Sunflower variety resource drought resistance identification method

Abstract

The invention discloses a sunflower variety resource drought resistance identification method, and relates to the technical field of drought resistance identification, and the method comprises the following identification steps: S1, germination period drought resistance identification; s2, seedling stage drought resistance identification; s3, identifying the drought resistance in the squaring stage. According to the sunflower variety resource drought resistance identification method, drought resistance identification evaluation is carried out on sunflowers in different stages, indoor germination stage PEG-6000, seedling stage and squaring stage natural drought stress treatment is adopted, principal component analysis, membership function analysis, stepwise regression analysis and other analysis are combined, and the sunflower germination stage, seedling stage and squaring stage drought resistance identification method is established. Evaluation indexes and drought resistance grading are determined, a systematic and comprehensive drought resistance identification system is formed, a simple, convenient, rapid and reliable identification method is provided for drought resistance evaluation of sunflower variety resources, the method is short in time period, labor cost is reduced, and the drought resistance of sunflower resource materials can be rapidly and efficiently identified.

Description

Technical Field

[0001] The invention relates to the technical field of drought resistance identification, in particular to a method for identifying drought resistance of sunflower variety resources. Background Art

[0002] Sunflower (Helianthus annuus L.) is not only one of the important oil crops in the world, but also the main oil crop and cash crop grown in arid and semi-arid areas of my country. With global warming, drought is becoming increasingly severe. Drought has become a major abiotic stress that affects the growth and production of crops, seriously affecting the sustainable development of agriculture. Since the main sunflower producing areas in my country are mostly distributed in arid and semi-arid areas, sunflowers are affected by drought at all stages of their growth. Drought has become one of the factors restricting sunflower production and economic development.

[0003] Although sunflower has strong drought resistance, there are large differences in drought resistance among different varieties, and the drought resistance of sunflower varies due to different drought resistance mechanisms at each stage of its growth. Therefore, it is of great significance to identify the drought resistance of sunflower variety resources at different periods, screen drought-resistant sunflower variety resources, and cultivate strong drought-resistant varieties to promote high and stable yields of sunflower. Establishing a simple, fast and effective drought resistance identification method is the basis for evaluating and screening the drought resistance of sunflower variety resources and cultivating drought-resistant varieties.

[0004] Simple, efficient and accurate drought resistance identification and evaluation methods are the basis for breeding drought-resistant varieties. Appropriate drought treatment methods and intuitive and effective key indicators are important factors for drought resistance identification in different periods. At present, the research on the identification method of sunflower drought resistance is relatively scattered and mostly concentrated in a certain period. The methods established by different researchers are inconsistent, which makes it difficult to compare the results of similar tests. At the same time, the established methods are complex and labor-intensive. Therefore, in order to form a standardized and systematic sunflower drought resistance identification and evaluation system, it is urgent to establish a simple, easy, fast and reliable method for identifying drought resistance of sunflower variety resources. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies in the prior art, the present invention provides a method for identifying drought resistance of sunflower variety resources, which solves the problems of the original drought resistance identification method, namely, a single identification period and an insufficiently systematic method.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for identifying drought resistance of sunflower variety resources, comprising the following identification steps:

[0009] S1. Identification of drought resistance during germination period:

[0010] S1.1, treating the sterilized sunflower seeds with PEG-6000;

[0011] S1.2. Continuously count the number of germinations from day 1 to day 7, measure the radicle length, plumule length and fresh weight of the germinated seeds on day 7, and calculate the germination rate, germination potential, relative germination rate, relative germination potential, relative radicle length, relative plumule length, relative fresh weight, drought resistance coefficient and drought damage coefficient; S1.3. Determine the screening concentration of PEG-6000;

[0012] S1.4, evaluate drought resistance during the germination period, and select varieties with strong drought resistance during the germination period according to the comprehensive evaluation value of drought resistance;

[0013] S1.5 Screening of key indicators during germination period;

[0014] S2. Drought resistance assessment at the seedling stage:

[0015] S2.1, germinating and sowing the selected sunflower seeds, and subjecting the seedlings to natural drought stress treatment when they grow four true leaves;

[0016] S2.2. When the soil moisture content dropped from 20%±1% to 6%±1% under natural drought conditions, the plant height, stem diameter, leaf area, leaf SPAD value, leaf relative water content, and root-crown ratio were measured, and the relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, and relative root-crown ratio were calculated;

[0017] S2.3, Comprehensive evaluation of drought resistance at the seedling stage, and screening of variety resources with strong drought resistance at the seedling stage according to the comprehensive evaluation value of drought resistance at the seedling stage;

[0018] S2.4 Screening of key indicators at the seedling stage;

[0019] S3. Drought resistance assessment at the budding stage:

[0020] S3.1. Germinating and sowing the selected sunflower seeds, and subjecting the seedlings to natural drought stress treatment when they grow six pairs of true leaves;

[0021] S3.2. When the soil moisture content drops from 25%±1% to 6%±1% during natural drought and lasts for 5 days, measure the plant height, stem diameter, leaf area, leaf SPAD value, leaf relative water content, and sunflower disk diameter, and calculate the relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, and relative sunflower disk diameter;

[0022] S3.3 Evaluate drought resistance at the budding stage, and screen the variety resources with strong drought resistance at the budding stage based on the average value of the membership function value.

[0023] Preferably, in step S1.1, 3% sodium hypochlorite solution is used to disinfect the sunflower seeds.

[0024] Preferably, in step S1.2, the calculation formulas for the drought resistance coefficient, drought damage coefficient, germination rate, germination potential, relative germination rate, relative germination potential, relative radicle length, relative plumule length, and relative fresh weight are:

[0025] Drought resistance coefficient = measured index of treatment group / measured index of control group;

[0026] Drought damage coefficient = 1-drought resistance coefficient;

[0027] Germination rate = (total number of seeds germinated in 7 days / number of seeds tested) × 100%;

[0028] Germination potential = (total number of germinated seeds on the 4th day / number of test seeds) × 100%;

[0029] Relative germination rate = (treatment germination rate / control germination rate) × 100%;

[0030] Relative germination potential = (germination potential of treatment / germination potential of control) × 100%;

[0031] Relative radicle length = (treatment radicle length / control radicle length) × 100%;

[0032] Relative germ length = (treatment germ length / control germ length) × 100%;

[0033] Relative fresh weight = (treatment fresh weight / control fresh weight) × 100%.

[0034] Preferably, in step S1.3, determining the PEG-6000 screening concentration specifically includes: the PEG concentration corresponding to a 50% decrease in the drought damage coefficient of each index of relative germination potential, relative germination rate, relative embryo length, relative radicle length, and relative fresh weight, which are 20.11%, 22.59%, 14.49%, 22.79%, and 22.92%, respectively.

[0035] Preferably, in step S2.1, natural drought stress treatment is performed when the seedlings grow four true leaves.

[0036] Preferably, in step S2.2, the calculation formulas for relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, and relative root-to-crown ratio are:

[0037] Relative plant height = (treated plant height / control plant height) × 100%;

[0038] Relative stem diameter = (treated stem diameter / control stem diameter) × 100%;

[0039] Relative leaf area = (treated leaf area / control leaf area) × 100%;

[0040] Relative SPAD value = (treatment SPAD value / control SPAD value) × 100%;

[0041] Relative leaf water content = (treated leaf water content / control leaf water content) × 100%;

[0042] Relative root-to-shoot ratio=(root-to-shoot ratio of treatment / root-to-shoot ratio of control)×100%.

[0043] Preferably, in step S3.2, the calculation formulas for relative plant height, relative stem thickness, relative leaf area, relative SPAD value, relative leaf water content, and relative sunflower disk diameter are as follows:

[0044] Relative plant height = (treated plant height / control plant height) × 100%;

[0045] Relative stem diameter = (treated stem diameter / control stem diameter) × 100%;

[0046] Relative leaf area = (treated leaf area / control leaf area) × 100%;

[0047] Relative SPAD value = (treatment SPAD value / control SPAD value) × 100%;

[0048] Relative leaf water content = (treated leaf water content / control leaf water content) × 100%;

[0049] Relative sunflower disk diameter = (treated sunflower disk diameter / control sunflower disk diameter) × 100%.

[0050] Preferably, in the step S1.4, the drought resistance evaluation at the germination stage, the comprehensive drought resistance evaluation at the seedling stage in the step S2.3, and the comprehensive drought resistance evaluation at the budding stage in the step S3.3 adopt the method of seeking membership function in fuzzy mathematics.

[0051] Preferably, the formula for comprehensive evaluation of drought resistance of each variety is:

[0052] A: X ij =t ij / T ij ,i=1,2,...,n,j=1,2,...,n;

[0053] B:

[0054] C:

[0055] D:

[0056] E:

[0057] Where: A In the formula X ij is the drought resistance coefficient, t ij To process the measured value, T ij is the control value, in formula B and C, u(X ij ) represents the drought resistance membership function value of index j of variety i, x min and x max Respectively represent the maximum and minimum measured values ​​of each variety index. If the measured value of the resistance index is positively correlated with the resistance, use formula A, otherwise use formula B;

[0058] Formula D is the weight of each comprehensive indicator, and w in formula C is j It represents the importance of the jth comprehensive index among all comprehensive indexes, i.e., its weight, p j represents the contribution rate of the jth comprehensive index of each sunflower variety obtained by principal component analysis;

[0059] In formula E, the D value is the comprehensive evaluation value of drought resistance of each sunflower variety obtained by comprehensive index evaluation under drought stress conditions.

[0060] (III) Beneficial effects

[0061] The invention provides a method for identifying drought resistance of sunflower variety resources. Compared with the prior art, the method has the following beneficial effects: the method for identifying drought resistance of sunflower variety resources, by evaluating drought resistance of sunflowers at different stages, adopting PEG-6000 at the germination stage indoor, natural drought stress treatment at the seedling stage and the budding stage, combining principal component, membership function method, stepwise regression and other analyses, establishes a method for identifying drought resistance of sunflowers at the germination stage, seedling stage and budding stage, determines evaluation indicators and drought resistance classification, forms a systematic and comprehensive drought resistance identification system, and provides a simple, easy, fast and reliable identification method for evaluating drought resistance of sunflower variety resources. The method has a short time cycle, and only takes one week from the time when the sunflower seedlings grow to 4 true leaves and the stress begins and the treatment ends. Frequent watering is not required in the treatment stage, which reduces labor costs, and can quickly and efficiently identify the drought resistance of sunflower resource materials. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] Example 1

[0064] The steps for drought resistance identification of sunflower during germination are as follows:

[0065] 1) Preparation of PEG-6000 solution: prepare PEG-6000 solutions with concentrations of 0%, 15%, 18%, 21%, and 25%;

[0066] 2) Seed preparation: Select seeds of uniform size and full grains, treat them with 3% sodium hypochlorite solution for 10 minutes, and then rinse them with distilled water three times to obtain sterilized sunflower seeds;

[0067] 3) Drought stress treatment: The seeds were spread flat on a culture dish lined with two layers of filter paper, 50 seeds were evenly placed, and each treatment was repeated 3 times. A fixed amount of PEG-6000 solution of different concentrations (0-25%) was added (preferably to soak the filter paper and seeds). The same volume of distilled water was added as a control. Then, the seeds were placed in a light incubator at 25°C ± 1°C. After that, the double-layer filter paper with the same amount of solution of the corresponding stress concentration or distilled water was replaced every 2 days to keep the concentration constant.

[0068] Investigation and evaluation: The germination potential was determined on the 4th day; the germination rate, radicle length, plumule length and fresh weight were determined on the 7th day. Five plants were randomly selected from each culture dish for measurement and the average value was taken. The germination standard was that the radicle broke through the seed coat by 2 mm. The germination rate, germination potential, relative germination rate, relative germination potential, relative radicle length, relative plumule length, relative fresh weight, drought resistance coefficient and drought damage coefficient were calculated, among which:

[0069] Drought resistance coefficient = measured index of treatment group / measured index of control group;

[0070] Drought damage coefficient = 1-drought resistance coefficient;

[0071] Germination rate = (total number of seeds germinated in 7 days / number of seeds tested) × 100%;

[0072] Germination potential = (total number of germinated seeds on the 4th day / number of test seeds) × 100%;

[0073] Relative germination rate = (treatment germination rate / control germination rate) × 100%;

[0074] Relative germination potential = (germination potential of treatment / germination potential of control) × 100%;

[0075] Relative radicle length = (treatment radicle length / control radicle length) × 100%;

[0076] Relative germ length = (treatment germ length / control germ length) × 100%;

[0077] Relative fresh weight = (treatment fresh weight / control fresh weight) × 100%;

[0078] 4) Determination of the appropriate screening concentration: When the drought damage coefficient of the relative germination potential, relative germination rate, relative embryo length, relative radicle length, and relative fresh weight decreased by 50%, the corresponding PEG concentrations were 20.11%, 22.59%, 14.49%, 22.79%, and 22.92%, respectively. When the average drought damage coefficient was 50%, the corresponding PEG concentration was 20.58%, which was closest to the 21% PEG concentration. Therefore, the 21% PEG-6000 concentration was used as the appropriate concentration for drought resistance identification and screening during the germination period;

[0079] 5) Evaluation of drought resistance during germination: The method of seeking membership function in fuzzy mathematics was used to conduct a comprehensive evaluation of drought resistance of each variety. The formula is:

[0080] A: X ij =t ij / T ij ,i=1,2,...,n,j=1,2,...,n;

[0081] B:

[0082] C:

[0083] D:

[0084] E:

[0085] Where: A In the formula X ij is the drought resistance coefficient, t ij To process the measured value, T ij is the control value, in formula B and C, u(X ij ) represents the drought resistance membership function value of index j of variety i, x min and x max Respectively represent the maximum and minimum measured values ​​of each variety index. If the measured value of the resistance index is positively correlated with the resistance, use formula A, otherwise use formula B;

[0086] Formula D is the weight of each comprehensive indicator, and w in formula C is j It represents the importance of the jth comprehensive index among all comprehensive indexes, i.e., its weight, p j represents the contribution rate of the jth comprehensive index of each sunflower variety obtained by principal component analysis;

[0087] In formula E, the D value is the comprehensive evaluation value of drought resistance of each sunflower variety obtained by comprehensive index evaluation under drought stress conditions.

[0088] Comprehensive evaluation of drought resistance: The relative germination rate, relative germination potential, relative embryo length, relative radicle length, relative fresh weight and other indicators of 12 sunflower variety resources under 21% PEG-6000 simulated drought stress conditions during the germination period were subjected to factor and principal component analysis using SPSS26.0 software to obtain the principal component analysis results and D value (Table 1).

[0089] Table 1 Results of principal component analysis of germination period

[0090] variety PCI PCII μ1 μ2 D value A1×197 -0.630 0.413 0.252 0.460 0.331 No. 67 1.485 1.127 1.000 0.672 0.876 No. 35 1.132 -0.033 0.875 0.327 0.668 Y5A×YJMR2 -0.851 -0.390 0.174 0.221 0.192 Yimin 303 -0.596 2.231 0.265 1.000 0.542 JK202 -1.165 0.861 0.0634 0.593 0.263 JK108 -1.344 -0.986 0.000 0.044 0.017 1606A×Ly-4R 1.074 -0.067 0.855 0.316 0.652 1606A×303 -0.080 -0.477 0.447 0.195 0.352 F15-2A×303-1R 1.271 -0.711 0.925 0.126 0.623 Jiuyang 309 -0.311 -0.830 0.365 0.091 0.262 YA150×H1 0.018 -1.135 0.481 0.000 0.300 Weight / % 62.258 37.742

[0091] Dimensionality reduction was achieved through principal component analysis, and the original five evaluation indicators were transformed into two new independent comprehensive indicators, with a cumulative contribution rate of 84.87%, covering most of the information carried by the original indicators. The drought resistance membership function values ​​μ of the two comprehensive indicators were calculated according to formula B: 1芽 , μ 2芽 .

[0092] According to the contribution rate of each comprehensive indicator, its weight is calculated using formula D. After calculation, the weights of the two comprehensive indicators are 62.26% and 37.74% respectively.

[0093] Calculate the comprehensive drought resistance evaluation D of each variety according to formula E 芽 Value, D 芽 =0.6226μ 1芽 +0.33774μ 2芽 , and according to D 芽 The values ​​were used to rank the drought resistance of the plants during the germination period.

[0094] According to the comprehensive drought resistance evaluation 芽 The drought resistance of sunflower during the germination period was divided into five levels: very strong, strong, medium, weak and very weak. The grading standards are shown in Table 2.

[0095] Table 2 Drought resistance classification of sunflower during germination period

[0096] level Comprehensive drought resistance evaluation D value Drought resistance classification 1 ≥0.800 Very strong 2 0.599～0.799 powerful 3 0.350～0.599 medium 4 0.200～0.350 weak 5 ＜0.200 Very weak

[0097] 6) Stepwise regression to screen key indicators:

[0098] Based on the relative germination potential, relative germination rate, relative radicle length, relative plumule length and relative fresh weight measured during the germination period, multiple stepwise regression analysis was performed using SPSS to establish a drought resistance model for sunflower during the germination period (Table 3), and three key indicators of the germination period, namely relative germination rate, relative radicle length and relative plumule length, were screened out.

[0099] Table 3 Drought resistance model of sunflower during germination period

[0100]

[0101]

[0102] Example 2

[0103] The steps for drought resistance identification of sunflower seedlings are as follows:

[0104] 1) Material preparation

[0105] Seed selection and germination: Select seeds of uniform size and full grains, spread them flat on a culture dish lined with 2 layers of filter paper, add appropriate amount of distilled water for germination for 24 hours, and place them in an incubator or a room with suitable temperature at 25℃±1℃.

[0106] 2) Drought stress treatment

[0107] Sowing: After the seeds are germinated and white, select the healthy seeds that are white and sow them in a nutrient pot with an inner diameter of 31cm and a depth of 33cm in time. The test soil is field topsoil: nutrient soil: vermiculite = 1:1:2, and each pot is filled with 3.2kg±0.1kg of mixed soil; the hole sowing method is adopted, and 5 holes are sown in each pot. When the seedlings grow two true leaves, the seedlings are thinned out and 5 seedlings are fixed; the drought simulation adopts the natural drought method, and the stress treatment begins when the four true leaves grow; the control group maintains 20% absolute soil moisture content, and the treatment group is watered once before the stress and then no longer watered.

[0108] 3) Survey indicators

[0109] When the soil moisture content naturally dropped to 6% ± 1% during drought, the relevant indicators were measured, repeated 3 times, and watered once every 2 days during the experiment. The watering time and frequency were adjusted according to the changes in temperature and soil moisture content. Five plants were selected from each pot to measure plant height, stem diameter, leaf area, leaf relative water content, SPAD value, and root-crown ratio.

[0110] Soil moisture content was measured using a soil moisture display instrument (SIN-TH8);

[0111] Stem diameter was measured with a vernier caliper (the first node near the cotyledon), unit: mm, relative stem diameter = (treated stem diameter / control stem diameter) × 100%;

[0112] Plant height: measured with a ruler, the length from the stem base to the top of the plant, in cm, relative plant height = (treated plant height / control plant height) × 100%;

[0113] Leaf area: Use the coefficient method to measure leaf length and leaf width, and calculate the leaf area according to the formula "leaf area = 0.67 × leaf length × leaf width", unit: cm 2 ;Relative leaf area=(treated leaf area / control leaf area)×100%;

[0114] Leaf SPAD determination: Use a portable chlorophyll meter (SPAD-502PLUS, Japan) to measure the middle part of the second to last pair of true leaves of each treatment plant, repeat 3 times, and take the average value. Relative SPAD value = (treatment SPAD value / control SPAD value) × 100%;

[0115] Root-to-crown ratio: The root-to-crown ratio was calculated by measuring the above-ground fresh weight and underground fresh weight according to the formula "root-to-crown ratio (fresh weight) = underground fresh weight / above-ground fresh weight", relative root-to-crown ratio = (treatment root-to-crown ratio / control root-to-crown ratio) × 100%;

[0116] Leaf relative water content: saturation method was used, and the calculation formula was "leaf relative water content = (leaf fresh weight - leaf dry weight) / (leaf saturated weight - leaf dry weight), relative leaf (relative) water content = (treatment leaf relative water content / control leaf relative water content) × 100%.

[0117] 4) Comprehensive evaluation of drought resistance at the seedling stage: The method of seeking membership function in fuzzy mathematics was used to conduct a comprehensive evaluation of drought resistance of each variety. The formula is:

[0118] A: X ij =t ij / T ij ,i=1,2,...,n,j=1,2,...,n;

[0119] B:

[0120] C:

[0121] D:

[0122] E:

[0123] Where: A In the formula X ij is the drought resistance coefficient, t ij To process the measured value, T ij is the control value, in formula B and C, u(X ij ) represents the drought resistance membership function value of index j of variety i, x min and x max Respectively represent the maximum and minimum measured values ​​of each variety index. If the measured value of the resistance index is positively correlated with the resistance, use formula A, otherwise use formula B;

[0124] Formula D is the weight of each comprehensive indicator, and w in formula C is j It represents the importance of the jth comprehensive index among all comprehensive indexes, i.e., its weight, p j represents the contribution rate of the jth comprehensive index of each sunflower variety obtained by principal component analysis;

[0125] In the formula E, D is the comprehensive evaluation value of drought resistance of each sunflower variety obtained by comprehensive index evaluation under drought stress conditions.

[0126] Comprehensive evaluation of drought resistance: SPSS26.0 software was used to perform factor and principal component analysis based on the relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, relative root-to-crown ratio and other indicators measured for 19 different drought-resistant sunflower varieties, and the principal component analysis results and D value were obtained (Table 4).

[0127] Table 4 Results of principal component analysis at seedling stage

[0128]

[0129]

[0130] The dimensionality reduction was achieved through principal component analysis, and the original six evaluation indicators were transformed into three new independent comprehensive indicators, with a cumulative contribution rate of 85.40%, covering most of the information carried by the original indicators. The drought resistance membership function values ​​μ of the three comprehensive indicators were calculated according to formula B. 1苗 , μ 2苗 , μ 3苗 .

[0131] According to the contribution rate of each comprehensive indicator, its weight is calculated using formula D. After calculation, the weights of the two comprehensive indicators are 61.44%, 21.18%, and 17.38% respectively.

[0132] Calculate the comprehensive drought resistance evaluation D of each variety according to formula E 芽 Value, D 苗 =0.6143μ 1苗 +0.2118μ 2苗 +0.1738μ 3苗 , and according to D 苗 The values ​​were used to rank the drought resistance of the plants at the seedling stage.

[0133] According to the comprehensive drought resistance evaluation D 苗 The drought resistance of sunflower seedlings was divided into five levels: very strong, strong, medium, weak and very weak. The grading standards are shown in Table 5.

[0134] Table 5 Drought resistance classification of sunflower seedlings

[0135] level Comprehensive drought resistance evaluation D value Drought resistance classification 1 ≥0.700 Very strong 2 0.499～0.699 powerful 3 0.350～0.499 medium 4 0.200～0.350 weak 5 ＜0.200 Very weak

[0136] 5) Stepwise regression screening of key indicators: Based on the measured values ​​of relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, and relative root-crown ratio at the seedling stage, SPSS was used for multivariate stepwise regression analysis to establish a drought resistance model for sunflower seedlings (Table 6), and screened out four key indicators of the seedling stage: relative plant height, relative stem diameter, relative leaf area, and relative root-crown ratio.

[0137] Table 6 Drought resistance model of sunflower seedlings

[0138]

[0139] Example 3

[0140] The steps for drought resistance identification of sunflowers during the budding period are as follows:

[0141] 1) Material preparation

[0142] Seed selection and germination: Select seeds of uniform size and full grains, spread them flat on a culture dish lined with 2 layers of filter paper, add appropriate amount of distilled water for germination for 24 hours, and place them in an incubator or a room with suitable temperature at 25℃±1℃.

[0143] 2) Drought stress treatment

[0144] Sowing: After the seeds are germinated and white, select the healthy seeds that are white and sow in time in a nutrient pot with an inner diameter of 31 cm and a depth of 33 cm; the experimental soil is field topsoil: nutrient soil: vermiculite = 1:1:2, and each pot is filled with 3.2kg±0.1kg of mixed soil; the hole sowing method is adopted, 3 holes are sown in each pot, and 6 times are repeated. Thinning begins when the seedlings grow two true leaves, and 3 seedlings are determined. Thinning is done again when there are three pairs of true leaves, and one plant is retained in each pot, and the growth of each variety of plants is kept consistent as much as possible; the plant drought simulation adopts the natural drought method, and the stress treatment begins with six pairs of true leaves; the control group maintains 25% absolute soil moisture content, and the treatment group is watered once before stress and then no longer watered.

[0145] 3) Survey indicators

[0146] During the experiment, water was applied once every 2 days. When the soil moisture content dropped from 25%±1% to 6%±1% during natural drought and lasted for 5 days, plant height, stem diameter, leaf area, leaf SPAD value, leaf relative water content, and sunflower disk diameter were measured, and relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, and relative sunflower disk diameter were calculated.

[0147] Soil moisture content was measured using a soil moisture display instrument (SIN-TH8);

[0148] Plant height: measured with a ruler, the length from the stem base to the top of the plant, in cm, relative plant height = (treated plant height / control plant height) × 100%;

[0149] Stem diameter was measured with a vernier caliper (the first node near the cotyledon), unit: mm, relative stem diameter = (treated stem diameter / control stem diameter) × 100%;

[0150] Leaf area: Use the coefficient method to measure leaf length and leaf width, and calculate the leaf area according to the formula "leaf area = 0.67 × leaf length × leaf width", unit: cm 2 ;Relative leaf area=(treated leaf area / control leaf area)×100%;

[0151] Sunflower disk diameter: measured with a ruler, unit: cm, relative sunflower disk diameter = (treatment sunflower disk diameter / control sunflower disk diameter) × 100%;

[0152] Leaf SPAD determination: A portable chlorophyll meter (SPAD-502PLUS, Japan) was used to measure the middle part of the 3rd and 4th pairs of functional leaves from top to bottom of each treated plant, repeated 3 times, and the average value was taken; relative SPAD value = (treatment SPAD value / control SPAD value) × 100%;

[0153] Relative water content of leaves: using the saturation method, the calculation formula is:

[0154] Relative water content of leaves = (fresh weight of leaves - dry weight of leaves) / (saturated weight of leaves - dry weight of leaves),

[0155] Relative leaf (relative) water content = (relative water content of treated leaves / relative water content of control leaves) × 100%;

[0156] 4) Comprehensive evaluation of drought resistance at the budding stage: The method of seeking membership function in fuzzy mathematics is used to conduct a comprehensive evaluation of drought resistance of each variety. The formula is:

[0157] A: X ij =t ij / T ij ,i=1,2,...,n,j=1,2,...,n;

[0158] B:

[0159] C:

[0160] Drought resistance evaluation at the budding stage, and screening to obtain variety resources with strong drought resistance at the budding stage based on the average value of the membership function value;

[0161] Where: A In the formula X ij is the drought resistance coefficient, t ij To process the measured value, T ij is the control value, in formula B and C, u(X ij) represents the drought resistance membership function value of index j of variety i, x min and x max Respectively represent the maximum and minimum measured values ​​of each variety index. If the measured value of the resistance index is positively correlated with the resistance, use formula A, otherwise use formula B;

[0162] Comprehensive evaluation of drought resistance: Based on the relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, relative sunflower disk diameter and other indicators measured by 6 different drought-resistant sunflower varieties, the membership function values ​​of each indicator were calculated according to formula B, and then the average membership function value was calculated based on the membership function values ​​of each indicator (Table 7). According to the comprehensive drought resistance evaluation D value, the drought resistance of sunflowers at the bud stage was divided into five levels: very strong, strong, medium, weak and very weak. The grading standards are shown in Table 8.

[0163] Table 7 Membership function values ​​and rankings of drought resistance indicators at the budding stage

[0164]

[0165]

[0166] Table 8 Drought resistance classification of sunflower at bud stage

[0167] level Comprehensive drought resistance evaluation D value Drought resistance classification 1 ≥0.700 Very strong 2 0.499～0.699 powerful 3 0.350～0.499 medium 4 0.200～0.350 weak 5 ＜0.200 Very weak

[0168] In this embodiment, drought resistance identification and evaluation of sunflowers at different stages were carried out, PEG-6000 was used in the indoor germination stage, and natural drought stress treatment was used in the seedling and budding stages. The principal component, membership function method, stepwise regression and other analyses were combined to establish a drought resistance identification method for sunflowers at the germination, seedling and budding stages, determine the evaluation indicators and drought resistance classification, and form a systematic and comprehensive drought resistance identification system, thereby providing a simple, easy, fast and reliable identification method for the drought resistance evaluation of sunflower variety resources. The method has a short time period, reduces labor costs, and can quickly and efficiently identify the drought resistance of sunflower resource materials.

[0169] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0170] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0171] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for identifying drought resistance of sunflower variety resources, characterized in that: The identification steps include: S1. Identification of drought resistance during germination period: S1.1, treating the sterilized sunflower seeds with PEG-6000; S1.

2. Continuously count the number of germinations from the 1st to the 7th day, measure the radicle length, plumule length and fresh weight of the germinated seeds on the 7th day, and calculate the germination rate, germination potential, relative germination rate, relative germination potential, relative radicle length, relative plumule length, relative fresh weight, drought resistance coefficient and drought damage coefficient; S1.3, determine the PEG-6000 screening concentration; S1.4, evaluate drought resistance during the germination period, and select varieties with strong drought resistance during the germination period according to the comprehensive evaluation value of drought resistance; S1.5 Screening of key indicators during germination period; S2. Drought resistance assessment at the seedling stage: S2.1, germinating and sowing the selected sunflower seeds, and subjecting the seedlings to natural drought stress treatment when they grow four true leaves; S2.

2. When the soil moisture content dropped from 20%±1% to 6%±1% under natural drought conditions, the plant height, stem diameter, leaf area, leaf SPAD value, leaf relative water content, and root-crown ratio were measured, and the relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, and relative root-crown ratio were calculated; S2.3, Comprehensive evaluation of drought resistance at the seedling stage, and screening of variety resources with strong drought resistance at the seedling stage according to the comprehensive evaluation value of drought resistance at the seedling stage; S2.4 Screening of key indicators at the seedling stage; S3. Drought resistance assessment at the budding stage: S3.

1. Germinating and sowing the selected sunflower seeds, and subjecting the seedlings to natural drought stress treatment when they grow six pairs of true leaves; S3.

2. When the soil moisture content drops from 25%±1% to 6%±1% during natural drought and lasts for 5 days, measure the plant height, stem diameter, leaf area, leaf SPAD value, leaf relative water content, and sunflower disk diameter, and calculate the relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, and relative sunflower disk diameter; S3.3 Evaluate drought resistance at the budding stage, and screen out variety resources with strong drought resistance at the budding stage based on the average membership function value.

2. The method for identifying drought resistance of sunflower variety resources according to claim 1, characterized in that: In the step S1.1, 3% sodium hypochlorite solution is used to disinfect the sunflower seeds.

3. The method for identifying drought resistance of sunflower variety resources according to claim 1, characterized in that: In step S1.2, the calculation formulas for the drought resistance coefficient, drought damage coefficient, germination rate, germination potential, relative germination rate, relative germination potential, relative radicle length, relative plumule length, and relative fresh weight are: Drought resistance coefficient = measured index of treatment group / measured index of control group; Drought damage coefficient = 1-drought resistance coefficient; Germination rate = (total number of seeds germinated in 7 days / number of seeds tested) × 100%; Germination potential = (total number of germinated seeds on the 4th day / number of test seeds) × 100%; Relative germination rate = (treatment germination rate / control germination rate) × 100%; Relative germination potential = (germination potential of treatment / germination potential of control) × 100%; Relative radicle length = (treatment radicle length / control radicle length) × 100%; Relative germ length = (treatment germ length / control germ length) × 100%; Relative fresh weight = (treatment fresh weight / control fresh weight) × 100%.

4. The method for identifying drought resistance of sunflower variety resources according to claim 1, characterized in that: In the step S1.3, the PEG-6000 screening concentration is determined to specifically include: the PEG concentration corresponding to a 50% decrease in the drought damage coefficient of the relative germination potential, relative germination rate, relative embryo length, relative radicle length, and relative fresh weight, which are 20.11%, 22.59%, 14.49%, 22.79%, and 22.92%, respectively.

5. The method for identifying drought resistance of sunflower variety resources according to claim 1, characterized in that: In the step S2.1, the natural drought stress treatment is carried out when the seedlings grow four true leaves; in the step S3.1, the natural drought stress treatment is carried out when the seedlings grow six pairs of true leaves.

6. The method for identifying drought resistance of sunflower variety resources according to claim 1, characterized in that: In step S2.2, the calculation formulas for relative plant height, relative stem diameter, relative leaf area, relative SPAD value, relative leaf water content, and relative root-to-crown ratio are: Relative plant height = (treated plant height / control plant height) × 100%; Relative stem diameter = (treated stem diameter / control stem diameter) × 100%; Relative leaf area = (treated leaf area / control leaf area) × 100%; Relative SPAD value = (treatment SPAD value / control SPAD value) × 100%; Relative leaf water content = (treated leaf water content / control leaf water content) × 100%; Relative root-to-shoot ratio=(root-to-shoot ratio of treatment / root-to-shoot ratio of control)×100%.

7. The method for identifying drought resistance of sunflower variety resources according to claim 1, characterized in that: In step S3.2, the calculation formulas for relative plant height, relative stem thickness, relative leaf area, relative SPAD value, relative leaf water content, and relative sunflower disk diameter are as follows: Relative plant height = (treated plant height / control plant height) × 100%; Relative stem diameter = (treated stem diameter / control stem diameter) × 100%; Relative leaf area = (treated leaf area / control leaf area) × 100%; Relative SPAD value = (treatment SPAD value / control SPAD value) × 100%; Relative leaf water content = (treated leaf water content / control leaf water content) × 100%; Relative sunflower disk diameter = (treated sunflower disk diameter / control sunflower disk diameter) × 100%.

8. The method for identifying drought resistance of sunflower variety resources according to claim 1, characterized in that: In the step S1.4, the drought resistance evaluation at the germination stage, the comprehensive drought resistance evaluation at the seedling stage in step S2.3 and the comprehensive drought resistance evaluation at the budding stage in step S3.3 adopt the method of seeking membership function in fuzzy mathematics.

9. The method for identifying drought resistance of sunflower variety resources according to claim 8, characterized in that: The formula for comprehensive evaluation of drought resistance of each variety is: A:X ij =t ij / T ij ,i=1,2,...,n,j=1,2,...,n; B： C： D： E： Where: A In the formula X ij is the drought resistance coefficient, t ij To process the measured value, T ij is the control value, in formula B and C, u(X ij ) represents the drought resistance membership function value of index j of variety i, x min and x max Respectively represent the maximum and minimum measured values ​​of each variety index. If the measured value of the resistance index is positively correlated with the resistance, use formula A, otherwise use formula B; Formula D is the weight of each comprehensive indicator, and w in formula C is j It represents the importance of the jth comprehensive index among all comprehensive indexes, i.e., its weight, p j represents the contribution rate of the jth comprehensive index of each sunflower variety obtained by principal component analysis; In formula E, the D value is the comprehensive evaluation value of drought resistance of each sunflower variety obtained by comprehensive index evaluation under drought stress conditions.

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