Method for rapidly identifying waterlogging tolerance of cotton germplasm

Abstract

The application belongs to the technical field of cotton germplasm waterlogging tolerance, and specifically provides a method for rapidly identifying the waterlogging tolerance of cotton germplasm. The method provided by the application comprises the following steps: taking Zhongmian 9101 as a waterlogging-sensitive control and Zhongmian 9001 as a waterlogging-tolerant control, using indoor double-pot simulation waterlogging technology to perform waterlogging treatment on four-leaf expected evaluation materials, then removing the waterlogging and performing light treatment, and observing the wilting degree of the leaves of different cotton materials. The application establishes a rapid and efficient indoor method for identifying the waterlogging tolerance of cotton materials, overcomes the shortcomings of the prior art, such as a long period, high cost, and being easily affected by external factors such as environment, and the like. The method is fast in identification speed, accurate and intuitive in effect, strong in controllability, and can batch-screen waterlogging-tolerant cotton germplasm resources or breeding materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cotton germplasm waterlogging tolerance, and particularly relates to a method for rapidly identifying cotton germplasm waterlogging tolerance. BACKGROUND

[0002] Under the background of global warming, the frequency and intensity of extreme precipitation events gradually increase, often causing waterlogging in farmland, leading to waterlogging damage of crops. Waterlogging stress affects about 10% of the cultivated land area in the world, and is one of the most important limiting factors affecting crop yield. Depending on crop species, soil type and duration of stress, waterlogging stress can cause 15% to 80% yield loss, or even no yield.

[0003] At present, a large number of reports have been made at home and abroad on the influence of waterlogging stress on plant growth and development. Waterlogging stress first leads to root hypoxia, hinders the growth and development of root system, causes the root system to significantly decrease in strength, and leads to the limitation of water and nutrient absorption and utilization by the root system; at the same time, the accumulation of excessive reactive oxygen species (ROS) in the plant body under waterlogging stress will cause leaf chlorosis and early senescence, affect photosynthetic product accumulation, and ultimately lead to reduced plant yield. As a kind of continuous abiotic stress, in addition to the stress during waterlogging, the recovery period after waterlogging will also cause damage to plants. When the plant is exposed to air again after waterlogging, the metabolites produced by anaerobic respiration in the plant body will be oxidized into more toxic substances, such as ethanol oxidized into acetaldehyde. Moreover, a large amount of active oxygen ions will be produced in the plant body, and the accumulation of excessive active oxygen ions will lead to the death of plant cells, which will affect the recovery growth of plants after waterlogging. Therefore, the recovery condition of plants after waterlogging is also an important indicator for measuring the waterlogging tolerance of plants.

[0004] Cotton (Gossypium hirsutum L.) is one of the important economic crops in the world, and is not only a major agricultural product but also a raw material for the textile industry, which is highly valued by cotton-producing countries around the world. Generally, cotton has poor waterlogging tolerance and is one of the crops that are easily affected by waterlogging stress. In recent years, with the increasing frequency of flood disasters, the period of cotton field disasters is no longer limited to the flowering and boll stage, and the seedling stage, squaring stage and boll opening stage may also occur. In addition, in recent years, cotton has been planted in coastal saline-alkali land and waterlogged land, and waterlogging stress has become a natural disaster that cotton will encounter throughout its growth period. Planting waterlogging-tolerant varieties is an important means to cope with the adverse effects of heavy rainfall on cultivation, so it is particularly important to quickly screen and identify waterlogging-tolerant germplasm resources from a rich cotton resource. SUMMARY

[0005] Traditional identification of plant flooding tolerance mainly adopts field irrigation or potting waterlogging treatment, and physiological and biochemical indexes of the plant are determined during waterlogging, such as the method, although the data measured are more accurate, when identifying large-scale materials, it is easy to be affected by external factors such as environment, and field identification needs to consume a large amount of material and human resources. At the same time, the visible damage of short-term waterlogging to the plant is generally not immediately manifested, but begins to be obviously manifested in the recovery growth period after the waterlogging is removed. Therefore, whether the plant can quickly recover to the life state after the waterlogging is removed may be more critical to the flooding tolerance.

[0006] However, the current research mainly focuses on the identification of some crops, economic crops and the like in the short-term waterlogging stress process, but the identification of the flooding tolerance of the plant in the recovery period after the waterlogging is rarely studied.

[0007] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a method for rapidly identifying the flooding tolerance of cotton germplasm; the waterlogging simulation technology of double pots is adopted to evaluate the flooding tolerance of cotton by the wilting degree of the leaf of the cotton seedling in the recovery period after the waterlogging stress. The present application provides a simple, practical, scientific and novel evaluation method for the flooding tolerance of cotton varieties, which can effectively shorten the identification time, improve the efficiency, is suitable for large-scale identification of cotton germplasm resources, and can provide technical support for the screening of flooding-tolerant cotton germplasm and the breeding of varieties.

[0008] In the first aspect, the present application provides a method for rapidly identifying the flooding tolerance of cotton germplasm, comprising: waterlogging and dark treatment of the cotton material, and then removing the waterlogging and light treatment, wherein the wilting degree of the leaf of the cotton material is used as an identification index of the flooding tolerance.

[0009] In the method for rapidly identifying the flooding tolerance of cotton germplasm provided by the present application, the flooding tolerance is identified at the four-leaf stage of the cotton material.

[0010] In the method for rapidly identifying the flooding tolerance of cotton germplasm provided by the present application, the waterlogging treatment in the room is waterlogging and dark treatment, the time is 90-100h, and the light treatment time after removing the waterlogging is 6-10h.

[0011] In the natural conditions, the waterlogging treatment time is 40-50h, and the light treatment time after removing the waterlogging is 4-6h.

[0012] In the method for rapidly identifying the flooding tolerance of cotton germplasm provided by the present application, the waterlogging treatment in the room is simulated by double pots.

[0013] In the present application, the waterlogging treatment is that the water is submerged to the soil surface by 2-5cm, and more preferably, in the waterlogging treatment, the water is submerged to the soil surface by 3cm.

[0014] More specifically, in the room, the waterlogging dark treatment time is 96h, and the light treatment time after removing waterlogging is 8h; in the natural conditions, the waterlogging dark treatment time is 48h, and the light treatment time after removing waterlogging is 4h.

[0015] In the method for rapidly identifying the waterlogging tolerance of cotton germplasm provided by the application, the wilting of the leaves refers to the wilting and bending of the top of the plant and the softness and drooping of the leaves.

[0016] In the method for rapidly identifying the waterlogging tolerance of cotton germplasm provided by the application, Zhongmian 9101 is used as a waterlogging sensitive type control, and Zhongmian 9001 is used as a waterlogging tolerant type control.

[0017] In the method for rapidly identifying the waterlogging tolerance of cotton germplasm provided by the application, if the wilting degree of the leaves of the cotton material is the same as that of Zhongmian 9101, the cotton material is determined as a waterlogging sensitive cotton.

[0018] In the method for rapidly identifying the waterlogging tolerance of cotton germplasm provided by the application, if the wilting degree of the leaves of the cotton material is the same as that of Zhongmian 9001, the cotton material is determined as a waterlogging tolerant cotton.

[0019] The application has the following beneficial effects:

[0020] The application first proposes that a waterlogging dark treatment of 90-100h + light treatment of 6-10h after removing waterlogging is performed on cotton seedlings at the four-leaf stage, and the waterlogging tolerance can be effectively distinguished by observing the wilting degree of the leaves of the cotton material, and the above results are verified by field waterlogging tests in natural environments.

[0021] The application uses indoor double-pot simulation waterlogging technology to establish a rapid and efficient indoor method for identifying the waterlogging tolerance of cotton materials, and overcomes the shortcomings of the prior art, such as a long period, high cost, and being easily affected by external factors such as the environment.

[0022] Compared with the prior art, the application is a simple, practical, scientific and novel method for evaluating the waterlogging tolerance of cotton varieties, and provides technical support for related research on waterlogging tolerant cotton. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 is the weather condition of the experimental field of the Cotton Research Institute of the Chinese Academy of Agricultural Sciences from July 21 to 30, 2021.

[0025] Figure 2 A and B are the wilting degree of leaves of different cotton materials after waterlogging treatment, wherein A is the wilting degree of leaves after 48h of field waterlogging + 4h of removing waterlogging light; B is the comparison of cotton after waterlogging treatment in the late growth stage.

[0026] Figure 3 A and B are the wilting degree difference comparison of leaves of different cotton materials after continuous waterlogging stress, wherein A is waterlogging stress for 5 days; B is waterlogging stress for 6 days; the light / dark length in waterlogging stress treatment is 12h / 12h.

[0027] Figure 4 A and B are the wilting degree difference comparison of leaves of different cotton materials under different waterlogging treatment conditions, wherein the waterlogging treatment condition of A is waterlogging dark treatment for 24h + removing waterlogging light for 8h; the waterlogging treatment condition of B is waterlogging dark treatment for 48h + removing waterlogging light for 8h; the waterlogging treatment condition of C is waterlogging dark treatment for 72h + removing waterlogging light for 8h; the waterlogging treatment condition of D is waterlogging dark treatment for 96h + removing waterlogging light for 8h.

[0028] Figure 5 A and B are the wilting degree difference comparison of leaves of different cotton materials after 96h of waterlogging dark treatment + 8h of removing waterlogging light.

[0029] Figure 6 A is the weather condition of the test field of the Cotton Research Institute of Chinese Academy of Agricultural Sciences from July 1 to 10, 2022.

[0030] Figure 7 A is the wilting degree difference comparison of leaves of different cotton materials after 48h of field waterlogging + 4h of removing waterlogging light. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] The cotton 9101 used in the sensitive material and the cotton 9001 used in the waterlogging-resistant material are both cotton varieties on the market. The sensitive material cotton 9101 and the waterlogging-resistant material cotton 9001 used this time are from the Cotton Research Institute of Chinese Academy of Agricultural Sciences.

[0033] Example 1

[0034] To investigate the flood tolerance of different cotton varieties in the field under natural conditions, the effects of short-term natural flooding (approximately 48 hours later, rainwater was pumped out by a small diesel engine to relieve flood stress) on different cotton varieties were observed in experimental fields of the Cotton Research Institute, Chinese Academy of Agricultural Sciences, using the waterlogging conditions caused by heavy rainfall on July 22-23, 2021. For details on the average total radiation, average temperature, and precipitation in late 2021, please refer to [link to relevant data]. Figure 1 The rainfall on July 22nd and 23rd reached 201.3 mm and 102.2 mm respectively, with average total radiation of 56.6 W / m². 2 and 47.6W m 2 On July 24th, the sky cleared, and the average total radiation reached 295.1 W / m². 2 .

[0035] The investigation revealed that after approximately 48 hours of flooding stress plus 4 hours of light exposure following the removal of flooding, multiple cotton varieties in the experimental field exhibited leaf wilting. Among them, Zhongmian 9101 was most significantly affected, with its plant tips wilting and bending, and all leaves showing varying degrees of wilting and drooping. Zhongmian 9001 showed better waterlogging tolerance, with its plants remaining relatively upright and growing well, and its leaves not wilting (see...). Figure 2 (A). Due to higher rainfall in the second half of 2021 compared to previous years, the sensitive cotton variety 9101 frequently exhibited leaf wilting after rain during the later stages of its growth, resulting in significant boll shedding and thus greatly impacting cotton yield (see A). Figure 2 (B).

[0036] To establish a rapid and convenient method for identifying the waterlogging tolerance of different cotton varieties, an indoor double-pot waterlogging condition screening study was conducted using the sensitive cotton variety Zhongmian 9101 and the waterlogging-tolerant cotton variety Zhongmian 9001, selected from field screening. The degree of leaf wilting after waterlogging stress treatment was used as an indicator to evaluate the waterlogging tolerance of different cotton varieties. During the experiment, it was found that the control group plants grew normally; therefore, only the treated group plants were observed. After 5 days of continuous waterlogging stress treatment, no wilting occurred in the leaves of any of the different cotton varieties (see...). Figure 3 (A); however, after 6 days of continuous waterlogging stress, the leaves of all different cotton materials showed slight wilting, and the differences between different materials were not significant (see A). Figure 3 (B).

[0037] Example 2

[0038] To simulate the low-oxygen and low-light conditions of plant roots subjected to waterlogging in nature, and to restore oxygen and light conditions after removing the submerged roots, this study also included a waterlogging stress treatment under dark conditions, followed by a light treatment after removing the submerged roots. The results showed that neither the 24-hour waterlogging and dark treatment plus 8 hours of light after removing the submerged roots, nor the 48-hour waterlogging and dark treatment plus 8 hours of light after removing the submerged roots, resulted in wilting of leaves in any of the different cotton materials (see...). Figure 4 (A, B). After 72 hours of waterlogging and darkness treatment followed by 8 hours of light exposure after removing the waterlogging, the leaves of all cotton materials showed slight wilting, but the differences between the different materials were not significant (see A, B). Figure 4 (C). After 96 hours of waterlogging and darkness treatment followed by 8 hours of light removal, the wilting degree of leaves in different cotton materials tended to worsen, and the differences in the degree of leaf wilting among different cotton materials were significant (see C). Figure 4 (D); Among them, the plants of the flood-tolerant cotton 9001 were basically upright, with the lowest leaves softening and drooping, while the middle and upper leaves were naturally extended; while the plant tips of the sensitive cotton 9101 wilted and bent, and all leaves showed severe wilting and drooping. Therefore, indoor simulation of waterlogging stress treatment, and observation of the degree of leaf wilting of cotton materials after 96 hours of waterlogging in darkness followed by 8 hours of light removal after waterlogging, can effectively distinguish the flood tolerance of different materials.

[0039] Example 3

[0040] To verify the accuracy of the indoor assessment conditions for the waterlogging tolerance of cotton materials, Zhong 0102 and Zhongmian 9421 were used as test materials, and Zhongmian 9101 and Zhongmian 9001 were used as sensitive and waterlogging tolerant controls, respectively. After a 96-hour period of waterlogging in darkness followed by an 8-hour period of light exposure after removing the waterlogging, the degree of leaf wilting was observed in different cotton materials (see...). Figure 5 The results showed that the plants of Zhongmian 9421 were basically upright, with no obvious wilting of the leaves, and there was no significant difference from the flood-resistant material Zhongmian 9001; while the top of the plants of Zhong0102 were wilted and bent, the bottom leaves were soft and drooping, and the middle and upper leaves showed slight wilting, which was similar to the overall performance of the sensitive material Zhongmian 9101.

[0041] Example 4

[0042] To verify the accuracy of indoor assessments of cotton material flood tolerance, field assessments of flood tolerance under natural conditions were conducted. Using the flooding conditions caused by heavy rainfall on July 5-6, 2022, the effects of short-term natural flooding (approximately 48 hours later, rainwater was pumped out by a small diesel engine, thus relieving the flood stress) on the flood tolerance of different cotton varieties, 0102, Zhongmian 9421, Zhongmian 9101, and Zhongmian 9001, were observed in experimental fields at the Cotton Research Institute of the Chinese Academy of Agricultural Sciences. Details of the average total radiation, average temperature, and precipitation in early 2022 are available in [link to relevant data]. Figure 6Among them, the precipitation on July 5 and 6 reached 181.8 mm and 80.3 mm, respectively, and the average total radiation was 41.1 Wm 2 and 82.5 Wm 2 , respectively; on July 6, the sky was clear, and the average total radiation reached 321.2 Wm 2 .

[0043] The results showed that after about 48 h of waterlogging stress and 4 h of removing waterlogging light, the test field of Zhongmian 9101 and Zhong 0102 was obviously affected by waterlogging stress, the top of the plants was wilting and bending, and all the leaves were wilting and drooping to different degrees; Zhongmian 9001 and Zhongmian 9421 had better waterlogging resistance, the plants were basically straight and grew well, and only the top leaves had slight wilting phenomenon (see Figure 7 ). The waterlogging resistance of different cotton materials in the field was basically consistent with that in the room.

[0044] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for rapidly identifying the waterlogging tolerance of cotton germplasm, characterized in that, include: The cotton material was subjected to water flooding treatment, followed by removal of water and light treatment. The degree of leaf wilting of the cotton material was used as an indicator of waterlogging tolerance. Waterlogging resistance was assessed in cotton materials at the four-leaf stage. Indoors, the flooding treatment is a flooding and darkness treatment for 90-100 hours, followed by a light treatment for 6-10 hours after the flooding is removed. Under natural conditions, the water flooding treatment time is 40-50 hours, and the light treatment time after removing the water flooding time is 4-6 hours.

2. The method according to claim 1, characterized in that, The indoor area uses a double-layered basin to simulate flooding.

3. The method according to claim 1 or 2, characterized in that, The wilting of leaves refers to the wilting and bending of the plant tip and the softening and drooping of the leaves.

4. The method according to claim 1 or 2, characterized in that, Zhongmian 9101 was used as a flood-sensitive control and Zhongmian 9001 was used as a flood-resistant control.

5. The method according to claim 4, characterized in that, If the degree of wilting of the cotton material leaves is the same as that of Zhongmian 9101, then it is determined to be waterlogging-sensitive cotton.

6. The method according to claim 4, characterized in that, If the degree of leaf wilting of the cotton material is the same as that of Zhongmian 9001, it is determined to be a waterlogging-resistant cotton.

Images