Rapid evaluation method for heat resistance phenotype of non-heading Chinese cabbage

Abstract

The invention discloses a rapid evaluation method for heat resistance phenotypes of non-heading Chinese cabbages. The method comprises the following steps: step 1, performing standardized seedling culture under the conditions of day and night constant temperature of 22 DEG C / 18 DEG C, relative humidity of 60%, illumination for 16h / darkness for 8h and light intensity of 20000Lux; step 2, extreme high temperature stress treatment: the temperature is 49 + / -0.5 DEG C, the humidity is 60%-70%, the illumination intensity is 20000Lux, treatment is performed for 8 hours, and then culture is recovered; step 3, observing phenotypic indexes including survival rate S, leaf damage index D, plant height inhibition rate H and new leaf germination number N; 4, constructing a comprehensive evaluation model, and calculating a heat resistance index HI; 5, plant heat resistance phenotype rapid evaluation. According to the method, variety heat resistance accurate classification is achieved, professional instruments are not needed, the single cycle only needs 20 days, the supply pressure of non-heading Chinese cabbages in the high-temperature season is remarkably relieved, breeding standardization of stress-resistant varieties is promoted, and agricultural sustainable development is promoted.

Description

Technical Field

[0001] The present invention relates to an evaluation method, in particular to a rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage, belonging to the technical field of agricultural variety identification. Background Art

[0002] Non-heading Chinese cabbage (Brassica campestris ssp. chinensis) is native to China and belongs to the genus Brassica in the Cruciferae family. It is deeply loved by the public because of its rich nutritional value, strong adaptability, and simple cultivation methods. Non-heading Chinese cabbage prefers cool temperatures. In the hot and rainy summer, high temperatures can cause the growth and development of non-heading Chinese cabbage to slow down, the leaves to be damaged, the quality to decrease, and the yield to decline. The global greenhouse effect inevitably leads to extreme high-temperature phenomena in the climate. The increase in temperature has been determined to be the most harmful environmental factor, having a profound impact on the development and growth of plants. In field investigations, it is found that non-heading Chinese cabbage often shows phenomena such as growth inhibition, high seedling death rate, poor taste, water loss and wilting, yellowing of leaves, and rotting of the whole plant when encountering continuous high-temperature weather in summer. Under extreme high-temperature stress, the photosynthesis of non-heading Chinese cabbage is blocked, the transpiration is enhanced, and the respiration is increased, resulting in weakened reproductive growth and slow growth.

[0003] Establishing a heat tolerance evaluation system for non-heading Chinese cabbage, screening heat-tolerant germplasm resources, and cultivating excellent heat-tolerant varieties to alleviate the impact of high-temperature stress on non-heading Chinese cabbage are currently urgent problems to be solved. At present, in traditional methods, the key conditions such as the temperature, duration, and environmental parameters (such as humidity and light) of high-temperature stress are often described vaguely, and the treatment schemes adopted in different studies vary greatly, resulting in the lack of comparability of experimental results. For example, the traditional heat tolerance identification method in the field has a long cycle, a single index, and is interfered by rainfall, pests and diseases, etc., with poor repeatability. It ignores dynamic phenotypes such as the ability to recover growth and lacks a quantitative grading system. Different researchers have significant differences in the definition of "heat tolerance", which affects the promotion of varieties. Therefore, there is an urgent need to develop a rapid and efficient heat evaluation method for non-heading Chinese cabbage. Summary of the Invention

[0004] In order to solve the deficiencies of the above technologies, the present invention provides a rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage, including the following evaluation steps:

[0006] Step 1, standardized seedling raising: Sow seeds in a seedling raising substrate, and carry out under the conditions of constant day and night temperature: 22°C / 18°C, relative humidity: 60%, light cycle: 16 h of light / 8 h of darkness, and light intensity: 20000 Lux;

[0007] Step 2. Extreme high temperature stress treatment and recovery culture: The conditions for short-term extreme high temperature stress treatment are as follows: the temperature is controlled at 49 ± 0.5 °C, the humidity is 60%-70%, the light intensity is 20000 Lux, and the treatment lasts for 8 hours;

[0008] Subsequently, recovery culture is carried out. The conditions for recovery culture are as follows: the temperature is kept constant at 22 °C / 18 °C day and night for 24 h, and the light intensity of 20000 Lux is maintained;

[0009] Step 3. Observation of phenotypic indicators: The observed phenotypic indicators include survival rate S, leaf damage index D, plant height inhibition rate H, and number of new leaves germinated N;

[0010] Step 4. Construct a comprehensive evaluation model and calculate the heat tolerance index HI. The calculation formula is as follows:

[0011] HI = 0.45S + 0.3(1 - D) + 0.15(1 - H) + 0.1N

[0012] Step 5. Based on the calculation results of the heat tolerance index HI, a rapid phenotypic evaluation of plant heat tolerance is carried out.

[0013] Preferably, in Step 1, sowing is carried out using a seedling tray. The seedling substrate is filled into the seedling tray, and 1 seed is sown in each hole. The tray with the covered substrate is placed in a supporting tray, and water is added and placed in an artificial climate chamber for standardized seedling cultivation.

[0014] Preferably, in Step 1, on the 20th day after sowing and cultivation, seedlings with 3-4 true leaves and a plant height of 8-10 cm are selected for subsequent extreme high temperature stress treatment.

[0015] Preferably, in Step 3, the observation method for the survival rate S is as follows: the number of surviving plants is counted 3 days after the end of the recovery culture treatment. The calculation formula is as follows:

[0016] S(%) = (number of surviving plants / total number of plants) * 100%.

[0017] Preferably, in Step 3, according to the degree of leaf damage, the 0-4 level grading scoring method is used to determine the leaf damage index D. Specifically, there are:

[0018] Level 0 indicates that the leaves are completely normal, without wilting or discoloration, and the leaf damage index D ≤ 0.1;

[0019] Level 1 indicates that when the leaf margin is slightly wilted and there is no yellowing, 0.1 < leaf damage index D ≤ 0.4;

[0020] Level 2 indicates that 1 / 3 of the leaf area is yellowed or scorched, 0.4 < leaf damage index D ≤ 0.7;

[0021] Level 3 indicates that 2 / 3 of the leaf area is yellowed or scorched, and 0.7 < leaf damage index D ≤ 0.9;

[0022] Level 4 indicates that the leaves wither and fall off, and the leaf damage index D > 0.9.

[0023] Preferably, in step 3, the observation method of the plant height inhibition rate H is as follows: Measure the plant height 3 days after the end of the recovery culture treatment, and the calculation formula is:

[0024] H(%) = (control plant height - treated plant height) / control plant height * 100%.

[0025] Preferably, in step 3, count the number of true leaves with a length ≥ 1 cm newly grown from the heart leaf part and record it as the number of new leaf germinations N.

[0026] Preferably, in step 4, the weights of the survival rate S, leaf damage index D, plant height inhibition rate H, and number of new leaf germinations N are determined by the analytic hierarchy process, and the calculation formula for constructing the heat tolerance index HI includes the following process:

[0027] 4.1 Establish a hierarchical structure model: Decompose the heat tolerance evaluation problem into an objective layer, a criterion layer, and a scheme layer; among them, the objective layer is the heat tolerance index HI; the criterion layer is phenotypic indicators, including the survival rate S, leaf damage index D, plant height inhibition rate H, and number of new leaf germinations N; the scheme layer is different non-heading Chinese cabbage varieties;

[0028] 4.2 Calculate the weight vector: Calculate the weight vector of each phenotypic indicator by performing mathematical operations on the judgment matrix.

[0029] Preferably, in step 5, a grading standard for classifying the heat tolerance of plants is constructed, and the grading standard is as follows:

[0030] When the heat tolerance index HI ≥ 0.9, it indicates that the plant is highly heat-tolerant;

[0031] When 0.6 ≤ heat tolerance index HI < 0.9, it indicates that the plant is moderately heat-tolerant;

[0032] When the heat tolerance index HI < 0.6, it indicates that the plant is heat-sensitive.

[0033] The present invention discloses a rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage, and proposes a rapid evaluation method based on extreme high temperature stress (49 °C / 8 h extreme high temperature) and multi-dimensional phenotypic observation (survival rate, leaf damage index, recovery growth index). By constructing a quantitative grading model through the analytic hierarchy process, taking the heat tolerance index (HI) as the core index, accurate classification of the heat tolerance of varieties is realized. This method does not require professional instruments, and only 20 days are needed for a single cycle, significantly alleviating the supply pressure of non-heading Chinese cabbage in the high-temperature season, promoting the standardization of the breeding of stress-resistant varieties, and promoting the sustainable development of agriculture. Brief Description of the Drawings

[0034] Figure 1 It is a schematic flow chart of the present invention.

[0035] Figure 2 It is a diagram showing the plant states before and after heat shock treatment in an embodiment of the present invention. Detailed Embodiment

[0036] The present invention will be further described in detail below in conjunction with the drawings and the detailed embodiment.

[0037] The present invention provides a rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage, which realizes the rapid and efficient screening of heat-tolerant non-heading Chinese cabbage through extreme high-temperature stress treatment combined with multi-dimensional phenotype observation, as Figure 1 shown, the rapid evaluation method includes the following steps:

[0038] Step 1, standardized seedling raising: Sow seeds in a seedling substrate and place them in an artificial climate chamber for standardized cultivation;

[0039] Usually, a seedling tray is used for sowing. The seedling substrate (such as peat) is filled into the seedling tray, and 1 seed is sown in each hole. The tray with the covered substrate is put into a supporting tray, and water is added and placed in an artificial climate chamber for standardized seedling cultivation.

[0040] The standardized cultivation conditions are: constant temperature day and night: 22°C / 18°C (that is, 22°C constant temperature during the day and 18°C constant temperature at night), relative humidity: 60%, photoperiod: light 16h / dark 8h (that is, light 16h and dark 8h alternate), light intensity: 20000Lux;

[0041] On the 20th day after sowing and cultivation, select seedlings with 3-4 true leaves and a plant height of 8-10 cm for subsequent extreme high-temperature stress treatment.

[0042] Step 2, extreme high-temperature stress treatment and recovery cultivation

[0043] In traditional research, the conditions such as temperature, duration, humidity, and light of high-temperature stress are often unclear, and the parameters used in different studies vary greatly, resulting in a lack of comparability of experimental results. The present invention clarifies the condition parameters of short-term extreme high-temperature treatment and the condition parameters of recovery cultivation. These precise parameter settings enable the experimental environment to be accurately controlled and repeated, effectively solving the problem of unclear condition parameters in traditional research and providing a reliable basis for the comparison of experimental results between different experiments.

[0044] Specifically, short-term extreme high temperature treatment is carried out in an artificial climate chamber. The conditions for short-term extreme high temperature stress treatment are as follows: the temperature is controlled at 49±0.5°C, the humidity is 60%-70%, the light intensity is 20000 Lux, and the treatment lasts for 8 hours.

[0045] Subsequently, recovery culture is carried out. The conditions for recovery culture are as follows: constant temperature of 22°C / 18°C day and night for 24 hours, and the same light conditions are maintained (i.e., light intensity of 20000 Lux).

[0046] In this step, through the "short-term" extreme high temperature stress treatment, optimizations are achieved in terms of efficiency, focusing on key indicators, and simulating actual extreme situations. In terms of efficiency, the short-term extreme high temperature treatment only takes 8 hours, and the entire evaluation cycle for a single cycle only takes 20 days. Compared with the traditional method, the cycle is greatly shortened, and the heat tolerance of a large number of varieties can be evaluated in a short time, significantly improving the research efficiency and helping to quickly screen out heat-tolerant varieties. In terms of focusing on key indicators, the short-term treatment can more intensively observe the immediate damage of non-heading Chinese cabbage under extreme high temperature. Indicators such as survival rate and leaf damage index can directly reflect the resistance of the plant to extreme high temperature, avoiding the interference of other factors in the long-term treatment and making the research results more targeted. In terms of simulating the actual situation, in the natural environment, non-heading Chinese cabbage may suddenly encounter short-term extreme high temperature weather. The "short-term extreme high temperature" treatment can better simulate this actual situation, and the obtained evaluation results are more in line with the actual production needs, which is of great significance for guiding agricultural production.

[0047] Step 3. Observation of phenotypic indicators

[0048] By studying the growth state and physiological changes of non-heading Chinese cabbage under high temperature stress, relevant phenotypic indicators are determined, including four key phenotypic indicators: survival rate (S), leaf damage index (D), plant height inhibition rate (H), and number of new leaves germinated (N). They reflect the heat tolerance of non-heading Chinese cabbage from different angles.

[0049] Among them, the survival rate (S) directly reflects the degree of influence of extreme high temperature on the survival of the plant. The higher the proportion of surviving plants, the stronger the survival ability of the variety under extreme high temperature.

[0050] The leaf damage index (D) adopts a grading scoring method (0-4 levels); the grade is divided according to the degree of leaf damage. For example, level 0 means the leaf is completely normal without wilting or discoloration; level 4 means the whole leaf withers and falls off. By assigning corresponding values to different levels, the damage degree of the leaf under extreme high temperature can be quantified.

[0051] The plant height inhibition rate (H) is measured 3 days after recovery culture. This indicator reflects the inhibition of extreme high temperature on the growth of the plant. The lower the inhibition rate, the stronger the growth recovery ability of the plant after recovery culture.

[0052] The statistics of the number of newly germinated leaves (N) is the number of true leaves newly grown from the heart leaf part. The number of newly germinated leaves reflects the regeneration ability of the plant after suffering extreme high temperature stress. The more the number of newly germinated leaves, the stronger the recovery ability of the plant.

[0053] Therefore, after the extreme high temperature stress treatment and the recovery culture treatment, the observation of four key phenotypic indicators, namely survival rate (S), leaf damage index (D), plant height inhibition rate (H), and number of newly germinated leaves (N), is carried out. The specific methods are as follows:

[0054] (1) Survival rate (S): The number of surviving plants is counted 3 days after the treatment. The calculation formula is: S(%) = (number of surviving plants / total number of plants) * 100%;

[0055] (2) Leaf damage index (D): The grading scoring method (0 - 4 levels) is adopted:

[0056]

[0057]

[0058] (3) Plant height inhibition rate (H): The plant height is measured 3 days after the recovery culture. The calculation formula is: H(%) = (control plant height - treated plant height) / control plant height * 100%;

[0059] (4) Number of newly germinated leaves (N): The number of true leaves newly grown from the heart leaf part (length ≥ 1 cm) is counted.

[0060] Step 4: Construct a comprehensive evaluation model:

[0061] In the present invention, the analytic hierarchy process (AHP) is used to determine the weights of the survival rate (S), leaf damage index (D), plant height inhibition rate (H), and number of newly germinated leaves (N). In order to combine these four phenotypic indicators to form an index that can comprehensively reflect the heat tolerance of non-heading Chinese cabbage, the analytic hierarchy process is used to determine the weights of each indicator. The analytic hierarchy process is a multi-criteria decision-making method that combines qualitative and quantitative methods. Its basic steps are as follows:

[0062] 4.1 Establish a hierarchical structure model: Decompose the heat tolerance evaluation problem into an objective layer (heat tolerance index), a criterion layer (survival rate, leaf damage index, plant height inhibition rate, number of newly germinated leaves), and a scheme layer (different non-heading Chinese cabbage varieties);

[0063] 4.2 Calculate the weight vector: By performing mathematical operations on the judgment matrix, the weight vector of each indicator is calculated.

[0064] After the above steps, the weight of the survival rate was determined to be 0.45, the weight of the leaf damage index was 0.3, the weight of the plant height inhibition rate was 0.15, and the weight of the number of new leaves germinated was 0.1.

[0065] 4.3 Construction of the calculation formula for the heat tolerance index (HI)

[0066] Based on the determined phenotypic indicators and their weights, the calculation formula for the heat tolerance index (HI) is: HI = 0.45S + 0.3(1 - D) + 0.15(1 - H) + 0.1N.

[0067] In the formula, the form of (1 - D) is adopted for the leaf damage index because the lower the damage index, the better the heat tolerance. After such treatment, the change trend is consistent with other indicators, which is convenient for comprehensive calculation. Through this formula, the information of the four phenotypic indicators is integrated to obtain a value that can quantify the heat tolerance of non-heading Chinese cabbage, thereby realizing a rapid and accurate evaluation of the heat tolerance of different varieties.

[0068] Step 5: Based on the calculation results of the heat tolerance index (HI), perform a rapid phenotypic evaluation of the plant heat tolerance.

[0069] Compare the calculation results of the heat tolerance index (HI) with the grading standard to determine the heat tolerance level of the current plant. The grading standard is shown in the following table:

[0070]

[0071] [Example]

[0072] This example discloses a rapid phenotypic evaluation method for the heat tolerance of non-heading Chinese cabbage. Through short-term extreme high temperature (49 ± 0.5 °C / 8 h) stress treatment, the heat tolerance phenotypes of 6 non-heading Chinese cabbage varieties were evaluated.

[0073] The 6 non-heading Chinese cabbage varieties are Youmei No. 2, Yanqing, Xialong 18, Waltz Beauty, Suzhouqing, and 20 - 1g - 100. The specific treatment process is as follows:

[0074] Standardized seedling raising: The nursery substrate is selected as the peat of the Wosong brand of Dayi Agricultural Technology Co., Ltd. It is filled into a 105-hole seedling tray, and 1 seed is sown in each hole. The seedling tray covered with the substrate is placed in a supporting tray, and water is added and placed in an artificial climate chamber (Ningbo Yanghui Instrument Co., Ltd., model RDA - 1000A) with a day-night temperature of 22 °C / 18 °C, a relative humidity of 60%, a light cycle of 16 h of light / 8 h of darkness, and a light intensity of 20000 Lux. High-temperature treatment is carried out on the 20th day after sowing (with 3 - 4 true leaves and a plant height of 8 - 10 cm).

[0075] Short-term extreme high temperature treatment: The equipment used was a Yanghui artificial climate chamber, model: RDA-1000A, with the following conditions: temperature 49 ± 0.5 °C, humidity 60%-70%, light intensity 20,000 Lux, for 8 hours; then recovery culture was carried out, with a day-night temperature of 22 °C / 18 °C for 24 h, maintaining the same light conditions.

[0076] Observation of phenotypic indicators: The observed indicators included survival rate (S), leaf damage index (D), plant height inhibition rate (H), and number of newly germinated leaves (N);

[0077] Comprehensive evaluation model: Based on the analytic hierarchy process, the heat tolerance index (HI) was calculated, and the heat tolerance phenotype of each variety was evaluated based on the grading standard table.

[0078] The plant states before and after heat shock were as Figure 2 shown, and the observed results and the calculated heat tolerance index (HI) results are shown in the following table:

[0079]

[0080] From the experimental results, it can be seen that Youmei No. 2 (HI = 0.835) and Waltz Beauty (HI = 0.655) showed medium heat tolerance, with survival rates of 90% and 70% respectively, leaf damage indices of 0.3 and 0.55, and both germinated 1 new leaf; for the remaining varieties (Yanqing, Xialong 18, Suzhouqing, 20-1g-100), HI was <0.6, belonging to the heat-sensitive type, with a survival rate ≤40%, a leaf damage index ≥0.5, and no new leaves germinated. The research shows that the survival rate and leaf damage index are the core indicators for distinguishing heat tolerance, and the ability to germinate new leaves can assist in evaluating the recovery potential. This method realizes the rapid and accurate grading of variety heat tolerance through multi-dimensional quantitative indicators, providing an effective tool for screening stress-resistant germplasms.

[0081] In summary, for the rapid evaluation method of the heat tolerance phenotype of non-heading Chinese cabbage disclosed in the present invention, it has the following technical advantages:

[0082] 1) Standardized processing flow: Clearly define the time-temperature combination of high temperature stress, solve the problem of fuzzy treatment conditions in traditional methods. These precise parameter settings enable the experimental environment to be accurately controlled and repeated, effectively solving the problem of unclear condition parameters in traditional research, and providing a reliable basis for comparing the results between different experiments;

[0083] 2) Dynamic phenotype observation: Combine immediate damage (survival rate, damage index) with recovery ability (plant height inhibition rate, new leaf germination) to comprehensively evaluate heat tolerance, making the evaluation results more accurate;

[0084] 3) Quantitative grading system: Determine the weights through the analytic hierarchy process, convert multiple indicators into a single index, which is convenient for large-scale variety screening.

[0085] 4) Achieve "efficient and rapid" screening and evaluation. The single-cycle of the entire evaluation period only takes 20 days, which is greatly shortened compared with the traditional method. It can evaluate the heat resistance of a large number of varieties in a short time, significantly improving the research efficiency and helping to quickly screen out heat-resistant varieties.

[0086] The above embodiments are not limitations to the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present invention also fall within the protection scope of the present invention.

Claims

1. A rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage, characterized in that: It includes the following evaluation steps: Step 1, standardized seedling raising: Sow seeds in a seedling-raising substrate, and carry out under the conditions of constant day and night temperature: 22°C / 18°C, relative humidity: 60%, photoperiod: 16 h of light / 8 h of darkness, light intensity: 20000 Lux; Step 2, extreme high temperature stress treatment and recovery culture: The conditions for short-term extreme high temperature stress treatment are: the temperature is controlled at 49±0.5°C, the humidity is 60%-70%, the light intensity is 20000 Lux, and the treatment lasts for 8 hours; Subsequently, carry out recovery culture, and the conditions for recovery culture are: culture at a constant day and night temperature of 22°C / 18°C for 24 h, and maintain a light intensity of 20000 Lux; Step 3, observation of phenotypic indicators: The observed phenotypic indicators include survival rate S, leaf damage index D, plant height inhibition rate H, and number of newly germinated leaves N; Step 4, construct a comprehensive evaluation model, calculate the heat tolerance index HI, and the calculation formula is: HI = 0.45S + 0.3(1 - D) + 0.15(1 - H) + 0.1N Step 5, based on the calculation results of the heat tolerance index HI, conduct a rapid evaluation of the plant heat tolerance phenotype.

2. The rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage according to claim 1, characterized in that: In step 1, use a seedling-raising tray for sowing, fill the seedling-raising substrate into the seedling-raising tray, sow 1 seed in each hole, put the tray covered with the substrate into a supporting tray, add water and place it in an artificial climate chamber for standardized seedling raising.

3. The rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage according to claim 2, wherein: In step 1, on the 20th day after sowing and cultivation, select seedlings with 3-4 true leaves and a plant height of 8-10 cm for subsequent extreme high temperature stress treatment.

4. The rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage according to claim 1, wherein: In step 3, the observation method of the survival rate S is: count the number of surviving plants 3 days after the end of the recovery culture treatment, and the calculation formula is: S(%) = (number of surviving plants / total number of plants)×100%.

5. The rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage according to claim 4, characterized in that: In step 3, according to the degree of leaf damage, use a 0-4 level grading scoring method to determine the leaf damage index D, specifically: Level 0 means the leaves are completely normal, without wilting or discoloration, and the leaf damage index D≤0.1; Level 1 means when the leaf margin is slightly wilted and there is no yellowing, 0.1 < leaf damage index D≤0.4; Level 2 means that 1 / 3 of the leaf area is yellowed or scorched, 0.4 < leaf damage index D≤0.7; Level 3 means that 2 / 3 of the leaf area is yellowed or scorched, 0.7 < leaf damage index D≤0.9; Level 4 means the leaves wither and fall off, and the leaf damage index D>0.

9.

6. The rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage according to claim 5, characterized in that: In step 3, the observation method of the plant height inhibition rate H is: measure the plant height 3 days after the end of the recovery culture treatment, and the calculation formula is: H(%) = (control plant height - treated plant height) / control plant height×100%.

7. The rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage according to claim 5, characterized in that: In step 3, count the number of true leaves with a length ≥1 cm newly grown from the heart leaf part and record it as the number of newly germinated leaves N.

8. The rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage according to claim 1, characterized in that: In step 4, determine the weights of the survival rate S, leaf damage index D, plant height inhibition rate H, and number of newly germinated leaves N by the analytic hierarchy process, and construct the calculation formula of the heat tolerance index HI, including the following process: 4.1 Establish a hierarchical structure model: Decompose the heat tolerance evaluation problem into an objective layer, a criterion layer, and a scheme layer; among them, the objective layer is the heat tolerance index HI; the criterion layer is phenotypic indicators, including survival rate S, leaf damage index D, plant height inhibition rate H, and number of new leaves germinated N; the scheme layer is different non-heading Chinese cabbage varieties; 4.2 Calculate the weight vector: Calculate the weight vector of each phenotypic indicator by performing mathematical operations on the judgment matrix.

9. The rapid evaluation method for the heat tolerance phenotype of non-heading Chinese cabbage according to claim 1, characterized in that: In step 5, a grading standard for classifying the heat tolerance level of plants was constructed, and the grading standard is as follows: When the heat tolerance index HI ≥ 0.9, it indicates that the plant is highly heat-tolerant; When 0.6 ≤ heat tolerance index HI < 0.9, it indicates that the plant is moderately heat-tolerant; When the heat tolerance index HI < 0.6, it indicates that the plant is heat-sensitive.

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