Sesame stain tolerance identification and evaluation method

Abstract

The invention belongs to the technical field of agricultural planting, and particularly relates to a sesame waterlogging resistance identification and evaluation method. The method comprises the following steps: preparing simulated waterlogging-resistant environment conditions, sowing to-be-identified sesame germplasm, performing simulated waterlogging treatment, judging waterlogging resistance and the like. In the application, through investigation and statistics of the early-stage sesame growth cycle, the inventor finds that the optimal opportunity for screening, identifying and evaluating the sesame waterlogging tolerance is the full-bloom stage of the sesame, and the waterlogging tolerance of different germplasm resources can be rapidly, simply and accurately distinguished in the period. Under the condition, the inventor further establishes a sesame waterlogging tolerance identification and evaluation method by standardizing and optimizing related simulation experiment conditions and perfecting related evaluation standards. Based on the method, not only can the waterlogging tolerance of different sesame germplasm samples be intuitively, conveniently and accurately evaluated, but also the high waterlogging tolerance germplasm can be identified and screened out, so that a good technical support can be provided for subsequent new waterlogging tolerance sesame variety cultivation.

Description

Technical Field

[0001] The present application belongs to the field of agricultural planting technology, and specifically relates to a method for identifying and evaluating sesame's resistance to waterlogging. Background Art

[0002] Sesame( Sesamum indicum Sesame (L.), a plant of the genus Sesamum in the family Pedulaceae, is one of the world's most important, high-quality oil crops. Studies have shown that sesame seeds contain approximately 50-60% oil, with unsaturated fatty acids such as oleic acid and linoleic acid accounting for over 80% of the total fatty acids. Sesame seeds are also rich in antioxidants such as sesamol and sesamolinol, which are beneficial to human health.

[0003] In agricultural production, my country's main sesame-producing areas are primarily located in Henan, Hubei, Anhui, and Jiangxi. However, given my country's climate, these regions experience concentrated rainfall from July to August each year, making farmland highly susceptible to waterlogging. During this period, sesame seeds are typically in their flowering or grain-filling stages. Consequently, waterlogging can severely impact sesame yield and quality.

[0004] Research on sesame growth patterns indicates that the period from early flowering to peak flowering is the most sensitive to waterlogging. Under waterlogging stress, the net photosynthetic rate and chlorophyll content of sesame plants decrease significantly, manifesting as iron-deficiency yellowing of new leaves, elongated stem growth, and decreased biomass and seed yield. In severe cases of waterlogging, plants may wilt permanently or even die. Furthermore, soil-borne diseases such as stem blight often occur alongside sesame waterlogging, exacerbating the damage to the plant and affecting the expression and evaluation of waterlogging tolerance.

[0005] In short, from the perspective of breeding new sesame stress-resistant varieties, establishing a set of efficient and accurate sesame waterlogging tolerance identification and evaluation methods to accurately evaluate the waterlogging tolerance characteristics of different sesame germplasms is of great technical significance for the rapid breeding of new varieties with strong waterlogging tolerance. Summary of the Invention

[0006] In view of the need for screening and identifying the stress resistance of sesame varieties, the purpose of this application is to provide a method for identifying and evaluating the waterlogging tolerance of sesame, thereby laying a certain technical foundation for the breeding of new stress-resistant sesame varieties.

[0007] The technical solutions adopted in this application are described in detail as follows.

[0008] A method for identifying and evaluating the waterlogging resistance of sesame seeds comprises the following steps: (1) Preparation of simulated waterlogging-resistant environmental conditions Prepare several sesame planting ponds (soil-resistant ponds) and fill them with disinfected soil for later use. Specific pond specifications and soil treatment methods are as follows: Specifications of the pool body (waterlogging-resistant pool): length × width × height = 24m × 5m × 1.2m (in the height design, after filling with soil, the height above the ground is 0.2m and the depth underground is 1m to ensure sufficient growth needs of sesame roots); When disinfecting the soil, use the method of mixing dazomet into the soil for disinfection treatment (the dosage and usage method can be referred to the product manual of dazomet, or for reference: in the case of the above pool body specifications, the dosage of dazomet is 10 catties; the disinfection operation method is for reference: after filling the pool body with soil evenly mixed with dazomet, water to keep the soil humidity at about 60 - 70%, cover with film and seal for about 20 days, after the sealing is over, uncover the film, turn over the land and sun it for 10 days, then turn over the land once again and level the land, and then water can be applied to prepare for sowing sesame seeds); (II) Sowing of sesame germplasm to be identified For each sesame germplasm sample to be screened and identified, select 10g of impurity-free, healthy and plump seeds and sow them in the pool body prepared in step (I); The sowing specifications are for reference: single-row sowing, row spacing 40cm, row length 5m; at the same time, design a control group;​​​​​​​​​​​​​​​​​​​​Level 3 moderately waterlogging-tolerant (MR), 20 < WR ≤ 40, with a small number of plants wilting, light yellow and wilted leaves, wrinkled and not fallen; capsule pericarp wrinkled; Level 4 waterlogging-sensitive (S), 40 < WR ≤ 60, with most plants wilting, yellow and curled leaves, and partial leaf shedding; capsule pericarp wrinkled; Level 5 highly waterlogging-sensitive (HS), 60 < WR ≤ 100, with绝大部分 plants wilting and tending to die, low plant growth; leaves curled and shed, stem rotted; root phloem rotted and died, extending from the root to the stem, xylem dark brown and exposed.

[0010] In this application, through the investigation and statistics of the early sesame growth cycle, the inventor found that the best time for screening, identifying, and evaluating the waterlogging tolerance of sesame is the full flowering stage of sesame. During this period, the waterlogging tolerance of different germplasm resources can be distinguished more quickly, simply, and accurately. In this case, the inventor further constructed a method for identifying and evaluating the waterlogging tolerance of sesame by standardizing and optimizing relevant simulation experimental conditions and improving relevant evaluation criteria. Based on this method, not only can the waterlogging tolerance of different sesame germplasm samples be evaluated intuitively, conveniently, and accurately, but high waterlogging-tolerant germplasms can also be identified and screened, which can provide good technical support for the subsequent cultivation of new waterlogging-tolerant sesame varieties. Therefore, it has good practical technical value for sesame breeding, and at the same time provides good reference for the cultivation of new waterlogging-tolerant varieties and the identification and evaluation of waterlogging tolerance of other crops. Brief Description of the Drawings

[0011] Figure 1 It is a comparative chart of the phenotypes of sesame germplasms with typical different waterlogging tolerance levels; among them: a is highly waterlogging-tolerant; b is waterlogging-tolerant; c is moderately waterlogging-tolerant; d is waterlogging-sensitive; e is highly waterlogging-sensitive; Figure 2 It is the distribution of the wilting rate WR of 300 sesame samples under simulated waterlogging treatment in 2022; Figure 3 It is the distribution of the wilting rate WR of 300 sesame samples under simulated waterlogging treatment in 2023; Figure 4 It is the comparative distribution of the wilting rate WR of 300 sesame samples under waterlogging treatment in 2022 and 2023; Figure 5 It is the typical field phenotypes of the highly waterlogging-tolerant sesame germplasm WT50 at different times after 36-hour flooding treatment; among them: a is the 3rd day after flooding treatment; b is the 5th day; c is the 7th day; d is the 9th day; e is the 11th day; f is the 13th day; g is the 15th day. Detailed Description of the Invention

[0012] The present application will be further explained below with reference to the accompanying drawings and examples. Before specifically introducing the following examples, a brief description of some of the experimental materials involved in the following examples is given below.

[0013] Related sesame ingredients: The 300 different sesame germplasm samples involved in the following examples (because the implementation of the technical solution of this application does not depend on specific varieties (germplasm), and because there are many varieties of germplasm, the specific varieties (germplasm) names are not listed here) are all common and commonly used germplasm (variety) materials in existing sesame cultivation or breeding research, and are publicly available on the market or in relevant public germplasm resource banks. Since the applicant is a professional scientific research institution with a public germplasm bank that has long-term collection and preservation of relevant germplasm resources, the use of the relevant germplasm materials complies with relevant administrative regulations. The sesame "WT50" involved in the following examples is the code name of the sesame germplasm currently being screened by the inventors during their experiments. It is only presented as an experimental result, and the implementation and application of the technical solution of this application does not depend on this germplasm; Related reagents: Soil fungicide dazomethane (an organic compound with the molecular formula C5H 10 N2S2), a common and commonly used high-efficiency, low-toxic, residue-free, environmentally friendly, broad-spectrum soil fumigant disinfectant on the market.

[0014] Example 1 This example takes the waterlogging tolerance experiment of 300 different sesame germplasm samples randomly screened in 2022 and 2023 as an example, and briefly introduces the waterlogging tolerance identification and evaluation method constructed in this application as follows.

[0015] (1) Preparation of simulated waterlogging-resistant environmental conditions Prepare several sesame planting ponds (soil-resistant ponds) and fill them with disinfected soil for later use. The specific pond specifications and soil treatment methods are as follows: Pond body (waterlogging-resistant pond) specifications: length × width × height = 24m × 5m × 1.2m (after filling with soil, the ground height is 0.2m and the underground depth is 1m to ensure sufficient space for the growth of sesame roots); When disinfecting the soil, use the method of mixing dazoline into the soil for disinfection. The specific operation reference is: under the above-mentioned pool specifications, the amount of dazoline used is 10 pounds; the disinfection operation method is: after the pool is evenly filled with soil mixed with dazoline, water it to keep the soil moisture at around 60~70%, cover it with film and let it air for about 20 days. After the air is aired, remove the film, turn the land over and dry it for 10 days, then turn the land over again and level it. After that, water it and prepare to sow sesame seeds.

[0016] (2) Sowing of sesame germplasm to be identified For each sesame germplasm sample to be screened and identified, select 10g of healthy and plump seeds free of impurities and sow them in the pool prepared in step (1); The sowing specifications were: single row sowing, row spacing 40 cm, row length 5 m; a control group was also designed (Yuzhi No. 11 was used as the control); Under the conditions of the pond body specifications in step (1) and the above-mentioned sowing specifications, 51 sesame germplasms were sown in each pond body (waterlogging-tolerant pond); After sowing, normal water and fertilizer management is carried out.

[0017] (3) Simulated waterlogging treatment Based on preliminary experiments and actual agricultural planting conditions, the damage caused by waterlogging in sesame is mainly manifested from the peak flowering stage to the grain filling and maturity stage. When waterlogging treatment is carried out during this period, the phenotypic differences between different sesame germplasms are large, which facilitates screening, differentiation and evaluation. Therefore, when simulating waterlogging treatment, the peak flowering stage is selected for simulated waterlogging treatment. The specific treatment is: When the sesame seeds reach their peak flowering stage in step (2) (around mid-July), water the pond (do this on a sunny day) and keep the water level at least 2 cm above the soil. Start timing for 36 hours. After the timing ends, drain the water from the pond until there is no water on the soil surface.

[0018] It should be explained that during the preliminary experiments, the inventors used the 10 most commonly used sesame varieties in current agricultural planting as experimental materials, and conducted treatment tests with flooding times of 24h, 36h, and 48h, respectively, and investigated the waterlogging tolerance in the later stage. The results showed that when the flooding time was 24h, the symptoms of waterlogging damage in the germplasm materials were not obvious, and the differences between different germplasms were not significant, making it difficult to effectively distinguish the differences in their waterlogging tolerance. However, if the flooding time was extended to 48h, the impact of waterlogging damage was too great, resulting in severe wilting in most germplasm materials, making it basically impossible to effectively carry out the differentiation work, and having little reference value for waterlogging tolerance identification and screening. Under the 36h flooding treatment, the differences in waterlogging tolerance of the germplasm materials began to appear significantly, and the waterlogging tolerance levels of different germplasms could be better distinguished. Therefore, from the perspective of operational convenience, uniformity, and distinguishability, it is most appropriate to conduct waterlogging tolerance identification after 36h of flooding.

[0019] (IV) Determination of stain resistance After 7 days of drainage in step (3), investigate and count the growth of the samples to be identified, and determine the waterlogging resistance of each sample.

[0020] During the survey and statistics, the plant wilting rate (WR) index is calculated ("wilting" refers to an irreversible state of the plant caused by physiological water shortage, which eventually manifests as the plant drying up). The specific calculation formula is as follows: Wilting rate (WR, %) = Number of wilted plants / Total number of plants × 100.

[0021] The typical shape phenotypes of germplasm samples with different waterlogging tolerance characteristics are as Figure 1 shown. The statistical results of the wilting rate WR of different germplasm samples in 2022 and 2023 are as Figure 2 , Figure 3 shown, and the comparison results between the two years are as Figure 4 shown. Based on these statistical results, on the one hand, it can be seen that the screening and identification results constructed in this application are relatively stable and have good operability. On the other hand, it can also be seen that the number of waterlogging-tolerant varieties in current sesame germplasm is relatively small. Further, combined with the relevant statistical results, the determination and grading criteria for different waterlogging tolerance characteristics are finally determined as follows: Level 1, highly waterlogging-tolerant (HR), WR ≤ 5, plants grow normally, capsules develop and expand normally without shrinking, lower leaves are light yellow without deformation,舒展无脱落; Level 2, waterlogging-tolerant (R), 5 < WR ≤ 20, occasionally very few plants wilt, leaves are light yellow and wilted, wrinkled but not fallen; capsule skin is wrinkled; Level 3, moderately waterlogging-tolerant (MR), 20 < WR ≤ 40, a small number of plants wilt, leaves are light yellow and wilted, wrinkled but not fallen; capsule skin is wrinkled; Level 4, waterlogging-sensitive, 40 < WR ≤ 60, most plants wilt, leaves are yellow and curled, and some leaves fall off; capsule skin is wrinkled; Level 5, extremely waterlogging-sensitive (HS), 60 < WR ≤ 100, most plants wilt and tend to die, plant growth is low; leaves are curled and fallen, stem is rotten; root phloem is rotten and dead, and extends from the root to the stem, xylem is dark brown and exposed.

[0022] It should be emphasized that the above waterlogging tolerance judgment criteria are obtained based on long-term actual field observations and practical experience of a large number of sesame germplasm materials. It can comprehensively reflect the overall growth status and damage degree of plants after waterlogging stress, covering the characteristics of multiple key parts such as plant appearance, leaves, capsules, stems and roots. These phenotypic characteristics can be directly observed by the naked eye or judged through simple operations in practical applications, and have high accuracy for preliminary waterlogging tolerance assessment, which can meet the judgment needs in most production and scientific research scenarios.

[0023] Based on the above criteria, the inventor's existing WT050 germplasm was evaluated and identified. It can be seen that the germplasm WT050 exhibits good highly waterlogging-tolerant characteristics (typical phenotypes are as Figure 5 shown), and is expected to be used for further breeding of waterlogging-tolerant new varieties.

Claims

1. A method for identifying and evaluating the waterlogging resistance of sesame, characterized in that: The method includes the following steps: (1) Preparation for simulating waterlogging-resistant environment conditions Prepare several pools for planting sesame, and fill the pools with disinfected soil for standby; (2) Sowing of sesame germplasm to be identified For the sesame germplasm samples to be screened and identified, select seeds without impurities and healthy and plump ones, and sow them in the pools prepared in step (1); After sowing, conduct normal water and fertilizer management; (3) Simulating waterlogging treatment When simulating waterlogging treatment, select the full-bloom stage for simulating waterlogging treatment; specifically in the treatment: When the sesame in step (2) grows to the full-bloom stage, irrigate the pool and keep the water level continuously above the soil surface by more than 2 cm to start timing; after the timing ends, drain the accumulated water in the pool until there is no accumulated water on the soil surface; (4) Judgment of waterlogging resistance Seven days after draining in step (3), investigate and count the growth conditions of the samples to be identified, and judge the waterlogging resistance ability of each sample.

2. The method for identifying and evaluating the waterlogging resistance of sesame according to claim 1, wherein: In step (1), the pool (waterlogging-resistant pool specification: length × width × height = 24 m × 5 m × 1.2 m).

3. The method for identifying and evaluating the waterlogging resistance of sesame according to claim 1, wherein: In step (1), when disinfecting the soil, use the method of mixing dazomet into the soil for disinfection treatment.

4. The method for identifying and evaluating the waterlogging resistance of sesame according to claim 1, wherein: In step (2), the sowing specification is: single-row sowing, row spacing 40 cm, row length 5 m.

5. The method for identifying and evaluating the waterlogging resistance of sesame according to claim 1, wherein: In step (3), the timing is 24 - 48 h.

6. The method for identifying and evaluating the waterlogging resistance of sesame according to claim 5, wherein: In step (3), the timing is 36 h.

7. The method for identifying and evaluating the waterlogging resistance of sesame according to claim 1, wherein: In step (4), the judgment and grading criteria for waterlogging resistance are as follows: Grade 1, strong waterlogging resistance HR, WR ≤ 5, the plants grow normally, the capsules develop and expand normally without shrinking, the lower leaves are light yellow without deformation, unfolded and without falling off; Grade 2, waterlogging resistance R, 5 < WR ≤ 20, occasionally very few plants wilt, the leaves are light yellow and wilted, wrinkled and not fallen off; the capsule skin is wrinkled; Grade 3, medium waterlogging resistance MR, 20 < WR ≤ 40, a small number of plants wilt, the leaves are light yellow and wilted, wrinkled and not fallen off; the capsule skin is wrinkled; Grade 4, waterlogging sensitivity S, 40 < WR ≤ 60, most plants wilt, the leaves are yellow and curled, and some leaves fall off; the capsule skin is wrinkled; Grade 5, extremely waterlogging-sensitive HS, 60 < WR ≤ 100, most plants wilt and tend to die, the plant growth amount is low; the leaves are curled and fallen off, the stem is rotten; the root phloem is rotten and dead, and extends from the root to the stem, and the xylem is dark brown and exposed.

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