阅读说明：本技术 一种氮高效小麦品种的筛选方法 (Method for screening nitrogen-efficient wheat varieties ) 是由 宋晓 许端阳 黄晨晨 黄绍敏 张珂珂 王沙沙 于 2020-12-29 设计创作，主要内容包括：本发明公开了一种氮高效小麦品种的筛选方法。所述筛选方法包括以下步骤：(1)小麦氮素利用效率农学参数适用性评估；(2)小麦农学参数高光谱反演模型优选；(3)氮素利用效率高光谱反演与氮高效小麦品种筛选。所述筛选方法以小麦为代表性作物,选择多项农学参数指标对氮素利用效率进行联合模拟,并作为氮高效品种筛选的依据,以农学参数为连接点,根据“植被指数-农学参数-氮效率”之间的关系,提出了融合植被指数与农学参数的氮高效小麦品种筛选方法,所述筛选方法高效、精确。(The invention discloses a method for screening a nitrogen efficient wheat variety. The screening method comprises the following steps: (1) assessing the applicability of the agronomic parameters of the wheat nitrogen utilization efficiency; (2) optimizing a wheat agronomic parameter hyperspectral inversion model; (3) performing high spectral inversion on nitrogen utilization efficiency and screening nitrogen-efficient wheat varieties. The screening method takes wheat as a representative crop, selects multiple agronomic parameter indexes to carry out combined simulation on nitrogen utilization efficiency, and is used as a basis for screening nitrogen efficient varieties, takes agronomic parameters as connection points, and provides the nitrogen efficient wheat variety screening method fusing vegetation indexes and agronomic parameters according to the relation between vegetation indexes-agronomic parameters-nitrogen efficiency.)

1. A method for screening a nitrogen-containing high-efficiency wheat variety is characterized by comprising the following steps:

(1) assessing the applicability of the agronomic parameters of the wheat nitrogen utilization efficiency;

(2) optimizing a wheat agronomic parameter hyperspectral inversion model;

(3) performing high spectral inversion on nitrogen utilization efficiency and screening nitrogen-efficient wheat varieties.

2. The method of screening for a nitrogen-efficient wheat variety of claim 1, wherein step (1) comprises: under different fertilization treatments, the relationship between the nitrogen utilization efficiency of a plurality of wheat varieties and the agronomic parameters in different growth periods is analyzed, the applicability and contribution of the agronomic parameters in different growth periods in the aspect of predicting the nitrogen utilization efficiency are evaluated, and the important agronomic parameter index, the combination form and the optimal growth period for evaluating the nitrogen utilization efficiency of the wheat are determined.

3. The method for screening the nitrogen-efficient wheat variety as claimed in claim 1 or 2, wherein the agronomic parameters include shoot and leave nitrogen content, overground biomass, leaf area index, chlorophyll content, wheat grain weight.

4. The method of claim 2, wherein the amount of the wheat variety to be tested is at least 25 parts.

5. The method for screening a nitrogen-efficient wheat variety as claimed in claim 2, wherein said step (1) further comprises: a plurality of wheat varieties with obvious differences in nitrogen utilization efficiency are screened in advance to serve as test wheat.

6. The method of claim 1, wherein step (2) comprises: monitoring canopy hyperspectral data of different wheat varieties and different growth periods to be tested, and determining the sensitive wave band range of each agronomic parameter; and evaluating the spectrum vegetation index for inverting the agronomic parameters, preferably selecting the spectrum vegetation index with higher correlation, establishing a regression equation, and optimizing and evaluating the regression equation, thereby preferably selecting the wheat agronomic parameter hyperspectral inversion model.

7. The method of claim 6, wherein the sensitive band ranges of the agronomic parameters are determined using correlation analysis, stepwise multiple regression techniques.

8. The method of claim 6, wherein the Root Mean Square Error (RMSE) and the fitting determination coefficient (R) are used²And optimizing and evaluating the regression equation by using the average relative error RE statistical variable.

9. The method of screening for a nitrogen-efficient wheat variety of claim 1, wherein step (3) comprises: constructing a wheat nitrogen utilization efficiency hyperspectral inversion model by using the optimized spectral vegetation index by using the agronomic parameters as linkage points, inverting the nitrogen utilization efficiency of a plurality of wheat varieties, and verifying the model according to the actually measured wheat nitrogen utilization efficiency data; and (3) screening and classifying the wheat nitrogen high-efficiency varieties according to the nitrogen utilization efficiency evaluation standards of the low-nitrogen high-efficiency wheat varieties and the high-nitrogen high-efficiency wheat varieties and by combining the inversion results.

10. The method of claim 9, wherein the spectral vegetation index and calculation formula comprises:

Technical Field

The invention belongs to the technical field of wheat breeding, and particularly relates to a method for screening a nitrogen-efficient wheat variety.

Background

Nitrogen is the first mineral nutrient element essential for crop growth, and its nutrient efficiency directly affects crop yield and quality, so called "life element". Based on the dual requirements of economic benefit and ecological environment protection, improving the utilization rate of nitrogen fertilizer becomes a leading-edge problem of agricultural scientific and technological innovation and an important requirement for guaranteeing the food safety in China. The genetic potential of the nitrogen absorbed and utilized by crops is excavated, the crop varieties with high nitrogen utilization rate are screened, and the nitrogen fertilizer utilization rate is improved, so that higher yield is obtained under a certain nitrogen fertilizer input.

At present, more screening methods and screening indexes for nitrogen-enriched varieties are reported. However, the previous studies are mostly based on¹³C、¹⁵The N isotope tracer technique, physiological biochemical analysis method and the like are used for measuring the agronomic characters and physiological characteristics of crops, but the N isotope tracer technique, the physiological biochemical analysis method and the like are difficult to be applied in time and generally due to the defects of destructiveness, high analysis cost and time and labor waste. Therefore, the research and development of a rapid, real-time and low-cost monitoring technology and the improvement of the nitrogen efficient variety breeding efficiency are urgently needed on the basis of screening a few secondary character indexes which have close relations with the nitrogen fertilizer utilization rate and can be rapidly determined or investigated in the field.

With the rapid development of science and technology, the remote sensing technology, especially the hyperspectral remote sensing technology overcomes the defects of complexity, labor and force consumption of the traditional measuring method, can quickly, effectively and nondestructively obtain a large amount of continuous spectrum information in a non-contact way, and provides possibility for monitoring the growth and nutrition conditions of crops in real time and estimating the agronomic parameters, yield, quality and the like of the crops. Taking the crop nitrogen nutrition diagnosis as an example, when the state of the crop nitrogen changes, morphological structures such as leaf color and the like change accordingly, so that absorption, reflection and transmission of the spectrum are influenced, and the change of the spectral characteristics provides a theoretical basis for diagnosis and monitoring of the crop nitrogen nutrition condition. Besides the nitrogen content of crops, a large number of researches show that the vegetation index constructed based on a plurality of sensitive wave bands also has better inversion capability on agronomic indexes closely related to the nitrogen efficiency of the crops, such as the crop yield, the leaf area index, the chlorophyll content and the like.

Based on the analysis, the method is feasible to perform nondestructive monitoring on the nitrogen content of the crops and related agronomic indexes by means of a hyperspectral remote sensing technology so as to analyze the utilization efficiency of nitrogen of different varieties. However, from the viewpoint of supporting nitrogen high-efficiency product screening species, there still exist some problems, which are mainly reflected in the following two aspects: firstly, the previous research mostly aims at the same variety, measures the hyperspectral data of crop canopies under the same nitrogen level (mainly nitrogen-free or low-nitrogen level), extracts nitrogen sensitive wave bands and further constructs related spectral indexes and inversion models; the models have great limitation on the screening application of large-scale nitrogen high-efficiency varieties, the applicability of main crops in China is not clear, and the varieties of 'low nitrogen high-efficiency' (the low nitrogen high-efficiency varieties can efficiently absorb organic nitrogen mineralized in soil and environmental nitrogen from other sources under the similar yield level so as to achieve the purpose of saving nitrogen fertilizer) and 'high nitrogen high-efficiency' (the high nitrogen high-efficiency varieties can further improve the yield along with the increase of the nitrogen fertilizer input on the basis of high yield), are not strong in model popularization and application capability. Secondly, the previous research is carried out on the inversion of single indexes of the nitrogen content of the leaves and the canopy layer by multiple choices, and the inversion is used as the basis for screening the high-efficiency varieties of nitrogen; the combined simulation of other agronomic parameter indexes such as comprehensive crop yield, leaf area index and chlorophyll content on the nitrogen utilization efficiency is lacked, the characterization capability of related agronomic parameters on the nitrogen utilization efficiency under different growth periods is not evaluated enough, and the accuracy of nitrogen-efficient variety screening needs to be further improved.

Disclosure of Invention

The invention aims to: aiming at the problems in the prior art, the invention provides a method for screening a nitrogen-efficient wheat variety, which quickly and accurately inverts the nitrogen utilization efficiency of the wheat according to the transfer relationship among the related indexes of vegetation index-agronomic parameter-nitrogen utilization efficiency to screen the nitrogen-efficient wheat variety so as to provide a theoretical basis for breeding the high-nitrogen-yield efficient wheat variety.

The technical scheme adopted by the invention is as follows:

a method for screening nitrogen high-efficiency wheat varieties. The screening method comprises the following steps:

(1) assessing the applicability of the agronomic parameters of the wheat nitrogen utilization efficiency;

(2) optimizing a wheat agronomic parameter hyperspectral inversion model;

(3) performing high spectral inversion on nitrogen utilization efficiency and screening nitrogen-efficient wheat varieties.

The method for screening the nitrogen-efficient wheat varieties is based on the cross frontier of the national crop nitrogen-efficient variety screening practice and the agricultural science and remote sensing science in China, and by means of the hyperspectral remote sensing technology, a long-term positioning fertilizer efficiency test of 30 years, namely a national moisture soil fertility and fertilizer benefit long-term monitoring station, is taken as a platform, wheat is taken as a representative crop, on the basis of the evaluation of the applicability of agronomic parameters closely related to the nitrogen utilization rate, a model capable of accurately estimating the agronomic parameters is constructed and optimized by the hyperspectral remote sensing technology, the nitrogen-efficient wheat varieties are screened out, theoretical basis and technical support are provided for screening the main crop nitrogen-efficient varieties in China, and the method has important significance for improving the utilization rate of crop nitrogen fertilizers, reducing agricultural non-point source pollution and guaranteeing national grain safety.

Further, according to the method for screening the nitrogen-enriched wheat variety provided by the invention, the step (1) comprises the following steps: under different fertilization treatments, the relationship between the nitrogen utilization efficiency of a plurality of wheat varieties and the agronomic parameters in different growth periods is analyzed, the applicability and contribution of the agronomic parameters in different growth periods in the aspect of predicting the nitrogen utilization efficiency are evaluated, and the important agronomic parameter index, the combination form and the optimal growth period for evaluating the nitrogen utilization efficiency of the wheat are determined.

Further, according to the screening method of the nitrogen-enriched high-efficiency wheat variety provided by the invention, the agronomic parameters comprise stem leaf nitrogen content, overground part biomass, leaf area index, chlorophyll content and wheat grain weight.

Further, according to the screening method of the nitrogen-enriched high-efficiency wheat variety, provided by the invention, the tested wheat variety is at least 25 parts.

Further, according to the method for screening the nitrogen-enriched wheat variety provided by the invention, the step (1) further comprises the following steps: a plurality of wheat varieties with obvious differences in nitrogen utilization efficiency are screened in advance to serve as test wheat.

Further, according to the method for screening the nitrogen-enriched wheat variety provided by the invention, the step (2) comprises the following steps: monitoring canopy hyperspectral data of different wheat varieties and different growth periods to be tested, and determining the sensitive wave band range of each agronomic parameter; and evaluating the spectrum vegetation index for inverting the agronomic parameters, preferably selecting the spectrum vegetation index with higher correlation, establishing a regression equation, and optimizing and evaluating the regression equation, thereby preferably selecting the wheat agronomic parameter hyperspectral inversion model.

Further, according to the screening method of the nitrogen-enriched high-efficiency wheat variety, provided by the invention, the sensitive wave band range of each agronomic parameter is determined by utilizing correlation analysis and stepwise multiple regression technology.

Further, according to the method for screening the nitrogen-efficient wheat variety, provided by the invention, the root mean square error RMSE and the fitting decision coefficient R are utilized²And optimizing and evaluating the regression equation by using the average relative error RE statistical variable.

Further, according to the method for screening the nitrogen-enriched wheat variety provided by the invention, the step (3) comprises the following steps: constructing a wheat nitrogen utilization efficiency hyperspectral inversion model by using the optimized spectral vegetation index by using the agronomic parameters as linkage points, inverting the nitrogen utilization efficiency of a plurality of wheat varieties, and verifying the model according to the actually measured wheat nitrogen utilization efficiency data; and (3) screening and classifying the wheat nitrogen high-efficiency varieties according to the nitrogen utilization efficiency evaluation standards of the low-nitrogen high-efficiency wheat varieties and the high-nitrogen high-efficiency wheat varieties and by combining the inversion results.

Further, according to the method for screening the nitrogen-enriched efficient wheat variety provided by the invention, the spectral vegetation index and the calculation formula comprise:

the invention has the following beneficial effects:

(1) the screening index and the screening method of nitrogen efficiency in the invention take wheat as representative crops, research different wheat genotype varieties and different fertilizing conditions, and are different from the previous researches which mostly take rice and corn as research objects, so the invention supplements the screening method of nitrogen efficiency wheat varieties;

(2) according to the method, multiple agronomic parameter indexes are selected to carry out combined simulation on the nitrogen utilization efficiency and serve as the basis for screening the nitrogen efficient varieties, so that the characterization capability of the related agronomic parameters on the nitrogen utilization efficiency under different growth periods is fully evaluated, and the accuracy of screening the nitrogen efficient varieties is further improved;

(3) the invention provides a nitrogen efficient wheat variety screening method fusing vegetation indexes and agronomic parameters by taking the agronomic parameters as connection points according to the relation between the vegetation indexes, the agronomic parameters and the nitrogen efficiency, and the screening method is efficient and accurate;

(4) according to the method, a physiological and biochemical index monitoring model is constructed by utilizing the hyperspectral characteristics among wheat varieties, and then the related indexes of nitrogen efficiency are evaluated, wherein the nitrogen content of crops and the related agronomic indexes need to be monitored in a nondestructive mode by means of a hyperspectral remote sensing technology, so that the whole screening method is more efficient.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 shows a technical scheme of the method for screening nitrogen-enriched wheat varieties of the present invention.

Detailed Description

The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the following examples.

(1) Agricultural parameter applicability evaluation of wheat nitrogen utilization efficiency

Summary of the experiment: the test is set at 'national long-term monitoring test station for moisture soil fertility and fertilizer benefit-Zhengzhou'. The soil type was moisture soil, and the nutrient condition of the basal soil sample was 8.3 in pH and 10.1 g/kg in Soil Organic Matter (SOM) at the beginning of the 1990 study^-1The alkaline hydrolysis Nitrogen (Alkali-hydrosable Nitrogen) of the soil is 76.6mg kg^-1Effective phosphorus (Olsen-P) ═ 6.5 mg/kg^-1Effective potassium (Exchangeable K) ═ 74.5 mg/kg^-1Total nitrogen (Total N) in soil is 0.65 g/kg^-1Soil Total phosphorus (Total P) is 0.64 g/kg^-1Total K in soil is 16.9 g/kg^-1.4 different fertilization treatments were selected for this study: (1) CK blank (no planting, no fertilization); (2) NPK (nitrogen, phosphorus and potassium fertilizer application); (3) MNPK (M refers to organic fertilizer, organic fertilizer + NPK fertilizer); (4) SMNPK (S means straw returning, straw returning and NPK fertilizer). The fertilizer types, the amounts and the like are applied in different regions every year according to a long-term test design scheme, and the fertilizer types, the amounts and the like are shown in a table 1. The nitrogen fertilizer applied was studied to be urea [ CO (NH)₂)₂]The phosphate fertilizer is calcium dihydrogen phosphate [ Ca (H) ]₂PO4)₂]The potassium fertilizer is potassium sulfate (K)₂SO₄) The organic fertilizer is cow dung, and the straw is corn straw in the same season. The test cells are completely randomly arranged, and the area of each cell is 54m²Repeat 3 times.

TABLE 1 test treatment and amount of fertilised fertilizer (kg/hm)²)

Test materials: based on the previous research, 30 parts of wheat varieties with stable heredity and excellent characters and obvious nitrogen efficiency difference are selected from 130 parts of wheat variety materials for testing.

The test method comprises the following steps: respectively measuring the nitrogen content of stem leaves, the biomass of overground parts, the leaf area index, the chlorophyll content and the like in the rising period, the jointing period, the flowering period and the mature period of the wheat, and measuring the yield (grain weight of the wheat) of the wheat in the mature period.

Nitrogen content: the nitrogen content of the plants, the stems and the leaves is measured by a Kjeldahl method.

Aerial biomass: while the spectral data was acquired, the area of each wheat plant taken for treatment was 0.20 square meters (0.5 meters, 2 rows), and each sample point was taken horizontally from the ground. All green leaves were separated from the stem, de-enzymed at 105 ℃ for 30 minutes, and oven-dried at 70 ℃ until a constant weight was reached (weighing every 2 hours, values < 0.0005 measured 2 times before and after), and weighed for dry weight. Weighing the total dry weight of leaves, the total dry weight of green leaves and the dry weight of organs at other parts of plants, and then converting into dry weight per unit land area (g.DW.m)^-2) The dried samples were stored in plastic bags for subsequent analysis.

Leaf area index: and measuring the leaf area by adopting a coefficient method while acquiring the spectral data, and calculating the leaf area index. Leaf Area Index (LAI) is the individual leaf area x plants per square meter.

Chlorophyll content: immediately taking the middle parts of 20 fresh leaves on the upper part of 5 representative wheat plants in each cell after the spectrum measurement, cutting into pieces, uniformly mixing, weighing 025g, extracting with 95% ethanol, performing color comparison at 470nm, 649nm and 665nm respectively with a UV-1601 type ultraviolet spectrophotometer, and calculating the chlorophyll content.

Grain weight of wheat grains: taking 1m in mature period per cell²Representing a sample section, manually harvesting and threshing, naturally drying and weighing, and calculating the yield of seeds per hectare; and the number of ears per square meter is investigated, and 20 single stems are simultaneously taken to measure the number of ears and thousand grain weight.

And performing variance analysis, correlation coefficient calculation and regression model fitting on the survey data by adopting SPSS17.0 software, analyzing the relation between each agronomic parameter and the nitrogen utilization rate, and screening the agronomic parameters with high correlation as indirect indexes for evaluating the nitrogen utilization rate.

(2) Wheat agronomic parameter hyperspectral inversion model optimization

Summary of the experiment: the same as in (1)

The test method comprises the following steps: and (3) respectively adopting an ASD Fieldspc FR2500 spectrometer to obtain the vertical angle spectral reflectivity of the wheat plant in the rising period, the jointing period, the flowering period and the mature period of the wheat, and adding a soil background spectrum. The wave band range of an ASD Fieldspc FR2500 spectrometer is 350-2500nm, and the field angle is 25 degrees; wherein, the wavelength range of 350-1000nm, the spectral resolution is 3nm, and the sampling interval is 1.4 nm; the spectral resolution of the 1000-plus 2500nm waveband range is 10nm, and the sampling interval is 2 nm. The spectrum measurement is carried out on cloudy and windless sunny days, and the measurement time is 10:00-14: 00. When in measurement, the vertical distance from the probe of the sensor to the top of the wheat canopy is 1.0m, the measurement is repeated for 10 times within the view field range, the average value is taken, the ground view field is within the diameter range of 0.44m, the average value is used as the spectral reflection value of the cell, and the standard white board correction is carried out in time during the measurement process.

Based on hyperspectral monitoring data, the correlation between the reflection spectra of the wheat canopies in different growth periods and the agronomic parameters is analyzed, and the spectrum band sensitive to the agronomic parameters is selected. Based on the sensitive bands and literature analysis, a number of commonly used spectral vegetation indices were summarized (table 2). Analyzing and comparing the quantitative relation between the spectrum vegetation index and the agronomic parameters, screening out the vegetation index with the best correlation with the agronomic parameters, establishing an inversion model, and according to the inversion model R²And evaluating the model by the root mean square error RMSE and the average relative error RE, and preferably selecting the wheat agronomic parameter hyperspectral inversion model. The calculation and modeling were realized by SPSS17.0 and MATLAB software.

TABLE 2 calculation method of spectral vegetation index

(3) Nitrogen utilization efficiency hyperspectral inversion and nitrogen efficient wheat variety screening

Constructing a wheat nitrogen utilization efficiency hyperspectral inversion model based on a quantitative relation between the wheat nitrogen utilization efficiency and an agronomic parameter and an optimized agronomic parameter hyperspectral inversion model by using a model nesting method, and inverting the nitrogen utilization efficiency of 30 wheat varieties; and (3) verifying the inversion result of the model by combining the actually measured data of the utilization efficiency of the nitrogen of the wheat and through the root mean square error RMSE (formula 1), the average relative error RE (formula 2) and the like. On the basis, the nitrogen utilization efficiency judgment standard of the wheat varieties of low-nitrogen high-efficiency and high-nitrogen high-efficiency is established according to the analysis of the document Meta and the long-term positioning observation data of the national moisture soil fertility and fertilizer benefit long-term monitoring test station. And finally, screening and classifying the wheat nitrogen high-efficiency varieties by combining the inversion result of the wheat nitrogen utilization efficiency high spectrum model.

In the formula: p_iAnd O_iRespectively are a predicted value and an actual measurement value, and n is the number of samples; if RE<10%, the precision and accuracy of the model are high; the second is 10%<RE<20 percent; if RE>30%, the accuracy and precision of the model are poor.