm / d for three consecutive days, the duration of a single dark period interruption is extended to 1.2-1.5 times the original duration; when the plant height growth rate is less than 1 mm / d for three consecutive days, the duration of a single dark period interruption is shortened to 0.6-0.8 times the original duration.

4. The rapid breeding method for inducing photomorphogenesis in maize for plant factories as described in claim 1, characterized in that, After the dark period interruption treatment ends and the induction growth stage begins, a 4-7 day light environment transition period is first implemented. During this transition period, the light source is gradually transitioned from a mixture of red and far-red light to a mixture of red and blue light. Specifically, the illumination time is increased by 0.5-1 hour per day, and the photosynthetically active photon flux density is decreased by 40-80 μmol / (m²) per day. 2 ·s), while increasing the percentage of blue light photon flux density in the mixed light by 2%-5% daily until the percentage of blue light photon flux density reaches 16.7%-25%, which corresponds to a photon flux density ratio of red light to blue light of 3:1 to 5:

1.

5. The rapid breeding method for inducing photomorphogenesis in maize for plant factories as described in claim 1, characterized in that, During the post-induction growth stage, before the corn plants complete tasseling, the ratio of red light to blue light photon flux density is controlled between 3:1 and 4:1; after the corn plants complete tasseling, the ratio of red light to blue light photon flux density is switched to between 4:1 and 5:

1.

6. The rapid breeding method for inducing photomorphogenesis in maize for plant factories as described in claim 1, characterized in that, During the post-induction growth stage, starting from the date the corn plant finishes silking, the mass concentration ratio of nitrogen to potassium in the nutrient solution is adjusted from 1:2 to 1:3 to 1:4 to 1:6, and the photon flux density ratio of red light to blue light is adjusted to 5:1 to 7:1, continuing until seed harvest.

7. The rapid breeding method for inducing photomorphogenesis in maize for plant factories as described in claim 1, characterized in that, A vertical, three-dimensional cultivation rack is used for tiered planting. Two rows of corn are planted on each layer of the rack, with a row spacing of 20-30 cm and a plant spacing of 10-15 cm. A movable LED light source module is installed above each layer of the rack. The distance between the light source module and the corn canopy is maintained at 30-40 cm before entering the dark interruption treatment stage. After entering the dark interruption treatment stage, the distance is shortened to 20-30 cm. After entering the induction growth stage, the distance is restored to 30-40 cm.

8. The rapid breeding method for inducing photomorphogenesis in maize for plant factories as described in claim 1, characterized in that, During the post-induction growth stage, the daytime temperature was set to 24°C-26°C, the nighttime temperature to 18°C-20°C, the relative humidity to 50%-60%, and the carbon dioxide concentration to 1200-1500 ppm.

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