CN118126835A

CN118126835A - Application of sclerotinia attenuated strain DT-8 in corn yield increase, corn growth promoting yield increasing agent and preparation method thereof

Info

Publication number: CN118126835A
Application number: CN202410088796.4A
Authority: CN
Inventors: 姜道宏; 宁功臣; 谢甲涛; 付艳苹; 程家森; 李博; 陈桃; 于晓
Original assignee: Hubei Hongshan Laboratory
Current assignee: Hubei Hongshan Laboratory
Priority date: 2024-01-22
Filing date: 2024-01-22
Publication date: 2024-06-04

Abstract

The invention belongs to the technical field of crop cultivation, and particularly relates to application of a sclerotinia sclerotiorum attenuated strain DT-8 in corn yield increase and a corn growth promoting yield increasing agent and a preparation method thereof, wherein the preservation number of the sclerotinia sclerotiorum attenuated strain DT-8 is as follows: the sclerotinia sclerotiorum attenuated strain DT-8 can remarkably promote the growth of corn and improve the yield of corn, and has the advantages of high stability, low cost and good effect. The invention provides a corn growth promoting and yield increasing agent, and a sclerotinia sclerotiorum attenuated strain DT-8 carries a DNA virus SsHADV-1 related to attenuated virus, has no pathogenicity to crops, has higher safety, and can be widely used in production. The invention also provides a preparation method of the corn growth promoting yield increasing agent, which utilizes beneficial biological resources to promote healthy growth of corn and increase the yield of corn per unit area, and is a green and environment-friendly way.

Description

Application of sclerotinia attenuated strain DT-8 in corn yield increase, corn growth promoting yield increasing agent and preparation method thereof

Technical Field

The invention belongs to the technical field of crop cultivation, and particularly relates to application of sclerotinia sclerotiorum attenuated strain DT-8 in corn yield increase, a corn growth-promoting yield increasing agent and a preparation method thereof.

Background

Corn is not only a main grain crop, but also an important feed and industrial raw material, is an important source of industries such as food processing, light industry, medicine and the like, has a planting area of over 6 hundred million mu in China, and is a first large grain crop. The corn harvesting area in China is the first place in the world, and is also the large country of corn consumption and trade, and the total consumption is the second place in the world, which is more than 1/4 of the world; corn feeding consumption is the first global place, and is nearly 1/3 of the global; the imported corn amount of China accounts for more than 10% of the world, and the international market dependency degree is relatively high. In recent years, as the demand of people for farm and grazing products is increasing, the demand of the farm and grazing industry for feed corn is increasing dramatically. In 2019, the U.S. corn is 10532.3kg/ha (kg/hectare), while the corn yield in China is 6317.1kg/ha (FAO, 2020), and the lifting space is extremely large. Therefore, it is needed to provide a green and environment-friendly way for promoting healthy growth of corn and improving the yield of corn per unit area.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide an application of a sclerotinia attenuated strain DT-8 in corn yield increase, a corn growth promoting yield increasing agent and a preparation method thereof. The sclerotinia attenuated strain DT-8 can remarkably promote the growth of corn, improve the yield of corn, and has the advantages of high stability, low cost and good effect.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides application of a sclerotinia sclerotiorum attenuated strain DT-8 in promoting growth and/or increasing yield of corn, wherein the preservation number of the sclerotinia sclerotiorum attenuated strain DT-8 is as follows: cctcc No. m 2019328.

Preferably, the method comprises initiating corn seeds with an aqueous suspension of said sclerotinia attenuated strain DT-8, said initiating comprising immersing the seeds in said aqueous suspension.

Preferably, the mass-to-volume ratio of the seeds to the aqueous suspension is 4-6 kg: 400-600 mL, wherein the seed soaking temperature is 18-22 ℃ and the seed soaking time is 8-16 h.

Preferably, the method comprises spraying an aqueous suspension of the sclerotinia attenuated strain DT-8 in the corn adult stage.

Preferably, the spraying dosage is 200-400 mL/mu.

Preferably, the spraying comprises spraying once in the earlier stage of heading.

The invention provides a corn growth promoting and yield increasing agent, which comprises the following raw materials: sclerotinia sclerotiorum attenuated strain DT-8 fermentation liquor, streptomycin sulfate and trehalose; the preservation number of the sclerotinia attenuated strain DT-8 is as follows: cctcc No. m 2019328.

Preferably, the adding amount of the streptomycin sulfate is 0.01-0.1% of the total mass of the fermentation liquor of the sclerotinia sclerotiorum attenuated strain DT-8, and the adding amount of the trehalose is 2-6% of the total mass of the fermentation liquor of the sclerotinia sclerotiorum attenuated strain DT-8.

The invention also provides a preparation method of the corn growth-promoting yield-increasing agent, which comprises the following steps: fermenting the sclerotinia attenuated strain DT-8 to obtain fermentation liquor; mixing the fermentation liquor with streptomycin sulfate and trehalose to obtain the corn growth-promoting yield-increasing agent.

Preferably, the fermentation temperature is 18-22 ℃, the fermentation pH is 6.5-7.3, and the fermentation time is 50-70 h.

The beneficial effects are that: the invention provides an application of a sclerotinia sclerotiorum attenuated strain DT-8 in promoting corn growth and increasing corn yield, wherein the sclerotinia sclerotiorum attenuated strain DT-8 can remarkably promote corn growth and increase corn yield, and has the advantages of high stability, low cost and good effect.

The invention provides a corn growth promoting and yield increasing agent, which has the advantages that a sclerotinia attenuated strain DT-8 carries an attenuated related DNA virus SsHADV-1, has no pathogenicity to crops such as rape, wheat, corn and the like, has higher safety, and can be widely used in production.

The invention also provides a preparation method of the corn growth promoting yield increasing agent, which utilizes beneficial biological resources to promote healthy growth of corn and increase the yield of corn per unit area, and is a green and environment-friendly way.

Biological preservation information

The sclerotinia sclerotiorum attenuated strain (Sclerotinia sclerotiorum) DT-8 is preserved in China center for type culture Collection (CCTCC for short) in 5 months and 5 days of 2019, and the specific preservation address is university of Wuhan and the preservation number is: cctccc No. m 2019328.

Drawings

FIG. 1 is a graph comparing the effects of DT-8 initiation on seed germination; wherein, the left graph is a real object, and the right graph is a germination rate comparison result;

FIG. 2 is a comparative graph of DT-8 initiation to promote maize seedling growth (30 d); wherein A: comparative graph of indoor maize seedlings, left comparative example 1, right example 1; b: indoor seedling height; c: seedlings maximum She Shechang; d: maximum leaf width of seedlings; e: fresh weight of seedlings;

FIG. 3 is a comparative graph of DT-8 initiation promotion of field corn growth; wherein A: the field corn growth condition; b: the field corn plant height; c: the diameter of the basal stems of the corn in the field;

FIG. 4 is a comparative graph of DT-8 initiation to promote the development of three leaves of corn cobs in the field; wherein A: she Shechang on the rod; b: leaf length in the rod; c: a lower She Shechang of the rod; d: leaf width on the stick; e: leaf width in the stick; f: leaf width of lower leaf of stick;

FIG. 5 is a graph showing comparison of chlorophyll content of corn leaves; wherein A: chlorophyll content of leaf on stick; b: leaf chlorophyll content in the stick; c: chlorophyll content of the leaf under the stick;

FIG. 6 is a graph comparing leaf nitrogen and H ₂ O content of maize plants; wherein A: she Shedan content on the rod; b: leaf nitrogen content in the rod; c: nitrogen content of the lower leaf of the rod; d: leaf water content on the stick; e: leaf water content in the rod; f: the water content of the lower leaves of the rod;

FIG. 7 is a graph comparing corn root system activity;

FIG. 8 is a graph comparing corn stalk base diameters;

FIG. 9 is a physical diagram of the diameter of the basal part of the corn stalk.

Detailed Description

The invention provides application of a sclerotinia sclerotiorum attenuated strain DT-8 in promoting growth and/or increasing yield of corn, wherein the preservation number of the sclerotinia sclerotiorum attenuated strain DT-8 is as follows: cctccc No. m 2019328.

In the invention, the sclerotinia sclerotiorum attenuated strain DT-8 carries DNA virus SsHADV-1 related to attenuated virus, and the sclerotinia sclerotiorum attenuated strain DT-8 is derived from rape plants in natural fields. Sequence of DNA virus SsHADV-1: see GenBank, accession number KM598384.1. The invention relates to a sclerotinia attenuated strain DT-8, which has been studied in detail in the early stage, and has recorded colony information, screening mode, phenotype, action and other information (Yu X,Li B,Fu Y,Jiang D*,Ghabrial SA,Li G,Peng P,Xie J,Cheng J,Huang J,Yi X.A Geminivirus-related DNA mycovirus that confers hypovirulence to a plant pathogenic fungus.Proc Natl Acad Sci USA 2011,107:8387-8392;Tian B,Xie J,Fu Y,Cheng J,Li B,Chen T,Zhao Y,Gao Z,Yang Y,Barbetti MJ,Tyler BM,Jiang D*.A cosmopolitan fungal pathogen ofdicots adopts an endophytic lifestyle on cereal crops and protects them from major fungal diseases.ISME J 2020,14:3120-3135).

When the sclerotinia sclerotiorum attenuated strain DT-8 is applied to the promotion of corn growth and the increase of corn yield, the method preferably comprises the step of initiating corn seeds by utilizing an aqueous suspension of the sclerotinia sclerotiorum attenuated strain DT-8.

The initiation according to the invention preferably comprises immersing seeds in an aqueous suspension of said sclerotinia attenuated strain DT-8. The seed soaking process of the present invention preferably further comprises the steps of sterilizing and soaking the seeds. The seeds are preferably sterilized first, the sterilizing agent is preferably 84 sterilizing liquid, and the concentration of the 84 sterilizing liquid is preferably 2% -10%, more preferably 3% -8%, and most preferably 5%. The sterilization time is preferably 2 to 20min, more preferably 5 to 15min, and most preferably 5min; the disinfection is preferably followed by rinsing with clear water, and the rinsing times are preferably 2 to 5 times, more preferably 3 to 4 times, and most preferably 4 times; the time for each flushing is preferably 0.5 to 3min, more preferably 1 to 2min, most preferably 1min. The invention preferably soaks the sterilized seeds, the soaking solution is preferably sterile water, the soaking time is preferably 8-12 h, more preferably 9-11 h, most preferably 10h, and the seeds are soaked in the water suspension when the seeds are swelled by water absorption but are not exposed to white.

In the invention, when seeds are placed in the water suspension for seed soaking, the mass volume ratio of the seeds to the water suspension is preferably 4-6 kg:400 to 600mL, more preferably 4.5 to 5.5kg: 450-550 mL, most preferably 5kg:500mL; the seed soaking temperature is preferably 18-22 ℃, more preferably 19-21 ℃ and most preferably 20 ℃; the seed soaking time is preferably 8-16 hours, more preferably 10-14 hours, most preferably 12 hours, and then the seed surface hypha is in a non-sticky state for sowing or the seed surface hypha is air-dried to constant weight and then stored in a room temperature ventilation drying place for 6-12 months. The preparation method of the DT-8 aqueous suspension comprises the following steps: fermenting the sclerotinia attenuated strain DT-8 to obtain fermentation liquor; mixing the fermentation broth with streptomycin sulfate and trehalose to obtain an aqueous suspension. The preparation method of the DT-8 aqueous suspension is the same as the preparation method of the corn growth-promoting yield-increasing agent.

The application of the sclerotinia attenuated strain DT-8 to the promotion of corn growth and the increase of corn yield preferably comprises spraying the aqueous suspension during the corn plant formation period.

The invention preferably sprays the sclerotinia sclerotiorum attenuated bacterial strain DT-8 aqueous suspension in the corn adult stage, wherein the spraying dosage is preferably 200-400 mL/mu, more preferably 250-350 mL/mu, and most preferably 300 mL/mu. In the embodiment of the invention, the number of the viable bacteria of the selected water suspending agent is 1.4X10 ⁵ cfu/mL. In the spraying process, the whole plant is sprayed after the water is added into the sclerotinia sclerotiorum attenuated strain DT-8 water suspension, and the volume mass ratio of the sclerotinia sclerotiorum attenuated strain DT-8 water suspension to water is preferably 200-400 mL:20 to 40kg, more preferably 250 to 350mL: 25-35 kg, most preferably 300mL:30kg.

The spraying according to the invention preferably comprises spraying once in the early heading stage.

The present invention is not particularly limited to the above-described raw materials, and may be commercially available products known to those skilled in the art, unless otherwise specified.

The addition amount of the streptomycin sulfate is preferably 0.01-0.1% of the total mass of the fermentation liquor of the sclerotinia sclerotiorum attenuated strain DT-8, more preferably 0.03-0.08%, most preferably 0.05%, and the streptomycin sulfate is a preservative; the addition amount of the trehalose is preferably 2-6% of the total mass of the fermentation liquor of the sclerotinia sclerotiorum attenuated strain DT-8, more preferably 3-5%, most preferably 4%, and the trehalose is used as a protective agent.

The invention preferably firstly carries out fermentation treatment on the sclerotinia sclerotiorum attenuated strain DT-8 to obtain fermentation liquor. The temperature of the fermentation is preferably 18-22 ℃, more preferably 19-21 ℃ and most preferably 20 ℃; the pH of the fermentation is preferably 6.5 to 7.3, more preferably 6.7 to 7.1, most preferably 6.9; the fermentation time is preferably 50 to 70 hours, more preferably 55 to 65 hours, and most preferably 60 hours. The fermentation according to the present invention preferably further includes stirring, and the stirring speed is preferably 100 to 200r/min, more preferably 120 to 180r/min, and most preferably 150r/min.

The fermentation liquor, streptomycin sulfate and trehalose are mixed according to the proportion to obtain the corn growth-promoting yield-increasing agent, and the viable count of the corn growth-promoting yield-increasing agent is preferably 1.4X10 ⁵ cfu/mL.

For further explanation of the present invention, the application of the sclerotinia attenuated strain DT-8 in corn yield increase and the corn growth promoting agent and the preparation method thereof are described in detail below with reference to the accompanying drawings and examples, but they are not to be construed as limiting the scope of the present invention.

Example 1

Basic information of the sclerotinia attenuated strain DT-8: the sclerotinia sclerotiorum attenuated strain DT-8 carries DNA virus SsHADV-1 related to attenuated virus, the sclerotinia sclerotiorum attenuated strain DT-8 is derived from rape plants in natural fields, and is stored in China Center for Type Culture Collection (CCTCC) in university of Wuhan according to requirements in 5 th and 5 th of 2019, wherein the preservation number is: cctccc No. m 2019328.

Sequence of DNA virus SsHADV-1: see GenBank, accession number KM598384.1.

Preparation of bacterial strain DT-8 aqueous suspension: the sclerotinia attenuated strain DT-8 is cultured in a 50L fermenter at 20 ℃ and 150r/min for 60 hours at pH 6.9. To the obtained fermentation broth, 0.05% streptomycin sulfate and 4% trehalose were added to prepare an aqueous suspension, the viable count of which was 1.4X10 ⁵ cfu/mL.

Initiation of corn seeds: the corn variety is the same as 188. Sterilizing wheat seeds with 5% 84 disinfectant for 5min, and washing with clear water for three times each for 1min; soaking corn seeds in sterile water for 8 hours, when the seeds are swelled by water absorption but not exposed to white, uniformly mixing the sclerotinia sclerotiorum attenuated strain DT-8 water suspending agent with the corn seeds (500 mL water suspending agent/5 kg corn seeds) at room temperature (20 ℃), uniformly mixing and standing for 12 hours to enable the surfaces of the seeds to be fully attached with hypha, and sowing when the hypha on the surfaces of the seeds are in a non-sticky state.

Comparative example 1

The procedure was carried out in the same manner as in example 1 except that after the corn seeds were immersed in the sterilized water for 8 hours, they were allowed to stand for 12 hours under the same conditions as in example 1; the subsequent treatment step of the water suspending agent of the sclerotinia attenuated strain DT-8 is omitted.

Test example 1

The initiated corn seeds of example 1 and the sterile water-soaked corn seeds of comparative example 1 were placed in vermiculite with a moisture content of 75% and moisturized and pregerminated at a constant temperature of 20 ℃ for 7 days, with three replicates per treatment, 100 corn seeds per replicate. The number of germinated seeds in each parallel repeat was counted and the statistics are shown in fig. 1 and table 1.

TABLE 1 influence of DT-8 initiation on seed germination (%)

The results of fig. 1 and table 1 show that the germination rate of corn seeds treated by the sclerotinia attenuated strain DT-8 is 97.67%, and the germination rate of corn seeds of comparative example 1 is 97.67%, indicating that the treatment by the sclerotinia attenuated strain DT-8 has no significant effect on the germination rate of corn seeds.

Test example 2

Greenhouse cultivation: the initiated corn seeds of example 1 and the sterile water-soaked corn seeds of comparative example 1 were planted in the soil of a culture dish and in a greenhouse at 20 ℃. After 30d (four-leaf period), the plant height, fresh weight, maximum She Shechang, leaf width and the respective statistics of maize seedlings were carried out, and the results are shown in fig. 2 and table 2.

TABLE 2DT-8 initiation of promoting maize seedling growth results (30 d)

The results of fig. 2 and table 2 show that the plant height, maximum She Shechang and leaf width of the maize seedling stage initiated by DT-8 in example 1 are significantly increased compared with comparative example 1 by 26.30%, 21.1% and 78.72%, respectively; meanwhile, the fresh weight of the overground part is improved by 11.71 percent compared with the comparative example 1. DT-8 initiation was shown to significantly promote maize seedling growth.

Test example 3

And (3) field cultivation: cell experiments were performed on corn treated with sclerotinia attenuated strain DT-8 from the initiated corn seeds of example 1 and the sterile water-soaked corn seeds of comparative example 1 in the agricultural university of North Hubei province test field in 7 months of 2022. Treatment and control 7 duplicate cells were each set, 2×15m ² per cell, and a guard row was set, without any other treatment during the growth period, without fertilizer. After 60d (grain period) planting, five points are randomly taken from each cell by adopting a five-point sampling method, five plants are randomly taken from each point, and the plant height, the stem thickness, the leaf length and the leaf width of the three leaves of the corn are inspected by using a tape measure, a vernier caliper and the like, and the results are shown in figures 3, 4 and table 3.

TABLE 3DT-8 initiate promotion of maize seedling growth results (60 d)

The results of fig. 3, 4 and table 3 show that the plant height of example 1 is improved by 9.2%, the stem thickness is improved by 25.3%, the leaf length and the leaf width of the upper leaf in the rod clover are respectively improved by 13.6% and 17.6%, the leaf length and the leaf width of the middle leaf are respectively improved by 14.2% and 16.1%, and the leaf length and the leaf width of the lower leaf are respectively improved by 9.1% and 16.3%, compared with the comparative example 1. The DT-8 initiation has obvious promotion effect on the growth of corn seedlings.

Since chlorophyll content is closely related to photosynthesis efficiency, the relative chlorophyll content of corn leaves in the field was detected by the principle of absorption of leaves at wavelengths of 650nm and 940nm using a plant nutrition analyzer (HED-YD plant nutrition analyzer, shandong Hall electronics Co., ltd.) at 60d (grain stage), and the results are shown in FIG. 5 and Table 4.

TABLE 4 chlorophyll content of corn leaves

The results in fig. 5 and table 4 show that the chlorophyll content of the three leaves of the corn cob, three leaves of example 1 initiated by DT-8 is significantly improved by 17.9%, 17.3% and 24.2% relative to the water treatment control corn, respectively. On the surface, seed initiation increases corn cob trilobate chlorophyll content.

Since nitrogen and magnesium in mineral elements are main components of chlorophyll, in the planting of 60d (grain period), a plant nutrition analyzer (HED-YD plant nutrition analyzer, shandong Hall electronic technology Co., ltd.) was further used to determine the leaf nitrogen content of the three leaves of the field corn cob according to the correlation between chlorophyll and nitrogen content, and the leaf moisture of the three leaves of the field corn cob was determined according to the correlation between leaf moisture content, leaf spectral reflectance and spectral index, and the results are shown in FIG. 6 and Table 5.

TABLE 5 leaf nitrogen and H ₂ O content of maize plants

The results in fig. 6 and table 5 show that the nitrogen content of the three corn cobs treated with DT-8 priming in example 1 was significantly higher than that of the control treated corn, while the leaf moisture was significantly lower than that of the control group. The seed initiation is shown to increase nitrogen content in leaves of maize plants and decrease H ₂ O content.

The corn root system activity was quantitatively determined by spectrophotometry using triphenylmethyl chloride (TTF) generated after reduction of triphenyltetrazolium chloride (TTC) as an index, and the results are shown in fig. 7 and table 6. The specific detection steps are as follows:

Preparing a TTC standard curve: 0.2mL of a 0.4% TTC solution was placed in a large tube, 9.8mL of ethyl acetate was added, and a small amount of Na ₂S₂O₄ powder was added and shaken well to immediately yield a red TTF. The TTF concentration in this solution was 80. Mu.g/mL. Respectively taking 0.25mL, 0.50mL, 1.00mL, 1.50mL and 2.00mL of the solution, placing the solutions into a 10mL graduated test tube, fixing the volume by using ethyl acetate to obtain a series of standard solutions containing 20 mug, 40 mug, 80 mug, 120 mug and 160 mug of TTF, taking ethyl acetate as a reference, measuring absorbance at 485nm wavelength, and drawing a standard curve; 0.5g of root tip sample was weighed, placed in a beaker, 5mL each of a 0.4% TTC solution and a phosphate buffer (pH 7.0) was added, the root was sufficiently immersed in the solution, and the temperature was kept dark at 37℃for 1 to 2 hours, immediately thereafter, 2mL of 1M sulfuric acid was added to stop the reaction. (meanwhile, a blank experiment is carried out, sulfuric acid is added firstly, then a root sample is added, no sulfuric acid is added after dark heat preservation at 37 ℃, and the solution concentration and the operation steps are the same as above); taking out the roots, sucking the water with filter paper, placing into a mortar, adding 3-4 mL of ethyl acetate, fully grinding, transferring the red extracting solution into a graduated test tube, washing the residues with a small amount of ethyl acetate for 2-3 times, transferring all the residues into the graduated test tube, finally adding ethyl acetate to make the total amount 10mL, colorizing at a wavelength of 485nm by using a spectrophotometer, measuring the absorbance by taking a blank test as a reference, and calculating the TTC reduction by referring to a standard curve (y=338.09x+6.735, R ² =0.9999).

Table 6 corn root system vigor

The results of fig. 7 and table 6 show that the root system activity of the corn plants initiated by DT-8 in example 1 is significantly higher than that in comparative example 1, and the root system activity is improved by 54.13%. It is shown that seed priming improves corn root system activity.

Example 2

The procedure of example 1 was followed except that the maize variety was Zhengdan 958.

Comparative example 2

The procedure is as in example 2, except that after 8h of soaking of the maize seed in sterile water, the subsequent treatment step of the aqueous suspension of the sclerotinia attenuated strain DT-8 is omitted.

Test example 4

And (3) field test: is implemented in Xiangyang city, hubei province, urban area, mountain town Hu Wancun. Yellow loam has moderate fertility and flatter topography. The previous crop is wheat, and the yield is 500kg. The soil is turned over in 5 months and 26 days of 2022, 50kg of fertilizer special for Shi Jinzheng big corns per mu is planted every 3 meters after soil preparation.

Corn seeds initiated by DT-8 in example 2 and corn seeds soaked by sterile water in comparative example 2 were sown on 28 days of 5 months at a planting density of 4500 plants/mu, 5 rows per cell, row spacing of 0.6m, plant spacing of 0.247m, and double plants per hole. The treatment and control were repeated with 3 cells each, arranged by the gap ratio method, with a cell area of 150m ² (3 m wide and 50m long). No other treatments were carried out during the growth period and no fertilizer was used.

Five-point sampling method is adopted in the harvest period, five points are randomly taken in each cell, five plants are randomly taken in each point, and the data of stem base diameter, growth period, plant height, spike length, spike thickness, line number, row grain number, seed yield, hundred grain weight, cell yield, reduced mu yield and the like are examined by using a tape measure, a vernier caliper and the like, and are shown in fig. 8, tables 7 and 8 in detail.

TABLE 7 Main Property in field-1

TABLE 8 Main Property in field-2

The results of fig. 8 and tables 7 and 8 show that the seed priming treatment has no significant effect on plant height, ear position, ear length, ear thickness, row number and hundred grain weight, but significantly reduces bald tip, significantly increases plant stem thickness, ear number, seed yield and yield, and increases cell yield by 1.91%, 8.05% and 6.17% respectively, compared with the adjacent control, with an average yield increase of 5.52%. It was shown that seeds initiated by DT-8 increased maize yield.

Example 3

The procedure of example 1 was followed except that the corn variety was a positive 508 and included the entire spray: the DT-8 water suspending agent is sprayed once in the heading stage, the viable count of the water suspending agent is 1.4X10 ⁵ cfu/mL, the dosage is 300 mL/mu, and the whole plant is sprayed after 30kg of water is added.

Comparative example 3

The procedure is as in example 3, except that after 8h of soaking of the maize seed in sterile water, the subsequent treatment step of the aqueous suspension of the sclerotinia attenuated strain DT-8 is omitted.

Comparative example 4

The procedure was carried out as in example 3, except that the step of spraying the whole plant with the aqueous suspension of the sclerotinia attenuated strain DT-8 was omitted after sowing.

Test example 5

And (3) field test: is implemented in Xiangyang City Xiangzhou district test field of Hubei province. Yellow clay, shallow soil layer, medium and even fertility and winter idle field.

Corn seeds of example 3 and comparative example 4 which were initiated with DT-8, and corn seeds of comparative example 3 which were soaked with sterile water were sown on 25 days of 5 months at a planting density of 4500 plants/mu. The cell area is 24m ², 6 rows per cell, the row spacing is 0.67m, and the plant spacing is 0.22m. Example 3 and comparative examples 3 and 4 each have 3 cell repetitions. And (3) normally managing water and fertilizer in the field of the corn, and not performing any other treatment and using no fertilizer. Example 3 the DT-8 aqueous suspension was sprayed once during the pre-heading period. Examining plant height, spike height and basal stem thickness in the harvest period; the data of bald tip length, ear number, row number and yield are shown in Table 9.

TABLE 9 Main traits of corn in field

The results in Table 9 show that the yield of example 1 is increased by 5.9% compared with the comparative example, and that the seed priming treatment has no significant effect on the maize plant height, the ear position, the stem thickness, the ear line number and the row grain number, and significantly reduces bald tip. It is shown that seed initiation and adult stage spraying increases corn yield.

Therefore, the sclerotinia sclerotiorum attenuated strain DT-8 can obviously promote the growth of corn, improve the yield of corn, and has high stability, low cost and good effect.

Although the foregoing embodiments have been described in some, but not all, embodiments of the invention, it should be understood that other embodiments may be devised in accordance with the present embodiments without departing from the spirit and scope of the invention.

Claims

1. The application of the sclerotinia sclerotiorum attenuated strain DT-8 in promoting the growth and/or increasing the yield of corn is characterized in that the preservation number of the sclerotinia sclerotiorum attenuated strain DT-8 is as follows: cctccc No. m 2019328.

2. The use according to claim 1, comprising the priming of maize seeds with an aqueous suspension of said sclerotinia attenuated strain DT-8, said priming comprising the immersion of the seeds in said aqueous suspension.

3. Use according to claim 2, characterized in that the mass-to-volume ratio of seeds to aqueous suspension is 4-6 kg: 400-600 mL, wherein the seed soaking temperature is 18-22 ℃ and the seed soaking time is 8-16 h.

4. The use according to claim 1, comprising spraying an aqueous suspension of said sclerotinia attenuated strain DT-8 during maize plant formation.

5. The use according to claim 4, wherein the amount of spraying is 200-400 mL/mu.

6. The use according to claim 5, wherein said spraying comprises spraying once at the early stage of heading.

7. The corn growth promoting and yield increasing agent is characterized by comprising the following raw materials: sclerotinia sclerotiorum attenuated strain DT-8 fermentation liquor, streptomycin sulfate and trehalose; the preservation number of the sclerotinia attenuated strain DT-8 is as follows: cctcc No. m 2019328.

8. The corn growth promoting and yield increasing agent according to claim 7, wherein the adding amount of streptomycin sulfate is 0.01% -0.1% of the total mass of the fermentation liquor of the sclerotinia sclerotiorum attenuated strain DT-8, and the adding amount of trehalose is 2% -6% of the total mass of the fermentation liquor of the sclerotinia sclerotiorum attenuated strain DT-8.

9. The method for preparing the corn growth-promoting yield-increasing agent according to claim 7 or 8, which is characterized by comprising the following steps: fermenting the sclerotinia attenuated strain DT-8 to obtain fermentation liquor; mixing the fermentation liquor with streptomycin sulfate and trehalose to obtain the corn growth-promoting yield-increasing agent.

10. The method according to claim 9, wherein the fermentation temperature is 18 to 22 ℃, the fermentation pH is 6.5 to 7.3, and the fermentation time is 50 to 70 hours.