Method for improving insect resistance of Bt cotton based on amino acid

Abstract

The invention discloses a method for improving insect resistance of Bt cotton based on amino acid, which comprises the following step: after the Bt cotton blooms, spraying an amino acid composition on cotton plants. According to the invention, the amino acid composition is sprayed on cotton plants of Bt cotton after blooming so as to improve the insect resistance of the Bt cotton. By means of the method, the Bt insecticidal protein concentration of Bt cotton leaves can be increased by 38.9%-41.2%, the Bt insecticidal protein concentration of cotton bolls can be increased by 25.5%-29.8%, the number of hundreds of cotton bollworms can be decreased by 33.2%-38.6%, the damage of the cotton bollworms to squaring and bolls is decreased by 31.2%-37.6%, the boll weight is increased by 5.5%-6.3%, and the yield is increased by 6.7%-8.3%.

Description

Technical Field

[0001] The present invention relates to the field of agricultural technologies, and particularly relates to a method for improving the insect resistance of Bt cotton based on amino acids. Background Art

[0002] Bt transgenic (CryⅠAc) insect-resistant cotton (Bt cotton) has good insecticidal effects and can significantly reduce the corresponding amount of pesticides used, thus being widely used in cotton cultivation in China. However, the expression of its insect resistance is unstable, and the insecticidal effect is only 40%. In terms of time, the Bt insect resistance is high during the seedling and bud stages and decreases after flowering; in terms of space, the Bt insect resistance is different in different organs and at different growth stages of the same organ. Generally, the insect resistance of leaves is high and that of reproductive organs is low. Since the feeding organs of cotton bollworms are mainly the leaves and reproductive organs (buds, flowers, and bolls) of cotton, the above-mentioned expression characteristics of Bt insect resistance are not conducive to the control effect of related pests such as cotton bollworms.

[0003] The insect resistance of Bt cotton is mainly related to the concentration of Bt insecticidal protein. Therefore, the insecticidal protein concentration of Bt cotton can be increased by regulating the protein synthesis in leaves and reproductive organs, thereby improving the insect resistance. It has now been found that increasing nitrogen fertilizer in the soil and spraying urea externally on the roots can, to a certain extent, improve the insect resistance of leaves and buds, flowers, and bolls, but the improvement is only about 20%, and there is a risk of causing excessive growth of cotton and reducing the yield. Summary of the Invention

[0004] Aiming at the technical problems that the insect resistance of Bt cotton significantly decreases after flowering, especially the Bt insect resistance is even lower during the flower and boll stages and still requires pesticides to control cotton bollworms, etc., the present invention provides a method for improving the insect resistance of Bt cotton based on amino acids, so as to achieve the purpose of reducing pesticides and increasing production and efficiency of cotton.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] The present invention provides a method for improving the insect resistance of Bt cotton based on amino acids, comprising the following steps:

[0007] After the Bt cotton is in full bloom, spray the amino acid composition on the cotton plants of Bt cotton.

[0008] As a preferred embodiment, the amino acid composition is composed of aspartic acid, glutamic acid, proline, methionine, and arginine.

[0009] As a preferred embodiment, the amino acid composition is an aqueous solution.

[0010] As a preferred embodiment, in the aqueous solution, the concentration of a single amino acid is 20 - 30 mg / kg; in the technical solution of the present invention, the concentration refers to the mass of amino acids in the unit aqueous solution.

[0011] As a preferred embodiment, the amino acid composition is composed of equal masses of aspartic acid, glutamic acid, proline, methionine and arginine;

[0012] In some specific embodiments, the amino acid composition is first formulated into a high-concentration aqueous solution and diluted with water to the target concentration before spraying.

[0013] As a preferred embodiment, after the Bt cotton is in full bloom, it is sprayed once every 5 to 7 days.

[0014] As a preferred embodiment, the planting density of the Bt cotton is 6,000 to 12,000 plants per mu.

[0015] As a preferred embodiment, the total mass of amino acids sprayed once is 3,000 to 4,000 mg per mu.

[0016] As a preferred embodiment, the total number of sprayings is 2 to 4 times.

[0017] The above technical solution has the following advantages or beneficial effects: The present invention uses an amino acid composition to spray the cotton plants of Bt cotton after full bloom to improve the insect resistance of Bt cotton.

[0018] The present invention has the following advantages:

[0019] 1. The method provided by the present invention can increase the Bt protein concentration in the leaves of Bt cotton by 38.9 to 41.2%, the Bt protein concentration in the cotton bolls by 25.5 to 29.8%, the number of cotton bollworms per 100 cotton plants by 33.2 - 38.6%, and the damage of cotton bollworms to flower buds and bolls by 31.2 to 37.6%;

[0020] 2. The method provided by the present invention can not only improve the insect resistance, but also increase the boll weight of Bt cotton by 5.5 to 6.3% and the yield by 6.7 to 8.3%;

[0021] 3. The natural amino acids such as aspartic acid used in the present invention are green compounds and will not produce corresponding toxic and side effects on organisms and the natural environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a result graph after feeding cotton bollworms with the boll shells of Bt cotton in Example 1 and Comparative Example 1 of the present invention for 24 hours.

[0023] Figure 2 It is a result graph after feeding cotton bollworms with the flower buds of Bt cotton in Example 1 and Comparative Example 1 of the present invention for 24 hours.

[0024] Figure 3 It is a result graph after feeding cotton bollworms with the flowers of Bt cotton in Example 1 and Comparative Example 1 of the present invention for 24 hours.

[0025] Figure 4 This is the result graph after feeding the unginned cotton of Bt cotton in Example 1 and Comparative Example 1 of the present invention to Helicoverpa armigera for 24 hours. Detailed implementation manners

[0026] The following embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Therefore, the detailed descriptions in the embodiments of the present invention provided below are not intended to limit the scope of the claimed invention, but merely represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

[0027] In the present invention, unless otherwise specified, all devices and raw materials can be purchased from the market or are commonly used in this industry. The methods in the following embodiments are conventional methods in this field unless otherwise specified.

[0028] Example 1

[0029] Prepare an aqueous solution of a composition of aspartic acid, glutamic acid, proline, methionine and arginine, with the concentration of each amino acid being 25 mg / kg. Spray the cotton plants every 6 days after the full bloom of Bt cotton, and spray continuously for 3 times; the planting density of Bt cotton is 6000 - 12000 plants / mu, and the spraying amount of the solution per mu each time is 30 kg.

[0030] Comparative Example 1

[0031] In this comparative example, the Bt cotton with the same growth state in the adjacent field of Example 1 was used as the experimental object, and clear water was sprayed during the same period.

[0032] The present invention conducted corresponding investigations on the damage situation of Helicoverpa armigera to the Bt cotton in Example 1 and Comparative Example 1 and the yield situation caused by the damage of Helicoverpa armigera. Specifically, it was entrusted to Zhao Jianming, a technician from Dafeng Rice and Wheat Breeding Farm. The test results are shown in Figures 1 to 4 and Table 1.

[0033] Figure 1 This is the result graph after feeding the cotton boll shell of cotton to Helicoverpa armigera for 24 hours. It can be seen from the graph that the Helicoverpa armigera treated with amino acids in Example 1 (right graph) stopped feeding or died, while the Helicoverpa armigera not treated with amino acids in Comparative Example 1 (left graph) still survived. This shows that the concentration of Bt insecticidal protein in the cotton boll shell treated with amino acids in Example 1 can kill Helicoverpa armigera, while the concentration of Bt protein in the cotton boll shell of Comparative Example 1 cannot kill Helicoverpa armigera.

[0034] Figure 2The figure shows the results after feeding Helicoverpa armigera on cotton buds for 24 hours. As can be seen from the figure, the Helicoverpa armigera stopped feeding or died after being treated with amino acids in Example 1 (right figure), while the Helicoverpa armigera in Comparative Example 1 without amino acid treatment (right figure) remained alive. This shows that the concentration of Bt insecticidal protein in the cotton buds treated with amino acids in Example 1 can kill Helicoverpa armigera, while the concentration of Bt protein in the untreated cotton buds cannot kill Helicoverpa armigera.

[0035] Figure 3 The figure shows the results after feeding Helicoverpa armigera on cotton flowers for 24 hours. As can be seen from the figure, the Helicoverpa armigera stopped feeding or died after being treated with amino acids in Example 1 (right figure), while the Helicoverpa armigera in Comparative Example 1 without amino acid treatment (left figure) remained alive. This shows that the concentration of Bt insecticidal protein in the flowers treated with amino acids in Example 1 can kill Helicoverpa armigera, while the concentration of Bt protein in the untreated flowers cannot kill Helicoverpa armigera.

[0036] Figure 4 The figure shows the results after feeding Helicoverpa armigera on unginned cotton for 24 hours. As can be seen from the figure, the Helicoverpa armigera stopped feeding or died after being treated with amino acids in Example 1 (right figure), while the Helicoverpa armigera in Comparative Example 1 without amino acid treatment (left figure) remained alive. This shows that the concentration of Bt insecticidal protein in the unginned cotton treated with amino acids in Example 1 can kill Helicoverpa armigera, while the concentration of Bt protein in the untreated unginned cotton cannot kill Helicoverpa armigera.

[0037] Table 1 Helicoverpa armigera damage and cotton yield in Example 1 and Comparative Example 1

[0038]

[0039] As can be seen from the above table, compared with Comparative Example 1, the Bt protein concentration in the leaves decreased by 40.1% and the Bt protein concentration in the cotton bolls decreased by 27.7% in Example 1; the number of insects on the cotton bolls per 100 cotton plants decreased by 35.9%, and the insect damage rate of flower buds and cotton bolls decreased by 32.0%; the boll weight increased by 0.3 g, and the unginned cotton yield per mu increased by 16.7 kg. Thus, it can be seen that the present invention can reduce the amount of pesticides per mu by more than 30% and increase the cotton yield by 7%.

[0040] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for improving the insect resistance of Bt cotton based on amino acids, characterized in that, Comprising the following steps: After the Bt cotton is in full bloom, spray the amino acid composition on the cotton plants of the Bt cotton.

2. The method according to claim 1, wherein The amino acid composition is composed of aspartic acid, glutamic acid, proline, methionine and arginine.

3. The method according to claim 1, wherein The amino acid composition is an aqueous solution.

4. The method according to claim 3, characterized in that, In the aqueous solution, the concentration of a single amino acid is 20-30 mg / kg.

5. The method according to claim 2, characterized in that, The amino acid composition is composed of equal masses of aspartic acid, glutamic acid, proline, methionine and arginine.

6. The method according to claim 1, wherein After the Bt cotton is in full bloom, spray once every 5-7 days.

7. The method according to claim 6, characterized in that, The total mass of the amino acids sprayed each time is 3000-4000 mg / mu.

8. The method according to claim 6, characterized in that The total number of sprays is 2-4 times.

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