Method for identifying and judging shade tolerance of soybean variety in corn and soybean intercropping mode

Abstract

The invention provides a shade tolerance identification and judgment method for soybean varieties in a corn and soybean intercropping mode, which comprises the following steps: selecting corn varieties, planting row ratio, sowing time and sowing mode, and recording the growth and development of main characters of soybeans in each period. According to the method for identifying the shade tolerance of the soybean breeding material and the soybean variety, the method for identifying the shade tolerance of the breeding material and the soybean variety is provided for soybean breeding and soybean production, the breeding time can be effectively shortened, the breeding efficiency can be improved, and the method is suitable for large-scale popularization and application. And soybean varieties or breeding materials with strong shade tolerance can be rapidly screened for production. According to the method for identifying and judging the shade tolerance of the soybean variety, the soybean variety with high shade tolerance can be effectively screened out, powerful technical support is provided for popularization and application of a corn and soybean intercropping mode, the land utilization rate and the total yield of crops are increased, and agricultural sustainable development is achieved.

Description

Technical Field

[0001] The invention relates to the field of agriculture, and in particular to a method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern. Background Art

[0002] Soybeans are the main food, vegetable, oil and feed crops in my country because they are rich in protein, fat and contain a variety of physiologically active substances. More than 60% of the protein and 40% of the oil needed by the Chinese people mainly depend on the production of soybeans. However, due to the low net profit of soybeans (compared with corn, flue-cured tobacco, etc.), intercropping of soybeans with corn, fruit trees and other crops is a common habitual planting method in the main soybean producing areas in southern and northwestern my country. Intercropping of soybeans is an effective way to improve the ecological conditions of dryland soil, improve comprehensive economic benefits and increase farmers' income. In production, intercropping of soybeans has the advantages of nitrogen fixation and fertilization, low-carbon production, strong demand, less labor, low cost and high efficiency. Therefore, intercropping of soybeans will still occupy an important position in future agricultural production.

[0003] In intercropping soybean production, the most important technology is to select shade-tolerant soybean varieties. Soybeans are warm-loving and light-demanding crops. When soybeans are shaded and blocked by other crops during their growth, they will inevitably undergo physiological and biochemical responses, which will be reflected in the growth and development of phenotypic traits. In view of the actual production practice of soybeans intercropped with tall-stalked crops such as corn, soybeans are sown at the same time as corn under the conditions of corn shading and blocking, so that soybeans grow synchronously with corn throughout the growth and development process and mature before corn. The main traits of soybeans during the growth and development process are used as the basic basis to judge the shade tolerance of soybean varieties. The selected strong shade-tolerant varieties are mainly used for the promotion of intercropping with corn in production.

[0004] Through the intercropping of soybeans and corn, certain soybean shade tolerance evaluation standards are formulated, which can be used by breeders to select shade-tolerant soybean varieties, and can also be used to screen shade-tolerant soybean varieties in production. It is a basic technology for assisting soybean breeding and screening shade-tolerant soybean varieties in production. It has certain application value in soybean breeding and soybean production. In modern agricultural production, the corn-soybean intercropping model has attracted much attention because it can efficiently utilize land resources and increase total crop yields. The Ministry of Agriculture and Rural Affairs vigorously promotes the soybean-corn strip composite planting technology in the Huanghuaihai, Southwest, and Northwest regions from 2022 to 2024, which is a good proof. However, in this intercropping model, soybeans grow under the shade of corn, and their shade tolerance is crucial to the yield. Therefore, a method for identifying and judging the shade tolerance of soybean varieties in the corn-soybean intercropping model is proposed. Summary of the invention

[0005] The purpose of the present invention is to address the problems raised by the existing background technology. In order to achieve the above invention purpose, the present invention provides the following technical solution: a method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern, comprising the following steps:

[0006] Step 1: Select corn varieties and planting row ratio, sowing period, sowing method, and set soybean seed clearing comparison;

[0007] Step 2, recording the growth and development of the main traits of soybeans at different stages, and determining the correlation index between the traits and shade tolerance;

[0008] Step 3, determining shade tolerance according to trait indicators;

[0009] Step 4: The evaluation method is applied to the shade tolerance identification of soybean breeding materials and varieties.

[0010] As a preferred technical solution of the present invention, step 1, select corn varieties, specifically select semi-compact varieties with a plant height of 250 to 280 cm, which are suitable for normal growth in the identification experimental area; the identified soybean materials and varieties can grow normally under clear seed conditions and under the ecological conditions of the identification experimental area.

[0011] As a preferred technical solution of the present invention, step 1, the field layout of the intercropping row ratio of soybeans and corn adopts the method of planting 2 rows of corn and 2 rows of soybeans alternately; the length of each plot is 6 meters and the width is 2.2 meters; 2 repetitions are adopted, and a random block design is adopted; the soybean clearing is compared once, without repetition.

[0012] The row and plant spacing of soybean and corn intercropping field layout: 40 cm between soybeans, 40 cm between soybeans and corn, 50 cm between corn; plant spacing: 40 cm between corn holes, double plant spot sowing, 15 holes per row, 30 seedlings per row, soybean furrow sowing, 10 cm plant spacing, 60 seedlings per row, 120 plants per plot.

[0013] Soybean field layout: The row length of the plot is 6 meters, the width is 1.6 meters, and the area is 9.6 square meters. There are 4 rows of soybeans, each row is 6 meters long, the row spacing is 40 centimeters, the plant spacing is 10 centimeters, 60 seedlings are left in each row, and each plot has 4 rows, totaling 240 plants. The 120 plants in the middle 2 rows are used as test samples.

[0014] As a preferred technical solution of the present invention, step 1, the sowing period is the normal sowing period of soybeans and corn, and the sowing method is specifically as follows: sowing in a flat plot with medium to high soil fertility, where the soil is suitable for the growth of soybeans and corn; sowing in the spring when the growth period of crops is suitable, and the soil temperature reaches above 12° for more than 7 consecutive days.

[0015] As a preferred technical solution of the present invention, step 1, fertilizing during sowing specifically includes applying base fertilizer and topdressing fertilizer;

[0016] The base fertilizer: ternary compound fertilizer N15% + P 2 O 5 15%+K 2 O15%, 0.3 kg per plot, 0.2 kg in corn holes, 0.1 kg in soybean furrows;

[0017] The topdressing application: 0.3 kg of urea per plot for corn, applied between 2 rows of corn twice during the small and large trumpet stages, but no application for soybeans.

[0018] As a preferred technical solution of the present invention, step 2, recording the growth and development of the main traits of soybeans at various stages, includes survey and recording items, field trait surveys, and indoor seed testing.

[0019] As a preferred technical solution of the present invention, the survey and record items are 2 states and 4 traits of the material varieties surveyed and recorded in the field or tested and identified indoors;

[0020] The two states include effective mature plants and lodging degree;

[0021] The four traits include plant height, number of effective pods per plant, number of grains per plant, and grain weight per plant.

[0022] As a preferred technical solution of the present invention, the field trait investigation and indoor testing include effective mature plants and lodging degree;

[0023] The effective mature plants: surveyed when soybeans matured, and recorded the effective mature plants of two rows of identification materials (variety) in each test plot, and surveyed the effective mature plants of the two middle rows in the clear seed control plot (the two side rows were not surveyed);

[0024] The lodging degree: investigate and record the lodging degree of soybeans in the plot, observe the lodging degree of plants before and after maturity, record the number of lodging plants, and determine the lodging level;

[0025] Plant height, number of effective pods per plant, number of grains per plant, and grain weight per plant: In each soybean mature row, 15 consecutive plants out of the middle 30 plants excluding the two ends 1.5 meters away were collected for testing. In the seed-clearing control plot, 30 effective mature plants of identification materials (varieties) in the two middle rows were collected for testing (the plants in the two side rows and 1.5 meters on both sides were not allowed to be collected). Each plot took the average of the 30 samples.

[0026] As a preferred technical solution of the present invention, step 3, the calculation method for determining the shade tolerance performance according to the trait index is:

[0027] Effective mature plant rate = number of effective mature plants in intercropping / number of effective mature plants in seed clearing*100;

[0028] Score = effective mature plant rate / 10 (maximum 10 points);

[0029] Lodging level = 0, 1, 2, 3, 4;

[0030] Score = Level 0: 10 points, Level 1: 9 points, Level 2: 8 points, Level 3: 7 points, Level 4: 6 points (maximum 10 points);

[0031] Plant height difference = | intercropping plant height with corn - plant height after clearing seed | absolute value;

[0032] Score = 10 points for less than 5 cm, 9 points for 5-10 cm, 8 points for 10-15 cm, 7 points for 15-20 cm, 6 points for more than 20 cm (maximum 10 points);

[0033] Single plant grain weight (g) = average result of 30 tested plants;

[0034] Score = intercropping grain weight per plant with corn / clear seeding grain weight per plant*10 (maximum 10 points);

[0035] Number of grains per plant (grains) = average result of 30 tested plants;

[0036] Score = number of grains per plant in intercropping with corn / number of grains per plant in clearing seed*10 (maximum 10 points);

[0037] Number of single effective pods = average result of 30 tested plants;

[0038] Score = number of effective pods per intercrop with corn / number of effective pods per clear seed*10 (maximum 10 points);

[0039] Total shade tolerance score = effective maturity rate (%) score + lodging level (level) score + plant height difference (cm) score + single plant grain weight (g) score + single plant grain number (grains) score + single plant effective pod number (pieces) score; (maximum 60 points).

[0040] As a preferred technical solution of the present invention, step 4, the evaluation method is applied to the evaluation index of shade tolerance identification of soybean breeding materials and varieties: shade tolerance performance is divided into 6 levels:

[0041] Level 1: Strong shade tolerance: 50-60 points;

[0042] Level 2: Strong shade tolerance: 40-50 points;

[0043] Level 3: Moderate shade tolerance: 30-40 points;

[0044] Level 4: shade intolerance: 20-30 points;

[0045] Level 5: Severe shade intolerance: 10-20 points;

[0046] Level 6: Severe shade intolerance: 0 to 10 points.

[0047] Compared with the prior art, the invention has the following beneficial effects: In the scheme of the invention, it provides basic technology for soybean breeding and soybean production, and a method for identifying breeding materials and shade tolerance of varieties. The application of this technology can effectively shorten the breeding time, improve breeding efficiency, and quickly screen soybean varieties or breeding materials with strong shade tolerance for production. It is a public welfare basic application technology with certain social benefits.

[0048] The soybean variety shade tolerance identification and evaluation method provided by the present invention has the advantages of scientificity, accuracy, strong operability, etc. Through this method, soybean varieties with strong shade tolerance can be effectively screened out, providing strong technical support for the promotion and application of corn and soybean intercropping patterns, helping to improve land utilization and total crop yields, and achieving sustainable agricultural development. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the process provided by the present invention;

[0050] Figure 2 The invention provides a graph of the results of a shade-tolerant variety screening test set up in various locations. DETAILED DESCRIPTION

[0051] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0052] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features and technical solutions in the embodiments can be combined with each other without conflict. It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0053] Example 1: Please refer to Figure 1-Figure 2 A method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern comprises the following steps:

[0054] Step 1: Select corn varieties and planting row ratio, sowing period, sowing method, and set soybean seed clearing comparison;

[0055] Step 2, recording the growth and development of the main traits of soybeans at different stages, and determining the correlation index between the traits and shade tolerance;

[0056] Step 3, determining shade tolerance according to trait indicators;

[0057] Step 4: The evaluation method is applied to the shade tolerance identification of soybean breeding materials and varieties.

[0058] Step 1: Select corn varieties, specifically semi-compact varieties with a plant height of 250 to 280 cm that are suitable for normal growth in the identification experimental area; the identified soybean materials and varieties can grow normally under clear seed conditions and the ecological conditions of the identification experimental area.

[0059] Step 1. The field layout of the soybean-corn intercropping row ratio adopts the method of planting 2 rows of corn and 2 rows of soybeans alternately; the length of each plot is 6 meters and the width is 2.2 meters; 2 repetitions are adopted, and a randomized block design is adopted; the soybean seed clearing comparison is performed once, without repetition.

[0060] The row and plant spacing of soybean and corn intercropping field layout: 40 cm between soybeans, 40 cm between soybeans and corn, 50 cm between corn; plant spacing: 40 cm between corn holes, double plant spot sowing, 15 holes per row, 30 seedlings per row, soybean furrow sowing, 10 cm plant spacing, 60 seedlings per row, 120 plants per plot.

[0061] Soybean field layout: The row length of the plot is 6 meters, the width is 1.6 meters, and the area is 9.6 square meters. There are 4 rows of soybeans, each row is 6 meters long, the row spacing is 40 centimeters, the plant spacing is 10 centimeters, 60 seedlings are left in each row, and each plot has 4 rows, totaling 240 plants. The 120 plants in the middle 2 rows are used as test samples.

[0062] Step 1. The sowing period is the normal sowing period for soybeans and corn. The specific sowing method is: sow in flat land with medium to high soil fertility, and the soil is suitable for the growth of soybeans and corn; sow in the spring when the soil temperature reaches above 12° for more than 7 consecutive days during the suitable growth period of crops.

[0063] Step 1: Fertilization during sowing specifically includes base fertilizer and topdressing;

[0064] Base fertilizer: Apply triple compound fertilizer N15% + P 2 O 5 15%+K 2 O15%, 0.3 kg per plot, 0.2 kg in corn holes, 0.1 kg in soybean furrows;

[0065] Apply topdressing fertilizer: Apply 0.3 kg of urea per plot for corn, twice between 2 rows of corn during the small and large trumpet stages. No topdressing is required for soybeans.

[0066] Step 2: Record the main characteristics of soybeans at different growth stages, including survey and recording items, field characteristic surveys, and indoor seed testing.

[0067] The survey and record items are 2 states and 4 traits of the variety of materials surveyed and recorded in the field or tested and identified indoors;

[0068] The 2 states include the number of effective mature plants and the degree of lodging;

[0069] The four traits include plant height, number of effective pods per plant, number of grains per plant, and grain weight per plant.

[0070] Field trait investigation and indoor testing include effective mature plants and lodging degree;

[0071] Effective mature plants: Survey when soybeans are mature, record the effective mature plants of two rows of identification materials (variety) in each test plot, and survey the effective mature plants of the two middle rows in the clear seed control plot (the two side rows are not surveyed);

[0072] Lodging degree: Investigate and record the lodging degree of soybeans in the plot, observe the lodging degree of plants before and after maturity, record the number of lodging plants, and determine the lodging level;

[0073] Plant height, number of effective pods per plant, number of grains per plant, and grain weight per plant: In each soybean mature row, 15 consecutive plants out of the middle 30 plants excluding the two ends 1.5 meters away were collected for testing. In the seed-clearing control plot, 30 effective mature plants of identification materials (varieties) in the two middle rows were collected for testing (the plants in the two side rows and 1.5 meters on both sides were not allowed to be collected). Each plot took the average of the 30 samples.

[0074] Step 3: The calculation method for determining shade tolerance based on trait indicators is:

[0075] Effective mature plant rate = number of effective mature plants in intercropping / number of effective mature plants in seed clearing*100;

[0076] Score = effective mature plant rate / 10 (maximum 10 points);

[0077] Lodging level = | intercropping plant height with corn - plant height after seed removal | absolute value;

[0078] Score = Level 0: 10 points, Level 1: 9 points, Level 2: 8 points, Level 3: 7 points, Level 4: 6 points (maximum 10 points);

[0079] Plant height difference = (plant height after intercropping with corn - plant height after clearing seed);

[0080] Score = 10 points for less than 5 cm, 9 points for 5-10 cm, 8 points for 10-15 cm, 7 points for 15-20 cm, 6 points for more than 20 cm (maximum 10 points);

[0081] Single plant grain weight (g) = average result of 30 tested plants;

[0082] Score = intercropping grain weight per plant with corn / clear seeding grain weight per plant*10 (maximum 10 points);

[0083] Number of grains per plant (grains) = average result of 30 tested plants;

[0084] Score = number of grains per plant in intercropping with corn / number of grains per plant in clearing seed*10 (maximum 10 points);

[0085] Number of single effective pods = average result of 30 tested plants;

[0086] Score = number of effective pods per intercrop with corn / number of effective pods per clear seed*10 (maximum 10 points);

[0087] Total shade tolerance score = effective maturity rate (%) score + lodging level (level) score + plant height difference (cm) score + single plant grain weight (g) score + single plant grain number (grains) score + single plant effective pod number (pieces) score; (maximum 60 points).

[0088] Step 4: Evaluation method The evaluation index used for shade tolerance identification of soybean breeding materials and varieties is: Shade tolerance is divided into 6 levels:

[0089] Level 1: Strong shade tolerance: 50-60 points;

[0090] Level 2: Strong shade tolerance: 40-50 points;

[0091] Level 3: Moderate shade tolerance: 30-40 points;

[0092] Level 4: shade intolerance: 20-30 points;

[0093] Level 5: Severe shade intolerance: 10-20 points;

[0094] Level 6: Severe shade intolerance: 0 to 10 points.

[0095] Principle of the method for identifying and judging the shade tolerance of soybean varieties in the intercropping mode of corn and soybean: soybean growth requires the absorption of light energy, the production of chlorophyll, and the formation of its own substances. Therefore, light is a necessary condition for the normal growth of soybeans. However, due to the genetic differences and physiological changes between soybean varieties, the light intensity required by each soybean variety during the growth process is not exactly the same, and the ability to absorb light is also different. In other words, there are large differences in the shade tolerance of soybean varieties. This difference will be manifested as changes in certain growth states and traits during the growth process. Since corn is a tall crop, the plant is taller than soybeans during the growth process, which has a greater impact on the absorption of light energy during the growth of soybeans. By setting up the intercropping mode of corn and soybeans, under the light conditions of naturally blocking soybeans during the growth of corn, it is feasible to identify and judge the shade tolerance of soybean varieties by associating growth states and trait change indicators. The purpose is to select varieties that absorb light energy more strongly or require less light energy through identification and evaluation, that is, varieties that can grow normally under intercropping conditions with corn, and define them as varieties with strong shade tolerance for production application or breeding.

[0096] Technical trials

[0097] In order to screen out shade-tolerant soybean breeding materials and varieties suitable for intercropping with corn, more than 20 intercropping comparison screening tests of corn and soybean were set up in Guiyang, Zunyi, Dafang and other places from 2016 to 2024. The methods were improved in the experimental setting, and more than 400 breeding materials and varieties bred by national soybean breeders and soybean breeders in Guizhou Province were introduced to participate in multiple groups of tests. The changes in variety phenotypic traits and physiological indicators in each test were analyzed, and technical parameters with certain rules were obtained through the analysis of test data to formulate this standard.

[0098] At the same time, a time-space experiment of soybean and corn intercropping was carried out as an auxiliary experiment of this standard. Ten experiments were carried out on the soybean and corn row ratio, plant spacing configuration and sowing time configuration. Through the analysis of the test results, the timely sowing period and reasonable field configuration parameters of this method were determined:

[0099] Table 1: Results of shade-tolerant variety screening trials in various regions from 2016 to 2024

[0100]

[0101]

[0102] In order to select shade-tolerant varieties, a method for identifying and judging the shade tolerance of soybean varieties in corn-soybean intercropping pattern was proposed.

[0103] Experimental example

[0104] Material

[0105] Corn varieties: Select semi-compact varieties with a plant height of 250 to 280 cm and suitable for normal growth in the identification experimental area.

[0106] Soybean materials (variety): objects that need to be identified. The identified soybean materials and varieties can grow normally under the clear seed conditions and the ecological conditions of the identification experimental area (otherwise, the identification materials (variety) that cannot grow and mature normally cannot determine the identification results normally).

[0107] Experimental field setup

[0108] The identification was carried out by adopting the planting method of "corn ‖ soybean", that is, intercropping the soybean varieties (materials) to be identified with corn, with a row ratio of 2:2 (i.e., intercropping 2 rows of corn and 2 rows of soybeans), and the plot was repeated twice, with a random block design, and the plot length was 6 meters, the width was 2.2 meters, and the area was 13.2 square meters. Each plot was set as [2 rows of corn: 2 rows of identification materials (variety): 2 rows of corn]. Row spacing: 40 cm between soybeans and soybeans, 40 cm between soybeans and corn, and 50 cm between corn and corn. Plant spacing: corn hole spacing was 40 cm, double plant spot sowing, 15 holes per row, and 30 seedlings per row. Soybeans (identification materials) were sown in furrows, with a plant spacing of 10 cm, 60 seedlings per row, and 120 plants per plot.

[0109] The identification materials (variety) were compared with the same period of clearing. The clearing plot was 6 meters long, 1.6 meters wide, and 9.6 square meters in area. There were 4 rows of soybeans, 6 meters long, 40 centimeters between rows, and 10 centimeters between plants. 60 seedlings were left in each row, and 240 plants were left in each plot with 4 rows. The 120 plants in the middle 2 rows were used as test samples.

[0110] Environmental conditions

[0111] The experiment was set up in a flat plot with medium to high soil fertility, and the soil was suitable for the growth of soybeans and corn. During the suitable growth period of crops in spring, when the soil temperature reaches above 12° for more than 7 days, sowing can be carried out.

[0112] Fertilization

[0113] Base fertilizer: Apply triple compound fertilizer (N15% + P 2 O 5 15%+K 2 O15%), 0.3 kg per plot, 0.2 kg in corn holes, 0.1 kg in soybean furrows.

[0114] Apply topdressing fertilizer: Apply 0.3 kg of urea per plot for corn, twice between 2 rows of corn during the small and large trumpet stages. No topdressing is required for soybeans.

[0115] Experimental Procedure

[0116] Field sowing

[0117] Soybeans and corn were sown during the normal sowing period in the area where the identification experiment was conducted.

[0118] Field management

[0119] Thin the corn and identification materials in a timely manner according to the design, strictly set the number of soybean seedlings at 60 per row (120 per plot) and the number of corn seedlings at 30 per row, apply fertilizers on time and in the appropriate amount, and manage the rest according to the routine management of local corn and soybean planting.

[0120] Survey, Recording and Calculation Methods

[0121] Survey record items

[0122] Two states and four traits of the material (variety) recorded in field surveys or identified in indoor testing. Two states: (1) Number of effective mature plants; (2) Degree of lodging. Four traits: (1) Plant height; (2) Number of effective pods per plant; (3) Number of grains per plant; (4) Grain weight per plant.

[0123] Field trait investigation and indoor seed testing methods

[0124] Effective mature plants: Survey when soybeans are mature, record the effective mature plants of 2 rows of identification materials (variety) in each test plot, and survey the effective mature plants of the 2 middle rows in the clear seed control plot (the 2 side rows are not surveyed).

[0125] Lodging degree: Investigate and record the lodging degree of soybeans in the plot, observe the lodging degree of plants before and after maturity, record the number of lodged plants, and assess the lodging level.

[0126] Plant height, number of effective pods per plant, number of grains per plant, and grain weight per plant: In each soybean mature row, 15 consecutive plants out of the middle 30 plants excluding the two ends 1.5 meters away were collected for testing. In the seed-clearing control plot, 30 effective mature plants of identification materials (varieties) in the two middle rows were collected for testing (the plants in the two side rows and 1.5 meters on both sides were not allowed to be collected). Each plot took the average of the 30 samples.

[0127] The lodging degree (grade), plant height, number of valid pods per plant, number of grains per plant, and grain weight per plant are carried out in accordance with the standards specified in GB / T19557.4-2004.

[0128] Calculation method for judging shade tolerance level

[0129] Effective mature plant rate = number of effective mature plants in intercropping / number of effective mature plants in seed clearing*100;

[0130] Score = effective mature plant rate / 10 (maximum 10 points)

[0131] Lodging level = | intercropping plant height with corn - plant height after seed removal | absolute value;

[0132] Score = Level 0: 10 points, Level 1: 9 points, Level 2: 8 points, Level 3: 7 points, Level 4: 6 points (maximum 10 points);

[0133] Plant height difference = (plant height after intercropping with corn - plant height after clearing seed);

[0134] Score = 10 points for less than 5 cm, 9 points for 5-10 cm, 8 points for 10-15 cm, 7 points for 15-20 cm, 6 points for more than 20 cm (maximum 10 points).

[0135] Single plant grain weight (g) = average result of 30 tested plants;

[0136] Score = intercropping grain weight per plant with corn / clear seed grain weight per plant*10. (maximum 10 points)

[0137] Number of grains per plant (grains) = average result of 30 tested plants;

[0138] Score = number of grains per plant in intercropping with corn / number of grains per plant in clearing seed*10. (maximum 10 points)

[0139] Number of single effective pods = average result of 30 tested plants;

[0140] Score = Number of effective pods per intercropping with corn / Number of effective pods per clearing seed*10. (Maximum 10 points)

[0141] Total shade tolerance score = effective maturity rate (%) score + lodging level (level) score + plant height difference (cm) score + single plant grain weight (g) score + single plant grain number (grains) score + single plant effective pod number (pieces) score; (maximum 60 points).

[0142] Evaluation index of shade tolerance level

[0143] Shade tolerance is divided into 6 levels:

[0144] Level 1: Strong shade tolerance: 50-60 points;

[0145] Level 2: Strong shade tolerance: 40-50 points;

[0146] Level 3: Moderate shade tolerance: 30-40 points;

[0147] Level 4: shade intolerance: 20-30 points;

[0148] Level 5: Severe shade intolerance: 10-20 points;

[0149] Level 6: Severe shade intolerance: 0 to 10 points.

[0150] Strictly follow the above steps of experimental design, field management, trait investigation and shade tolerance level evaluation. During the experiment, it is imperative to ensure that all operations comply with relevant standards and specifications, and that data records are accurate, complete and reliable. Finally, based on the calculated shade tolerance comprehensive score, the shade tolerance of soybean varieties is objectively and accurately evaluated, providing a scientific basis for selecting suitable corn and soybean intercropping varieties in agricultural production.

[0151] The soybean variety shade tolerance identification and evaluation method provided by the present invention has the advantages of scientificity, accuracy, strong operability, etc. Through this method, soybean varieties with strong shade tolerance can be effectively screened out, providing strong technical support for the promotion and application of corn and soybean intercropping patterns, helping to improve land utilization and total crop yields, and achieving sustainable agricultural development.

[0152] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the above specific implementation methods. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the invention are included in the scope of the claims of the present invention.

Claims

1. A method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern, characterized in that: The following steps are involved: Step 1: Select corn varieties and planting row ratio, sowing period, sowing method, and set soybean seed clearing comparison; Step 2, recording the growth and development of the main traits of soybeans at different stages, and determining the correlation index between the traits and shade tolerance; Step 3, determining shade tolerance according to trait indicators; Step 4: The evaluation method is applied to the shade tolerance identification of soybean breeding materials and varieties.

2. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 1, characterized in that: Step 1: Select corn varieties, specifically semi-compact varieties with a plant height of 250 to 280 cm that are suitable for normal growth in the identification experimental area; the identified soybean materials and varieties can grow normally under clear seed conditions and the ecological conditions of the identification experimental area.

3. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 2, characterized in that: Step 1. The field layout of the soybean-corn intercropping row ratio adopts the method of planting 2 rows of corn and 2 rows of soybeans alternately; the length of each plot is 6 meters and the width is 2.2 meters; 2 repetitions are adopted, and a randomized block design is adopted; the soybean seed clearing comparison is performed once, without repetition. The row spacing of soybean and corn intercropping in the field is 40 cm between soybeans, 40 cm between soybeans and corn, and 50 cm between corn. Plant spacing: Corn holes are 40 cm apart, double-plant sowing, 15 holes per row, 30 seedlings per row, soybeans are sown in furrows, 10 cm apart, 60 seedlings per row, 120 plants per plot. Soybean field layout: The row length of the plot is 6 meters, the width is 1.6 meters, and the area is 9.6 square meters. There are 4 rows of soybeans, each row is 6 meters long, the row spacing is 40 centimeters, the plant spacing is 10 centimeters, 60 seedlings are left in each row, and each plot has 4 rows, totaling 240 plants. The 120 plants in the middle 2 rows are used as test samples.

4. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 3, characterized in that: Step 1. The sowing period is the normal sowing period for soybeans and corn. The specific sowing method is: sow in flat land with medium to high soil fertility, and the soil is suitable for the growth of soybeans and corn; sow in the spring when the soil temperature reaches above 12° for more than 7 consecutive days during the suitable growth period of crops.

5. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 4, characterized in that: Step 1: Fertilization during sowing specifically includes base fertilizer and topdressing; The base fertilizer is: 0.3 kg of triple compound fertilizer N15% + P2O515% + K2O15% per plot, 0.2 kg in the corn hole, and 0.1 kg in the soybean ditch; The topdressing application: For corn, apply 0.3 kg of urea per plot, twice between 2 rows of corn during the small and large trumpet stages, but not for soybeans.

6. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 5, characterized in that: Step 2: Record the main characteristics of soybeans at different growth stages, including survey and recording items, field characteristic surveys, and indoor seed testing.

7. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 6, characterized in that: The survey and record items are 2 states and 4 traits of the varieties of materials surveyed and recorded in the field or tested and identified indoors; The two states include effective mature plants and lodging degree; The four traits include plant height, number of effective pods per plant, number of grains per plant, and grain weight per plant.

8. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 7, characterized in that: The field trait investigation and indoor testing include effective mature plants and lodging degree; The effective mature plants: surveyed when soybeans matured, and recorded the effective mature plants of two rows of identification materials (variety) in each test plot, and surveyed the effective mature plants of the two middle rows in the clear seed control plot (the two side rows were not surveyed); The lodging degree: investigate and record the lodging degree of soybeans in the plot, observe the lodging degree of plants before and after maturity, record the number of lodging plants, and determine the lodging level; Plant height, number of effective pods per plant, number of grains per plant, and grain weight per plant: In each soybean mature row, 15 consecutive plants out of the middle 30 plants excluding the two ends 1.5 meters away were collected for testing. In the seed-clearing control plot, 30 effective mature plants of identification materials (varieties) in the two middle rows were collected for testing (the plants in the two side rows and 1.5 meters on both sides were not allowed to be collected). Each plot took the average of the 30 samples.

9. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 8, characterized in that: Step 3: The calculation method for determining shade tolerance based on trait indicators is: Effective mature plant rate = number of effective mature plants in intercropping / number of effective mature plants in seed clearing*100; Score = effective mature plant rate / 10 (maximum 10 points); Lodging level = 0, 1, 2, 3, 4; Score = Level 0: 10 points, Level 1: 9 points, Level 2: 8 points, Level 3: 7 points, Level 4: 6 points (maximum 10 points); Plant height difference = | intercropping plant height with corn - plant height after clearing seed | absolute value; Score = 10 points for less than 5 cm, 9 points for 5-10 cm, 8 points for 10-15 cm, 7 points for 15-20 cm, 6 points for more than 20 cm (maximum 10 points); Single plant grain weight (g) = average result of 30 tested plants; Score = intercropping grain weight per plant with corn / clear seeding grain weight per plant*10 (maximum 10 points); Number of grains per plant (grains) = average result of 30 tested plants; Score = number of grains per plant in intercropping with corn / number of grains per plant in clearing seed*10 (maximum 10 points); Number of single effective pods = average result of 30 tested plants; Score = number of effective pods per intercrop with corn / number of effective pods per clear seed*10 (maximum 10 points); Total shade tolerance score = effective maturity rate (%) score + lodging level (level) score + plant height difference (cm) score + single plant grain weight (g) score + single plant grain number (grains) score + single plant effective pod number (pieces) score; (maximum 60 points).

10. The method for identifying and judging the shade tolerance of soybean varieties in a corn-soybean intercropping pattern according to claim 9, characterized in that: Step 4: Evaluation method The evaluation index used for shade tolerance identification of soybean breeding materials and varieties is: Shade tolerance is divided into 6 levels: Level 1: Strong shade tolerance: 50-60 points; Level 2: Strong shade tolerance: 40-50 points; Level 3: Moderate shade tolerance: 30-40 points; Level 4: shade intolerance: 20-30 points; Level 5: Severe shade intolerance: 10-20 points; Level 6: Severe shade intolerance: 0 to 10 points.

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