A method for accurately identifying salt tolerance of rice in reproductive growth stage

Abstract

The application discloses a rice reproductive growth period salt tolerance precise identification and evaluation method, and relates to the technical field of crop genetic breeding and stress tolerance identification.The application method is short in operation time, reliable in obtained identification result, and high in repeatability, and the application method realizes precise identification of rice reproductive growth period salt tolerance by monitoring and dynamically stabilizing salt concentration every day, and applying stable and uniform salt stress in a key period of reproductive growth in a greenhouse environment.The application adopts a modular cultivation design, is convenient for high-throughput screening, is isolated from natural interference in the greenhouse environment, realizes standardized operation, and is efficient.The evaluation index combines multi-dimensional indexes such as international standard salt damage score and yield stability index, realizes comprehensive and objective quantitative evaluation from a phenotype to yield, effectively solves the industry pain points of uneven salt distribution and unstable results in traditional field identification, and provides a reliable key technical tool for accelerating salt-tolerant rice variety breeding and supporting salt and alkali land resource development and utilization.

Description

Technical Field

[0001] This invention relates to the field of crop genetics and breeding and stress tolerance identification technology, and more specifically to a method for accurate identification of salt tolerance during the reproductive growth stage of rice. Background Technology

[0002] The reproductive growth stage of rice (booting-flowering-grain filling and maturity) is the stage where salt stress response is most sensitive and yield loss is most significant. Salt tolerance during this period directly determines the adaptability and yield stability of varieties in saline-alkali soils. Accurate, efficient, and repeatable identification of salt tolerance during the reproductive growth stage is the core technical support for salt-tolerant rice germplasm screening, variety breeding, and research on stress resistance mechanisms. However, existing phenotypic identification methods suffer from drawbacks such as long cycles, significant interference, and low throughput (the reproductive growth stage covers booting-maturity, 3–5 months per season; pollen fertility, spikelet fertilization, and grain filling under salt stress are easily affected by light, temperature, and water, resulting in poor repeatability; identification is mainly based on single plants / plots, making batch screening difficult). Furthermore, stress simulation is disconnected from field planting (the salt concentration and ion composition in artificial hydroponics / soil cultivation differ greatly from real saline-alkali soil; controllable conditions are difficult to reproduce field-induced complex stress, limiting the generalizability of the results; while field identification is close to actual production, uneven soil salinity distribution and significant climate influence make it difficult to accurately reflect the results). Precise control of stress intensity is insufficient, and the established indicator system has limitations (it mainly focuses on endpoint indicators such as seed setting rate and single-plant grain weight, which are difficult to reflect dynamic damage under stress; the correlation between salt tolerance during the reproductive stage and the bud / seedling stage is weak, and early identification cannot replace it, which is prone to misjudgment; the indicators are not representative enough under combined stress (salt + alkali + nutrient imbalance); the molecular identification method is inefficient (salt tolerance during the reproductive stage is controlled by multiple genes, QTL mapping is limited and the effect is weak; existing molecular markers are mostly for the seedling stage, there is a lack of markers specifically for the reproductive stage, the marker-phenotype matching degree is low, and the auxiliary selection is inaccurate).

[0003] Therefore, providing a short-cycle, high-efficiency method for identifying the salt tolerance of rice germplasm is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] This invention provides a method for accurately identifying the salt tolerance of rice during its reproductive growth stage.

[0005] To solve the above-mentioned technical problems, this application adopts the following technical solution:

[0006] A method for accurately identifying salt tolerance during the reproductive growth stage of rice, the method comprising the following steps: S1 Pretreatment before salt stress: The rice seeds to be tested and the control seeds were cultivated in a field with the same soil texture and fertility according to conventional methods; S2 Salt Stress Treatment: Salt stress treatment is applied to rice in the late jointing stage, so that the entire reproductive growth stage of rice is in a salt stress environment. The salt concentration in the cultivation substrate was adjusted using an artificially prepared NaCl solution, and a salt concentration treatment group and a non-salt stress control group were set up; the EC of the salt concentration treatment group was 8 ds / m, and the EC of the non-salt stress control group was <2 ds / m. During salt stress, the EC value of the culture medium was monitored daily, and the salt concentration of each group was kept stable by irrigating with NaCl solution or replacing the NaCl solution. S3 Data Statistics and Result Determination: At the rice maturity stage, the salt tolerance of the rice seeds to be tested was determined according to the standards in the table below:

[0007] Preferably, in the S1 pretreatment before salt stress, rice seeds are cultivated to the late tillering stage using conventional methods. The rice seedlings are then transplanted with soil into perforated containers, which are placed in a transfer box. The transfer box is then moved to a ventilated greenhouse, where the rice is cultivated to the late jointing stage. The control seeds are divided into a salt-tolerant control and a salt-sensitive control. The salt-tolerant control is Yuxiangyouzhan, and the salt-sensitive control is IR29.

[0008] Compared with the prior art, the present invention has the following beneficial effects: This invention applies stable and uniform salt stress during critical reproductive growth stages by monitoring and dynamically stabilizing salt concentration daily. The operation is quick, and the identification results are reliable and highly reproducible. The modular cultivation design facilitates high-throughput screening, and the greenhouse environment isolates natural disturbances, achieving standardized and efficient operation. The evaluation indicators combine international standard salt damage scores and yield stability indices, providing a comprehensive, objective, and quantitative evaluation from phenotype to yield.

[0009] This invention, serving as a highly efficient "precision screening platform," primarily supports modern salt-tolerant rice breeding and cutting-edge research. It can be used for large-scale germplasm resource identification, targeted selection of hybrid offspring, and the discovery of salt-tolerant genes. Simultaneously, its stable stress environment is also suitable for research on the physiological mechanisms of salt damage, evaluation of stress-resistant cultivation techniques, and verification of the effectiveness of biological / chemical salt-tolerant agents. This invention effectively addresses the industry pain points of uneven salt content and unstable results in traditional field identification, transforming complex and variable natural stresses into precisely controllable scientific experiments in the laboratory. It provides a reliable key technological tool for accelerating the breeding of salt-tolerant rice varieties and supporting the development and utilization of saline-alkali land resources. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0011] Figure 1 Transplanting rice plants with soil attached to them into transport boxes during the later tillering stage; Figure 2 Two replicates of the salt treatment and a freshwater control treatment were provided at the site. Figure 3 Two replicates were used for the freshwater control and the salt treatment. Figure 4 This serves as a reference for evaluating salt tolerance levels. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0014] In this invention, the term "late tillering stage" refers to the period from when the total number of tillers in a rice field reaches its peak until the beginning of jointing.

[0015] In this invention, the term "late jointing stage" refers to the period from the beginning of elongation of the basal internodes of rice to the beginning of panicle formation.

[0016] The term "early spikelet differentiation period" in this invention refers to the period from the beginning of early spikelet differentiation to maturity.

[0017] In this invention, the term maturity period refers to the time when more than 90% of the grains on the whole plant reach yellow ripeness.

[0018] Example 1 1. Material selection: Salt-tolerant rice variety: Yuxiangyouzhan; Salt-sensitive rice variety: IR29 2. Pretreatment before salt stress Rice is cultivated in fields with uniform soil texture and fertility using conventional methods. During the tillering stage, the rice plants are transplanted with soil into perforated containers. These containers are then placed in transfer boxes, which are then moved to ventilated greenhouses to continue cultivating the rice until the jointing stage.

[0019] The specific operation is as follows: individual rice plants, with soil attached, are transplanted into perforated containers and integrated into treatment units. These containers are then placed in a transfer box containing a solution of 0.1% compound fertilizer (N:15%, P2O5:15%, K2O:15%). As an example, in this embodiment, the perforated container is a PVC pipe (100mm in diameter). 130mm high, with 25 holes drilled in the pipe wall), turnover box (650mm long) Width 405 (Height 150mm). 1 plant / tube, 15 plants / box (see appendix) Figure 1 ).

[0020] 3. Salt stress treatment In the late jointing stage, rice was subjected to salt stress treatment to ensure that the entire reproductive growth stage of rice (from panicle differentiation to maturity) was under salt stress. The salt concentration of the water in the transfer box was adjusted using artificially prepared NaCl solution, and a salt concentration treatment group (EC = 8 dS / m) and a non-salt stress control group (EC < 2 dS / m) were set up.

[0021] During salt stress, the EC value of the culture medium was monitored daily, and the salt concentration of each group was maintained stable by irrigation with NaCl solution or by replacing the NaCl solution (see Appendix). Figure 2 ).

[0022] 4. Phenotypic Data Collection and Evaluation Indicators During the rice maturity period, agronomic traits and visual salt damage of the rice were measured and statistically analyzed, and graded according to the standards in Table 1 (see Appendix). Figure 3 ).

[0023] 4.1 Agronomic traits Plant height (PH): Length (cm) from the base of the stem to the top of the ear, measured at maturity.

[0024] Filled Grain Rate (%): Number of filled grains / Total number of grains × 100%.

[0025] 4.2 Visual Salt Injury Score (SES): The plants subjected to salt stress were scored according to the standard evaluation system (Table 1) (see Appendix). Figure 4 ): Table 1

[0026] Example 2 Using the method of Example 1, the salt tolerance of rice germplasms in Table 2 during their reproductive growth period was evaluated. Yuxiangyouzhan was used as the salt tolerance control, and IR29 was used as the salt sensitivity control. The experimental results are shown in Table 2. The method of this invention accurately distinguishes the salt tolerance of all rice germplasms.

[0027] Table 2

[0028] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0029] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for accurately identifying salt tolerance during the reproductive growth stage of rice, characterized in that, The identification method includes the following steps: S1 Pretreatment before salt stress: The rice seeds to be tested and the control seeds were cultivated in a field with the same soil texture and fertility according to conventional methods; S2 Salt Stress Treatment: Salt stress treatment is applied to rice in the late jointing stage, so that the entire reproductive growth stage of rice is in a salt stress environment. The salt concentration in the cultivation substrate was adjusted using an artificially prepared NaCl solution, and a salt concentration treatment group and a non-salt stress control group were set up; the EC of the salt concentration treatment group was 8 ds / m, and the EC of the non-salt stress control group was <2 ds / m. During salt stress, the EC value of the culture medium was monitored daily, and the salt concentration of each group was kept stable by irrigating with NaCl solution or replacing the NaCl solution. S3 Data Statistics and Result Determination: At the rice maturity stage, the salt tolerance of the rice seeds to be tested was determined according to the standards in the table below:

2. The method for accurate identification of salt tolerance during the reproductive growth stage of rice according to claim 1, characterized in that, In the pretreatment of S1 salt stress, rice seeds were cultivated to the late tillering stage using conventional methods. The rice seedlings were then transplanted with soil into perforated containers, which were placed in a transfer box. The transfer box was then moved to a ventilated greenhouse, where the rice was cultivated to the late jointing stage. The control seeds were divided into a salt-tolerant control and a salt-sensitive control. The salt-tolerant control was Yuxiangyouzhan, and the salt-sensitive control was IR29.

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