Method for rapid evaluation of rice quality and application thereof

Abstract

This invention discloses a method and its application for rapidly assessing rice quality. The method includes the following steps: S1. Using multiple South China indica rice varieties as evaluation materials, 40 days after flowering, the leaf sheath of the flag leaf is collected, and the total chlorophyll content of the leaf sheath is detected; S2. After harvesting mature rice, the protein content of the rice is determined; S3. SPSS statistical software is used to perform statistical analysis on the physicochemical parameters and index data of the leaf sheath of the same variety; S4. It is found that the total chlorophyll content of the leaf sheath and the protein content of the rice are highly significantly positively correlated. Using the method of this invention, the protein content of rice can be rapidly assessed by detecting the chlorophyll content of the flag leaf sheath of South China indica rice in the later stages of growth, greatly saving breeding and screening time and providing a new screening and evaluation method for rapidly cultivating high-quality rice varieties.

Description

Technical Field

[0001] This invention relates to the field of crop breeding technology, specifically to a method and application for rapidly assessing rice quality using the chemical composition of rice flag leaf sheaths. Background Technology

[0002] Rice is the grain crop with the highest sown area, total output, and yield per unit area in my country, and has always held a dominant position in grain production and consumption. With the development of my country's economy and the improvement of people's living standards, increasingly higher requirements have been placed on the quality of rice, namely "from eating enough to eating well". Therefore, cultivating high-quality rice varieties has important practical value.

[0003] Protein is the second largest component of rice grains, accounting for 8-10%, and is an important indicator of rice's taste and nutritional quality. In rice breeding, the protein content can only be tested using specialized equipment after the rice has been harvested, threshed, dried, processed, and ground into powder. Testing this quality indicator involves testing a small number of grains at a time, is time-consuming, complex, and requires sophisticated equipment, making it unsuitable for large-scale selection of superior rice lines. Taking Guangdong rice breeding as an example, the crucial period for selecting superior rice lines (seed selection) is only 3-5 days, requiring the processing of tens of thousands of breeding materials—a short timeframe and a heavy workload. If the protein content of individual rice plants could be assessed in advance based on the correlation traits of the rice lines, the efficiency of selecting high-quality rice would be significantly improved. However, there are currently no reports of its application in predicting and assessing rice milling rate and protein content. Summary of the Invention

[0004] The purpose of this invention is to provide a method and application for rapidly evaluating rice quality.

[0005] According to one aspect of the present invention, a method for rapidly assessing rice quality is provided, comprising the following steps: S1. Using multiple South China indica rice varieties as evaluation materials, 40 days after flowering of the above South China indica rice varieties, the leaf sheath of the rice flag leaf was taken and the physicochemical parameters of the leaf sheath were tested, including the total chlorophyll content. S2. After the above 14 South China indica rice varieties have been harvested and matured, the mature rice will be used as samples to determine the nutritional quality-related indicators of the rice, including protein content. S3. SPSS statistical software was used to perform statistical analysis on the physicochemical parameters and index data of leaf sheaths of the same variety; S4. After data analysis, it was found that the total chlorophyll content of the leaf sheath was significantly positively correlated with the protein content of rice. That is, 40 days after flowering of the indica rice variety in South China, the leaf sheath of the flag leaf of rice was taken and the chlorophyll content of the leaf sheath was tested and compared. The higher the chlorophyll content of the leaf sheath, the higher the protein content of the rice and the better the quality of the rice.

[0006] In some embodiments, the physicochemical parameters also include chlorophyll a content, chlorophyll b content, carotenoid content, protein content, starch content, soluble sugar content, MOD content, and SOD content.

[0007] In some implementations, step S2 also measures indicators of rice processing, appearance, and cooking taste.

[0008] In some implementations, the indicators of rice processing, appearance, and cooking taste include brown rice rate, milled rice rate, head rice rate, chalkiness, chalky grain rate, transparency, grain length, grain length / width ratio, amylose content, gel consistency, alkali spreading value grade, transparency grade, and fat content.

[0009] In some implementations, in step S4, 40 days after the flowering of the South China indica rice variety, the leaf sheath of the rice flag leaf is taken and the chlorophyll b content of the leaf sheath is tested and compared. The higher the chlorophyll b content of the leaf sheath, the higher the protein content of the rice and the better the quality of the rice.

[0010] In some implementations, the South China Indica Rice is a South China Indica Rice variety with moderate amylose content and relatively uniform growth period.

[0011] In some implementations, the method for detecting the chlorophyll content of the leaf sheath in step S1 includes spectrophotometry, SPAD instrumentation, or visual observation.

[0012] In some implementations, the SPAD instrument method uses a SPAD502 instrument to directly detect the chlorophyll content of the leaf sheath in the field in 30 seconds.

[0013] In some implementations, the visual inspection method allows experienced breeders to visually judge subtle differences in leaf sheath color within seconds, especially in high-generation regions derived from the same hybrid combination, and to make a preliminary assessment of differences in rice protein content.

[0014] According to another aspect of the present invention, a method for rapidly assessing rice quality is provided for its application in predicting and assessing rice protein content and improving rice breeding efficiency.

[0015] The beneficial effects of this invention are as follows: This invention utilizes the chlorophyll content of leaf sheaths, especially chlorophyll b, 40 days after flowering in South China indica rice. This chlorophyll content shows a highly significant positive correlation with the protein content of rice. A predictive evaluation standard was obtained that in the later stages of growth in South China indica rice, the darker the leaf sheath color, the higher the chlorophyll content, and the higher the protein content of the produced rice. Using this predictive standard, the protein content of rice can be quickly assessed by detecting the chlorophyll content of leaf sheaths in the later stages of growth in South China indica rice. This greatly saves breeding and screening time and provides a new screening and evaluation method for rapidly cultivating high-quality rice varieties. Attached Figure Description

[0016] Figure 1 This is a correlation graph showing the content of chlorophyll b and the protein content of rice in Example 1 of the present invention. Detailed Implementation

[0017] The present invention is further described in detail through specific implementation examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. After reading this invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims. Unless otherwise specified, all raw materials and reagents of the present invention are commercially available.

[0018] Example 1

[0019] This embodiment selected 14 high-quality indica rice varieties from South China with moderate amylose content (16%–20%) and relatively consistent growth periods as experimental materials, such as Meixiangzhan 2, Huanghuazhan, and Nanjingxiangzhan. Planting method: Paddy fields with uniform soil fertility and good irrigation and drainage facilities were selected as experimental sites. Field seedling raising was adopted using a randomized block design with three replicates. The experimental plot area was 2.33 m × 1.17 m, with a plant spacing of 16.65 cm × 16.65 cm. Each plot had 7 rows of seedlings, with 14 seedlings per row, for a total of 98 seedlings. Sowing was on July 21, 2022, transplanting on August 7, 2022, and harvesting on November 15, 2022. All cultivation and management measures were the same.

[0020] A method for rapidly assessing rice quality includes the following steps: S1. Using the above 14 South China indica rice varieties as evaluation materials, 40 days after flowering, the leaf sheath of the rice flag leaf was collected, and multiple physicochemical parameters of the leaf sheath were detected. The physicochemical parameters included total chlorophyll content, chlorophyll a content, chlorophyll b content, carotenoid content, protein content, starch content, soluble sugar content, MOD content, and SOD content. Specifically, the total chlorophyll content of the leaf sheath could be detected by spectrophotometry, SPAD instrument method, or visual empirical method. S2. After the above 14 South China indica rice varieties have been harvested and matured, they have been dried and stored for 2 months. Mature rice samples were taken and the processing, appearance, cooking taste, and nutritional quality of the rice were measured. The indicators included protein content, brown rice rate, milled rice rate, head rice rate, chalkiness, chalky grain rate, transparency, grain length, grain length / width ratio, amylose content, gel consistency, alkali spreading value grade, transparency grade, and fat content. S3. SPSS statistical software was used to perform statistical analysis on multiple physicochemical parameters and index data of leaf sheaths of the same variety; S4. Data analysis revealed a highly significant positive correlation between the total chlorophyll content of the leaf sheath and the protein content of rice, as shown in Table 1. Figure 1 . Table 1. Correlation analysis data between physicochemical parameters of leaf sheath and rice quality.

[0021]

[0022] From Table 1 and Figure 1 It is known that the total chlorophyll content in the leaf sheath, especially the chlorophyll b content, is significantly positively correlated with the protein content of rice. Furthermore, the SOD activity in the leaf sheath is also significantly positively correlated with the protein and starch content of rice. Therefore, considering the convenience and practicality of large-scale breeding operations, priority should be given to using the chlorophyll content (especially chlorophyll b) in the leaf sheath to assess and predict the protein content of rice. Specifically, 40 days after flowering of indica rice varieties in South China, the leaf sheaths of the flag leaves are collected, and the chlorophyll content of the leaf sheaths is measured for comparison. The higher the chlorophyll content of the leaf sheath, the higher the protein content of the rice, and the better the quality of the rice.

[0023] The above descriptions are merely some embodiments of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for rapidly assessing rice quality, characterized in that, Includes the following steps: S1. Using multiple South China indica rice varieties as evaluation materials, 40 days after flowering of the above-mentioned South China indica rice varieties, the leaf sheath of the rice flag leaf was taken and the physicochemical parameters of the leaf sheath were detected. The physicochemical parameters include the total chlorophyll content. S2. After the above 14 South China indica rice varieties have been harvested and matured, the mature rice is taken as a sample and the nutritional quality-related indicators of the rice are measured, including the protein content. S3. SPSS statistical software was used to perform statistical analysis on the physicochemical parameters and index data of the leaf sheaths of the same variety; S4. After data analysis, it was found that the total chlorophyll content of the leaf sheath was significantly positively correlated with the protein content of rice. That is, 40 days after flowering of the indica rice variety in South China, the leaf sheath of the flag leaf of rice was taken and the chlorophyll content of the leaf sheath was tested and compared. The higher the chlorophyll content of the leaf sheath, the higher the protein content of the rice and the better the quality of the rice.

2. The method for rapidly evaluating rice quality according to claim 1, characterized in that, The physicochemical parameters also include chlorophyll a content, chlorophyll b content, carotenoid content, protein content, starch content, soluble sugar content, MOD content, and SOD content.

3. The method for rapidly evaluating rice quality according to claim 1, characterized in that, In step S2, the processing, appearance, and cooking taste of rice are also measured.

4. The method for rapidly evaluating rice quality according to claim 3, characterized in that, The indicators for the processing, appearance, and cooking taste of the rice include brown rice rate, milled rice rate, head rice rate, chalkiness, chalky grain rate, transparency, grain length, grain length / width ratio, amylose content, gel consistency, alkali spreading value grade, transparency grade, and fat content.

5. The method for rapidly evaluating rice quality according to claim 2, characterized in that, In step S4, 40 days after the flowering of the South China indica rice variety, the leaf sheath of the rice flag leaf is taken and the chlorophyll b content of the leaf sheath is tested and compared. The higher the chlorophyll b content of the leaf sheath, the higher the protein content of the rice and the better the quality of the rice.

6. The method for rapidly evaluating rice quality according to claim 1, characterized in that, The South China indica rice mentioned refers to South China indica rice with moderate amylose content and relatively uniform growth period.

7. The method for rapidly evaluating rice quality according to claim 1, characterized in that, The methods for detecting the chlorophyll content of the leaf sheath in step S1 include spectrophotometry, SPAD instrument method, or visual and empirical method.

8. The method for rapidly evaluating rice quality according to claim 7, characterized in that, The SPAD instrument method uses the SPAD502 instrument, which can directly detect the chlorophyll content of leaf sheaths in the field in 30 seconds.

9. The method for rapidly evaluating rice quality according to claim 1, characterized in that, The visual inspection method allows experienced breeders to visually judge subtle differences in leaf sheath color within seconds, especially in high-generation regions derived from the same hybrid combination, and can preliminarily assess differences in rice protein content.

10. The application of the method for rapidly assessing rice quality as described in claims 1-9 in predicting and assessing rice protein content and improving rice breeding efficiency.

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