Method for selecting soybean varieties suitable for soybean cultivation

Abstract

The present invention discloses a method for selecting soybean varieties suitable for bean moth breeding, which firstly performs preliminary screening through multiple batches of bagging and isolation feeding, then observes the leaf loss rate of the varieties taken in the net room, then investigates the leaf biomass and agronomic traits of the soybean varieties, and finally selects excellent varieties through net room isolation feeding. Specifically, the bagging and isolation feeding test uses the inverted three leaves of the living plant to feed the larvae, and the weight of the single larvae at 15 or 18 days old is used as the main indicator to perform preliminary screening of the susceptible germplasm, and the susceptible germplasm preliminarily screened is combined with the larval weight of the plot, the leaf area loss rate and the leaf biomass of the single plant to perform further comprehensive screening of soybean varieties suitable for bean moth breeding. The selection of excellent varieties is to conduct a net room isolation plot breeding test on the further selected soybean varieties, compare the actual yield of larvae of different varieties under the net room breeding conditions, the larval survival rate and the distribution of the weight of the single larvae, and finally select the soybean varieties suitable for bean moth breeding.

Description

Technical Field

[0001] The invention relates to a method for selecting soybean varieties suitable for soybean cultivation, and belongs to the technical field of soybean insect susceptibility evaluation methods. Background Art

[0002] The larvae of the bean moth (Clanis bilineata tsingtauica Mell), commonly known as bean moth, are nutritious edible insects. The bean moth feeds on soybean leaves. The crude protein content of the bean moth's dry weight can reach 65.5%, and the essential amino acids contained in the insect body account for 52.84% of the total amino acid content; crude fat accounts for 23.68%, of which unsaturated fatty acids account for 64.17%. The bean moth larvae are rich in protein resources, and have a higher protein content than the traditional sources of animal protein for humans, such as pigs, cattle, and sheep. In addition, the greenhouse gases emitted during insect breeding are much lower than those of traditional animal husbandry, and the insect breeding cycle is short, and the breeding process has less environmental pressure, which is more conducive to environmental protection than traditional breeding. The breeding of edible insects can help alleviate the pressure on land and water resources caused by the rapid population growth and ensure food security.

[0003] In production, the main method of breeding bean hawkmoths is to raise them in soybean fields, that is, to grow soybeans and raise bean worms. Different soybean varieties have different susceptibility to bean hawkmoths. Selecting appropriate methods to screen susceptible varieties for breeding bean hawkmoths is expected to increase the yield of bean hawkmoth larvae and increase farmers' income. However, there is currently a lack of methods for screening soybean varieties suitable for bean hawkmoth breeding.

[0004] The differences in plant resistance to leaf-feeding insects (insect sensitivity and insect resistance are two aspects of the same thing) are mainly manifested in three aspects: resistance to biotics, resistance to selection, and tolerance to harm. The evaluation methods for plant resistance to biotics are also mainly based on the above three aspects. Resistance to biotics mainly refers to the damage caused by plants to feeding insects by their own physical and chemical properties to reduce the harm suffered by themselves. At present, the evaluation methods for biotics mostly use indoor biological testing. Plant samples are taken indoors to compare the growth and development process and reproductive capacity of insects after feeding on different plant materials. The main indicators used include insect mortality, reproductive period, body weight, egg production, etc.

[0005] Resistance to selection refers to the way plants reduce their own damage by avoiding insect feeding and egg-laying. In the prior art, the evaluation methods for resistance to selection mainly include two types: indoor and outdoor. The outdoor resistance to selection evaluation includes the field natural insect source method and the artificial insect inoculation method in the mesh room. The field natural insect source method uses natural pests as the insect source to investigate the degree of damage to different plants under natural damage conditions. The main indicators investigated include insect population density, number of insect bags, leaf area loss rate, etc. Artificial insect inoculation in the mesh room can study the degree of damage of a certain type of insect to different materials. It is to plant multiple varieties in the same mesh room and let insects feed freely. It is suitable for large-scale evaluation of crop varieties' resistance to a single pest. Indoor identification is suitable for comparing the resistance to selection of a small number of materials. It is to use culture dishes indoors to evaluate the resistance to selection of leaves of different soybean varieties.

[0006] Harm tolerance emphasizes that plants can reduce losses through their own recovery ability after being damaged by insect feeding. The indicators used to evaluate the harm tolerance of different types of plants are also different, mainly including plant growth status and yield-related traits. In the evaluation of the harm tolerance of gramineous crops, researchers have used indicators such as rice yield, number of tillers, number of dead cores, grain weight per ear, and thousand-grain weight.

[0007] At present, the high-throughput insect resistance evaluation method is mainly based on the evaluation of resistance to organisms and selection. There is a high-throughput selection resistance identification method, which uses a 32-hole seedling tray as a test tool to identify the resistance to selection of soybean materials in the seedling stage in a closed net room, and uses the leaf area loss rate as an insect resistance index. The germplasm resources are evaluated 3 days after the insect damage. Its selection resistance evaluation is fast and requires less labor, but the evaluation based solely on the leaf area loss rate is subject to greater subjective influence. The larval biological indicators used in the identification of resistance are more objective and stable, and resistance is the main insect resistance mechanism of crops. However, the life cycle of the bean moth is long, the entire larval period is about 32 days, and the feeding amount is large, so it is not suitable for indoor resistance evaluation.

[0008] Different soybean varieties have different adaptability to the larvae of bean hawkmoth. Adaptability is the opposite of insect resistance. Adaptability and insect resistance are two sides of the same coin in the interaction between insects and plants. How to screen out soybean varieties suitable for bean hawkmoth breeding and improve breeding efficiency are issues that must be addressed in soybean breeding. The screening of varieties suitable for bean hawkmoth breeding is affected by a variety of breeding factors, and there is currently no efficient, convenient and accurate evaluation method. Breeding bean hawkmoths in different environments and sowing seasons will affect their growth and development, and different environments will also affect the agronomic traits of soybeans. Therefore, it is necessary to select different bean hawkmoth adaptability identification methods according to the breeding environment and production methods of the bean moth. Summary of the invention

[0009] In order to adapt to different breeding environments and screen out special soybean varieties suitable for breeding of bean moth in different environments, the purpose of the present invention is to provide a method for selecting soybean varieties suitable for breeding of bean moth, which uses living soybean leaves to isolate and feed bean moth larvae, and evaluates the adaptability of soybean varieties to bean moth larvae based on larval weight, larval survival rate, larval weight in plots and larvae ratio in each weight range.

[0010] The present invention adopts the following technical scheme: a method for selecting soybean varieties suitable for bean hornworm breeding, which comprises the following steps: firstly preparing bean hornworm eggs and soybean varieties to be screened, and then planting soybeans and feeding bean hornworm larvae and analyzing the results, specifically comprising:

[0011] Step S1: bagging and isolation feeding: (1) Sowing the soybean varieties to be screened in holes in a net room or in a field away from the pesticide application area. When the number of identified soybean varieties is more than 50, each net room is used as a block group; when the number of identified soybean varieties is less than 20, all soybean varieties are used as a block group, and multiple blocks are arranged in one net room; when the number of identified soybean varieties is between 20 and 50, any of the above two methods is adopted; (2) When sowing in spring or autumn, wait until the soybeans grow to the V4 stage; when sowing in summer, wait until more than 50% of the soybean varieties grow to the V6-R1 stage, bagging and hanging eggs are carried out, and the eggs are placed in the bagging and hanging ... The method comprises the following steps: preparing a mesh bag with one end open and the other end closed, placing eggs of the bean moth that are about to hatch in the mesh bag, and then placing a mesh bag with eggs in it on each soybean plant hole. After the mesh bag is placed on two inverted trefoil leaves, the open end of the mesh bag is tied tightly; at the same time, the agronomic traits of the inverted trefoil leaves, such as leaf length, leaf width, leaf area, total number of compound leaves, lodging and growth period of the soybean plants are recorded; (3) after the eggs hatch, until the 9th day after the larvae feed on the leaves, the number of surviving larvae is recorded and weighed for the first time. During the first weighing, larvae with the same growth and development and similar size are selected from each mesh bag, and the number of larvae selected from each mesh bag is The number of larvae selected is equal, and the number of larvae selected is between 3 and 8. The remaining larvae are taken away and the total weight of the selected larvae is recorded. When the number of larvae selected is less than 5, the number of larvae and the total weight of the larvae are recorded; (4) After the first weighing, replace the large mesh bag, put the selected fixed number of larvae into the large mesh bag, put the large mesh bag on the unfed inverted trefoil of the plant, and tie the opening of the mesh bag tightly; (5) Weigh the leaves on the 12th, 15th, 18th and 21st days after the larvae feed on the leaves, and record the total weight of the larvae in each mesh bag and the number of surviving larvae; after each weighing, the number of surviving larvae is counted. The larvae are placed in a net bag and put back on each hole of the plant that was originally inoculated. When the net bag is put back on, the net bag should be put on the inverted trefoil that has not been bitten; (6) After each weighing, the average weight of the larvae in each net bag is calculated, and the larval survival rate is calculated. The average weight of the larvae is the weight of a single larva, and the total weight of the larvae is the weight of the larvae in the small area. The weight of the larvae in the small area at the first weighing is the total weight of the same number of larvae selected. The survival rate is calculated each time based on the number of larvae retained in the net bag at the first weighing; (7) Repeat the process of bagging and isolating and feeding in different seasons, that is, repeat the above steps (1) to (6);

[0012] Step S2: Preliminary screening of insect-susceptible soybean materials is performed according to any of the following methods: (1) Using the ranking of the weight of a single larvae fed on a certain day from heavy to light as an indicator, select the soybean varieties that rank in the top 20% in terms of the weight of a single larvae in bagged isolation feeding as the insect-susceptible materials. If the insect-susceptible material reaches the top 20% in terms of the weight of a single larvae in bagged isolation feeding for more than two times, the insect-susceptible material is a relatively stable insect-susceptible variety, i.e., the insect-susceptible variety that is preliminarily screened; (2) Using the weight of a single larvae fed on a certain day as an indicator, select the soybean varieties that reach a specified weight in terms of the weight of a single larvae in bagged isolation feeding for more than two times, the insect-susceptible material is a relatively stable insect-susceptible variety, i.e., the insect-susceptible variety that is preliminarily screened;

[0013] Step S3: Free choice of feeding in the net room: (1) Sowing the soybean varieties to be screened in holes or rows in the net room, with each net room as a block group; (2) When the soybeans grow to the V4 stage in spring and autumn sowing, and when the soybeans grow to the V6 stage in summer sowing, hanging eggs, specifically: prepare a net bag with an open end, put the bean moth eggs that are about to hatch in the net bag, and then put a net bag with eggs in each hole or each row of soybean plants, after the net bag is put on the inverted third leaf of the plant, tie the opening of the net bag tightly; (3) After the larvae hatch, release the larvae from the net bag on the 5th to 9th day of feeding, and the larvae feed freely in the net room; (4) When the overall leaf loss rate in the net room is observed to reach more than 5%, record the leaf loss rate of each soybean variety in the net room;

[0014] Step S4: Investigation of soybean biomass and agronomic traits: (1) Sowing the soybean varieties to be screened in rows in the field or in a net room, with the varieties arranged randomly, with one row for each variety, and three replicates; (2) In each sowing season, at the V6 and R6 stages of soybean growth, picking the middle leaflets or the entire inverted trefoil of the soybean plant, and taking three leaves from each variety as replicates. After the leaves are picked, they are put into sampling bags and temporarily stored in an ice box for preservation, and then brought back to the room for scanning. The scanned leaves are put into labeled paper bags according to different varieties and dried at 80°C for three days, and then weighed; at the same time, the agronomic traits of each variety are investigated, specifically measuring plant height, number of main stem nodes, number of branches, number of branch nodes, total number of compound leaves, internode length and single plant leaf biomass;

[0015] Step S5: further comprehensive screening of insect-susceptible soybean varieties: the insect-susceptible varieties obtained by preliminary screening are analyzed in terms of single larval weight, plot larval weight, leaf area loss rate and single plant leaf biomass. The single larval weight and plot larval weight are the average values ​​of the 15th or 18th day of feeding of each batch of bagged isolation feeding in step S1, the leaf loss rate is the result of the 14th day of larval feeding in step S3, and the single plant leaf biomass is the result in step S4. The comprehensive performance of different varieties in the above indicators is ranked, and the varieties ranked in the top five in more than two indicators are determined as the insect-susceptible varieties for further comprehensive screening;

[0016] Step S6: Selection of excellent soybean varieties for cultivation in isolated feeding in net rooms: (1) Sowing the insect-susceptible varieties that have been further comprehensively screened in net rooms, each of which is 2m×2m in size, sowing one soybean variety in each net room, and each net room as a plot; (2) When the soybeans grow to the V4 stage in spring and autumn sowing, and when the soybeans grow to the V6 stage in summer sowing, hanging eggs are carried out, specifically: prepare a net bag with one end open, put the milky white soybean hawk moth eggs that are about to hatch in the net bag, put the net bag on the inverted third leaf of the plant, and then tie the opening of the net bag tightly, put four net bags in each net room, put 20 eggs in each bag, that is, hang 20 eggs per square meter; (3) After the eggs are hatched, on the 5th to 6th day after the larvae feed, hang eggs in the net bag. After 9 days (the 5th day in August and the 9th day in September, i.e., the number of days may vary depending on the temperature and the growth of the larvae), the larvae are released from the net bag and allowed to feed freely in the net room; (4) On the 24th to 26th day of feeding, all the larvae in each net room are caught, counted and weighed one by one. At the same time, the weight of the bean moth is divided into different weight intervals according to the weight of a single larva, and the larvae are classified and counted, and the proportion of larvae in each weight interval is calculated; (5) The survival rate of larvae in each net room, the total weight of larvae in a single net room, the proportion of larvae greater than or equal to 6g and the average weight of a single larvae are compared. When these four indicators of a certain variety rank in the top five, the variety is finally determined to be a soybean variety suitable for bean cultivation.

[0017] In step S1, the soybean leaves placed in the net bag when hanging eggs are the inverted three leaves of the soybean plant, that is, the third fully expanded compound leaf from the top of the plant from top to bottom. When replacing the leaves in the net bag, the inverted three leaves of other plants in the same hole are selected.

[0018] In step S2, the weight of a single larvae that has fed for 15 or 18 days or its ranking is used as an indicator to preliminarily screen the susceptible soybean materials in a summer net room with an average temperature of 29.7 degrees; the weight of a single larvae that has fed for 18 days or its ranking is used as an indicator to preliminarily screen the susceptible soybean materials in a summer open air with an average temperature of 28.8 degrees and in an autumn net room with an average temperature of 27.0 degrees; in the second method in step S2, the specified weight of a single larvae that is 18 days old is 1.70 grams, 2.70 grams and greater than 0.55 grams when sowing in spring, summer and autumn, respectively.

[0019] The mesh bags used in step (2) of step S1, step S3 and step S6 are all small mesh bags with a length of 20 cm and a width of 15 cm. The large mesh bag used in step S1 is 40 cm long and 30 cm wide. Both the small mesh bag and the large mesh bag are transparent gauze mesh bags. A drawstring is provided at one end of the opening of the mesh bag, and an inner pocket is provided on the inner side of the mesh bag.

[0020] In step S1, step S3 and step S4, the size of the net house used is 4-50m in length and 4-8m in width. The net house is spliced ​​by a steel frame structure and covered with a 40-60 mesh insect-proof net. The insect-proof net around the net house is buried 25-35 cm under the soil; the size of the net house used in step S6 is 2m×2m; in steps S1 and S3, a group of soybean varieties are sown in one net house, which is repeated 3 times, and in S6, one soybean variety is sown in one net house, which is repeated 3 times.

[0021] In step S1, the bagging isolation feeding process is carried out once in spring, summer and autumn respectively, 5 seedlings are planted in each hole, 12 eggs are placed in each mesh bag, and 5 larvae are retained by the first weighing; in spring and summer, the plants are tall, and the row spacing × hole spacing of hole sowing is 0.6m×0.6m, while in autumn, the plants are shorter, and the row spacing × hole spacing of hole sowing is 0.6m×0.5m or less.

[0022] In step S1, the number of eggs in each mesh bag is adjusted between 10 and 30 according to the difference in identification season and egg hatching rate, but the number of eggs in each mesh bag is the same in the same batch of tests, and the eggs used are eggs laid on the same day and about to hatch, while the unhealthy and undeveloped eggs such as shrunken eggs and eggs that are not white are removed; according to the identification season, the age of the larvae and the growth and development of the larvae, the leaf biomass required is estimated, and the inverted three leaves of other plants in the same hole are added to the mesh bag every 1 to 3 days; when the bean moth is 3 years old, that is, 9-15 days old, it is replaced with a large mesh bag, and the summer When sowing, the net bags are replaced when the bean moth is 9-12 days old. When sowing in spring and autumn, the net bags are replaced when the bean moth is 12-15 days old. When the larvae develop to the third instar, i.e. 9-15 days old, the extreme individuals in the net bags are eliminated, and the number of larvae retained is adjusted between 3 and 8 according to the identification season and leaf biomass. According to the identification season and the growth and development of the larvae, when the larvae develop to the third instar, the larvae in the net bags are weighed and counted. The adaptability indicators include the weight of a single larva, the weight of larvae in a small area and the survival rate of larvae, among which the average weight of a single larvae at 12-18 days old is the best indicator.

[0023] In step S3, the row spacing × hole spacing is 0.3 m × 0.3 m, 5 seedlings are planted in each hole, and the leaf loss rate on the 11th, 12th, 13th and 14th days of larval feeding is investigated respectively; in step (3) of step S3, the number of days the larvae are released from the net bag is 5-9 days, and the position of the larvae is manually adjusted so that the larvae are evenly distributed in the net room.

[0024] In step S4, row sowing is adopted in the field or in a net room, with a row length of 1-4 m, a row spacing of 0.5 m, and a plant spacing of 0.1 m, and thinning is carried out in the V1 stage of soybean growth; in step S6, the row spacing × the hole spacing of hole sowing is 0.4 m × 0.5 m, and 3 seedlings are fixed in each hole.

[0025] In step S1, summer sowing, V6 stage, and bagging and isolation feeding are carried out on inverted clover, and the average single larvae weight from 15 days to 21 days old is used as the evaluation index. This can most accurately and efficiently evaluate the adaptability of soybean varieties to the bean moth, and can be used for the initial screening of hundreds of varieties of adaptable varieties; in step S6, the larval survival rate, the larval weight of the plot, and the proportion of larvae in each weight range are important evaluation indicators, which are suitable for the selection of less than 20 varieties of adaptable varieties.

[0026] The beneficial effects of the present invention are as follows: the present invention provides a method for selecting soybean varieties specifically for breeding bean hawkmoths, and the insect-susceptible germplasm is initially screened by using the weight of a single larva on the 12th to 21st day (the 15th day is the best) of the larvae feeding on the living plants as the main index through bag isolation feeding experiments. The insect-susceptible germplasm initially screened is further screened for soybean varieties suitable for breeding bean hawkmoths in combination with the larval weight of the plot, the leaf area loss rate, and the leaf biomass of a single plant (which can be estimated by multiplying the number of compound leaves of a single plant and the area of ​​the inverted trefoil leaf). Then, the further screened soybean varieties are subjected to a net room isolation breeding test, and the actual yield of larvae, the larval survival rate, and the distribution of larvae in each weight range under the conditions of net room breeding of different varieties are compared, and finally the soybean varieties suitable for breeding bean hawkmoths are screened.

[0027] The present invention combines the evaluation of soybean susceptibility to hawkmoth with the investigation of agronomic traits of soybean varieties, establishes a relatively complete soybean variety selection method for hawkmoth breeding, and selects excellent susceptibility germplasm resources. The bag isolation feeding test can distinguish the susceptibility differences between varieties at an early stage, and the larval weight index can directly reflect the larval yield, and the feeding selection test is subject to a relatively large subjective influence when manually judging the leaf area loss value. Therefore, the bag isolation feeding test is selected as the main method for evaluating soybean susceptibility to hawkmoth; the weight of single larvae and the weight of larvae in the plot at the 9th, 12th, 15th, 18th, and 21st day of larval feeding can reflect the differences between varieties, and the difference on the 15th day is the largest. The bag isolation feeding test is suitable for the early and middle stages of larval growth because the space in the bag is relatively small. The bag isolation feeding experiment needs to ensure sufficient hole spacing. The net room isolation breeding test found that the larval yield, larval survival rate, and interval distribution of larval weight of varieties with equivalent bag isolation susceptibility under actual breeding conditions still have significant differences, and the varieties can be further screened. Then, based on the average weight of a single larva on the 15th day in multiple bag-isolated feeding experiments, combined with a comprehensive evaluation of the average larval weight in the plot, leaf area loss rate and single plant leaf biomass, soybean materials suitable for bean hawkmoth breeding were further screened from the initially screened soybean insect-susceptible materials, and finally soybean materials suitable for bean hawkmoth breeding were obtained through a net house isolation breeding experiment.

[0028] The screening method of the present invention is carried out in a net house or in the field, which is suitable for the characteristics of long growth period and large feeding amount of bean hawkmoth larvae, and the leaves fed always grow on living plants. The screening method is more objective and scientific, and through multiple manual identifications and multiple parameter evaluations, it tries to overcome the shortcomings of relying solely on leaf loss rate evaluation that is greatly influenced by subjectivity and the traditional antibiotic identification that involves collecting leaves back to the laboratory for artificial breeding, which causes the leaves to be affected by physiological and biochemical changes due to leaving the plants.

[0029] According to the agronomic traits of soybeans and the weight of 15-day-old larvae, soybean varieties for bean moth breeding are screened, and corresponding soybean varieties should be screened for different regions, seasons and different breeding environments. By comparing the results of each breeding factor combination, it is believed that bagging and isolation feeding are carried out on summer sowing, V6 stage, and inverted three leaves, and the average single larval weight is used as an indicator for evaluation, which can most accurately and efficiently evaluate the adaptability of soybean varieties to bean moth. According to the identification site and isolation feeding method, it is subdivided into net room bag isolation feeding method (step S1), field bag isolation feeding method (step S1) and net room isolation feeding method (step S6). The first two are isolated and fed to bean moth by net bags, while the latter is directly isolated and fed to bean moth by net room. In the net room isolation feeding method, the proportion of high-quality larvae (single head larvae weight greater than 6 grams) is counted as an indicator, so as to screen excellent varieties in terms of yield and quality. The net room isolation feeding method can be used to perform a more detailed adaptation evaluation on a small amount of soybean materials screened out by the first two bag isolation feeding methods. The two types of identification methods complement and verify each other, thereby screening soybean materials suitable for bean hawkmoth breeding on a large scale, efficiently and accurately.

[0030] The present invention selects the most appropriate screening method for different test environments and experimental purposes. The net room bag isolation feeding method uses a net room greenhouse as the planting place for soybean materials, and adopts bag isolation feeding; the field bag isolation feeding method uses fields that are not polluted by pesticides and suitable seasons to plant soybeans, and adopts bag isolation feeding. In the net room bag isolation feeding method and the field bag isolation feeding method, when the larvae grow to the third instar, the larvae in the net bag are weighed and the number of larvae is recorded; in the net room (small area) isolation feeding method, when the larvae grow to the end of the fifth instar, the larvae in the net room are weighed separately and the number of larvae is recorded, and the results are close to the actual breeding mode; different methods select the appropriate soybean growth stage and larval growth days, which can better evaluate the adaptability of soybeans to the larvae of the bean moth. In general, it has the following advantages:

[0031] (1) Applicable to different environmental conditions: The net-bagging isolation feeding method provides a growth environment for the larvae of the bean moth that is close to the actual net-bagging environment for soybean cultivation. At the same time, the net bags limit the feeding range of the larvae of the bean moth, so that they can only feed on the leaves of one soybean variety during their growth and development, which is convenient for comparison between different soybean varieties. This method can be used to simply and quickly allow the larvae to feed on a single variety and ensure the survival rate of the larvae; the field bag isolation feeding method provides a growth environment for the bean moth that is an open-air environment without a net room, which is similar to the open-air environment for soybean cultivation in production. At the same time, the net bags limit the feeding range of the bean moth, so that they can only feed on the leaves of one soybean variety during their growth and development, which is convenient for comparison between different soybean varieties. This method can force the larvae to feed and ensure the survival rate of the larvae; the net-bagging isolation feeding method provides a growth environment for the larvae of the bean moth that is the actual net-bagging cultivation environment. The larvae of the bean moth can move freely in the small net room to feed, which is consistent with the actual cultivation model, but the same variety is in the same net room, so they can move relatively freely, but the food is limited to the same variety.

[0032] (2) Each identification process is low-cost and highly practical: the net room bag isolation feeding method has the advantages of moderate cost, high practicality and high throughput; the field bag isolation feeding method has the advantages of low cost, high practicality and high throughput; the net room isolation feeding method is most similar to the real scene of artificial breeding, with strong practicality and high identification accuracy. The three in vivo identification methods for soybean adaptability to hawkmoth at the seedling and adult stages can all achieve the simple and efficient screening of soybean materials with good adaptability to hawkmoth in about 2 months; at the same time, the experimental equipment required for the entire identification process is simple, easy to obtain and can be recycled;

[0033] (3) Each identification process can complement and verify each other: the net room bag isolation feeding method can preliminarily screen soybean materials suitable for breeding bean moth in the net room; the field bag isolation feeding method can preliminarily screen soybean materials suitable for breeding bean moth in the field; the net room isolation feeding method can conduct a more detailed suitability evaluation on the small amount of soybean materials initially screened. The three soybean seedling and adult plant stage identification methods can screen soybean materials with good suitability for bean moth, providing germplasm resources for bean moth breeding.

[0034] (4) Each identification process is a live biocompatibility identification, and can be used for evaluation at the seedling and adult stages: The three in vivo identification methods for soybean seedling and adult stages to the hornworm all use live soybean plants for identification, and the feeding method of the hornworm is very close to the actual breeding. However, the traditional in vitro leaf biocompatibility (antibiotic) identification method is difficult to truly reflect the interaction between soybean plants and hornworm larvae in the field or in the net house because the leaves are separated from the plants, and their biochemical reactions will change, and the water is easy to evaporate.

[0035] (5) Each identification process has different efficiencies and can be used in different situations: The three soybean seedling and adult plant stages have significant differences in cultivation costs, seed costs, egg costs, number of surveys, survey time, land area and facility costs for the three methods of in vivo identification of soybean suitability for hawkmoths, so as to adapt to different test purposes and requirements. The net room bag isolation feeding method and the field bag isolation feeding method are both less than the net room isolation feeding method in terms of cultivation management, seed quantity, seed cost, egg quantity, egg cost, survey time, number of people surveyed per time, land area and facility costs; while the number of surveys is higher than the net room (plot) isolation feeding method. These differences in items lead to the three identification methods being able to adapt to different purposes, thereby screening out soybean materials suitable for different hawkmoth breeding conditions.

[0036] (6) Based on the results of multiple identification processes and multiple identification tests, it was concluded that the weight of a single larvae aged 12-21 days can be used as the best indicator for evaluating the suitability of the bag isolation feeding method, assisted by other indicators such as the weight of larvae in a small area and the survival rate of larvae. The larval survival rate, the weight of larvae in a small area and the proportion of larvae in each weight range can be used as the best indicators for evaluating the suitability of the net room isolation feeding method, assisted by other indicators such as the weight of a single larvae.

[0037] (7) On the 9th day after egg hatching, remove the extreme larvae from the mesh bag, leaving 5 larvae, and replace them with a large 40*30 cm mesh bag. Fresh living leaves on the plants are replaced every two days to ensure that each larva has enough growth space to reduce errors.

[0038] (8) Screen out soybean varieties suitable for breeding bean hawkmoth larvae in spring, summer and autumn respectively, and soybean varieties that are commonly used for breeding bean hawkmoth larvae in spring and summer. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a table of the names of the 54 soybean varieties used in the experiment and their corresponding material numbers;

[0040] Figure 2 These are the results of three experiments of bagging and isolated feeding;

[0041] Figure 3 This is a table of correlations between growth indicators of bean moth larvae in the 2020 bagging isolation feeding experiment;

[0042] Figure 4 This is a cluster analysis of the weight of single larvae of 54 soybean varieties;

[0043] Figure 5 It is a single head larvae weight difference map between the resistant and susceptible insect categories;

[0044] Figure 6 This is a selection list of varieties susceptible to hornworm larvae based on three bagging isolation feeding tests;

[0045] Figure 7 This is a statistical table of leaf area loss rates in the 2020 bean hawkmoth larvae feeding choice experiment;

[0046] Figure 8 It is the descriptive statistics and variance analysis table of agronomic traits related to rearing bean hawkmoth larvae in soybean resources;

[0047] Fig. 9 This is a table of correlations between 54 single larval weights and agronomic traits of soybean varieties in the 2020 bag isolation feeding trial;

[0048] Fig.10 This is a cluster analysis diagram of leaf biomass-related traits of 54 soybean varieties;

[0049] Fig.11 This is the t-test result diagram between cluster categories of agronomic traits of 54 soybean varieties;

[0050] Fig.12 This is the clustering result table of insect susceptibility and agronomic traits of 54 soybean varieties;

[0051] Fig.13 This is a table of various indicators of 11 insect-susceptible species obtained through preliminary screening;

[0052] Fig.14 This is a pie chart showing the weight distribution of single larvae of different varieties of cultivated bean moths;

[0053] Fig.15 It is a descriptive statistical table of the growth indicators of larvae fed with different soybean varieties;

[0054] Fig.16 This is a table of the yields of different soybean varieties fed to hornworms;

[0055] Fig.17 This is the descriptive statistics and variance analysis table of larval growth indicators of three isolation feeding suitability evaluation methods;

[0056] Fig.18 This is a comparison table of the identification efficiency of three isolation feeding suitability evaluation methods;

[0057] Fig.19 This is a graph showing the effects of different leaf positions and variety treatments on larval weights at different soybean growth stages and sowing seasons;

[0058] Fig. 20 The following are the trends of larval survival rates at different leaf positions and the interaction between leaf position and sowing season on larval survival rate;

[0059] Fig.21 It is the frequency distribution diagram of soybean resource leaf area;

[0060] Fig. 22 This is the variance analysis table of the average single larval weight and leaf area of ​​soybean resources;

[0061] Fig.23 This is a descriptive statistics table of the average single larval weight and leaf area of ​​soybean resources;

[0062] Fig.24 It is the frequency distribution diagram of the average single-head insect weight of soybean resources;

[0063] Fig.25 is a scatter plot of the average single larval weight and leaf area of ​​soybean resources;

[0064] Fig.26 It is the temperature and humidity changes in the net house in 2022 and 2023;

[0065] Fig. 27 It is the descriptive statistics and variance analysis table of larval growth indicators in different sowing seasons;

[0066] Fig.28 It is the descriptive statistics and variance analysis table of agronomic traits of plants in different sowing seasons;

[0067] Fig.29 It is a two-factor joint variance analysis table of larval growth index and soybean agronomic traits;

[0068] Fig.30 This is the difference diagram between the growth indicators of hawkmoth in different sowing seasons;

[0069] Fig.31 This is a diagram showing the differences in larval growth indicators and soybean agronomic traits between different sowing seasons;

[0070] Fig.32 It is a selection table of soybean varieties suitable for breeding of hawkmoth larvae in different sowing seasons;

[0071] Fig.33 It is a schematic diagram of the mesh bag used in the present invention. DETAILED DESCRIPTION

[0072] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0073] A method for screening soybean varieties suitable for bean hawkmoth breeding according to an embodiment of the present invention comprises the following steps: firstly preparing bean hawkmoth eggs and soybean varieties to be screened, then planting soybeans and feeding bean hawkmoth larvae and analyzing the results, specifically comprising the following steps:

[0074] The present invention

[0075] The method for selecting soybean varieties suitable for bean hornworm breeding comprises the following steps: firstly preparing bean hornworm eggs and soybean varieties to be screened, then planting soybeans and feeding bean hornworm larvae and analyzing the results, specifically comprising:

[0076] Step S1: bagging and isolation feeding: (1) Sowing the soybean varieties to be screened in holes in a net room or in a field away from the pesticide application area. When the number of identified soybean varieties is more than 50, each net room is used as a block group; when the number of identified soybean varieties is less than 20, all soybean varieties are used as a block group, and multiple blocks are arranged in one net room; when the number of identified soybean varieties is between 20 and 50, any of the above two methods is adopted; (2) When sowing in spring or autumn, wait until the soybeans grow to the V4 stage; when sowing in summer, wait until more than 50% of the soybean varieties grow to the V6-R1 stage, bagging and hanging eggs are carried out, and the eggs are placed in the bagging and hanging ... The method comprises the following steps: preparing a mesh bag with one end open and the other end closed, placing eggs of the bean moth that are about to hatch in the mesh bag, and then placing a mesh bag with eggs in it on each soybean plant hole. After the mesh bag is placed on two inverted trefoil leaves, the open end of the mesh bag is tied tightly; at the same time, the agronomic traits of the inverted trefoil leaves, such as leaf length, leaf width, leaf area, total number of compound leaves, lodging and growth period of the soybean plants are recorded; (3) after the eggs hatch, until the 9th day after the larvae feed on the leaves, the number of surviving larvae is recorded and weighed for the first time. During the first weighing, larvae with the same growth and development and similar size are selected from each mesh bag, and the number of larvae selected from each mesh bag is The number of larvae selected is equal, and the number of larvae selected is between 3 and 8. The remaining larvae are taken away and the total weight of the selected larvae is recorded. When the number of larvae selected is less than 5, the number of larvae and the total weight of the larvae are recorded; (4) After the first weighing, replace the large mesh bag, put the selected fixed number of larvae into the large mesh bag, put the large mesh bag on the unfed inverted trefoil of the plant, and tie the opening of the mesh bag tightly; (5) Weigh the leaves on the 12th, 15th, 18th and 21st days after the larvae feed on the leaves, and record the total weight of the larvae in each mesh bag and the number of surviving larvae; after each weighing, the number of surviving larvae is counted. The larvae are placed in a net bag and put back on each hole of the plant that was originally inoculated. When the net bag is put back on, the net bag should be put on the inverted trefoil that has not been bitten; (6) After each weighing, the average weight of the larvae in each net bag is calculated, and the larval survival rate is calculated. The average weight of the larvae is the weight of a single larva, and the total weight of the larvae is the weight of the larvae in the small area. The weight of the larvae in the small area at the first weighing is the total weight of the same number of larvae selected. The survival rate is calculated each time based on the number of larvae retained in the net bag at the first weighing; (7) Repeat the process of bagging and isolating and feeding in different seasons, that is, repeat the above steps (1) to (6);

[0077] In step S1, the soybean leaves placed in the net bag when hanging eggs are the inverted three leaves of the soybean plant, that is, the third fully expanded compound leaf from the top of the plant from top to bottom. When replacing the leaves in the net bag, the inverted three leaves of other plants in the same hole are selected.

[0078] In step S1, the bagging isolation feeding process is carried out once in spring, summer and autumn respectively, 5 seedlings are planted in each hole, 12 eggs are placed in each mesh bag, and 5 larvae are retained by the first weighing; in spring and summer, the plants are tall, and the row spacing × hole spacing of hole sowing is 0.6m×0.6m, while in autumn, the plants are shorter, and the row spacing × hole spacing of hole sowing is 0.6m×0.5m or less.

[0079] In step S1, the number of eggs in each mesh bag is adjusted between 10 and 30 according to the difference in identification season and egg hatching rate, but the number of eggs in each mesh bag is the same in the same batch of tests, and the eggs used are eggs laid on the same day and about to hatch, while the unhealthy and undeveloped eggs such as shrunken eggs and eggs that are not white are removed; according to the identification season, the age of the larvae and the growth and development of the larvae, the leaf biomass required is estimated, and the inverted three leaves of other plants in the same hole are added to the mesh bag every 1 to 3 days; when the bean moth is 3 years old, that is, 9-15 days old, it is replaced with a large mesh bag, and the summer When sowing, the net bags are replaced when the bean moth is 9-12 days old. When sowing in spring and autumn, the net bags are replaced when the bean moth is 12-15 days old. When the larvae develop to the third instar, i.e. 9-15 days old, the extreme individuals in the net bags are eliminated, and the number of larvae retained is adjusted between 3 and 8 according to the identification season and leaf biomass. According to the identification season and the growth and development of the larvae, when the larvae develop to the third instar, the larvae in the net bags are weighed and counted. The adaptability indicators include the weight of a single larva, the weight of larvae in a small area and the survival rate of larvae, among which the average weight of a single larvae at 12-18 days old is the best indicator.

[0080] In step S1, summer sowing, V6 stage, and bagging and isolation feeding are carried out on inverted clover, and the average single larvae weight from 15 days to 21 days old is used as the evaluation index. This can most accurately and efficiently evaluate the adaptability of soybean varieties to the bean moth, and can be used for the initial screening of hundreds of varieties of adaptable varieties; in step S6, the larval survival rate, the larval weight of the plot, and the proportion of larvae in each weight range are important evaluation indicators, which are suitable for the selection of less than 20 varieties of adaptable varieties.

[0081] Step S2: Preliminary screening of insect-susceptible soybean materials is performed according to any of the following methods: (1) Using the ranking of the weight of a single larvae fed on a certain day from heavy to light as an indicator, select the soybean varieties that rank in the top 20% in terms of the weight of a single larvae in bagged isolation feeding as the insect-susceptible materials. If the insect-susceptible material reaches the top 20% in terms of the weight of a single larvae in bagged isolation feeding for more than two times, the insect-susceptible material is a relatively stable insect-susceptible variety, i.e., the insect-susceptible variety that is preliminarily screened; (2) Using the weight of a single larvae fed on a certain day as an indicator, select the soybean varieties that reach a specified weight in terms of the weight of a single larvae in bagged isolation feeding for more than two times, the insect-susceptible material is a relatively stable insect-susceptible variety, i.e., the insect-susceptible variety that is preliminarily screened;

[0082] In step S2, the weight of a single larvae that has fed for 15 or 18 days or its ranking is used as an indicator to preliminarily screen the susceptible soybean materials in a summer net room with an average temperature of 29.7 degrees; the weight of a single larvae that has fed for 18 days or its ranking is used as an indicator to preliminarily screen the susceptible soybean materials in a summer open air with an average temperature of 28.8 degrees and in an autumn net room with an average temperature of 27.0 degrees; in the second method in step S2, the specified weight of a single larvae that is 18 days old is 1.70 grams, 2.70 grams and greater than 0.55 grams when sowing in spring, summer and autumn, respectively.

[0083] Step S3: Free choice of feeding in the net room: (1) Sowing the soybean varieties to be screened in holes or rows in the net room, with each net room as a block group; (2) When the soybeans grow to the V4 stage in spring and autumn sowing, and when the soybeans grow to the V6 stage in summer sowing, hanging eggs, specifically: prepare a net bag with an open end, put the bean moth eggs that are about to hatch in the net bag, and then put a net bag with eggs in each hole or each row of soybean plants, after the net bag is put on the inverted third leaf of the plant, tie the opening of the net bag tightly; (3) After the larvae hatch, release the larvae from the net bag on the 5th to 9th day of feeding, and the larvae feed freely in the net room; (4) When the overall leaf loss rate in the net room is observed to reach more than 5%, record the leaf loss rate of each soybean variety in the net room;

[0084] In step S3, the row spacing × hole spacing is 0.3 m × 0.3 m, 5 seedlings are planted in each hole, and the leaf loss rate on the 11th, 12th, 13th and 14th days of larval feeding is investigated respectively; in step (3) of step S3, the number of days the larvae are released from the net bag is 5-9 days, and the position of the larvae is manually adjusted so that the larvae are evenly distributed in the net room.

[0085] Step S4: Investigation of soybean biomass and agronomic traits: (1) Sowing the soybean varieties to be screened in rows in the field or in a net room, with the varieties arranged randomly, with one row for each variety, and three replicates; (2) In each sowing season, at the V6 and R6 stages of soybean growth, picking the middle leaflets or the entire inverted trefoil of the soybean plant, and taking three leaves from each variety as replicates. After the leaves are picked, they are put into sampling bags and temporarily stored in an ice box for preservation, and then brought back to the room for scanning. The scanned leaves are put into labeled paper bags according to different varieties and dried at 80°C for three days, and then weighed; at the same time, the agronomic traits of each variety are investigated, specifically measuring plant height, number of main stem nodes, number of branches, number of branch nodes, total number of compound leaves, internode length and single plant leaf biomass;

[0086] In step S4, row sowing is adopted in the field or in a net room, with a row length of 1-4 m, a row spacing of 0.5 m, and a plant spacing of 0.1 m, and thinning is carried out in the V1 stage of soybean growth; in step S6, the row spacing × the hole spacing of hole sowing is 0.4 m × 0.5 m, and 3 seedlings are fixed in each hole.

[0087] Step S5: further comprehensive screening of insect-susceptible soybean varieties: the insect-susceptible varieties obtained by preliminary screening are analyzed in terms of single larval weight, plot larval weight, leaf area loss rate and single plant leaf biomass. The single larval weight and plot larval weight are the average values ​​of the 15th or 18th day of feeding of each batch of bagged isolation feeding in step S1, the leaf loss rate is the result of the 14th day of larval feeding in step S3, and the single plant leaf biomass is the result in step S4. The comprehensive performance of different varieties in the above indicators is ranked, and the varieties ranked in the top five in more than two indicators are determined as the insect-susceptible varieties for further comprehensive screening;

[0088] Step S6: Selection of excellent soybean varieties for cultivation in isolated feeding in net rooms: (1) Sowing the insect-susceptible varieties that have been further comprehensively screened in net rooms, each of which is 2m×2m in size, sowing one soybean variety in each net room, and each net room as a plot; (2) When the soybeans grow to the V4 stage in spring and autumn sowing, and when the soybeans grow to the V6 stage in summer sowing, hanging eggs are carried out, specifically: prepare a net bag with one end open, put the milky white soybean hawk moth eggs that are about to hatch in the net bag, put the net bag on the inverted third leaf of the plant, and then tie the opening of the net bag tightly, put four net bags in each net room, put 20 eggs in each bag, that is, hang 20 eggs per square meter; (3) After the eggs are hatched, on the 5th to 6th day after the larvae feed, hang eggs in the net bag. After 9 days (the 5th day in August and the 9th day in September, i.e., the number of days may vary depending on the temperature and the growth of the larvae), the larvae are released from the net bag and allowed to feed freely in the net room; (4) On the 24th to 26th day of feeding, all the larvae in each net room are caught, counted and weighed one by one. At the same time, the weight of the bean moth is divided into different weight intervals according to the weight of a single larva, and the larvae are classified and counted, and the proportion of larvae in each weight interval is calculated; (5) The survival rate of larvae in each net room, the total weight of larvae in a single net room, the proportion of larvae greater than or equal to 6g and the average weight of a single larvae are compared. When these four indicators of a certain variety rank in the top five, the variety is finally determined to be a soybean variety suitable for bean cultivation.

[0089] The mesh bags used in step (2) of step S1, step S3 and step S6 are all small mesh bags with a length of 20 cm and a width of 15 cm. The large mesh bag used in step S1 is 40 cm long and 30 cm wide. Both the small mesh bag and the large mesh bag are transparent gauze mesh bags. A drawstring is provided at one end of the opening of the mesh bag, and an inner pocket is provided on the inner side of the mesh bag.

[0090] In step S1, step S3 and step S4, the size of the net house used is 4-50m in length and 4-8m in width. The net house is spliced ​​by a steel frame structure and covered with a 40-60 mesh insect-proof net. The insect-proof net around the net house is buried 25-35 cm under the soil; the size of the net house used in step S6 is 2m×2m; in steps S1 and S3, a group of soybean varieties are sown in one net house, which is repeated 3 times, and in S6, one soybean variety is sown in one net house, which is repeated 3 times.

[0091] The present invention is described in detail below in conjunction with specific experimental processes:

[0092] Experimental insects: The eggs of the bean moth used in the experiment came from the professional breeding base of the bean moth in Lianyungang City, Jiangsu Province. The eggs in the same batch were produced on the same day and had been disinfected.

[0093] Experimental site and materials: The field test site was located at the Wanjiang Base of Nanjing Agricultural University in Dangtu County, Ma'anshan City, Anhui Province (E118°37′22″, N 31°33′4″). Conventional field management was carried out on the experimental field, and the use of pesticides containing insecticides and repellents was restricted. The two sizes of net houses used in the experiment were both made of steel pipe frame structures and covered with white gauze. The sizes of the internal plots of the two sizes of net houses were 4m×6m (large net house) and 2m×2m (small net house), respectively. The net bags used in the experiment were rectangular net bags with a single-side opening and a drawstring. The net bags had two sizes, 30cm×40cm (large net bag) and 15cm×20cm (small net bag), and were all made of organza. The materials used in the experiment were 54 representative soybean materials for insect resistance (susceptibility) to chewing leaf-feeding insects. The soybean variety names corresponding to the material numbers are as follows: Figure 1 The mesh bag can also be made of a material similar to organza, and there can be an inner pocket inside the mesh bag, so that the larvae cannot move to other plant species at will after the eggs are hatched. The structure of the mesh bag used in the experiment is as follows Fig.33 shown.

[0094] Analysis of the test process and results of bagging isolation feeding:

[0095] Bagging isolation feeding experiment 1: 2020 summer sowing net indoor bagging isolation feeding experiment: A randomized block design was adopted, and 54 soybean varieties were sown in each net room (4m×6m), with a hole distance of 0.6m*0.6m, and three net rooms were used as three blocks. Sowing was carried out on July 8, 2020, and routine field management was carried out, with 5 seedlings per hole. On August 17, field eggs were hung, and the eggs to be hatched were put into net bags (15cm×20cm), and then two inverted three leaves were put into the net bags, and the bag mouth was tightened. One bag of eggs was put into each hole plant, and 12 eggs were put into each net bag.

[0096] The eggs hatched on August 19, and the first weighing began on the 9th day after the larvae fed on the leaves. During the first weighing, 5 larvae of similar size and growth were retained, and the rest were taken out of the net bag. A one-thousandth scale was used for weighing, and the weight of the larvae and the number of surviving larvae were recorded. The larvae were weighed on the 9th, 12th, and 15th days after feeding. At the end of each weighing, the surviving individuals of the 5 larvae were put into the net bag and put back on each hole of the plant originally inoculated, and the number of live larvae was recorded. After the first weighing, the larvae had grown in size and fed a larger amount, and needed a larger living space, so it was necessary to replace the large net bag (30cm×40cm).

[0097] Bagging isolation feeding experiment 2: 2021 spring sowing net indoor bagging isolation feeding experiment: On April 21, 2021, the above 54 soybean materials were subjected to spring sowing experiments. The sowing and management methods were the same as the 2020 summer sowing bagging isolation feeding experiment, and the bagging and egg hanging treatment was carried out on June 30. Each net bag contained the same number of eggs, which were put together. The larvae hatched on July 2, and the first larvae were weighed on July 10. The larvae were weighed on the 9th, 12th, 15th, 18th, 21st and 24th days of feeding, and the number of heads was recorded for each survey.

[0098] Bagging isolation feeding experiment 3: Bagging isolation feeding experiment under high-density cultivation of indoor soybeans in spring sowing nets in 2021: The materials used were the same as the 54 soybean materials mentioned above. The sowing date was April 25, 2021, with hole sowing, row spacing × hole spacing of 0.4m × 0.4m, and 5 seedlings per hole. Bagging eggs were hung on June 13, and the larvae hatched on June 16. The larval weights were measured on the 9th, 12th and 15th days of larval feeding, and the number of larvae was recorded.

[0099] The results of the above three bagging isolation feeding experiments are analyzed as follows: Figure 2 The results of the 2020 summer sowing network indoor bag isolation feeding test record analysis are shown in the figure below. Figure 2 The experimental batches in 2020 are shown in the analysis results of the indoor bagging isolation feeding test in the spring sowing network in 2021. Figure 2 The experimental batches in 2021 (1) are shown in the analysis results of the 2021 spring sowing network indoor bag isolation feeding test. Figure 2 The experimental batches in 2021 are shown in (2).

[0100] Performance of the indicators of the 2020 summer sowing net indoor bag isolation feeding test: On the 9th, 12th and 15th days of larval feeding, there were extremely significant differences in the weight of single larvae and the weight of larvae in small plots among different soybean varieties. As the larval feeding time increased, the mean weight of single larvae and the weight of small plots became larger and larger, and the F value also increased (the F value is the statistic of the F test, that is, the ratio of the variance between groups divided by the variance within groups), reaching the maximum on the 15th day, with the maximum F values ​​of single larval weight and small plot larval weight being 3.3 and 2.8, respectively. This result shows that as the size of the larvae increases, the differences between varieties are also increasing. There was no significant difference in the survival rate of larvae on the 12th and 15th days between varieties. The genetic coefficient of variation of the weight of single larvae and the weight of small plots on each day ranged from 20.2% to 30.2%, and the genetic coefficient of variation of the larval survival rate was small, at 8.0% and 12.4%, respectively. Correlation analysis of different larval growth indicators showed that the weight of single larvae and the weight of larvae in small plots on the 9th, 12th, and 15th days showed extremely significant positive correlation, with correlation coefficients of 0.76 to 0.99; the correlation coefficients of larval survival rate on each day with the weight of single larvae and the weight of larvae in small plots were not high. Therefore, larval survival rate is not suitable as an indicator for bag isolation feeding experiments. Figure 3 As shown in the table, Figure 3 In the data, 9SLW, 12SLW, and 15SLW are the weight of single larvae on the 9th, 12th, and 15th days of larval feeding, respectively; 9LWP, 12LWP, and 15LWP are the weight of larvae in the plot on the 9th, 12th, and 15th days of larval feeding, respectively; 12LSR and 15LSR are the survival rates on the 12th and 15th days of larval feeding, respectively.

[0101] Performance of indicators of the 2021 spring sowing net indoor bag isolation feeding test: The results of the 2021 spring sowing test showed that there were extremely significant differences in the weight of single larvae between varieties on the 9th, 12th and 15th days of larval feeding; there was no significant difference in the weight of single larvae on the 18th, 21st and 24th days; the maximum F value appeared on the 12th and 15th days, both of which were 1.9, and the F value gradually decreased after the 15th day. There were significant differences in the weight of larvae in the plots between varieties on the 9th, 12th, 15th and 18th days, but no significant differences on the 21st and 24th days. The maximum F value appeared on the 15th day, reaching an extremely significant difference of 2.1. With the increase in the number of feeding days, the survival rate of larvae continued to decline, and there was a significant difference in the survival rate of larvae between varieties on the 24th day. Comparing the performance of single larval weight and small plot larval weight in the two-year experiment, single larval weight showed extremely significant differences on the 9th, 12th and 15th days, while small plot larval weight only showed significant differences on the 9th and 12th days of the spring sowing experiment. Single larval weight can more stably reflect the differences in insect susceptibility among different varieties in the early and middle stages than small plot larval weight.

[0102] Performance of bagging and isolation feeding test indicators under high-density cultivation conditions of soybeans in indoor nets during the spring sowing of 2021: The results of the bagging and isolation feeding test under high-density cultivation of soybeans in indoor nets showed that there were extremely significant differences in the weight of single larvae and the weight of larvae in small plots between varieties only on the 15th day, and there was no significant difference in the weight of single larvae and the weight of larvae in small plots on the 9th and 12th days; there was no significant difference in the survival rate of larvae between varieties.

[0103] Selection of indicators for bag isolation feeding test: In the bag isolation feeding test in the net room, the main biological indicators of larvae are selected, with single larvae weight, larvae weight in small areas and larvae survival rate as indicators. Among them, the single larvae weight is the average weight of 5 larvae in each net bag, and the small area larvae weight is the total weight of 5 larvae in each net bag. The larval survival rate is calculated based on the number of larvae retained on the 9th day, such as the larval survival rate on the 12th day = the number of larvae surviving on the 12th day / the number of larvae surviving on the 9th day. When weighing the single larval weight on the 9th day, 5 larvae of uniform size and growth are selected from each net bag for weighing, and these 5 larvae are used thereafter. "Small area" refers to the area within a single net bag, but due to leaf replacement, it more accurately refers to a hole of plants.

[0104] Classification of insect susceptibility of varieties under isolated feeding in net chamber bags: The above test results show that the isolated feeding test in net chamber bags is suitable for the early and middle stages of larval feeding; the mortality rate gradually increases in the later stages, which may be due to the continuous increase in the size of the insect body, the narrow net bag environment is not suitable for the survival of the larvae, and the continuous weighing and leaf changing interferes with their normal growth.

[0105] K-means cluster analysis was performed on the weight of single larvae in different environments and on different days. The analysis results are as follows: Figure 4 As shown in the figure, 54 soybean varieties were divided into two groups: insect-resistant varieties and insect-susceptible varieties. Figure 4 The left side of the dashed line indicates varieties resistant to hawkmoth, and the right side indicates varieties susceptible to hawkmoth. Figure 5 As shown, the weight of single larvae in different environments and on different days showed extremely significant differences in the two groups, indicating that the classification results were stable; the insect-resistant group included P59 (Lamar) and the insect-susceptible group included P23 (Nannong 89-29), which were the insect-resistant and insect-susceptible control varieties of soybean to leaf-feeding pests, respectively, indicating that the classification results were accurate; it showed that the results of the bag-isolated feeding experiment in the net room could relatively stably and accurately reflect the differences in susceptibility between varieties, and the bag-isolated feeding experiment was suitable as a method for evaluating the susceptibility of different soybean varieties to the bean moth.

[0106] Preliminary screening of insect-susceptible (adaptable) soybean materials based on bag isolation test results:

[0107] Taking the weight of single larvae as an indicator, 15 soybean varieties with the largest weight of single larvae in three bagging isolation feeding experiments were selected as susceptible materials for preliminary screening of soybean germplasm resources susceptible to P. sphenoptera. A total of 11 relatively stable susceptible varieties were screened. The screening results are as follows: Figure 6 As shown in the table, three varieties, Nannong 89-29, Wujiang Qingdou 3 and York, were susceptible to insects in all three tests, while eight varieties, Juxian Qiudou A, Nannong 1138-2, Nannong Caidou No. 5, Nannong 88-31, Jianli Niumaohuang, Williams, Mianyang Baimaodou and Mosuo, were susceptible to insects in two tests. Figure 6 In the table, 2020 indicates the summer sowing net indoor bagging isolation feeding test; 2021 (1) indicates the 2021 spring sowing normal density bagging isolation feeding test; 2021 (2) indicates the 2021 spring sowing soybean high density cultivation bagging isolation feeding test. The ones in bold are soybean varieties that were susceptible to insects in all three tests, and the ones in italics and underlined are soybean varieties that were susceptible to insects in two tests.

[0108] Process and result analysis of free feeding test in the net room:

[0109] Feeding selection test in the net room: The materials used in this test are the same as the above-mentioned 54 soybean materials. The leaf area loss rate is used as an indicator to reflect the difference in insect susceptibility of different materials. A randomized block design was adopted, and three replicates were sown in the same net room with a row-hole spacing of 0.3m×0.3m. The sowing date was July 8, 2020, and 5 seedlings were set in each hole. On August 17, the eggs were bagged and hung with 15 eggs per bag, and one bag of eggs was hung in each hole. The eggs hatched on August 19, and the larvae were released from the net bag on the 5th day of larval feeding (August 23) and allowed to feed freely. The position of the larvae was adjusted appropriately by hand to make the larvae evenly distributed in the net room. When the damage (leaf area loss rate) between varieties in the net room showed a difference of more than 5%, the leaf area loss rate was investigated. The leaf loss rate is the proportion of the leaf area of ​​the whole soybean plant fed by the larvae to the original complete area. The leaf area loss rate of soybeans of various materials was investigated from August 29, and the leaf area loss rate was investigated on August 29, 30, 31 and September 1 (i.e., the 11th, 12th, 13th and 14th days of larval feeding). The investigation was stopped when the leaf area loss of plants in the net room no longer changed significantly (more than 5%).

[0110] The statistical results of blade loss rate are as follows: Figure 7As shown in the figure, with the increase of larval feeding time, the difference in leaf area loss rate among varieties gradually increased, reaching a significant level on the 13th day of larval feeding and an extremely significant level on the 14th day. The genetic coefficient of variation of leaf area loss rate varied between 35.1% and 39.1%. When the average leaf area loss rate of 54 insect-resistant soybean germplasm populations reached 38.4%, the difference among varieties reached a significant level, which shows that the observation time of feeding selection experiment should not be too early, and it is suitable to observe in the middle and late stages.

[0111] Soybean leaf biomass-related agronomic traits investigation test process and results:

[0112] The materials used in this experiment were the same as the above 54 soybean materials. They were sown in rows in a net room with a row length of 1m and a row spacing of 0.5m. The varieties were randomly arranged and one row was sown for each variety. Sowing was carried out on July 7, 2020, and thinning was carried out at the V1 stage (first leaf stage), with 10 seedlings per row. The V1 stage is the first leaf stage, when the first three-leaf compound leaf of the soybean plant unfolds.

[0113] Leaves were picked for scanning at the R6 stage (full grain stage). The R6 stage is the full grain stage. The pods with one node at the same position are full of green beans. Take the middle leaflet of the third leaf of the soybean plant, and take 3 leaves of each variety as a repeat. After the leaves are picked, they are put into sampling bags and temporarily stored in an ice box for freshness, and then brought back to the room for scanning. The scanned leaves are put into labeled paper bags according to different varieties and dried at 80°C for three days, and then weighed.

[0114] Soybean plants were harvested in batches according to maturity, and 5 plants of each variety were selected for agronomic character examination. Plant height, number of main stem nodes, and number of branches were measured according to the method compiled by Qiu Lijuan (2006). Number of branch nodes: record the number of nodes of each branch separately. Internode length was calculated by the formula: internode length = plant height / number of main stem nodes. Descriptive statistics and variance analysis of agronomic traits related to feeding bean moth larvae in soybean resources are shown in Figure 2. Figure 8 shown.

[0115] Comparison of agronomic traits of different soybean varieties: Bean moth larvae feed on bean leaves, so the biomass of individual leaflets and the biomass of individual leaves of soybean varieties are also important bases for the selection of varieties for breeding bean moths. The biomass of individual leaves is affected by the total number of nodes per plant (including the number of main stem nodes and the total number of branches), the dry weight of individual leaves, etc., so these agronomic traits are related to breeding bean moth larvae. There are significant variations in agronomic traits related to leaf biomass between different soybean varieties, such as Figure 8 As shown in the table, the dry weight of a single leaflet can vary by 5.0 times, while the leaf biomass of a single plant can vary by 13.8 times. There are significant differences in leaf biomass among soybean plants, and the increase in leaf biomass per plant can feed more larvae with fewer soybean plants, which is beneficial for breeding.

[0116] The correlation analysis between soybean agronomic traits and single larval weight was conducted. Fig. 9 As shown, Fig. 9 In the table, 9SLW = weight of a single larva on the 9th day, 12SLW = weight of a single larva on the 12th day, 15SLW = weight of a single larva on the 15th day, NN = total number of nodes per plant, PLDW = dry weight of a single leaf, LBPP = leaf biomass per plant, PLA = leaf area per plant, BN = number of branches per plant. Total number of nodes per plant = number of main stem nodes + number of branch nodes; leaf biomass per plant = 3 × dry weight of a single leaf × total number of nodes per plant. Fig. 9 It can be seen that the weight of a single larva on the 9th and 15th days was significantly positively correlated with the area of ​​a single leaf, and the weight of a single larva on the 12th and 15th days was significantly and extremely significantly positively correlated with the dry weight of a single leaf.

[0117] Comprehensive screening process and results of insect-susceptible varieties:

[0118] Five traits closely related to leaf biomass were selected from the agronomic traits investigated for cluster analysis. The analysis results are as follows: Fig.10 As shown in the figure, the 54 varieties are divided into two groups, the right side of the dotted line is the first group, and the left side of the dotted line is the second group. A t test is performed on each trait according to the classification data. The results are shown in Fig.11 As shown in the figure, there is a significant difference in the number of branches between the two groups, and there are extremely significant differences in the other traits, indicating that the classification results are accurate. Fig.11 The overall distribution of the first group in terms of single leaf area, single leaf dry weight, number of nodes, number of branches and other traits is higher than that of the second group, indicating that the soybean varieties in the first group have a higher leaf biomass per plant. Fig.12 As shown, Fig.12 The ones in bold are stable insect-susceptible species.

[0119] The insect weight, leaf loss rate and biomass of 11 susceptible species obtained from the preliminary screening of bagging isolation feeding experiment were analyzed. The results are as follows Fig.13 The data in bold are shown in the table, where the top five indicators in this table are shown. The varieties marked with * are ranked in the top five in a certain indicator, and the number of * represents the number of indicators that the variety ranks in the top five. The weight of a single larva is the average weight of a single larva on the 15th day of each variety selected in the three tests, and the weight of the larvae in the plot is calculated in the same way. Fig.12 and Fig.13 The results showed that among the 11 susceptible varieties, 7 varieties, including Wujiang Qingdou 3, Mianyang Baimaodou, Jianli Niumaohuang, Juxian Qiudou A, Nannong 88-31, Nannong 1138-2 and Nannong Caidou 5, had larger leaf biomass per plant.

[0120] Evaluate and grade the comprehensive performance of different varieties in multiple indicators. Fig.13As shown, Jianli Niumaohuang performed well in all indicators; Nannong 1138-2 and Nannong 89-29 ranked high in three indicators, among which Nannong 89-29 performed well in insect susceptibility indicators; Nannong Vegetable Bean No. 5, Nannong 88-31, Mianyang White Bean, York and Wujiang Green Bean 3 ranked high in two indicators; Williams, Juxian Autumn Bean A and Mosuo ranked low in all indicators.

[0121] Selection process and results of excellent insect-susceptible varieties in net house isolation culture:

[0122] Excellent variety net room isolation breeding test: This test selected 5 insect susceptible varieties screened in the net room bag isolation feeding test, namely Mianyang white hairy bean, Wujiang green bean 3, Nannong 1138-2, Nannong 88-31, Nannong 89-29. On this basis, the soybean variety Ruidou No. 1 was added as a control variety in production.

[0123] The experiment adopted a randomized block design with 3 replications in a 2m×2m net room, with a total of 18 net rooms. The seeds were sown on August 5, 2021, in hole sowing with a row-hole spacing of 0.4m×0.5m, and 3 seedlings were set in each hole. On September 13, the field was bagged and eggs were hung. When hanging eggs, 20 eggs were placed in each net bag (15cm×20cm), and each net room received 4 bags, that is, 20 eggs were hung per square meter. On September 24, the insects were released from the net bags, and the number of larvae of the same treatment of 3 replications was mixed; on October 9, the leaves in the net room were eaten up, and the larvae in the net room were weighed. When weighing, all the larvae in each net room were caught, counted, and weighed one by one. At the same time, the bean moth was divided into weight intervals according to the different single-head larval weights and classified and counted, and the proportion of larvae in each weight interval was calculated. The results are as follows Fig.14 shown.

[0124] Fig.15 This is a descriptive statistical table of larval weight and agronomic traits of soybean varieties under different soybean variety feeding conditions, indicating that there is no significant difference in the weight of single larvae of the bean moth fed with different varieties, and there is a very significant difference in the weight of larvae in the plot. A variance analysis of the proportion of larvae ≥ 6g found that there was a very significant difference in the proportion of larvae ≥ 6g between treatments under different soybean varieties ( Fig.15 ).from Fig.14 It can be seen that under the feeding condition of Nannong 88-31, the proportion of bean moth larvae ≥ 6g was the lowest, less than 50%, and under the feeding condition of Mianyang white hairy soybean, the proportion of bean moth larvae ≥ 6g was the highest, reaching 78.4%.

[0125] The yield of bean moth fed with different soybean varieties was compared. Fig.16 As shown, Fig.16 The letters after the data in the figure are the results of multiple comparisons. There are significant differences between the data marked with different letters (P<0.05). Fig.16 The results showed that the larval weight of the plot, the weight of the single larvae and the proportion of larvae ≥6g were higher in Wujiang Green Bean 3, Nannong 1138-2 and Mianyang White Bean, and the larval weight of the plot was significantly higher than that of Nannong 88-31 and Ruidou No. 1, and the proportion of larvae ≥6g was significantly higher than that of Nannong 89-29 and Nannong 88-31. Therefore, three soybean materials suitable for bean dan breeding were finally obtained, namely Wujiang Green Bean 3, Nannong 1138-2 and Mianyang White Bean.

[0126] Since the larvae of the bean moth are large in size, eat a lot, and each instar lasts for a long time, it is inconvenient to breed them indoors, and the mortality rate is often high when breeding indoors. In order to be closer to actual production, the present invention provides a method for bagging and isolating living plants in a net room, first planting healthy green soybean plants in the net room, then bagging and inoculating the larvae to restrict them to each soybean variety without interfering with each other, and finally evaluating the insect susceptibility of different soybean varieties by examining the biological indicators of the larvae after feeding on leaves of different soybean varieties.

[0127] During the experiment, it was found that too high a density of soybean cultivation in the net room would aggravate the entanglement and lodging of the plants. The soybean stalks could hardly support the net bags, and it was not conducive to the movement of field weighing personnel. The test process was more likely to cause damage to the plants. Therefore, when conducting a net room bag isolation feeding experiment, it is not advisable to plant soybeans too densely, such as not less than 0.4m×0.4m.

[0128] The bag isolation feeding test and feeding selection test of bean moth were compared. In the bag isolation feeding test in the net room, the weight of single larvae and the weight of larvae in the plot showed extremely significant differences among varieties on the 9th day of larval feeding, while the leaf area loss rate among varieties in the feeding selection test showed significant differences on the 13th day. Therefore, the bag isolation feeding test can distinguish the insect susceptibility of different varieties earlier. At the same time, the feeding selection test requires manual reading of the leaf area loss rate, which is greatly affected by subjective factors; the weight of larvae in the bag isolation feeding test is more objective and stable. Compared with the leaf area loss rate of the feeding selection test, the single larvae weight and the plot larvae weight used in the bag isolation feeding test can more intuitively reflect the increase in larval size and weight, and have stronger guiding significance for production. Therefore, the bag isolation feeding test is suitable as the main method for evaluating the insect susceptibility of soybean to bean moth, and the single larvae weight and the plot larvae weight on the 15th day of larval feeding are used as the best evaluation indicators.

[0129] The artificial inoculation method in a net house can be used to isolate the influence of other insects or natural enemies, ensure the uniqueness of the experimental insects, and evenly distribute the insects in the net house through human control. However, the leaf area loss rate still needs to be read manually, which has subjective errors and requires multiple training sessions.

[0130] The comparison process and results of bag isolation feeding and net house isolation feeding methods are as follows:

[0131] The experiment was conducted on April 22, 2023 in the experimental field of the Wanjiang Base of Nanjing Agricultural University, Dangtu County, Ma'anshan City, Anhui Province, and routine field management was carried out. The net house used in the experiment was made of a steel frame structure, and the outside of the net house was covered with a white gauze (40 mesh). The egg-protecting net bag used in the experiment was made of organza, and the specifications of the egg-protecting net bag were divided into large net bags (30cm×40cm) and small net bags (15cm×20cm). 14 representative soybean varieties included 7 domestic and foreign early-maturing soybean materials and 7 medium- and late-maturing soybean materials with good adaptability to bean moth. The net house bag isolation feeding method experiment was carried out in a large net house (4m×6m). The large net house was divided into 9 rows, 6 holes in each row, and 3 seedlings were set in each hole. A randomized block test design was adopted with 3 repetitions. The field bagging isolation feeding method test was carried out in the field row sowing soybeans, using a randomized block test design, 3 repetitions, the block size was 7m×1m, the row length was 1m, the row spacing was 0.5m, the plant spacing was 0.1m, and 10 seedlings were fixed in each row. The net room isolation feeding method test was carried out in a small net room, using a randomized block test design, 3 repetitions, and a block group contained 14 small net rooms. Soybeans were sown in holes in the small net room, and each small net room only planted the same variety, divided into 4 rows, 5 holes in each row, and 3 seedlings were fixed in each hole. The sowing time of soybean materials was the same as April 22, 2023. The bean moth eggs used in the experiment were all produced on the same day. On June 9, 2023, they were bagged and hung in the net house. 15 bean moth eggs that were about to hatch were placed in each small net bag, and 2 complete inverted trefoil were put into it. One net bag was put into one hole; one net bag was put into a row for bagging and hanging eggs in the field, and the rest of the operations were the same as the net house bagging and hanging eggs for isolated feeding; the net house (plot) isolation feeding experiment and the two types of bagging and hanging eggs for isolated feeding experiments were carried out simultaneously. 20 bean moth eggs that were about to hatch were placed in each small net bag, and 2 complete inverted trefoil were put into it. There were 5 net bags in each small net house.

[0132] The net room bag isolation feeding method and the field bag isolation feeding method start from the 4th day of egg hatching, and the leaves in the net bag are replaced every 2 days. When the eggs are hatched for 12 days, the small net bag (15cm×20cm) is replaced with a large net bag (30cm×40cm). On the 9th day of egg hatching, the extreme larvae are removed from the egg bag, leaving 5 larvae, so that each larva has enough growth space to reduce errors. At the 12th, 15th and 18th day of egg hatching, the larvae in the net bag are weighed and the number of larvae is recorded. After each weighing, the larvae are put back into the net bag and put on the original plant to continue isolation feeding. On the 4th day of egg hatching, the number of larvae hatched in each net bag in the small net room is counted, and then the larvae are no longer put back into the net bag, and the larvae are allowed to feed freely in the small net room. On the 25th day after the eggs were hatched, i.e., at 25 days old, all the larvae in each small mesh chamber were collected, counted, and weighed.

[0133] In the experiment of isolated feeding in net house bagging, the weight of single larvae of 12 and 15 days old of bean moth was significantly different among varieties, and the weight of single larvae of 18 days old was extremely significantly different among varieties, and the maximum F value appeared at 18 days old, which was 3.0; the weight of 12 and 15 days old of bean moth in small areas was significantly different among varieties, and the weight of 18 days old of small areas was extremely significantly different among varieties, and the maximum F value appeared at 18 days old, which was 3.8; the survival rate of 15 days old larvae was extremely significantly different among varieties, while the survival rate of 18 days old larvae was not significantly different among varieties. The genetic variation coefficient of single larvae weight of bean moth was 23.1% at 18 days old, and the genetic variation coefficient of small area larvae weight of bean moth was 24.7% at 18 days old ( Fig.17 ). In the figure, GCV is the genetic variation coefficient, h 2 is the heritability. *, * and * indicate significant differences at P≤0.05 and P≤0.01 levels, respectively.

[0134] In the field bagging and feeding isolation experiment, the weight of single larvae of 12 and 15 days old was significantly different among varieties, and the weight of single larvae of 18 days old was significantly different among varieties. The maximum F value was 2.9 at 15 days old. There were significant differences in the weight of 12 and 15 days old larvae in small plots among varieties, and there were significant differences in the weight of 18 days old larvae in small plots among varieties, with the maximum F value of 3.0. There were no significant differences in other larval growth indicators among varieties. The maximum genetic variation coefficient of single larval weight of 12 days old was 18.1%, and the maximum genetic variation coefficient of small plot larvae weight of 12 days old was 17.7% ( Fig.17 ).

[0135] In the isolated feeding experiment in the net house, the weight of single larvae at 25 days old was significantly different among varieties, and the weight of larvae in small plots at 25 days old and the survival rate of larvae were extremely significant among varieties ( Fig.17 ), the genetic variation coefficients of 25-day-old larval weight and larval survival rate were more than twice that of 25-day-old single larvae weight, indicating that these two indicators were better.

[0136] According to the descriptive statistics and variance analysis results of larval growth indicators of the three isolation feeding suitability evaluation methods, the net room bag isolation feeding method and the field bag isolation feeding method selected the weight of 15-day-old single larvae and the weight of larvae in the plot as the identification indicators, which are more representative and can greatly save the test time and land compared with the net room isolation feeding method. However, the growth of larvae in net bags in the net room and field bag isolation feeding methods is different from natural production. The net room isolation feeding method is closer to the actual breeding model, and its screening results are more reliable. Its evaluation results not only consider the suitability of soybean materials to bean moth larvae, but also include the agronomic traits of soybean materials and the effects of factors such as total leaf biomass on the yield of bean moth larvae.

[0137] from Fig.18 It can be seen that the net room bag isolation feeding method and the field bag isolation feeding method are all smaller than the net room plot isolation feeding method in terms of cultivation management, seed quantity, seed cost, egg quantity, egg cost, survey time, number of people surveyed per time, land area and facility cost; while the number of surveys is higher than the net room isolation feeding method (calculated based on the full identification of 14 soybean materials repeated three times, the total identification cost does not include facility costs.). These differences in items lead to the three identification methods being able to adapt to different purposes, thereby screening out soybean materials suitable for different bean moth breeding conditions.

[0138] Experiment on the effect of different sowing seasons and leaf positions on the growth of bean moth larvae: The experiment was conducted in the experimental field of the Wanjiang Base of Nanjing Agricultural University, Dangtu County, Ma'anshan City, Anhui Province on June 6, 2022, with conventional field management. The net house used in the experiment was made of a steel frame structure, and the outside of the net house was covered with a white gauze (40 mesh). The specifications of the net house were (length 6m×width 4m×height 2m). The mesh bag used in the experiment was made of organza, and the specifications of the mesh bag were divided into large mesh bags (30cm×40cm) and small mesh bags (15cm×20cm). The soybean germplasms Nannong 1138-2 and Nannong 89-29 with strong adaptability and the insect-resistant control variety Lamar were selected for research. The net house bagging isolation feeding experiment was carried out in the large net room, using a completely randomized experimental design. The sowing time of the summer sowing experiment was June 6, 2022. Soybeans were sown in the large net room, leaving 3 seedlings in each hole, with a row hole spacing of 0.6×0.6m, and 9 holes were repeated for each variety. The sowing time for the autumn sowing test was July 18, 2022, and the planting method was the same as that for the spring sowing test. The experiment used bean hawk moth eggs produced on the same day. The summer sowing test carried out V6 stage egg hanging bagging and isolation feeding on July 7, 2022. 15 bean hawk moth eggs that were about to hatch were placed in each small mesh bag. Two bags of eggs were hung on each plant hole, connected to the inverted three-leaf position (the upper part of the plant) and the positive three-leaf position (the third fully expanded compound leaf of the soybean plant from the bottom to the top). The autumn sowing test carried out V6 stage egg hanging on August 16, 2022, and R3 stage egg hanging on September 13, 2022. The egg hanging method was consistent with the summer sowing test. Starting from the 4th day of egg incubation, the leaves in the mesh bag were replaced every 2 days in the summer sowing test. When the eggs were hatched on the 9th day, the small mesh bag was replaced with a large mesh bag. On the 9th day of egg hatching, the extreme larvae were removed from the net bag, leaving 5 larvae, each larvae had enough growth space to reduce errors. On the 9th, 12th, 15th, 18th and 21st days of egg hatching, the larvae in the net bag were weighed and the number of larvae was recorded. After each weighing, the larvae were put back into the net bag and put on the original plant to continue bagging and feeding. The autumn sowing test method was the same as the summer sowing test.

[0139] Effects of different leaf positions and varieties on larval weights of soybeans at different growth stages and sowing seasons Fig.19 As shown, Fig.19In the figure, AC is the weight change trend of soybean larvae feeding on summer-sown soybeans at stage V6; DF is the weight change trend of soybean larvae feeding on autumn-sown soybeans at stage V6; GI is the weight change trend of soybean larvae feeding on autumn-sown soybeans at stage R3. STA: In summer-sown soybeans at stage V6, the larvae of the bean moth feed on the inverted three leaves; STB: In summer-sown soybeans at stage V6, the larvae of the bean moth feed on the right three leaves; ATA: In autumn-sown soybeans at stage V6, the larvae of the bean moth feed on the inverted three leaves; ATB: In autumn-sown soybeans at stage V6, the larvae of the bean moth feed on the right three leaves; RTA: In autumn-sown soybeans at stage R3, the larvae of the bean moth feed on the inverted three leaves; RTB: In autumn-sown soybeans at stage R3, the larvae of the bean moth feed on the right three leaves.

[0140] Under the summer sowing environment, the differences in larval weights between different leaf positions of soybean varieties with strong insect adaptability at V6 stage, Nannong 89-29 and Nannong 1138-2, gradually increased with the increase of feeding age. The weight of larvae fed on the inverted third leaf position was higher than that on the front third leaf position. The difference did not increase much after 15 days of age ( Fig.19 AB); the weight of larvae of the insect-resistant soybean variety Lamar did not change significantly with the increase of age when fed at different leaf positions ( Fig.19 C). Under the autumn sowing environment, the difference in larval weight between Nannong 89-29 and Nannong 1138-2 larvae fed at different leaf positions at V6 stage also gradually increased with age ( Fig.19 DE), but the degree was significantly weaker than that of summer sowing. There was no significant difference in the weight of larvae at different leaf positions with the increase of age of Lamar ( Fig.19 F). Under autumn sowing conditions, the weight change trend of bean moth larvae fed with Nannong 89-29 and Nannong 1138-2 in the R3 period ( Fig.19 GH) was similar to V6, but the degree of change was weaker than that of V6; when the insect-resistant variety Lamar was fed at R3, there was no significant difference in the weight of larvae at different leaf positions with increasing age ( Fig.19 I), and the weight of larvae at each age had no significant change compared with the V6 stage ( Fig.19 F, I).

[0141] The trends of larval survival rates at different leaf positions and the effects of leaf position and sowing season interaction on larval survival rates are shown in Figure 2. Fig. 20 As shown, Fig. 20AC is the survival rate trend of larvae at different ages feeding on different leaf positions; A: summer-sown soybean V6 stage; B: autumn-sown soybean V6 stage; C: autumn-sown soybean R3 stage. DE is the effect of leaf position and sowing season interaction on larval survival rate; D: 12-day-old larvae; E: 15-day-old larvae; F: 18-day-old larvae; G: 21-day-old larvae. STA: summer-sown soybean V6 stage, bean hornworm larvae feed on inverted three leaves; STB: summer-sown soybean V6 stage, bean hornworm larvae feed on positive three leaves; ATA: autumn-sown soybean V6 stage, bean hornworm larvae feed on inverted three leaves; ATB: autumn-sown soybean V6 stage, bean hornworm larvae feed on positive three leaves; RTA: autumn-sown soybean R3 stage, bean hornworm larvae feed on inverted three leaves; RTB: autumn-sown soybean R3 stage, bean hornworm larvae feed on positive three leaves.

[0142] The survival rate of larvae fed at different leaf positions in summer-sown soybeans at V6 stage was analyzed, and no significant difference was found. However, the survival rate of larvae fed at the inverted third leaf position in autumn-sown soybeans at V6 stage was significantly higher than that fed at the right third leaf position. The survival rate of 12- and 15-day-old larvae fed at the inverted third leaf position in autumn-sown soybeans at R3 stage was significantly higher than that fed at the right third leaf position, but the difference was relatively weaker than that in autumn-sown soybeans at V6 stage ( Fig. 20 The interaction between V6 stage and leaf position in different sowing seasons had an effect on the survival rate of larvae at different ages. The survival rate of the three leaves in the V6 stage of autumn sowing decreased significantly ( Fig. 20 middle DE).

[0143] Based on the comparison of the above two aspects, the inverted clover of soybean plants is the best leaf position for the live identification of soybean hornworm larvae in the seedling and adult stages. The best identification period is the V6 stage of summer sowing. After 15 days of age, there is a large difference in larval weight between leaf positions and between resistant and susceptible varieties, which can be used as a good identification period and indicator.

[0144] The process and results of the soybean variety selection test suitable for breeding of hawkmoths in different sowing seasons are as follows:

[0145] 1. Large-scale evaluation of the suitability of soybean germplasm resources: A total of 620 cultivated soybean germplasm resource groups, including 421 local varieties and 199 bred varieties, were used, and field bagging and isolation feeding were used for suitability evaluation. The test insect source came from the Lianyungang Bean Moth Breeding Base, and the experiment used eggs laid on the same day. It was conducted at the Wanjiang Base of Nanjing Agricultural University in Dangtu County, Ma'anshan City, Anhui Province in 2021, using a randomized block design, 1m row length, and 0.5m row spacing. About 20 seeds were sown in each row, and when they grew to the cotyledon stage, 10 plants were set per row. Routine field management, limit the use of pesticides containing insecticides and insect repellent ingredients.

[0146] When some soybean plants in the field are in the R1 stage, select the eggs laid on the same day, and after their color changes from green to white, put 15 eggs per bag into a small mesh bag. Select the plant in the middle of each row and stuff the inverted three leaves of the plant into the small mesh bag. After bagging, replace the leaves every 3 days, untie the mesh bag, take out the original leaves and keep the larvae in the bag, and stuff the inverted three leaves of the adjacent plant into the small mesh bag. On the 9th day after bagging, the small mesh bag needs to be replaced with a large mesh bag, and all the larvae in the small mesh bag are placed in the large mesh bag, and the inverted three leaves of the plant that has not been eaten are selected and stuffed into the large mesh bag. 15 days after inoculation, the mesh bag is taken back to the laboratory, and 5 larvae of similar size and consistent growth and development are selected from each bag for weighing (extremely large and small larvae are eliminated), and the larval weight is used as an indicator for evaluating adaptability.

[0147] 2. Leaf area differences between varieties: The leaf area measurement experiment was conducted from 2019 to 2021, and the experimental location was the same as above. When most plants in the entire Chinese soybean germplasm resource population were in the R1 stage, the middle single leaf of the inverted 3-leaf compound leaf was collected and scanned using the EPSON V300 scanner. Leaves from three soybean plants of the same variety in each plot were taken, and then calculated using the leaf measurement software. The frequency distribution of leaf area is shown in the figure below. Fig.21 As shown in Figure 2, it can be seen that the leaf area of ​​each leaf in the three environments is normally distributed; the variance analysis of the average single larval weight and leaf area is shown in Figure 2. Fig. 22 As shown in the table, there are significant differences in leaf area among varieties; Fig.23 As shown in Figure 2, the average leaf area of ​​each leaf under the three environments is only 18.05 cm 2 The largest average leaf area reached 116.50 cm 2 , the difference between the two is about 7 times. Therefore, the phenotypes of the three environments can be combined to screen out stable large-leaf varieties.

[0148] 3. Screening of large-leaf varieties susceptible to insects: The average single larvae weight is used as an indicator for suitability evaluation. Fig. 22 and Fig.23 The tables in the table show that the average single head larvae weight varies greatly and there are significant differences between varieties. The lightest single head larvae weight is 0.149g, and the heaviest is 1.990g, which is 13 times different. The large variation and significant differences between varieties indicate that this identification method can effectively screen and separate insect-resistant materials and insect-susceptible materials. Fig.24 The data in show that the weight of a single larva is normally distributed, which is consistent with the characteristic that insect resistance is a quantitative trait.

[0149] In order to select soybean varieties suitable for raising hornworm larvae, it is necessary to comprehensively consider the leaf area and average single larval weight to select varieties with large leaves and insects. The varieties that ranked in the top 30% after arranging these two indicators from large to small (single leaf area>60.32cm2 , the average single larvae weight> 1.23g), and finally obtained 54 relatively stable soybean varieties with large leaves and insects for further work, such as Fig.25 shown.

[0150] 4. Screening of insect-infected large-leaf varieties in different sowing seasons: The eggs used in each experiment were produced on the same day, and the eggs were artificially disinfected. Field trials were conducted at the Wanjiang Base of Nanjing Agricultural University in Dangtu County, with routine field management and restrictions on the use of pesticides containing insecticides and insect repellents. The net houses used in the experiment were all spliced ​​together with steel pipe skeleton structures, covered with white gauze (40 mesh), and the length and width of the net houses were 6m×4m. The specifications of the large mesh bags used during the experiment were 30cm×40cm, and the specifications of the small mesh bags were 15cm×20cm, all made of organza. The 54 soybean germplasm resources initially screened out above had 9 rows and 6 columns in each net room, totaling 54 holes. The autumn sowing experiment was sown on August 1, 2022, and the inverted three-leaf position of the soybean plant was bagged on September 1 to receive insects, with 15 eggs placed in each net bag (15cm×20cm). On September 10, the 9-day-old larvae were weighed for the first time, and 5 larvae with uniform growth were selected for weighing. After the remaining larvae were removed, the number of larvae was recorded for the net bags with less than 5 larvae, and the average insect weight in each net bag was calculated. The experiment ended after the fifth weighing. On October 1, the plant height, number of main stem nodes, number of branches, leaf length, leaf width, pod length and pod width of the net house plants were measured. The spring sowing experiment was sown on April 22, 2023, inoculated on June 8, and the larvae were weighed for the first time on June 20. The agronomic traits of the net house plants were measured on July 4. The summer sowing experiment was sown on June 22, 2023, inoculated on August 8, and the larvae were weighed for the first time on August 20. The agronomic traits of the plants in the net house were measured on September 3. The experimental methods of spring and summer sowing trials were consistent with those of autumn sowing trials, using a randomized block design with each net house as one block, two replicates for autumn sowing, and three replicates for spring and summer sowing.

[0151] Temperature and humidity changes in the net house in 2022 and 2023 Fig.26 As shown in the figure, A: Temperature change in the net room in 2022; B: Temperature change in the net room in 2023; C: Humidity change in the net room in 2022; D: Humidity change in the net room in 2023. The temperature in 2022 showed a trend of first rising and then falling. During the autumn sowing experiment, the temperature gradually dropped. Fig.26 As shown in A. The temperature gradually increased during the spring sowing test in 2023, reached the highest peak of the year during the summer sowing test, and gradually decreased during the autumn sowing test (due to heavy rain, this test failed). Overall, the average temperature during the summer sowing test was higher than that during the spring sowing test, and the average temperature during the spring sowing test was higher than that during the autumn sowing test. Fig.26As shown in B. During the 2022 autumn sowing experiment, the humidity fluctuated greatly, with the average humidity reaching 70.2% around September 13, 2022, and then dropped rapidly. Fig.26 As shown in C. During the 2023 spring sowing test, the average humidity first increased and then decreased. During the summer sowing test, the average humidity was relatively stable. During the 2023 autumn sowing test, the average humidity reached 75.5% on September 20, and then slowly decreased. Fig.26 As shown in D.

[0152] Descriptive statistics and variance analysis data of larval growth indicators in different sowing seasons are shown in Figure 2. Fig. 27 As shown in the figure, LW is the weight of a single larva; LWP is the weight of a small plot of larvae; LSR is the larval survival rate; the numbers after these letters indicate the number of days after the eggs hatch. GCV is the genetic coefficient of variation, h 2 is the heritability. *, * and * indicate significant differences at the P≤0.05 and P≤0.01 levels, respectively. Under the autumn sowing conditions in 2022, there were extremely significant differences in the weight of single larvae and the weight of larvae in the plot at 12, 18 and 21 days of age among varieties, and there were significant differences in the weight of single larvae and the weight of larvae in the plot at 15 days of age among varieties. There were extremely significant differences in the survival rate of bean hornworm larvae at 15 and 18 days of age among varieties, and there were significant differences in the survival rate of bean hornworm larvae at 12 and 21 days of age among varieties. There were no significant differences in other indicators among varieties. Under the spring sowing conditions in 2023, there were extremely significant differences in the weight of single larvae at 15, 18 and 25 days of age among varieties, there were significant differences in the weight of single larvae at 12 days of age among varieties, and there were significant differences in the weight of larvae in the plot at 15 and 18 days of age among varieties. There were no significant differences in other indicators among varieties. Under the summer sowing conditions in 2023, there were extremely significant differences in the weight of single larvae and larvae in small plots at 25 days old among varieties, there were significant differences in the weight of single larvae at 12, 15 and 18 days old among varieties, there were significant differences in the weight of larvae in small plots at 12 and 15 days old among varieties, and there were no significant differences in other indicators among varieties.

[0153] The weight of a single larva is the best and most stable among the three indicators, with the largest difference. There are significant differences between 12 and 25 days of age, which can be used as an identification indicator.

[0154] Descriptive statistics and variance analysis data of agronomic traits of plants in different sowing seasons are shown in Fig.28 As shown in the table, in the figure: PH: plant height; NMSN: number of main stem nodes; NB: number of branches; LA: area of ​​inverted trefoil; TCL: number of compound leaves; LDW: dry weight of inverted trefoil. GCV is the genetic variation coefficient, h 2is the heritability. *, * and * indicate significant differences at the P≤0.05 and P≤0.01 levels, respectively. Under the autumn sowing conditions of 2022, there were extremely significant differences in plant height, number of main stem nodes, number of branches and inverted trefoil leaf area among soybean varieties, with the genetic variation coefficient ranging from 9.8% to 43.4% and the heritability ranging from 87.1% to 92.7%. Under the spring sowing conditions of 2023, there were extremely significant differences in plant height, number of main stem nodes, number of branches, total number of compound leaves, inverted trefoil area and leaf dry weight among soybean varieties, with the genetic variation coefficient ranging from 12.2% to 27.3% and the heritability ranging from 88.6% to 92.9%. Under the summer sowing conditions of 2023, there were extremely significant differences in plant height, number of main stem nodes, number of branches, total number of compound leaves, inverted trefoil area and inverted trefoil dry weight among soybean varieties. The genetic variation coefficient varied between 14.3% and 27.3%, and the heritability varied between 88.8% and 96.6%.

[0155] The two-factor joint variance analysis data of larval growth index and soybean agronomic traits are shown in Fig.29 As shown in the table, in the figure: SS: sowing season; V: variety; LW: single larva weight; LWP: plot larva weight; the numbers after LW and LWP indicate the number of days the larvae grow after the eggs hatch. PH: plant height; NMSN: number of main stem nodes; NB: number of branches; LA: area of ​​inverted trifoliate leaves; TCL: number of compound leaves; LDW: dry weight of inverted trifoliate leaves; DF: degree of freedom. GCV is the genetic coefficient of variation, h 2 =Heritability. *, *, * indicate significant differences at P≤0.05 and P≤0.01 levels, respectively. The weight of single larvae and larvae in plots at different ages, the survival rate of 18-day-old larvae, soybean plant height, number of main stem nodes, number of branches, inverted trefoil leaf area, leaf dry weight and total number of compound leaves were significantly different among different sowing seasons, while the survival rate of 15-day-old larvae was not significantly different among different sowing seasons. The weight of single larvae at 15 and 18 days old was significantly different among different soybean varieties, and the height of soybean plant, number of main stem nodes, number of branches, inverted trefoil leaf area, leaf dry weight and total number of compound leaves were significantly different among different soybean varieties. There were significant differences in soybean plant height, number of main stem nodes, number of branches, inverted trefoil leaf area and total number of compound leaves between sowing seasons and soybean materials. There were extremely significant differences in the weight of single larvae and larvae in small plots at 12 days old, the survival rate of larvae at 15 days old, soybean plant height, number of main stem nodes, number of branches, area of ​​inverted trefoil, leaf dry weight and total number of compound leaves among the blocks. There were significant differences in the weight of single larvae and larvae in small plots at 15 days old, but there were no significant differences in the weight of single larvae and larvae in small plots among the blocks.

[0156] Differences in growth indicators of hawkmoth in different sowing seasons Fig.30As shown in the figure, A: scatter plot of single larval weight at 12, 15 and 18 days old under spring, summer and autumn sowing conditions; B: scatter plot of larval weight at 12, 15 and 18 days old in plots under spring, summer and autumn sowing conditions; the confidence interval of the ellipse is 95%. Under summer sowing conditions, the dispersion of single larval weight at 12, 15 and 18 days old and the larval weight in plots among varieties is the highest, and the increase in larval weight per unit time is the largest. The dispersion of larval growth indicators and the increase in larval weight under spring sowing conditions are second, and the lowest under autumn sowing conditions ( Fig.30 AB). Regardless of the weight of a single larva or a small area of ​​larvae, the larvae are larger and the difference between varieties is the greatest under summer sowing conditions, which is the most suitable season for screening bean varieties ( Fig.30 AB).

[0157] Under spring and summer sowing conditions, the weight of larvae in the plot and single larvae at 18 days old was significantly higher than that at 15 days old, and that at 15 days old was significantly higher than that at 12 days old ( Fig.31 AB), the survival rate of 15-day-old larvae was significantly higher than that of 18-day-old larvae ( Fig.31 C). Under autumn sowing conditions, the weight of larvae in the plot and the weight of individual larvae at 18 days old were significantly higher than those at 15 days old, and the weight of individual larvae at 15 days old was significantly higher than that at 12 days old, while there was no significant difference in the weight of larvae in the plot between 15 days old and 12 days old ( Fig.31 AB), and there was no significant difference in the survival rate of 15-day-old and 18-day-old larvae ( Fig.31 C).

[0158] The weight of larvae in plots of different ages and the weight of single larvae in summer sowing were significantly higher than those in spring sowing, and the weight of larvae in plots of different ages and the weight of single larvae in spring sowing were significantly higher than those in autumn sowing ( Fig.30 AB). There was no significant difference in the survival rate of 15-day-old larvae of bean moth under spring, summer and autumn sowing conditions. The survival rate of 18-day-old larvae of bean moth under autumn and summer sowing was significantly higher than that under spring sowing, but there was no significant difference between autumn and summer sowing ( Fig.31 C).

[0159] Differences in larval growth indicators and soybean agronomic traits between different sowing seasons Fig.31 As shown in the figure: A: weight of single larvae at 12, 15 and 18 days old; B: weight of larvae in plots at 12, 15 and 18 days old; C: survival rate of larvae at 15 and 18 days old; D: plant height; E: number of main stem nodes; F: number of branches; G: area of ​​inverted trefoil; H: dry weight of inverted trefoil; I: total number of compound leaves; J: leaf area per plant. The plant height of spring-sown soybean material was significantly higher than that of summer-sown, and the plant height of summer-sown soybean material was significantly higher than that of autumn-sown soybean material ( Fig.31 D). There was no significant difference in the number of main stem nodes between spring-sown and summer-sown soybean materials, and the number of main stem nodes of autumn-sown soybean materials was significantly lower than that of the other two sowing seasons ( Fig.31 E). The number of branches of soybean materials sown in summer was significantly higher than that sown in spring, and the number of branches of soybean materials sown in spring was significantly higher than that sown in autumn ( Fig.31F). The area of ​​the inverted three leaves of soybean materials sown in spring was significantly higher than that sown in summer, and the area of ​​the inverted three leaves of soybean materials sown in summer was significantly higher than that sown in autumn ( Fig.31 G). The dry weight of the inverted clover of soybean materials sown in spring was significantly higher than that sown in summer, and the dry weight of the inverted clover of soybean materials sown in summer was significantly higher than that sown in autumn ( Fig.31 H). The total number of compound leaves of soybean materials sown in summer was significantly higher than those sown in spring and autumn, while there was no significant difference between spring and autumn sowing ( Fig.31 I). The leaf area per plant of soybean material under spring sowing conditions was significantly higher than that under summer sowing, and the leaf area per plant under summer sowing was significantly higher than that under autumn sowing ( Fig.31 J).

[0160] The following table shows the selection of soybean varieties suitable for breeding larvae of bean moth: Fig.32 As shown in the figure, in the figure: the bold variety name is the selected soybean variety; the bold number is the top 5 of each index in each sowing season. The materials with * are ranked in the top 5 of a certain index, and the number of * represents the number of the top 5 indexes of the material. LW18: weight of single larvae at 18 days old; PH: plant height; IL: internode spacing; NB: number of branches; LA: area of ​​inverted trefoil; LDW: dry weight of inverted trefoil; TCL: total number of compound leaves. Under the spring sowing conditions in 2023, 10 soybean materials were selected based on the weight of single larvae of 18-day-old bean moth and the leaf area per plant as indicators. Combined with the comprehensive evaluation of plant height, internode spacing and number of branches, two soybean materials for bean moth breeding under spring sowing conditions were selected: short stem flat head yellow and foot hugging yellow. Under the summer sowing conditions in 2023, 10 soybean materials were selected based on the weight of single larvae of 18-day-old bean hawkmoth and the leaf area per plant as indicators. Combined with the comprehensive evaluation of plant height, internode spacing, and number of branches, three soybean materials for bean hawkmoth breeding under summer sowing conditions were selected: Fogang soybean, Shangrao August white, and green beans. Under the autumn sowing conditions in 2022, 10 soybean materials were selected based on the weight of single larvae of 18-day-old bean hawkmoth and the leaf area per plant as indicators. Combined with the comprehensive evaluation of plant height, internode spacing, and number of branches, three soybean materials for bean hawkmoth breeding under autumn sowing conditions were selected: large green beans, small yellow beans-2, and two yellow beans-1.

[0161] Bean moth feeds on soybean leaves for a living, and bean moth breeding will select varieties with large leaf biomass to improve the yield of bean moth per unit area. Therefore, the single leaflet biomass (positively correlated with the area of ​​the inverted three leaves and the dry weight of the inverted three leaves) and the individual plant leaf biomass of soybean varieties are also important bases for the selection of special varieties for bean moth breeding. The individual plant leaf biomass is affected by the main stem node number, the dry weight of a single leaf, the total number of branches, the total number of compound leaves, etc., so these agronomic traits are all related to the breeding of bean moth larvae. The present invention is through a comprehensive investigation of the properties such as single head larva weight, the larva weight of a small plot, the soybean leaf area loss rate and the soybean leaf biomass, and preliminarily screens out the soybean varieties suitable for bean moth breeding. The soybean varieties screened will also be subjected to a small plot breeding test in a net room, and the yield situation, the survival rate and the distribution of the larvae in each weight interval of each variety feeding bean moth under the actual breeding conditions are compared, and finally the special soybean varieties suitable for bean moth breeding are screened out.

[0162] The above screening of the present invention can be carried out in spring, summer and autumn respectively, and the breeding varieties suitable for a certain season are screened out respectively. The varieties suitable for breeding bean dan in spring have baojiaohuang and dwarf flat yellow, and the varieties suitable for breeding bean dan in summer have Shangrao August White and Fogang Soybean, baojiaohuang and green beans are better in spring sowing and summer sowing to the adaptability of bean hawk moth, and can be used as the general soybean variety of annual bean hawk moth breeding. By comparative analysis of larval growth factor, it is clear that suitable sowing period is spring and summer (the middle and lower reaches of the Yangtze River are from early April to the end of July), and suitable plant identification period is about soybean V6 stage, and leaf position is up and down three leaves. Summer is the best season for adaptability evaluation and can be used for the initial screening of variety, but in order to cater to the needs of the market and farmers, the selection of variety can be focused on in spring and summer, and the test parameters of different seasons should be fine-tuned. The soybean variety selection method suitable for bean dan breeding in different regions has a little difference due to reasons such as climate differences, and can be appropriately adjusted with reference to the adjustment scheme of different sowing season test parameters in the present invention.

[0163] The present invention establishes a method for selecting soybean varieties specially used for breeding bean hawkmoths. The susceptible germplasm is initially screened by using a bag isolation feeding test with the weight of a single larva on the 15th day after the larvae feed on the inverted third leaf on the living plant as the main index. The susceptible germplasm initially screened is further screened for soybean varieties suitable for breeding bean hawkmoths in combination with the larval weight in the plot, the leaf area loss rate and the biomass of the leaves per plant. Then, the further screened soybean varieties are subjected to a plot isolation breeding test, and the actual yield, survival rate and distribution of the larvae in each weight range of different varieties under the conditions of net house breeding are compared, and finally the soybean varieties suitable for breeding bean hawkmoths are screened.

Claims

1. A method for screening soybean varieties suitable for soybean cultivation, characterized in that: It includes the following steps: First, prepare the eggs of the bean moth and the soybean varieties to be screened, then plant soybeans, feed the bean moth larvae and analyze the results, including: Step S1: bagging and isolation feeding: (1) Sowing the soybean varieties to be screened in holes in a net room or in a field away from the pesticide application area. When the number of identified soybean varieties is more than 50, each net room is used as a block group; when the number of identified soybean varieties is less than 20, all soybean varieties are used as a block group, and multiple blocks are arranged in one net room; when the number of identified soybean varieties is between 20 and 50, any of the above two methods is adopted; (2) When sowing in spring or autumn, wait until the soybeans grow to the V4 stage; when sowing in summer, wait until more than 50% of the soybean varieties grow to the V6-R1 stage, bagging and hanging eggs are carried out, with The method is as follows: prepare a mesh bag with one end open and the other end closed, put the eggs of the bean moth that are about to hatch in the mesh bag, and then put a mesh bag with the eggs in it on each soybean plant hole. After the mesh bag is put on the two inverted trefoil leaves, tie the open end of the mesh bag tightly; at the same time, record the leaf length, leaf width, leaf area, total number of compound leaves, lodging and agronomic traits of the inverted trefoil leaves of the soybean plants; (3) After the eggs hatch, until the 9th day after the larvae feed on the leaves, record the number of surviving larvae and weigh them for the first time. During the first weighing, select larvae with the same growth and development and similar size from each mesh bag, and select the number of larvae from each mesh bag. If the number of larvae selected is equal to 3 and 8, the remaining larvae are taken away and the total weight of the selected larvae is recorded. If the number of larvae selected is less than 5, the number of larvae and the total weight of the larvae are recorded. (4) After the first weighing, replace the large mesh bag and put the selected fixed number of larvae into the large mesh bag. After the large mesh bag is put on the unfed inverted trefoil of the plant, the opening of the mesh bag is tied tightly. (5) The larvae are weighed on the 12th, 15th, 18th and 21st days after they feed on the leaves, and the total weight of the larvae in each mesh bag and the number of surviving larvae are recorded respectively. The number of surviving larvae in each mesh bag is recorded after each weighing. Put the larvae into the net bag and put them back on each hole of the plant that was originally inoculated. When putting the net bag back on, put the net bag on the inverted trefoil that has not been bitten; (6) After each weighing, calculate the average weight of the larvae in each net bag, and calculate the larval survival rate. The average weight of the larvae is the weight of a single larva, and the total weight of the larvae is the weight of the larvae in the small area. The weight of the larvae in the small area at the first weighing is the total weight of the same number of larvae selected. Each survival rate is calculated based on the number of larvae retained in the net bag at the first weighing; (7) Repeat the process of bagging and isolation feeding in different seasons, that is, repeat the above steps (1) to (6); Step S2: Preliminary screening of susceptible soybean materials: (1) Using the ranking of the weight of a single larvae fed on a certain day from heavy to light as an indicator, select the soybean varieties that rank in the top 20% in terms of the weight of a single larvae in bagged isolation feeding as the susceptible materials. If the susceptible materials reach the top 20% in terms of the weight of a single larvae in more than two bagged isolation feedings, then the susceptible materials are relatively stable susceptible varieties, i.e., the susceptible varieties preliminarily screened; or (2) Using the weight of a single larvae fed on a certain day as an indicator, select the soybean varieties that reach a specified weight in terms of the weight of a single larvae in bagged isolation feeding as the susceptible materials. If the susceptible materials reach the specified weight in more than two bagged isolation feedings, then the susceptible materials are relatively stable susceptible varieties, i.e., the susceptible varieties preliminarily screened; Step S3: Free choice of feeding in the net room: (1) Sowing the soybean varieties to be screened in holes or rows in the net room, with each net room as a block group; (2) When the soybeans grow to the V4 stage in spring and autumn sowing, and when the soybeans grow to the V6 stage in summer sowing, hanging eggs, specifically: prepare a net bag with an open end, put the bean moth eggs that are about to hatch in the net bag, and then put a net bag with eggs in each hole or each row of soybean plants, and after the net bag is put on the inverted third leaf of the plant, tie the opening of the net bag tightly; (3) After the larvae hatch, release the larvae from the net bag on the 5th to 9th day of feeding, and the larvae feed freely in the net room; (4) When the overall leaf loss rate in the net room is observed to reach more than 5%, record the leaf loss rate of each soybean variety in the net room; Step S4: Investigation of soybean biomass and agronomic traits: (1) Sowing the soybean varieties to be screened in rows in the field or in a net room, with the varieties arranged randomly, with one row for each variety and three replicates; (2) In each sowing season, at the V6 and R6 stages of soybean growth, pick the middle leaflets or the entire inverted trefoil of the soybean plant, and take three leaves from each variety as replicates. After the leaves are picked, they are put into sampling bags and temporarily stored in an ice box for preservation, and then brought back to the room for scanning. The scanned leaves are put into labeled paper bags according to different varieties and dried at 80°C for three days, and then weighed; at the same time, the agronomic traits of each variety are investigated, specifically measuring plant height, number of main stem nodes, number of branches, number of branch nodes, total number of compound leaves, internode length and single plant leaf biomass; Step S5: further comprehensive screening of insect-susceptible soybean varieties: the insect-susceptible varieties obtained by preliminary screening are analyzed in terms of single larval weight, plot larval weight, leaf area loss rate and single plant leaf biomass. The single larval weight and plot larval weight are the average values ​​of the 15th or 18th day of feeding of each batch of bagged isolation feeding in step S1, the leaf loss rate is the result of the 14th day of larval feeding in step S3, and the single plant leaf biomass is the result in step S4. The comprehensive performance of different varieties in the above indicators is ranked, and the varieties ranked in the top five in more than two indicators are determined as the insect-susceptible varieties for further comprehensive screening; Step S6: Selection of excellent soybean varieties for cultivation in net room isolation feeding: (1) Sowing the insect susceptible varieties selected in the net room, each net room is 2m×2m in size, sowing one soybean variety in each net room, and each net room is used as a plot; (2) When the soybeans grow to the V4 stage in spring and autumn sowing, and when the soybeans grow to the V6 stage in summer sowing, laying eggs, specifically: prepare a net bag with one end open, put the milky white soybean hawk moth eggs that are about to hatch in the net bag, put the net bag on the inverted third leaf of the plant, and then tie the opening of the net bag tightly, put four net bags in each net room, put 20 eggs in each bag, that is, 20 eggs per square meter; (3 ) After the eggs are hatched, the larvae are released from the net bag on the 5th to 9th day of feeding, and the larvae are allowed to feed freely in the net room; (4) On the 24th to 26th day of feeding, all the larvae in each net room are caught, counted and weighed one by one. At the same time, the bean moth is divided into weight intervals according to the different weights of single larvae and classified and counted, and the proportion of larvae in each weight interval is calculated; (5) The survival rate of larvae in each net room, the total weight of larvae in a single net room, the proportion of larvae greater than or equal to 6g and the average weight of single larvae are compared. When these four indicators of a certain variety are ranked in the top five, it is finally determined that the variety is suitable for soybean cultivation.

2. The method for screening soybean varieties suitable for soybean cultivation according to claim 1, characterized in that: In step S1, the soybean leaves placed in the net bag when hanging eggs are the inverted three leaves of the soybean plant, that is, the third fully expanded compound leaf from the top of the plant from top to bottom. When replacing the leaves in the net bag, the inverted three leaves of other plants in the same hole are selected.

3. The method for screening soybean varieties suitable for soybean cultivation according to claim 1, characterized in that: In step S2, the weight of a single larvae that has fed for 15 or 18 days or its ranking is used as an indicator to preliminarily screen the susceptible soybean materials in a summer net room with an average temperature of 29.7 degrees; the weight of a single larvae that has fed for 18 days or its ranking is used as an indicator to preliminarily screen the susceptible soybean materials in a summer open air with an average temperature of 28.8 degrees and in an autumn net room with an average temperature of 27.0 degrees; in the second method in step S2, the specified weight of a single larvae that is 18 days old is 1.70 grams, 2.70 grams and greater than 0.55 grams when sowing in spring, summer and autumn, respectively.

4. The method for screening soybean varieties suitable for soybean cultivation according to claim 1, characterized in that: The mesh bags used in step (2) of step S1, step S3 and step S6 are all small mesh bags with a length of 20 cm and a width of 15 cm. The large mesh bag used in step S1 is a large mesh bag with a length of 40 cm and a width of 30 cm. Both the small mesh bag and the large mesh bag are transparent gauze mesh bags. A drawstring is provided at one end of the opening of the mesh bag, and an inner pocket is provided on the inner side of the mesh bag.

5. The method for screening soybean varieties suitable for soybean cultivation according to claim 1, characterized in that: In step S1, step S3 and step S4, the size of the net house used is 4-50m in length and 4-8m in width. The net house is spliced ​​by a steel frame structure and covered with a 40-60 mesh insect-proof net. The insect-proof net around the net house is buried 25-35 cm under the soil; the size of the net house used in step S6 is 2m×2m; in steps S1 and S3, a group of soybean varieties are sown in one net house, which is repeated 3 times, and in step S6, one soybean variety is sown in one net house, which is repeated 3 times.

6. The method for screening soybean varieties suitable for soybean cultivation according to claim 1, characterized in that: In step S1, the bagging isolation feeding process is carried out once in spring, summer and autumn respectively, 5 seedlings are planted in each hole, 12 eggs are placed in each mesh bag, and 5 larvae are retained by the first weighing; in spring and summer, the plants are tall, and the row spacing × hole spacing of hole sowing is 0.6 m × 0.6 m, while in autumn, the plants are shorter, and the row spacing × hole spacing of hole sowing is 0.6 m × 0.5 m or less.

7. The method for screening soybean varieties suitable for soybean cultivation according to claim 6, characterized in that: In step S1, the number of eggs in each mesh bag is adjusted between 10 and 30 according to the difference in identification season and egg hatching rate, but the number of eggs in each mesh bag is the same in the same batch of tests, and the eggs used are eggs produced on the same day and about to hatch, and the shrunken eggs and the eggs that are not whitish, unhealthy, and undeveloped are removed; according to the identification season, the age of the larvae, and the growth and development of the larvae, the leaf biomass required is estimated, and the inverted trefoil of other plants in the same hole is added to the mesh bag every 1 to 3 days; when the bean moth is 3rd instar, i.e. 9-15 days old, the trefoil of other plants in the same hole is replaced Use large net bags. Replace the net bags when the bean moth is 9-12 days old during summer sowing, and replace the net bags when the bean moth is 12-15 days old during spring and autumn sowing. When the larvae develop to the third instar, that is, 9-15 days old, the number of retained larvae is adjusted between 3 and 8 heads according to the identification season and leaf biomass. According to the identification season and the growth and development of the larvae, when the larvae develop to the third instar, weigh and count the larvae in the net bags. The adaptability indicators include the weight of a single larva, the weight of larvae in a small area and the survival rate of larvae, among which the average weight of a single larvae at 12-18 days old is the best indicator.

8. The method for screening soybean varieties suitable for soybean cultivation according to claim 1, characterized in that: In step S3, the row spacing × hole spacing was 0.3 m × 0.3 m, 5 seedlings were planted in each hole, and the leaf loss rate on the 11th, 12th, 13th and 14th days of larval feeding was investigated respectively; in step (3) of step S3, the number of days the larvae were released from the net bag was 5-9 days, and the position of the larvae was manually adjusted to ensure that the larvae were evenly distributed in the net room.

9. The method for screening soybean varieties suitable for soybean cultivation according to claim 1, characterized in that: In step S4, row sowing is adopted in the field or in a net room, with a row length of 1-4 m, a row spacing of 0.5 m, and a plant spacing of 0.1 m, and thinning is performed in the V1 stage of soybean growth; in step S6, the row spacing × the hole spacing of hole sowing is 0.4 m × 0.5 m, and 3 seedlings are planted in each hole.

10. The method for screening soybean varieties suitable for soybean cultivation according to claim 1, characterized in that: In step S1, summer sowing, V6 stage, and inverted three leaves are used for bagging and isolation feeding, and the average single larvae weight from 15 days to 21 days old is used as an evaluation indicator.

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