A method for identifying salt tolerance in the field during the seedling stage using red leaf cotton

Abstract

The present invention discloses a method for field salt tolerance identification at the seedling stage using red-leaf cotton, which relates to the technical field of cotton field salt tolerance identification, including: selecting red-leaf cotton seeds; setting a concentration gradient and subjecting the red-leaf cotton seeds to salt stress using a sand culture method; sowing the red-leaf cotton seeds, comparing the emergence rates of the red-leaf cotton seeds at different concentrations, and selecting standardized seeds for field identification; selecting cotton seeds to be tested and selecting green-leaf cotton seeds for control; selecting fields with relatively uniform salinity, and sowing in a manner of one standardized seed and one test cotton seed / control cotton seed per hole; setting an emergence time and an emergence standard, calculating the relative emergence rate of the test cotton seeds, and performing salt tolerance classification. The present invention uses red-leaf standardized cotton materials and control cotton materials for calculation and classification, which can overcome the difficulty of uneven salinity distribution in saline-alkali land and achieve salt tolerance identification of a large number of cotton materials in the field.

Description

Technical Field

[0001] The invention relates to the technical field of cotton field salt tolerance identification, in particular to a method for using red-leaf cotton to identify field salt tolerance at the seedling stage. Background Art

[0002] Soil salinization is one of the major abiotic factors restricting agricultural development. In my country, where approximately a quarter of the country's cultivated land faces salinization, strengthening the comprehensive utilization of saline-alkali land is particularly important. Cotton is a pioneering crop in saline-alkali land, so identifying and identifying cotton varieties with salt tolerance and selecting those best suited for cultivation in saline-alkali land is crucial.

[0003] Currently, there are various methods for identifying salt tolerance in cotton varieties, but they are primarily categorized by location into laboratory identification and salt pond identification. The former allows for artificial control of stress concentrations, maximizing treatment consistency and resulting in more accurate identification. However, the laboratory environment differs significantly from that of the field, leading to significant discrepancies between identification results and those obtained during field cultivation. The latter, through the establishment of salt ponds, achieves both controlled salt stress concentrations and maximized simulation of natural conditions, providing more valuable insights. However, salt pond construction is costly, and due to the varying soil quality and climate conditions of saline-alkali land across different regions, salt pond identification cannot fully reflect the growing environment in saline-alkali soils. Therefore, developing a method suitable for identifying salt tolerance in saline-alkali soils is crucial.

[0004] The main difficulty in using saline-alkali land to directly conduct field salt tolerance identification is that the salinity distribution of saline-alkali land is uneven, making it difficult to ensure consistency in the treatment of different materials, resulting in the inability to compare the survey results due to different standards.

[0005] The present invention uses a red-leaf cotton with significant phenotypic differences from the material to be tested as a standard material, sows it together with the material to be tested, and calculates the standardized emergence rate of the test material relative to the red-leaf cotton in the same row to standardize the results of all the test materials for comparison and identification. Summary of the Invention

[0006] In response to the needs and shortcomings of current technological development, the present invention provides a method for identifying salt tolerance in the field at the seedling stage using red-leaf cotton.

[0007] The present invention provides a method for identifying salt tolerance in the field of red-leaf cotton at the seedling stage, and the technical solution adopted to solve the above-mentioned technical problems is as follows:

[0008] A method for identifying salt tolerance in the field at the seedling stage using red-leaf cotton comprises the following steps:

[0009] S1. Standardized seed selection for field testing:

[0010] S1.1. Select red-leaf cotton seeds from the cotton germplasm bank of the Chinese Academy of Agricultural Sciences;

[0011] S1.2. Set a concentration gradient and use the sand culture method to treat the red-leaf cotton seeds selected in S1.1 with salt stress; sow the red-leaf cotton seeds, compare the emergence rates of the red-leaf cotton seeds under different concentrations, and select standardized seeds for field identification;

[0012] S2. Select cotton seeds to be tested and obtain upland cotton variety Zhong 07 from the Cotton Research Institute of the Chinese Academy of Agricultural Sciences as green-leaf cotton seeds for control;

[0013] S3. Field sowing:

[0014] Select fields with relatively uniform salinity, sow one standardized seed and one test cotton seed / control cotton seed per hole, and then manage the fields normally;

[0015] S4, salt tolerance classification:

[0016] S4.1. Set the emergence time and emergence standard, and use the formula to calculate the relative emergence rate of the cotton seeds to be tested;

[0017] S4.2. Classify the salt tolerance of the cotton seeds according to their relative germination rates.

[0018] Optionally, step S1.2 is performed on the red leaf cotton seeds selected in step S1.1, and six groups of NaCl solution concentrations are set: 0 mM, 100 mM, 200 mM, 300 mM, 400 mM, and 500 mM, wherein the red leaf cotton seeds treated with 0 mM concentration serve as the control group, and the red leaf cotton seeds treated with 100 mM, 200 mM, 300 mM, 400 mM, and 500 mM concentrations serve as the treatment groups respectively;

[0019] After sowing red leaf cotton seeds, the emergence standard was the growth of the plants out of the soil. The emergence rate of red leaf cotton seeds at different concentrations was calculated according to the following formula:

[0020] Seedling emergence rate = number of seedlings in the treatment group / number of seedlings in the control group × 100%,

[0021] Based on the calculation results, standardized seeds for field testing are selected. The selected standardized seeds have the following characteristics:

[0022] (1) Under normal cultivation conditions, the cotton leaves are red, or have a phenotype that is visually distinguishable from the cotton to be tested;

[0023] (2) The germination rate of red-leaf cotton seeds gradually decreased with the increase of salt stress;

[0024] (3) The germination rate of red leaf cotton seeds was greater than 50% when stressed with 200 mM NaCl solution.

[0025] Further optionally, step S3 is performed to select fields with relatively uniform salinity, and in each field, m rows are sown with one standardized seed and one control green leaf cotton seed per hole, and n rows are sown with one standardized seed and one test cotton seed per hole, wherein m and n are not less than 1, and m is the number of rows. <n。

[0026] Preferably, 43 rows of seeds are sown in each field, of which 1 row is sown with one standardized seed and one control green leaf cotton seed in each hole, and 42 rows are sown with one standardized seed and one test cotton seed in each hole. Each row is 7.2m long, with a row spacing of 1.2m+0.45m, and adjacent holes in the same row are separated by 12cm-18cm.

[0027] Further optionally, step S4.1 is performed, and the seedling emergence time is set to 30 days, and the seedling emergence standard is set to the plant growing out of the soil;

[0028] When the seeds in the same field reach the germination time and meet the germination criteria, the relative germination rate of the tested cotton seeds is calculated according to the following formula:

[0029] Standardized emergence rate of cotton seeds to be tested = number of cotton seeds to be tested / number of red-leaf cotton seeds to be tested in the same hole × 100%,

[0030] Standardized germination rate of control green leaf cotton seeds = number of control green leaf cotton seeds germination / number of red leaf cotton seeds germination in the same hole as control green leaf cotton seeds × 100%,

[0031] Relative germination rate = standardized germination rate of tested cotton seeds / standardized germination rate of control green leaf cotton seeds × 50%.

[0032] Optionally, based on the following salt tolerance identification criteria, step S4.2 is performed to classify the salt tolerance of the cotton seeds to be tested:

[0033] The relative emergence rate is [0%, 25%), and the salt tolerance level is: sensitive,

[0034] The relative emergence rate is [25%, 50%), and the salt tolerance level is: not tolerant,

[0035] The relative emergence rate is [50%, 75%), and the salt tolerance level is: resistant,

[0036] The relative emergence rate is not less than 75%, and the salt tolerance level is: resistant.

[0037] The method of the present invention for identifying salt tolerance in the field at the seedling stage using red leaf cotton has the following beneficial effects compared with the prior art:

[0038] (1) The present invention uses red leaf standardized cotton materials and control cotton materials to calculate and grade, which can overcome the difficulty of uneven salinity distribution in saline-alkali land and realize salt tolerance identification of a large number of cotton materials in the field;

[0039] (2) The present invention is simple to operate, has low requirements for equipment and facilities, and has low manpower and material costs, and is conducive to realizing field salt tolerance identification in any natural environment;

[0040] (3) The present invention can realize salt tolerance identification in a natural planting environment. The salt-tolerant materials screened out by identification are suitable for the local climate and water and soil conditions and can be directly used for cotton production or variety improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Attachment Figure 1 This is a flow chart of the method of embodiment 1 of the present invention. DETAILED DESCRIPTION

[0042] In order to make the technical solution, the technical problems solved and the technical effects of the present invention more clear, the technical solution of the present invention is clearly and completely described below in conjunction with specific embodiments.

[0043] Example 1:

[0044] Reference Attachment Figure 1 This embodiment proposes a method for identifying salt tolerance in the field during the seedling stage using red-leaf cotton, comprising the following steps:

[0045] S1. Standardized seed selection for field testing:

[0046] S1.1. Select red-leaf cotton seeds from the cotton germplasm bank of the Chinese Academy of Agricultural Sciences;

[0047] S1.2. Set six groups of NaCl solution concentrations of 0mM, 100mM, 200mM, 300mM, 400mM and 500mM, and use the sand culture method to treat the red leaf cotton seeds selected in S1.1 with salt stress; among them, the red leaf cotton seeds under the 0mM concentration treatment were the control group, and the red leaf cotton seeds under the five groups of concentration treatments of 100mM, 200mM, 300mM, 400mM and 500mM were the treatment groups. It should be added that two replicates were set for each material and each concentration gradient, and 50 healthy and plump seeds were used in each replicate.

[0048] Red leaf cotton seeds were sown, the germination rates of red leaf cotton seeds at different concentrations were compared, and standardized seeds for field identification were selected.

[0049] Taking the emergence of plants from the soil as the criterion, the emergence rate of red leaf cotton seeds at different concentrations was calculated according to the following formula:

[0050] Seedling emergence rate = number of seedlings emerged in the treatment group / number of seedlings emerged in the control group × 100%.

[0051] Based on the calculation results, select standardized seeds for field testing. The selected standardized seeds should have the following characteristics:

[0052] (1) Under normal cultivation conditions, the cotton leaves are red, or have a phenotype that is visually distinguishable from the cotton to be tested;

[0053] (2) The germination rate of red-leaf cotton seeds gradually decreased with the increase of salt stress;

[0054] (3) The germination rate of red leaf cotton seeds was greater than 50% when stressed with 200 mM NaCl solution.

[0055] In this example, it was found that the red leaf cotton seeds treated with a concentration of 200 mM had the highest germination rate and met the characteristics that standardized seeds should have. Therefore, the red leaf cotton seeds treated with a concentration of 200 mM were used as standardized seeds for field identification.

[0056] S2. Upland cotton variety Zhong 07 was obtained from the stress resistance identification research group of the Cotton Research Institute of the Chinese Academy of Agricultural Sciences as a control green leaf cotton seed. Upland cotton variety Zhong 07 originated from the Cotton Research Institute of the Chinese Academy of Agricultural Sciences, the State Key Laboratory of Cotton Biology, and the Key Laboratory of Cotton Genetic Improvement. The research report "Analysis of differential protein expression in cotton leaves under salt stress" was published in Molecular Plant Breeding, Vol. 10, No. 1, pp. 48-54, 2012, by Cui Yupeng, Fan Baoxiang, Wang Delong, Wang Junjuan, Wang Shuai, and Ye Wuwei.

[0057] The approved varieties are collected as cotton seeds to be tested. The cotton seeds to be tested can be any type except 07 in Table 1, or other non-red leaf cotton seeds other than the types described in Table 1.

[0058] S3. Field sowing:

[0059] Select fields with relatively uniform salinity. In each field, plant m rows of cotton with one standardized seed and one control green leaf cotton seed per hole, and plant n rows of cotton with one standardized seed and one test cotton seed per hole, where m and n are not less than 1, and m <n。

[0060] In this embodiment, 43 rows of seeds were sown in each field, of which 1 row was sown with one standardized seed and one control green leaf cotton seed per hole, and 42 rows were sown with one standardized seed and one test cotton seed per hole. Each row was 7.2 m long, with a row spacing of 1.2 m + 0.45 m. Adjacent holes in the same row were spaced 12 cm to 18 cm apart.

[0061] S4, salt tolerance classification:

[0062] S4.1. Set the seedling emergence time to 30 days and the emergence standard to the plant growing out of the soil;

[0063] When the seeds in the same field reach the germination time and meet the germination criteria, the relative germination rate of the tested cotton seeds is calculated according to the following formula:

[0064] Standardized emergence rate of cotton seeds to be tested = number of cotton seeds to be tested / number of red-leaf cotton seeds to be tested in the same hole × 100%,

[0065] Standardized germination rate of control green leaf cotton seeds = number of control green leaf cotton seeds germination / number of red leaf cotton seeds germination in the same hole as control green leaf cotton seeds × 100%,

[0066] Relative germination rate = standardized germination rate of tested cotton seeds / standardized germination rate of control green leaf cotton seeds × 50%.

[0067] S4.2. Based on the following salt tolerance identification standards, the salt tolerance of the cotton seeds to be tested is graded according to their relative emergence rates:

[0068] The relative emergence rate is [0%, 25%), and the salt tolerance level is: sensitive,

[0069] The relative emergence rate is [25%, 50%), and the salt tolerance level is: not tolerant,

[0070] The relative emergence rate is [50%, 75%), and the salt tolerance level is: resistant,

[0071] The relative emergence rate is not less than 75%, and the salt tolerance level is: resistant.

[0072] It should be added that the experimental method "sand culture method" in this embodiment is recorded in the document "Gao Liying, Deng Yongsheng, Wang Xiaoge, Kong Fanjin, Shen Guifang, Wang Zongwen, Duan Bing, Wang Jinghui, Xu Dongdong, Han Zongfu: Comprehensive evaluation of drought resistance of different cotton varieties during seed germination period, Shandong Agricultural Science, 2023, 55(4): 34-41", and the salt tolerance classification reference standard is recorded in the document "Ye Wuwei, Liu Jinding: Identification technology and application of salt tolerance of cotton germplasm resources, China Cotton, 1998(09)".

[0073] Steps S1 to S4 are performed on the cotton seeds to be tested to obtain the salt tolerance classification of the selected cotton seeds to be tested. The specific types of cotton seeds to be tested and the classification results are shown in Table 1 below.

[0074] Table 1

[0075]

[0076]

[0077] In summary, the method of the present invention for field salt tolerance identification using red leaf cotton at the seedling stage, with the help of red leaf standardized cotton materials and control cotton materials for calculation and grading, can overcome the difficulty of uneven salinity distribution in saline-alkali land and realize salt tolerance identification of a large number of cotton materials in the field.

[0078] The above specific examples are used to illustrate the principles and implementation methods of the present invention in detail. These examples are only used to help understand the core technical content of the present invention. Based on the above specific embodiments of the present invention, any improvements and modifications made by those skilled in the art without departing from the principles of the present invention should fall within the scope of patent protection of the present invention.

Claims

1. A method for identifying salt tolerance in the field of red leaf cotton seedlings, characterized in that , including the following steps: S1. Standardized seed selection for field testing: S1.

1. Select red-leaf cotton seeds from the cotton germplasm bank of the Chinese Academy of Agricultural Sciences; S1.

2. Set a concentration gradient and use the sand culture method to treat the red-leaf cotton seeds selected in S1.1 with salt stress; sow the red-leaf cotton seeds, compare the emergence rates of the red-leaf cotton seeds under different concentrations, and select standardized seeds for field identification; S2. Select cotton seeds to be tested and obtain upland cotton variety Zhong 07 from the Cotton Research Institute of the Chinese Academy of Agricultural Sciences as green-leaf cotton seeds for control; S3. Field sowing: Select fields with relatively uniform salinity, sow one standardized seed and one test cotton seed / control cotton seed per hole, and then manage the fields normally; S4, salt tolerance classification: S4.

1. Set the emergence time and emergence standard, and use the formula to calculate the relative emergence rate of the cotton seeds to be tested; S4.

2. Classify the salt tolerance of the cotton seeds according to their relative germination rates.

2. The method for identifying salt tolerance in the field of red leaf cotton seedlings according to claim 1, wherein: Perform step S1.2 on the red-leaf cotton seeds selected in step S1.1, setting six groups of NaCl solution concentrations: 0 mM, 100 mM, 200 mM, 300 mM, 400 mM, and 500 mM. The red-leaf cotton seeds treated with 0 mM concentration served as the control group, and the red-leaf cotton seeds treated with 100 mM, 200 mM, 300 mM, 400 mM, and 500 mM concentrations served as the treatment groups. After sowing red leaf cotton seeds, the emergence standard was the growth of the plants out of the soil. The emergence rate of red leaf cotton seeds at different concentrations was calculated according to the following formula: Seedling emergence rate = number of seedlings in the treatment group / number of seedlings in the control group × 100%, Based on the calculation results, standardized seeds for field testing are selected. The selected standardized seeds have the following characteristics: (1) Under normal cultivation conditions, the cotton leaves are red, or have a phenotype that is visually distinguishable from the cotton to be tested; (2) The germination rate of red-leaf cotton seeds gradually decreased with the increase of salt stress; (3) The germination rate of red leaf cotton seeds was greater than 50% when stressed with 200 mM NaCl solution.

3. The method for identifying salt tolerance in the field of red leaf cotton at the seedling stage according to claim 1 or 2, wherein: Execute step S3, select fields with relatively uniform salinity, sow m rows of cotton in each field with one standardized seed and one control green leaf cotton seed per hole, and sow n rows of cotton in each field with one standardized seed and one test cotton seed per hole, where m and n are not less than 1, and m <n。 4. The method for identifying salt tolerance in the field of red leaf cotton seedlings according to claim 3, wherein: There are 43 rows of seeds sown in each field, of which 1 row is sown with one standardized seed and one control green leaf cotton seed in each hole, and 42 rows are sown with one standardized seed and one test cotton seed in each hole. Each row is 7.2m long, with a row spacing of 1.2m+0.45m, and adjacent holes in the same row are separated by 12cm-18cm.

5. The method for identifying salt tolerance in the field of red leaf cotton at the seedling stage according to claim 3, wherein: Execute step S4.1, set the seedling emergence time to 30 days, and set the seedling emergence standard to the plant growing out of the soil; When the seeds in the same field reach the germination time and meet the germination criteria, the relative germination rate of the tested cotton seeds is calculated according to the following formula: Standardized emergence rate of cotton seeds to be tested = number of cotton seeds to be tested / number of red-leaf cotton seeds to be tested in the same hole × 100%, Standardized germination rate of control green leaf cotton seeds = number of control green leaf cotton seeds germination / number of red leaf cotton seeds germination in the same hole as control green leaf cotton seeds × 100%, Relative germination rate = standardized germination rate of tested cotton seeds / standardized germination rate of control green leaf cotton seeds × 50%.

6. The method for identifying salt tolerance in the field of red leaf cotton seedlings according to claim 1, wherein: Based on the following salt tolerance identification standards, perform step S4.2 to classify the salt tolerance of the cotton seeds to be tested: The relative emergence rate is [0%, 25%), and the salt tolerance level is: sensitive, The relative emergence rate is [25%, 50%), and the salt tolerance level is: not tolerant, The relative emergence rate is [50%, 75%), and the salt tolerance level is: resistant, The relative emergence rate is not less than 75%, and the salt tolerance level is: resistant.

Images