Screening and evaluation method for rapidly evaluating water crack degree index character of sugarcane

Abstract

The invention provides a screening method for rapidly evaluating sugarcane water crack degree index characters. The screening method comprises the following steps: 1) determining to-be-screened agronomic characters related to sugarcane water crack; 2) investigating field measured values of agronomic characters related to sugarcane water cracking of different sugarcane varieties; 3) performing principal component analysis on the field measured value obtained in the step 2); 4) determining the index character for rapidly evaluating the water crack degree of the sugarcane according to the principal component analysis result and the investigation difficulty degree; 5) performing clustering analysis on different sugarcane varieties according to the field measured values of the index characters in the step 2) to obtain a water crack classification result; and 6) according to the field measured value and the clustering result, carrying out gradual discriminant analysis, and verifying the correct rate of the water crack classification result. The invention establishes a rapid evaluation system for the water crack of the sugarcane, which is simple, convenient and feasible, is simple and convenient to operate, can provide theoretical basis and scientific basis for sugarcane breeding, and has important practical application value.

Description

Technical Field

[0001] This invention relates to the field of sugarcane breeding technology, and in particular to a method for screening and evaluating indicators of sugarcane water cracking degree rapidly. Background Technology

[0002] Sugarcane is an important sugar crop and bioenergy crop in the world, occupying an important position in the world economy and agricultural production. Sugarcane growth cracks, also known as sugarcane water cracks, refer to the cracks that occur between the nodes of the sugarcane stem caused by water during the growth and development of sugarcane. These cracks penetrate deep into the tissue and are an irreversible damage that seriously affects the healthy and sustainable development of the sugarcane industry. The main harms of water cracks are as follows: (1) they lead to increased transpiration in sugarcane, resulting in reduced plant water and affecting plant growth; (2) they increase the incidence of sugarcane diseases and pests; (3) they damage the sugarcane stem tissue, reducing sugarcane yield and sugar content; (4) they affect the quality and appearance of the sugarcane, reducing economic benefits. Therefore, sugarcane water cracks have become an important agronomic trait to consider by fruit farmers and breeders. Water cracks are related to variety characteristics, climate environment and cultivation management conditions. Sugarcane varieties with softer outer skin are prone to water cracks; when sugarcane is in a prolonged drought and water shortage period, sudden irrigation or heavy rain can easily cause sugarcane water cracks. Water cracking can only be prevented, not controlled. Strengthening cultivation management measures, applying fertilizers rationally, managing water scientifically, and selecting and applying water-crack-free sugarcane varieties can all prevent sugarcane from developing water cracking. Among these measures, selecting water-crack-free sugarcane varieties is the most economical, direct, and effective preventive measure. Improving the water-crack trait in sugarcane and selecting water-crack-free sugarcane varieties has become an important task in sugarcane breeding.

[0003] Establishing an evaluation system for sugarcane agronomic traits through the screening of quantitative indicators has become a major method for comprehensive evaluation. Currently, research on sugarcane water cracking is limited, and evaluation techniques for sugarcane water cracking are lacking. Furthermore, there are numerous sugarcane varieties (lines) and many traits related to sugarcane water cracking, such as the number of water-cracked nodes, water-cracked node ratio, number of water-cracked stems, water cracking rate, total internode length, total water crack length, total water crack width, and total water crack depth. Therefore, how to comprehensively consider these traits and screen for rapid evaluation indicators of sugarcane water cracking, and establish an evaluation system for sugarcane water cracking, is an urgent problem to be solved in sugarcane breeding.

[0004] The purpose of this invention is to provide a rapid evaluation system for sugarcane water cracking, providing a theoretical basis and scientific evidence for sugarcane breeding.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for screening index traits for rapidly evaluating the degree of water cracking in sugarcane, comprising the following steps:

[0007] 1) Identify the agronomic traits related to sugarcane water cracking to be screened;

[0008] 2) Investigate field measurements of agronomic traits related to sugarcane water cracking in different sugarcane varieties;

[0009] 3) Perform principal component analysis on the field measurement values ​​obtained in step 2);

[0010] 4) Determine the index traits for rapidly evaluating the degree of water cracking in sugarcane based on the principal component analysis results and the difficulty of the investigation;

[0011] 5) Based on the field measurements of the index traits described in step 2), the sum of squares method was used to perform cluster analysis on different sugarcane varieties using Euclidean distance as a metric to obtain the water crack classification results;

[0012] 6) Based on the field measurements and clustering results, perform stepwise discriminant analysis to verify the accuracy of the water crack classification results.

[0013] Preferably, the agronomic traits related to sugarcane water cracking include the number of water-cracked nodes, the water-cracked node ratio, the number of water-cracked stems, the water cracking rate, the total internode length, the total water crack length, the total water crack width, and the total water crack depth.

[0014] The water-cracked node rate is the ratio of the number of water-cracked nodes per sugarcane plant to the total number of nodes, where the number of water-cracked nodes refers to the number of stem nodes on each sugarcane plant that have experienced water cracking.

[0015] The water cracking rate is the ratio of the number of water-cracked stems to the number of effective stems for each sugarcane variety. The number of water-cracked stems refers to the number of sugarcane plants with a height exceeding 100cm at maturity that have water cracking, and the number of effective stems refers to the number of sugarcane plants with a height exceeding 100cm at maturity.

[0016] The total internode length refers to the sum of the internode lengths of all water-cracked stem nodes of each sugarcane plant, and the total water-crack length refers to the sum of the water-crack lengths of all water-cracked stem nodes of each sugarcane plant.

[0017] The total width of water cracks refers to the sum of the maximum widths of all water cracks on each sugarcane plant.

[0018] The total water crack depth refers to the sum of all water crack depths for each sugarcane stalk.

[0019] Preferably, the indicative traits for rapidly evaluating the degree of water cracking in sugarcane in step 4) are the number of water-cracked nodes and the water cracking rate.

[0020] This invention also provides a method for evaluating the degree of sugarcane water cracking using the index traits obtained by the above-described screening method, comprising the following steps:

[0021] (1) Investigate the field measurement values ​​of the index traits of different sugarcane varieties for rapid evaluation of the degree of sugarcane water cracking.

[0022] (2) Sort the field measurement values ​​described in step (1) respectively;

[0023] (3) Based on the field measurements described in step (1), the sum of squares method is used to perform cluster analysis on different sugarcane varieties using Euclidean distance as a metric to obtain the water crack classification results.

[0024] Preferably, the classification in step (3) is as follows: Category 1 has few water cracks, Category 2 has moderate water cracks, and Category 3 has severe water cracks. Category 1 is further divided into Subgroup 1a (no water cracks) and Subgroup 1b (few water cracks).

[0025] Beneficial effects:

[0026] This invention provides a method for screening indicative traits that can rapidly evaluate the degree of water cracking in sugarcane. It selects traits that can rapidly evaluate sugarcane water cracking from multiple agronomic traits related to sugarcane water cracking, and establishes a rapid evaluation system for sugarcane water cracking. This method is simple, easy to implement, and can provide a theoretical basis and scientific evidence for sugarcane breeding, and has important practical application value. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the measurement of water crack length and water crack width in Example 1.

[0028] Figure 2 This is a scree plot from the principal component analysis of Example 1.

[0029] Figure 3 This is a cluster analysis diagram of 94 sugarcane varieties in Example 1.

[0030] Figure 4 This is a cluster analysis diagram of 100 sugarcane varieties in Example 2. Detailed Implementation

[0031] In the following embodiments of the present invention, each variety (line) is planted at 5m, with 16 buds planted per meter, for a total of 80 buds. The number of effective stems is not less than 20. Except for the number of stems with water cracking and the water cracking rate (X4), 5 parallel samples are investigated for each variety (line).

[0032] The methods for determining various agronomic traits in the following embodiments of the present invention are as follows:

[0033] The number of water-cracked nodes (X1) refers to the number of stem nodes with water cracks on each sugarcane plant;

[0034] Total number of nodes (Y1) refers to the number of stem nodes per sugarcane plant;

[0035] The water-cracked node ratio (X2) is the ratio of the number of water-cracked nodes (X1) to the total number of nodes (Y1) per sugarcane plant, and the formula is:

[0036] The number of water-cracked stems (X3) refers to the number of sugarcane plants of each variety that are over 100cm tall at maturity and have water cracks.

[0037] Effective stem number (Y2) refers to the number of sugarcane plants of each variety that have a plant height of more than 100cm at maturity;

[0038] The water cracking rate (X4) is the ratio of the number of water-cracked stems (X3) to the number of effective stems (Y2) for each sugarcane variety, and the formula is:

[0039] The total internode length (X5) refers to the sum of the internode lengths of all water-cracked stem nodes of each sugarcane plant. The internode length of the sugarcane is measured with a tape measure, and the unit is cm.

[0040] The total length of water cracks (X6) refers to the sum of the lengths of all water cracks in the stem nodes of each sugarcane plant. The length of each water crack is measured in cm using a stainless steel ruler.

[0041] The total width of water cracks (X7) refers to the sum of the maximum widths of all water cracks on each sugarcane plant. The maximum width of each water crack is measured using a stainless steel ruler, and the unit is cm.

[0042] The total water crack depth (X8) refers to the sum of all water crack depths for each sugarcane plant, in cm. The water crack depth (Y3) refers to the maximum length from the surface of the stalk skin vertically to the bottom of the crack in a sugarcane plant, in cm. The measurement method is as follows: a stainless steel strip (length × width × thickness of 50mm × 10mm × 0.1mm) is gently and vertically inserted into the bottom of the water crack in the sugarcane plant. The length of the stainless steel strip outside the sugarcane plant (Y4) is measured with a stainless steel ruler. The water crack depth (Y3) is calculated using the formula Y3 = 5 - Y4.

[0043] In the following embodiments of the present invention, IBM SPSS 22.0 software was used for principal component analysis, R 4.3.1 software was used for cluster analysis, and DPS 9.01 software was used for stepwise discriminant analysis.

[0044] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] A method for screening index traits for rapid evaluation of the degree of water cracking in sugarcane includes the following steps:

[0047] 1) In this embodiment, 94 sugarcane varieties (lines) were selected, and 8 index traits related to sugarcane water cracking were chosen, namely, number of water-cracked nodes (X1), water-cracked node rate (X2), number of water-cracked stems (X3), water cracking rate (X4), total internode length (X5), and total water cracking length (X6) (e.g., Figure 1 (as shown), total water crack width (X7) (as shown) Figure 1 (as shown), total water fracture depth (X8).

[0048] 2) Field measurements of agronomic traits related to sugarcane water cracking were investigated for different sugarcane varieties. The results are shown in Table 1.

[0049] Table 1 Field measurements of traits related to sugarcane water cracking

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] 3) Perform principal component analysis on the field measurements of X1, X2, X3, X4, X5, X6, X7 and X8. Extract principal components based on eigenvalues ​​greater than 1, and leave other parameters at their default values.

[0056] The results are shown in Table 2 and Figure 2 As shown:

[0057] Table 2. Principal component analysis results

[0058]

[0059]

[0060] 4) Based on the principal component analysis results and the ease of investigation, determine the index traits for rapidly evaluating the degree of sugarcane water cracking:

[0061] As shown in Table 2, the high load values ​​of water-cracked nodes (X1), water-cracked node ratio (X2), total internode length (X5), total water-cracked length (X6), total water-cracked width (X7), and total water-cracked depth (X8) in principal component 1 indicate the severity of water cracking in sugarcane. Because investigating the water-cracked node rate (X2), total internode length (X5), total water-crack length (X6), total water-crack width (X7), and total water-crack depth (X8) is extremely time-consuming, and in the process of investigating materials with severe water cracking, it took one person 22 days to investigate 94 varieties with 8 hours of investigation per day, which is time-consuming and labor-intensive and not suitable for large-scale evaluation. Therefore, the number of water-cracked nodes (X1), which is quick and easy to investigate, was selected as an indicator for quickly evaluating the severity of water cracking in sugarcane. In principal component 2, the number of water-cracked stems (X3) and the water-crack rate (X4) have high loadings, representing the prevalence of water cracking in sugarcane. The water-crack rate (X4), which can describe the distribution of water cracks, was selected as an indicator for quickly evaluating the prevalence of water cracking in sugarcane. In conclusion, the number of water-cracked nodes (X1) and the water-crack rate (X4) can be used as indicators for quickly evaluating the degree of water cracking in sugarcane.

[0062] 5) Based on the field measurements of the index traits described in step 2), cluster analysis was performed using the sum of squares (Ward's method) with Euclidean distance as the metric. The 94 sugarcane varieties (lines) were divided into three groups: Group 1 (few water cracks, 32 varieties (lines)); Group 2 (moderate water cracks, 46 varieties (lines)); and Group 3 (severe water cracks, 16 varieties (lines)). The results of the cluster analysis are as follows: Figure 3 As shown.

[0063] 6) Based on the field measurements and clustering results, stepwise discriminant analysis was performed. The results of the stepwise discriminant analysis are shown in Table 3.

[0064] Table 3. Discriminant performance of stepwise discriminant analysis

[0065]

[0066] As shown in Table 3, one sample in class 2 was misclassified as class 1, and three samples in class 3 were misclassified as class 2, with an overall correct classification rate of 95.74%. Therefore, the cluster analysis results in this embodiment are reliable, and the number of water-cracked nodes (X1) and the water-crack rate (X4) can be used for the rapid evaluation of water cracking in sugarcane.

[0067] Example 2

[0068] A method for evaluating water cracking in sugarcane includes the following steps:

[0069] (1) In this embodiment, 100 sugarcane varieties (lines) were selected, and the field measurement values ​​of the number of water-cracked nodes (X1) and the water-crack rate (X4) of each sugarcane variety (line) were obtained. The number of water-cracked nodes (X1) of 5 parallel samples were investigated for each variety (line), and the average value of the 5 parallel samples was taken, as shown in Table 4:

[0070] Table 4. Average values ​​of field measurements for the number of water-cracked nodes (X1) and the water-crack rate (X4).

[0071]

[0072]

[0073] (2) The field measurement values ​​in step (1) are sorted. The higher the water cracking rate, the more common the water cracking of sugarcane is. The lower the water cracking rate, the less common the water cracking of sugarcane is. The larger the number of water cracked nodes, the more severe the water cracking of sugarcane is. The smaller the number of water cracked nodes, the less severe the water cracking of sugarcane is.

[0074] (3) Based on the field measurements described in step (1), cluster analysis was performed on different sugarcane varieties using the sum of squares method (Ward's method) with Euclidean distance as the metric (cluster analysis results are shown in Figure 1). Figure 4 One hundred sugarcane varieties (lines) were divided into three categories: Category 1 (no or few water cracks, 64 varieties (lines); Category 2 (moderate water cracks, 29 varieties (lines); and Category 3 (severe water cracks, 7 varieties (lines)). Category 1 was further divided into two subgroups: Subgroup 1a (no water cracks, 36 varieties (lines)) and Subgroup 1b (few water cracks, 28 varieties (lines)).

[0075] Based on the field measurements and clustering results, stepwise discriminant analysis was performed. The results of the stepwise discriminant analysis are shown in Table 5.

[0076] Table 5. Discriminant performance of stepwise discriminant analysis

[0077]

[0078] As shown in Table 5, the correct classification accuracy for classes 1 and 3 was 100.00%, while 9 samples in class 2 were misclassified as class 1, resulting in an overall correct classification accuracy of 91.00%. This demonstrates the reliability of the cluster analysis results in this embodiment. In sugarcane breeding, the most important aspect is finding varieties with little or no water cracking, thus focusing more on the selection of class 1. Since class 1 had a 100% correct classification accuracy, it has practical value. Therefore, the rapid evaluation system for sugarcane water cracking established in this invention is simple, easy to implement, and provides a theoretical basis and scientific foundation for sugarcane breeding, possessing significant practical application value.

[0079] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for screening index traits for rapidly evaluating the degree of water cracking in sugarcane, characterized in that, Includes the following steps: 1) Identify the agronomic traits related to sugarcane water cracking to be screened; 2) Investigate field measurements of agronomic traits related to sugarcane water cracking in different sugarcane varieties; 3) Perform principal component analysis on the field measurement values ​​obtained in step 2); 4) Determine the index traits for rapidly evaluating the degree of water cracking in sugarcane based on the principal component analysis results and the difficulty of the investigation; 5) Based on the field measurements of the index traits described in step 2), the sum of squares method was used to perform cluster analysis on different sugarcane varieties using Euclidean distance as a metric to obtain the water crack classification results; 6) Based on the field measurements and clustering results, perform stepwise discriminant analysis to verify the accuracy of the water crack classification results.

2. The screening method as described in claim 1, characterized in that, The agronomic traits related to sugarcane water cracking include the number of water-cracked nodes, the water-cracked node ratio, the number of water-cracked stems, the water cracking rate, the total internode length, the total water crack length, the total water crack width, and the total water crack depth.

3. The screening method as described in claim 2, characterized in that, The water-cracked node rate is the ratio of the number of water-cracked nodes per sugarcane plant to the total number of nodes, where the number of water-cracked nodes refers to the number of stem nodes on each sugarcane plant that have experienced water cracking.

4. The screening method as described in claim 2, characterized in that, The water cracking rate is the ratio of the number of water-cracked stems to the number of effective stems for each sugarcane variety. The number of water-cracked stems refers to the number of sugarcane plants with a height exceeding 100cm at maturity that have water cracking, and the number of effective stems refers to the number of sugarcane plants with a height exceeding 100cm at maturity.

5. The screening method as described in claim 2, characterized in that, The total internode length refers to the sum of the internode lengths of all water-cracked stem nodes of each sugarcane plant, and the total water-crack length refers to the sum of the lengths of all water-cracked stem nodes of each sugarcane plant.

6. The screening method as described in claim 2, characterized in that, The total width of water cracks refers to the sum of the maximum widths of all water cracks on each sugarcane plant.

7. The screening method as described in claim 2, characterized in that, The total water crack depth refers to the sum of all water crack depths for each sugarcane stalk.

8. The screening method as described in claim 1, characterized in that, The indicative traits for rapidly evaluating the degree of water cracking in sugarcane, as described in step 4), are the number of water-cracked nodes and the water cracking rate.

9. A method for evaluating the degree of water cracking in sugarcane using the screening method described in any one of claims 1 to 8, characterized in that, Includes the following steps: (1) Investigate the field measurement values ​​of the index traits of different sugarcane varieties for rapid evaluation of the degree of sugarcane water cracking. (2) Sort the field measurement values ​​described in step (1) respectively; (3) Based on the field measurements described in step (1), the sum of squares method is used to perform cluster analysis on different sugarcane varieties using Euclidean distance as a metric to obtain the water crack classification results.

10. The evaluation method as described in claim 9, characterized in that, The classification in step (3) is as follows: Category 1 has few water cracks, Category 2 has moderate water cracks, and Category 3 has severe water cracks. Category 1 is further divided into Subgroup 1a (no water cracks) and Subgroup 1b (few water cracks).

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