Method for regulating flowering time of sugarcane hybrid parents by using ga3 and application thereof

Abstract

The application discloses a method for regulating flowering time of sugarcane hybrid parents by using GA3 and application, and is based on a "seesaw" regulation mode of a flowering promotion type gene ScFT4 and a flowering inhibition type gene ScFT1 and response characteristics to exogenous gibberellin GA3, wherein specific concentration GA3 is sprayed at different time nodes before and after swelling of flower buds of the sugarcane, so that the sugarcane hybrid parents can bloom in advance or delay bloom. 5mg / L GA3 is sprayed 60 days before swelling of the flower buds, and the plants bloom at least 6 days in advance; 5mg / L or 50mg / L GA3 is sprayed 30 days before swelling of the flower buds, and the flowering time is delayed by not less than 6 days or 18 days, respectively. The method can effectively solve the problem of non-meeting of flowering time of the sugarcane hybrid parents, significantly improve the efficiency of sugarcane hybrid breeding, and has important application prospect.

Description

Technical Field

[0001] This invention relates to the fields of plant molecular biology and sugarcane breeding technology, specifically a method and application of using GA3 to regulate the flowering time of sugarcane hybrid parents. Background Technology

[0002] Sugarcane originated in tropical and subtropical regions and is a high-efficiency C4 crop. It is one of the world's most important sugar and energy crops, contributing over 80% of global sugar production and approximately 40% of bioethanol feedstock. In my country, sucrose accounts for over 85% of the country's total sugar production, making it a core pillar for ensuring national sugar supply security. Hybrid breeding is the core pathway for sugarcane variety improvement. By combining the high-yield, high-sugar, and stress-resistant traits of both parents, the overall agronomic level of sugarcane can be significantly improved. However, this technology has long been limited by the bottleneck of mismatched flowering periods between parental lines. Different sugarcane varieties have significantly different flowering habits; early-flowering varieties mostly flower from late November to early December, while late-flowering varieties concentrate from late December to mid-January of the following year, with a flowering period spanning 45-60 days. Many excellent parental combinations cannot achieve targeted hybridization, severely restricting the breeding process.

[0003] Current sugarcane flowering period regulation techniques primarily rely on artificial photoperiod induction, which promotes flower bud differentiation by simulating short-day environments. This technique requires continuous treatment for 3-4 months, starting in mid-May, until flower bud swelling and differentiation in August or September, a cycle lasting 120-150 days. It not only necessitates the construction of dedicated control rooms but also incurs high energy and facility costs, and demands stringent operational precision. Furthermore, artificial photoperiod induction can only address the problem of non-flowering; its effect on synchronizing the flowering period of already flowering varieties is limited, failing to fundamentally solve the problem of asynchronous flowering.

[0004] Gibberellin (GA3), a key plant hormone, is widely involved in regulating plant growth and development. Exogenous GA3 treatment can regulate the flowering time of model plants such as Arabidopsis thaliana and rice. However, its application in sugarcane flowering regulation is still in its early stages. The regulatory effects of different treatment periods and concentrations on sugarcane flowering are not yet clear, and a systematic technical framework is lacking. Therefore, analyzing and applying the responses of sugarcane flowering genes to GA3, developing precise flowering time regulation techniques, and establishing a dual regulation method for advancing / delaying flowering are of great significance for overcoming the bottlenecks in sugarcane breeding. Summary of the Invention

[0005] The purpose of this invention is to provide a method and application for regulating the flowering time of sugarcane hybrid parents using GA3, based on a "seesaw" model of sugarcane flowering regulation, and a flowering-promoting type in the model. ScFT4 Genes and flowering suppression ScFT1By utilizing the gene's response characteristics to exogenous gibberellin GA3, a dual regulatory effect is achieved on the early and delayed flowering of sugarcane hybrid parents, solving the problem of asynchronous flowering in sugarcane hybrid parents. This invention is a method for precisely regulating the flowering time of sugarcane.

[0006] The technical solution of the present invention is as follows: This invention discloses sugarcane ScFT4 Genes and ScFT1 By studying the "seesaw" regulatory pattern of genes and their response characteristics to GA3, a precise regulation technology for sugarcane flowering time based on the temporal regulation of gene expression was established, providing an efficient and controllable technical solution for solving the problem of untimely flowering of sugarcane hybrid parents.

[0007] The specific steps of the technical solution of this invention are as follows: (1) Core gene regulation model: plant PEBP family FT Flowering-promoting type among gene members ScFT4 Genes and flowering suppression ScFT1 Genes exhibit a "seesaw" regulatory pattern in the artificial photoperiod-induced flowering process in sugarcane: ① Cloning and isolating from sugarcane a previously disclosed [product / method / product] ScFT1 Genes have antagonistic effects ScFT4 The gene was identified and verified to have the function of promoting earlier flowering in plants; ② Flowering-inhibiting type ScFT1 The gene is highly expressed during the vegetative growth stage, inhibiting the sugarcane flowering transition; ③ Flowering-promoting type ScFT4 Gene expression is specifically upregulated during the flowering induction stage, driving the sugarcane to transition from vegetative growth to reproductive growth. ④ The dynamic balance of the two genes directly determines the flowering time of sugarcane and plays a core role in regulating the sugarcane flowering process.

[0008] (2) GA3 response molecular characteristics: precise regulation by exogenous gibberellin GA3 treatment ScFT4 Genes and ScFT1 Gene expression sequence: ① Flowering-inhibiting type ScFT1 The gene responded rapidly to GA3, with expression levels reaching a peak 30 days after treatment and significantly downregulated after 60 days. ② Flowering-promoting type ScFT4 Gene response was delayed, and expression was significantly upregulated 90 days (i.e. 3 months) after treatment during the sugarcane flower bud swelling period; ③ The expression patterns of the two genes mentioned above can be artificially regulated by GA3 treatment, thereby controlling the flowering time of sugarcane.

[0009] (3) Flowering period regulation method: Based on the above gene response characteristics, a dual regulation technology for sugarcane flowering period was established: ① Advance flowering regulation: 60 days before the flower buds of the sugarcane hybrid parents swell, spray the leaves with a 5 mg / L gibberellin GA3 solution to promote flowering. ScFT4 Early high expression of genes advances the flowering time of plants by at least 6 days and improves the uniformity of flowering by more than 30%. ② Delayed flowering regulation: 30 days before the flower buds of the sugarcane hybrid parents swell, foliar spray with a 5 mg / L gibberellin GA3 solution to maintain the flowering-inhibiting type. ScFT1 High gene expression levels delay flowering by at least 6 days. Spraying with 50 mg / L gibberellin GA3 will delay flowering by at least 18 days.

[0010] (4) Synchronized Flowering Period Application: Utilizing the dual regulation technology of this invention, the flowering characteristics of different sugarcane hybrid parents can be precisely adjusted: ① For hybrid parent combinations with a flowering period difference of 15 to 30 days, flowering can be synchronized by delaying the flowering of early-flowering parents or advancing the flowering of late-flowering parents; ② The flowering synchronization rate can reach over 85%, and the success rate of hybrid pollination is increased by 40%-60%, significantly improving the efficiency of sugarcane hybrid breeding; ③This method is simple to operate and low in cost, and can be widely applied in sugarcane hybrid breeding.

[0011] Beneficial effects of the invention (1) Analyze the core control model and fill the technological gap. This invention reveals a "seesaw" model for sugarcane flowering regulation, clarifying the flowering-promoting type. ScFT4 Genes and repressors ScFT1 The dynamic equilibrium of genes was elucidated, revealing the temporal regulatory characteristics of gibberellin GA3 on two core genes, providing molecular biological theoretical support for the regulation of sugarcane flowering period.

[0012] (2) Establish a dual regulation method to achieve precise control. A dual regulation technology of "advanced flowering + delayed flowering" was constructed: spraying 5 mg / L GA3 60 days before flower bud swelling can make sugarcane flower at least 6 days earlier and improve the uniformity of flowering period by more than 30%; spraying 5 mg / L or 50 mg / L GA3 30 days before flower bud swelling can delay flowering by 6 days or more than 18 days respectively, to meet the needs of different flowering period regulation.

[0013] (3) Break through breeding bottlenecks and improve breeding efficiency This invention helps solve the problem of mismatched flowering periods in sugarcane hybrid parents: for parental combinations with flowering periods differing by 15-30 days, by delaying the flowering of early-flowering parents or advancing the flowering of late-flowering parents, the flowering synchronization rate can reach over 85%, achieving targeted hybridization. This helps accelerate the breeding process of high-yielding, high-sugar, and stress-resistant high-quality sugarcane varieties, providing technical support for ensuring national sugar supply security. Attached Figure Description

[0014] Figure 1 To overexpress sugarcane ScFT4 Schematic diagram of genes promoting early flowering in Arabidopsis thaliana.

[0015] Figure 2 sugarcane ScFT4 Genes and ScFT1 A schematic diagram illustrating the differences in gene expression levels in different tissues during the vegetative growth and reproductive growth stages. The tissues examined included mature leaves (V-ML), immature rolled leaves (V-IL), and shoot apical meristem tissue (V-SAM) during the vegetative growth stage; and mature leaves (R-ML), semi-expanded young leaves (R-IL), and young panicles during the reproductive growth stage, i.e., early panicle development.

[0016] Figure 3 During the sugarcane flowering transition ScFT4 Genes and ScFT1 A schematic diagram of the "seesaw" regulatory model of genes.

[0017] Figure 4 For the sugarcane "seesaw" adjustment system ScFT4 Genes and ScFT1 A schematic diagram illustrating the gene expression response to exogenous GA3 treatment. GA3: refers to the exogenous plant hormone gibberellin GA3; PPP3: refers to paclobutrazol, an inhibitor of gibberellin, used as a negative control. CK refers to the water spray control.

[0018] Figure 5 This diagram illustrates the effects of GA3 spraying at different time periods and concentration gradients; among them... Figure 5 A shows the effect of treatment 60 days before flower bud swelling; Figure 5 B represents the effect of treatment 30 days before flower bud swelling. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0020] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the field or according to the product instructions. Materials or instruments whose manufacturers are not specified are all conventional products that can be obtained by purchase.

[0021] Example 1: Sugarcane flowering-promoting gene ScFT4 Cloning and functional analysis (1) Sugarcane ScFT4 Gene cloning Preparation of cDNA template: Under photoperiodic flowering conditions (12.5 hours of light, 11.5 hours of darkness), leaves (+1 leaf) of the commercial sugarcane variety Yuetang 93-159 during the flower bud swelling and differentiation stage were selected, flash-frozen in liquid nitrogen, and ground into powder using a mortar and pestle. Total RNA was extracted using the Trans Zol™ Plant kit (ET121) from TransGen Biotech, and then cDNA samples were synthesized using the TransScript One-Step gDNA Removal and cDNA Synthesis SuperMix kit (TransGen AT311) for later use.

[0022] ScFT4 Gene cloning: Designed based on the sugarcane genome reference sequence ScFT4 Primers for full-length gene amplification: forward primer ScFT4 -95-F: 5'-acaacggactcctgttctcg-3' (SEQ ID No. 1) reverse primer ScFT4 -947-R: 5'-atacatatgcctgcaacctgc-3' (SEQ ID No. 2) Using the above cDNA as a template, PCR amplification was performed to obtain... ScFT4Gene. The reaction system consisted of 25 μL, including 2 μL of dNTPs (2.5 mmol / L), 1 μL each of forward and reverse primers (10 μmol / L), 2.5 μL of 10× Trans Taq HiFi buffer II, 2.5 μL of 10× GC Enhancer, 0.5 μL of Trans Taq HiFi DNA Polymerase (5 Units / μL), 2.5 μL of cDNA template, and 13 μL of ddH2O. The reaction program was: 94℃ pre-denaturation for 3 min; 94℃ denaturation for 30 s, 55℃ annealing for 40 s, 72℃ extension for 40 s, for a total of 32 cycles; and 72℃ extension for 10 min. The target gene band was recovered by gel electrophoresis, ligated into the pEASY vector, and transformed into competent cells. Positive clones were selected for sequencing verification.

[0023] (2) Sugarcane ScFT4 Gene function verification Overexpression vector construction: Extract the above ScFT4 Gene cloning plasmid DNA is amplified using specific primers containing restriction enzyme sites and protective bases. ScFT4 The CDS sequence of the gene was obtained. After recovery of the amplified product, it was double-digested with Xba I and Kpn I restriction endonucleases. Simultaneously, the pCAMBIA2301-KY vector was double-digested using the same restriction enzyme combination, and the linearized vector fragment was recovered. The digested target gene fragment and the linearized vector were mixed at a 3:1 molar ratio, T4 DNA ligase was added, and ligation was performed overnight at 16°C. The ligation product was transformed into *E. coli* DH5α competent cells, plated on LB agar containing 50 mg / L kanamycin, and incubated overnight at 37°C. Single colonies were picked for PCR identification, and plasmids were extracted from positive colonies and sequenced for verification. The overexpression vector OE-35S:: was successfully constructed. ScFT4 .

[0024] Agrobacterium-mediated genetic transformation of Arabidopsis thaliana: Recombinant vectors were transformed into Agrobacterium GV3101 competent cells using a freeze-thaw method. The transformed cells were plated on LB agar containing 50 mg / L kanamycin, 25 mg / L rifampin, and 25 mg / L gentamicin, and incubated in the dark at 28°C for 2-3 days. Single colonies were picked for PCR identification, and positive transformants were screened. Arabidopsis Col-0 ecotype seeds were sterilized and sown on MS agar, vernalized at 4°C for 3 days, and then transferred to a light incubator for cultivation until flowering. Positive Agrobacterium strains were cultured until an OD600 value of 0.8–1.0 was reached. The bacterial suspension was resuspended in a 1 / 2 MS solution containing 5% sucrose and 0.05% Silwet L-77. Arabidopsis inflorescences were immersed in the bacterial suspension for 30–60 seconds using the inflorescence immersion method, and after 24 hours of dark incubation, transferred to normal light conditions for cultivation. T0 generation seeds were harvested.

[0025] Positive plantlet detection and flowering phenotype observation: Resistant seedlings were screened from Arabidopsis thaliana T0 generation seeds on MS solid medium containing 40 mg / L kanamycin. T1 generation positive plants were obtained by PCR detection. The flowering time of T2 generation homozygous lines was observed and statistically analyzed. The results showed that overexpression of sugarcane... ScFT4 Transgenic Arabidopsis thaliana plants with the gene flowered 12 days earlier than the wild type (e.g. Figure 1 (As shown).

[0026] Example 2: ​ Genes and ​ Tissue-specific expression detection of genes The commercial sugarcane variety Yuetang 93-159 was used as the experimental material. Flowering was induced by photoperiod, with a photoperiod of 12.5 hours of light followed by 11.5 hours of darkness until flowering was induced. During this period, mature leaves (V-ML), immature rolled leaves (V-IL), and shoot apical meristem tissue (V-SAM) were collected during the vegetative growth stage; and mature leaves (R-ML), semi-expanded young leaves (R-IL), and young panicles were collected during the reproductive growth stage, i.e., early panicle development. Each sample contained three biological replicates, and the concentrations of various substances in the samples were analyzed. ​ Genes and ​ Changes in gene expression levels.

[0027] Using Trans Zol TM Total RNA was extracted from samples using the Plant kit (ET121), and the concentration and purity of RNA were detected using BioDrop Lite. cDNA templates were synthesized using a reverse transcription kit (Taiwan AT341-01) for quantitative real-time PCR analysis. Primer Premier 3 was used as the design. ​ Genes and ​ Genes, and internal reference genes ​ Specific primers: ​ -qPCR forward primer: 5'-GCAGCATTTGGGCAAGAGG-3' (SEQ ID No. 3) ​ -qPCR reverse primer: 5'-CGGGGCGTACACCGTCTG-3' (SEQ ID No. 4) ​ -qPCR forward primer: 5'-GGATCCTGATGCGCCTAATC-3' (SEQ ID No. 5) ​-qPCR reverse primer: 5'-GAGCTCTCGGCCAAAGCTAT-3' (SEQ ID No. 6) ​ -qPCR forward primer: 5'-CACGGCCACTGGAAGCA-3' (SEQ ID No. 7) ​ -qPCR reverse primer: 5'-TCCTCAGGGTTCCTGATGCC-3' (SEQ ID No. 8) The target gene real-time PCR system (25 μl) consisted of: FastStart Universal SYBR Green Master (ROX) 12.5 μl, q-PCR forward primer (120 nM) 0.3 μl, q-PCR reverse primer (120 nM) 0.3 μl, ddH2O 9.4 μl, and cDNA 2.5 μl. The real-time PCR amplification program was as follows: Pre-denaturation was performed at 50℃ for 2 min, 95℃ for 10 min; amplification was then performed at 95℃ for 15 s, 60℃ for 1 min, for 40 cycles; finally, melting curve analysis was performed at 95℃ for 15 s, 60℃ for 1 min, and 95℃ for 15 s.

[0028] Internal reference gene ​ Quantitative real-time PCR system (25 μl): FastStart Universal SYBR GreenMaster (ROX) 12.5 μl, q-PCR ​ Forward primer (220 nM) 0.25 μl, q-PCR ​ 0.25 μl of reverse primer (220 nM), 9.5 μl of ddH2O, and 2.5 μl of cDNA. The quantitative real-time PCR amplification procedure was the same as that for the target gene.

[0029] Use 2 -ΔΔCT The relative expression levels of genes were calculated using a method that showed: flowering inhibition type ​ The expression level of the allele was highest in mature leaves during the vegetative growth stage, and significantly downregulated in mature leaves during the flowering transition stage; conversely, the expression level of the flowering-promoting allele was lower. ​ and ​ The gene is highly expressed in leaves of reproductive growth. ​ This indicates that they play an important role in regulating the flowering time of sugarcane.

[0030] Example 3: Sugarcane flowering transition process ​ Analysis of the "seesaw" regulatory model of genes Experimental materials and treatment: Same as in Example 2.

[0031] Sample collection: Further, leaf samples (including 3 biological replicates) were collected during the flower bud swelling period, 60 days before flower bud swelling differentiation, and 30 days after flower bud swelling differentiation to detect flowering promoters (…). ​ Genes) and flowering inhibitors ( ​ The dynamic changes in the expression levels of genes.

[0032] RNA extraction and reverse transcription: Same as in Example 2.

[0033] Real-time quantitative PCR: Same as in Example 2.

[0034] Use 2 -ΔΔCT The relative expression levels of genes were calculated using a method that showed: flowering-promoting type ​ Genes and flowering suppression ​ Gene expression levels exhibit a dynamic "seesaw" relationship. This "seesaw" model determines the flowering time of sugarcane hybrid parents. ​ When the gene is highly expressed, sugarcane maintains vegetative growth; conversely, when... ​ Upregulation of gene expression promotes reproductive growth. ​ (As shown).

[0035] Table 1. Sugarcane flower bud swelling and differentiation before and after ​ Genes and ​ Analysis of gene expression level variation patterns

[0036] Example 4: Seesaw Model ​ Genes and ​ Gene response analysis to GA3 treatment Experimental materials and treatments: The Yunzhe 05-51 sugarcane variety was used as the experimental material. The material was planted in the sugarcane hybrid parent nursery. During the vigorous growth period of sugarcane in July, the sugarcane leaves were treated with 10 mg / L, 100 mg / L GA3 and PPP3 respectively.

[0037] Sample collection: Leaf samples (plus 1 leaf) were collected 1 day before spraying, and 30, 60, and 90 days after spraying, with 3 biological replicates. The "seesaw" model was used to detect... ​ Genes and ​ The response of genes to treatment with the exogenous plant hormone GA3.

[0038] RNA extraction and reverse transcription: Same as in Example 2.

[0039] Real-time quantitative PCR: Same as in Example 2.

[0040] Use 2 -ΔΔCT The relative expression levels of genes were calculated using a method that showed that after 30 days of GA3 treatment,​ Gene expression levels peak after 60 days, then decline after 90 days. ​ Upregulation of gene expression ( ​ (As shown).

[0041] Example 5: Application of regulating flowering time in sugarcane hybrid parents Experimental materials and treatments: The sugarcane variety Yunzhe 05-51 was used as the experimental material. The experimental material was subjected to continuous photoperiod-induced flowering treatment (12.5 hours of light and 11.5 hours of darkness). Sixty sugarcane plants with the same growth status were selected and randomly divided into three groups of 20 plants each.

[0042] Treatment methods: Group A (early flowering treatment): Spray with exogenous gibberellin GA3 at concentrations of 0.1 mg / L, 1 mg / L, 5 mg / L, 20 mg / L and 100 mg / L 60 days before flower bud swelling; Group B (delayed flowering treatment): Spray with exogenous gibberellin GA3 at concentrations of 0.1 mg / L, 1 mg / L, 5 mg / L, 20 mg / L and 50 mg / L 30 days before flower bud swelling; Group C (control group CK) was sprayed with an equal volume of water.

[0043] Flowering period observation: Regularly observe the flowering status of the plants and record the flowering time. Results showed: Group A: The flowering time of the 0.1 mg / L and 1 mg / L low-concentration GA3 treatments was not significantly different from the control; the flowering time of the 5 mg / L suitable concentration GA3 treatment was 6 days earlier than the control; however, the treatment with 20 mg / L and 100 mg / L high-concentration GA3 severely disrupted the "seesaw" regulatory system, and no flowering was observed after 6 months of treatment. ​ (As shown in A).

[0044] Group B: The flowering time of the 0.1 mg / L GA3 treatment was not significantly different from that of the control; the flowering time of the 1 mg / L GA3 treatment was 1-2 days earlier than that of the control; while the 5 mg / L and 50 mg / L GA3 treatments both showed a delayed flowering phenotype, flowering 6 days and 18 days later than the control, respectively. ​ As shown in B).

[0045] Synchronizing Flowering Dates: For parents with a flowering time difference of approximately 12 days, late-flowering parents can be treated with 5 mg / L GA3 60 days before flower bud swelling, and early-flowering parents can be treated with 5 mg / L GA3 30 days before flower bud swelling, thus achieving synchronized flowering dates. For parents with a flowering time difference of approximately 24 days, late-flowering parents can be treated with 5 mg / L GA3 60 days before flower bud swelling, and early-flowering parents can be treated with 50 mg / L GA3 30 days before flower bud swelling, achieving synchronized flowering dates. This invention is applicable to commonly used sugarcane hybrid parents such as Yunzhe 05-51, Yunzhe 08-1609, Yuetang 93-159, Xintaitang 22, and Guitang 11, and can significantly improve the efficiency of sugarcane hybrid breeding and the rate of directional hybridization.

[0046] For example, the parental combination of the early-flowering variety Yunzhe 05-51 (normal flowering time is November 25) and the late-flowering variety Yunzhe 08-1609 (normal flowering time is December 20) has a flowering period that differs by 30 days.

[0047] Solution: Delayed flowering treatment for Yunzhe 05-51: Spray 50mg / L GA3 30 days before flower bud swelling, delaying flowering by more than 18 days, and changing the start of flowering time to December 13; To advance the flowering of Yunzhe 08-1609, spray 5 mg / L GA3 60 days before flower bud swelling, which advanced the flowering by 9 days and changed the flowering start date to December 11.

[0048] Application effect: The peak blooming periods of the two varieties overlap by up to 10 days, with a flowering synchronization rate of 90%.

[0049] This invention utilizes a "seesaw" regulation model in sugarcane flowering control, employing the exogenous plant hormone gibberellin GA3 to regulate key processes in the model. ​ Genes and ​ The gene expression timing provides three methods to regulate the differences in flowering time between parental lines, which can be efficiently utilized in the application of simultaneous flowering of sugarcane parents. Different flowering time regulation effects obtained by treating sugarcane at different time points before and after flower bud swelling using the GA3 treatment concentration disclosed in this invention or undisclosed GA3 treatment concentrations are also within the scope of protection of this patent.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for regulating the flowering time of sugarcane hybrid parents by GA3, characterized in that Includes the following steps: ① Sugarcane flowering-promoting genes ScFT4 and flowering inhibition genes ScFT1 The "seesaw" regulation mode in the photoperiod-induced flowering process determines the flowering time of sugarcane; ② Exogenous GA3 treatment affected ScFT4 Genes and ScFT1 Gene expression timing and rebalancing time; ③ Early flowering regulation: 60 days before the flower buds of the sugarcane hybrid parents swell, spray the leaves with a 5 mg / L gibberellin GA3 solution to promote flowering. ScFT4 Early high expression of genes causes plants to flower earlier; ④ Delayed flowering regulation: 30 days before the flower buds of the sugarcane hybrid parents swell, spray the leaves with a gibberellin GA3 solution at a concentration of 5 mg / L or 50 mg / L to maintain flowering. ScFT1 High gene expression levels delay the flowering time of the plants.

2. The method according to claim 1, characterized in that: During the photoperiod-induced flowering process, the photoperiod consists of 12.5 hours of light and 11.5 hours of darkness until flowering is induced.

3. The method according to claim 1 or 2, characterized in that: In step ③, the early flowering regulation involves spraying a 5 mg / L gibberellin GA3 solution, which causes the plants to flower at least 6 days earlier and increases the uniformity of flowering by at least 30%.

4. The method according to claim 1 or 2, characterized in that: In step ④, the delayed flowering regulation is achieved by spraying 5 mg / L GA3, which delays flowering by at least 6 days, and by spraying 50 mg / L GA3, which delays flowering by at least 18 days.

5. The method according to claim 1, characterized in that: overexpression ScFT4 Genes promote earlier flowering in Arabidopsis thaliana.

6. The method according to claim 1, characterized in that: In the "seesaw" control mode during the flowering process described in step ①, ScFT1 High gene expression maintains the vegetative growth of sugarcane; conversely, ScFT4 High gene expression promotes the transformation of sugarcane reproductive growth.

7. The method according to claims 1-6, characterized in that: The flowering suppression gene described in step ② ScFT1 The expression level of the flowering-promoting gene reached its peak 30 days after GA3 treatment, decreased after 60 days, and peaked after 90 days. ScFT4 The expression level was upregulated.

8. The application of the method according to any one of claims 1-7 in solving the problem of asynchronous flowering of sugarcane hybrid parents, characterized in that: For hybrid parent combinations with a flowering period difference of 15 to 30 days, flowering can be synchronized by delaying the flowering of early-flowering parents or advancing the flowering of late-flowering parents, thereby improving the efficiency of sugarcane hybrid breeding.

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