Sampling method for shading stress test in wheat filling period

Abstract

The invention belongs to the technical field of agriculture, and particularly relates to a wheat filling stage shading stress test sampling method which comprises the following steps: selecting wheat of the same variety, and selecting a group of main stem ears which are consistent in growth vigor and bloom on the same day on the bloom day of the wheat of the variety for marking; respectively carrying out post-flowering shading treatment and non-shading treatment on the main stem ears with the marks; from the grain filling stage to the mature stage of the wheat, sampling the processed main stem ears at intervals, and recording agronomic character indexes of the main stem ears; the average ear grain number of the main stem ears subjected to shading treatment is used as a reference number, the main stem ears with the ear grain number close to the reference number in non-shading treatment are selected as non-shading samples, and the difference value range of the average ear grain number of the selected non-shading samples and the reference number is-1.5-1.5; according to the method, the sampling error is reduced, the shading test sampling process in the wheat filling period is optimized, and a new data analysis method is provided for the wheat filling test.

Description

Technical Field

[0001] The invention belongs to the technical field of agriculture, and in particular relates to a sampling method for a wheat shading stress test during the grain filling period. Background Art

[0002] Light is an essential environmental factor for wheat growth. Vegetation shading, rainy weather, and reduced total solar radiation from the ground can all reduce light intensity, affecting wheat plant photosynthesis and the accumulation of organic matter, leading to reduced yields. The grain filling period is a critical period for wheat growth. Insufficient light during this period will directly reduce wheat grain weight and affect yield. Therefore, studying the effect of shading on wheat ear filling is one of the focuses of agricultural researchers. However, in actual operation, the uniformity of ear sampling has a significant impact on the results of experimental treatments. The conventional sampling method is to select wheat ears that bloom on the same day in the field and grow uniformly and directly weigh the grain weight or thousand-grain weight. This sampling method is mostly based on visual observation and is highly dependent on experience. It lacks scientific and quantitative indicators and is prone to large errors. Summary of the Invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a sampling method for the shade stress test during the wheat filling period, which can optimize the sampling process of the shade stress test during the wheat filling period, reduce sampling errors, and provide scientific and quantitative guidance for sampling.

[0004] The specific technical solution adopted in the present invention is:

[0005] A sampling method for a wheat shading stress test during the grain filling period comprises the following steps:

[0006] S1. Select wheat of the same variety and mark a group of main stem ears with consistent growth on the day of flowering of the wheat variety;

[0007] S2. Divide the marked main stem ears into an experimental group and a control group, shade the main stem ears of the experimental group after flowering, and grow the main stem ears of the control group under natural conditions;

[0008] S3. From the wheat filling stage to the maturity stage, sampling was performed at intervals on the main stems and ears of the experimental group and the control group, and agronomic traits of each main stem and ear were recorded, wherein the agronomic traits included grain number and dry weight;

[0009] S4. The main stem ears sampled from the experimental group were shaded samples for the shade stress test. The average number of grains per ear of the shaded samples was used as the reference number. All main stem ears in the control group whose number of grains per ear was close to the reference number were selected as unshaded samples for the shade stress test. The difference between the average number of grains per ear of the selected unshaded samples and the reference number was in the range of (-1.5 to 1.5).

[0010] Preferably, in step S2, the main stem ears of the test group are shaded 3 days after flowering.

[0011] Preferably, in step S2, the shading treatment includes flag leaf shading treatment and ear stem shading treatment, and the main stem ears in the test group are divided into two parts, one part of the main stem ears is subjected to flag leaf shading treatment, and the other part of the main stem ears is subjected to ear stem shading treatment.

[0012] Preferably, in step S3, the agronomic trait indicators further include ear length and fresh weight.

[0013] Preferably, in step S3, the grains in each treated main stem ear are divided into strong grains and weak grains, and the number, fresh weight and dry weight of the strong grains and weak grains in each main stem ear are recorded respectively.

[0014] Preferably, the first and second grains of the spikelets in the main stem spike are recorded as strong grains, and the third and fourth grains are recorded as weak grains.

[0015] Preferably, in step S3, the main stem ears of the test group and the control group are sampled 14 days, 21 days, 28 days and 35 days after flowering, respectively.

[0016] Preferably, in step S3, the number of ears sampled in the control group is greater than the number of ears sampled in each test group.

[0017] The beneficial effects of the present invention are:

[0018] The present invention uses the sampling characteristic of grain number per ear to characterize uniform growth, and controls the difference in grain number per ear between shaded and unshaded samples to within 1.5 grains. When analyzing data, it no longer relies solely on conventional visual observation and experience, but selects samples for analysis based on controlling the difference in grain number per ear. Compared with conventional methods, the error in the sampling process is greatly reduced, and a new sampling and analysis method is provided for wheat filling tests, which can more realistically reflect the effect of shading treatment on wheat grain filling, conforms to existing scientific cognition and actual phenomena, and is more scientific and correct.

[0019] The sampling method of the present invention can provide accurate test results and reliable research conclusions, and is not only applicable to shading stress tests, but also to ear filling change analysis under other stress treatments.

[0020] The present invention also clarifies the specific sampling steps, making the entire sampling process more standardized and scientific, optimizing the sampling process of the wheat filling period shading experiment, and the standardized operating procedures improve the repeatability of the research, enabling other staff to repeat the experiment according to this method. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with specific embodiments:

[0022] A specific embodiment of the present invention relates to a sampling method for a wheat shading stress test during the grain filling period, which comprises the following steps:

[0023] S1. Select wheat of the same variety. On the day of flowering, select a group of 110 main stem ears of the same variety that grow in a consistent manner and bloom on the same day. Mark them with red paper tape. The term "consistent growth" in this manual is based on manual judgment by staff based on visual observation and experience.

[0024] S2. Three days after anthesis, 30 main stem ears with marked flag leaves were wrapped with tin foil and recorded as flag leaf shading treatment; another 30 main stem ears with marked lower stems and flag leaf sheaths were wrapped with tin foil and recorded as lower stem shading treatment; the remaining main stem ears were grown in a natural state and recorded as non-shading treatment.

[0025] S3. 14, 21, 28, and 35 days after flowering, take 6-10 main stem ears that were not shaded from each marked main stem ear, measure the ear length with a ruler, peel off the 1st and 2nd grains of the spikelet and record them as strong grains, and the 3rd and 4th grains as weak grains, separate the strong grains and weak grains, record the number of strong grains and weak grains in each ear, and weigh the fresh weight of strong grains and weak grains in each ear with a 1 / 10,000 balance (FA2004); take 5 main stem ears each treated with flag leaf shading and shading of the lower stem of the ear, peel off the strong grains and weak grains of each treatment, record the number of strong grains and weak grains of the 5 ears for each shading treatment, and weigh the fresh weight of the strong grains and weak grains of the 5 main stem ears for each shading treatment; after recording the fresh weight, place all samples in a 90°C oven to constant weight, and weigh the dry weight of each sample;

[0026] Fresh weight can supplement the information on weight changes of wheat grains at different stages of the filling process, and can provide a richer basis for analyzing the impact of shading on wheat growth; the analysis of strong and weak grains enables different researchers to classify grains and record data according to unified standards when conducting experiments, ensuring the consistency and comparability of the data; interval sampling after flowering can effectively monitor the growth changes of wheat at different stages of the filling process, which is helpful for analyzing the impact of shading stress on grain weight at different filling stages.

[0027] S4. Use the main stem ears of each shading treatment as the shaded samples for the shading stress test, use the average number of grains per ear of each shaded sample as the reference number, select all main stem ears in the unshaded treatment with a grain number close to the reference number as the unshaded samples for the shading stress test, and control the difference between the average number of grains per ear of the selected unshaded samples and the reference number to be within 1.5 grains. Select more main stem ears in the unshaded treatment for recording so that there are more main stem ears close to the reference number, providing a sufficient sample size for the test to reduce errors, and being able to truly and comprehensively reflect the growth status of wheat under the unshaded treatment, providing a stable and reliable reference standard for comparison with the data of the shaded treatment.

[0028] The formula for calculating the change in average grain dry weight under each shading treatment based on the samples collected is: change in average grain dry weight under shading treatment = [(average grain dry weight under shading treatment - average grain dry weight under unshading treatment) / average grain dry weight under unshading treatment] * 100%.

[0029] Since both spikelet differentiation and floret differentiation of wheat ears are completed before flowering, and the number of fertile grains per ear is basically determined after flowering, the present invention is suitable for analyzing the changes in ear filling under shading or other stress treatments that do not affect the development of grain number per ear after wheat flowering.

[0030] In this example, three wheat varieties, namely Shimai 26, Shiyou 17 and Jimai 22, were selected for sampling. The ears of the above wheat varieties are all spindle-shaped.

[0031] Taking Jimai 22 as an example, data from sampling 14 days after flowering show grain filling in both unshaded and shaded conditions (Table 1). Unshaded samples had spike lengths of approximately 8 cm and generally uniform growth. The average number of grains per spike was 33.2, with an average grain dry weight of 0.3536 g. Under flag leaf shading, the average number of grains per spike was 31.75, 1.45 fewer than in unshaded samples. Conventional calculations show that flag leaf shading reduces grain dry weight by 10.56%. Using 31.75 as a reference, samples with a similar average number of grains per spike were selected from the unshaded samples. This new unshaded sample, consisting of main stem spikes numbered 1, 3, 4, 5, 6, 7, 8, 9, and 10, yielded an average number of grains per spike of 32.4444 and a grain dry weight of 0.3472 g. Flag leaf shading reduces grain dry weight by 8.92%, a small change of 1.64 percentage points compared to conventional calculations.

[0032] Analysis of the data of Jimai 22 treated with shading of the stems below the ears 14 days after flowering showed that the average number of grains per ear was 27, which was 6.2 grains less than that of the conventional samples without shading. The difference in the number of grains per ear was large. The dry weight of the grains per ear was 10.56% lower when the stems below the ears were shaded than when there was no shading. The conclusion was that shading of the stems below the ears significantly affected the early grain filling of Jimai 22. This is inconsistent with the conclusion that wheat stem sheath photosynthesis has little effect on the early grain filling, but mainly affects the late grain filling. By adopting the analysis method of the present invention, main stem ears numbered 7, 8, 9, and 10 with a grain number of about 27 in conventional samples were selected as samples without shading treatment of the stem below the ear, and the average grain number per ear of the new samples was calculated to be 28, and the average grain dry weight per ear was 0.3085 g; under the shading treatment of the stem below the ear, the average grain number per ear was 27, and the average grain dry weight per ear was 0.3105 g. It was calculated that the shading of the stem below the ear increased the grain dry weight by 0.6483% compared with the no-shading treatment, and the conclusion was drawn that shading of the stem below the ear had no significant effect on the early grain filling of Jimai 22, which is consistent with the conclusion that the photosynthesis of wheat stem sheath has little effect on the early grain filling, but mainly affects the late grain filling, and the effectiveness of the present method was proved.

[0033] Table 1

[0034]

[0035] Table 2 shows the grain filling situation of Jimai 22 at 21 days, 28 days and 35 days after flowering without shading; Table 3 shows the grain filling situation of Shimai 26 at 14 days, 21 days, 28 days and 35 days after flowering without shading; Table 4 shows the grain filling situation of Shiyou 17 at 14 days, 21 days, 28 days and 35 days after flowering without shading.

[0036] Table 2

[0037]

[0038]

[0039] Table 3

[0040]

[0041]

[0042] Table 4

[0043]

[0044] According to Tables 2, 3 and 4, the sampling methods for different shading treatments of the three wheat varieties were verified respectively. Table 5 is a comparison of the filling conditions of the flag leaves of each wheat variety under shading treatment and without shading treatment. Table 6 is a comparison of the filling conditions of the lower stems of each wheat ear under shading treatment and without shading treatment.

[0045] Verification of the flag leaf shade sampling method for Shimai 26:

[0046] As can be seen from the data in Table 5, the data obtained by conventional sampling on the 14th and 21st days after flowering of Shimai 26 showed that the difference in the number of grains per spike between the flag leaf shade treatment and the unshaded treatment was 0.1 grain, which was not much different. On the 28th day after flowering, the number of grains per spike in the unshaded treatment obtained by conventional sampling was 37.875 grains, which was 1.125 grains more than that in the shaded treatment. The unshaded treatment was calibrated to 36.8571 grains using the number of grains per spike, which narrowed the difference in the number of grains per spike between the treatments to 0.1071 grains, but the change in the dry weight of the spike was 0.1071 grains. The decrease from 13.5398% became a decrease from 12.5289%, which is not a big change. Based on the above, 14 days after flowering, the sample treated with flag leaf shading had 1.45 fewer grains per ear than the sample treated without shading, but the variation range of grain dry weight per ear was small under the two analysis methods. This shows that the difference in grain number per ear between the sampling and calibration treatments was controlled within 1.5 grains, which had little effect on the results. Therefore, this method controlled the difference in grain number per ear within 1.5 grains to analyze the changes in grain weight per ear between the shaded and unshaded treatments. Under the conventional sampling and analysis method 35 days after flowering, the average dry weight of grains per ear of Shimai 26 under flag leaf shading was reduced by 17.0645% compared with the unshaded treatment. Analysis of the sampling data showed that the average number of grains per ear under the flag leaf shading treatment was 34.25, which was 5.5 grains less than the unshaded treatment. Taking the number of grains per ear sampled under the flag leaf shading treatment as a reference, unshaded treatment samples with similar number of grains per ear were selected, and finally the number of grains per ear was 35.5. The flag leaf shading treatment was compared with the calibrated unshaded treatment, and it was found that shading reduced the average dry weight of grains per ear by 10.0346%, which was a significant change compared with the pre-calibration change. Looking at the four sampling data of Shimai 26 during the filling period of the flag leaf shading treatment, it can be seen that the conventional sampling and analysis method of this experiment can meet the data analysis requirements for three times at 14 days, 21 days and 28 days after flowering. However, 35 days after flowering, the conventional sampling and analysis method produced a large error. The use of grain number per ear for calibration can effectively avoid sampling errors and make the results of the flag leaf shading test more accurate.

[0047] Verification of the sampling method for flag leaf shade of Shiyou 17:

[0048] Table 5 shows that 14 days after flowering, the average grain number per ear for Shiyou 17 in the conventional sampling of the unshaded treatment was 36.4, while that in the flag leaf shaded treatment was 42.4. This represents a significant difference of 6 grains per ear between the two samples. The average dry weight per ear for the unshaded treatment was 0.4348 g, while that for the flag leaf shaded treatment was 0.4296 g. Before calibration, the average grain dry weight under the shaded treatment decreased by 1.1823%. After calibration, the average grain number per ear for the unshaded treatment was adjusted to 41, resulting in a significant decrease of 9.3437% in the shaded treatment. This suggests that the large difference in grain number per ear in the conventional sampling affected the interpretation of the change in grain dry weight under the flag leaf shaded treatment. The calibration more accurately reflects the effect of flag leaf shade on grain dry weight.

[0049] At 21 days after flowering, conventional sampling showed an average kernel number per ear of 35.125 in the unshaded treatment and 37.5 in the flag leaf shaded treatment, a difference of 2.375 kernels. The average kernel dry weight per ear was 0.8473 g in the unshaded treatment and 0.8378 g in the flag leaf shaded treatment. Before calibration, the average kernel dry weight in the shaded treatment was reduced by 0.9500%. After calibration, the average kernel number per ear in the unshaded treatment was adjusted to 38, and the calculated average kernel dry weight in the shaded treatment was reduced by 9.1624%, a significant change. This suggests that conventional sampling, due to differences in kernel number per ear, can lead to inaccurate assessments of kernel dry weight changes, while calibration provides more reliable results.

[0050] At 28 days after flowering, conventional sampling showed an average grain number per ear of 38.8333 grains in the unshaded treatment and 36.25 grains in the flag leaf shaded treatment, a difference of 2.5833 grains. The average dry weight of grains per ear was 1.2121 g in the unshaded treatment and 1.0705 g in the flag leaf shaded treatment. Before calibration, the average grain dry weight per ear in the shaded treatment decreased by 11.6851%. After calibration, the average grain number per ear in the unshaded treatment was adjusted to 37 grains, while the average grain dry weight per ear in the shaded treatment decreased by 7.5565%, a significant change. This suggests that conventional sampling, influenced by the number of grains per ear, can lead to biased interpretation, while the calibrated sampling method is more accurate.

[0051] At 35 days after flowering, conventional sampling revealed an average grain number per ear of 36.1429 grains in the unshaded treatment and 32.5 grains in the flag leaf shaded treatment, a difference of 3.6429 grains. The average dry weight of grains per ear was 1.4243 g in the unshaded treatment and 1.0700 g in the flag leaf shaded treatment. Before calibration, the average grain dry weight per ear in the shaded treatment decreased by 24.8746%, a significant decrease. After calibration, the average grain number per ear in the unshaded treatment was adjusted to 31.6667 grains, while the average grain dry weight per ear in the shaded treatment decreased by 15.7480%, a significant change. This indicates that conventional sampling methods have large errors, and calibration using grain number per ear can effectively reduce these errors and provide more accurate results.

[0052] Verification of the flag leaf shade sampling method for Jimai 22:

[0053] At 14 days after flowering, as mentioned above, under the conventional sampling method, the difference in average number of grains per ear between the shaded and unshaded treatments was 1.45 grains. Within the range of 1.5 grains, the change in dry weight of grains per ear before and after calibration was not obvious.

[0054] At 21 days after flowering, conventional sampling revealed an average kernel count of 35.625 kernels per ear in the unshaded treatment, compared with 29.75 kernels in the flag leaf shaded treatment, a difference of 5.875 kernels. The average kernel dry weight per ear was 0.7739 g in the unshaded treatment and 0.6132 g in the flag leaf shaded treatment. Before calibration, the average kernel dry weight under shaded conditions was reduced by 20.7676%. After calibration, the average kernel count per ear in the unshaded treatment was adjusted to 31 kernels, and the calculated average kernel dry weight under shaded conditions was reduced by 6.8833%. This significant change indicates that the calibrated sampling method is more accurate.

[0055] At 28 days and 35 days after flowering, the average number of grains per ear in conventional sampling without shading was 32 and 35, respectively, while the average number of grains per ear in samples with flag leaf shading was 32 and 36, respectively. The difference in the number of grains per ear between the treatments was 0 and 1, respectively. The difference in the number of grains per ear was within 1.5 grains, so no calibration was performed.

[0056] Table 5

[0057]

[0058]

[0059]

[0060] Verification of the shade sampling method for the lower stem of Shimai 26 spike:

[0061] As shown in Table 6, 14 days after flowering, during routine sampling, the average number of grains per ear in the unshaded treatment was 34.9, while that in the shading treatment was 33.8. The difference between the two was only 1.1 grains, which was relatively small, so no calibration of the number of grains per ear was performed.

[0062] Conventional sampling was conducted 21 days after flowering. The average number of grains per ear in the unshaded treatment was 36.5, while that in the shading treatment was 40.2, a significant difference of 3.7 grains. The average dry weight of grains per ear in the unshaded treatment was 0.8025 g, while that in the shading treatment was 0.8807 g. Before calibration, the average grain dry weight in the shading treatment increased by 9.7470%. After calibration, the average number of grains per ear in the unshaded treatment was adjusted to 39.6667, and the average grain dry weight in the shading treatment increased by 1.3098% compared to the unshaded treatment. This indicates that the large variation in grain number per ear before calibration led to a significant bias in the estimation of grain dry weight changes. After calibration, the variation in grain number per ear was kept to a smaller range, and the results more accurately reflect the effect of shading in the shading treatment on grain dry weight, demonstrating the reliability of the calibrated sampling method.

[0063] At 28 days after flowering, conventional sampling revealed an average kernel count of 37.875 kernels per ear for the unshaded sample and 34.75 kernels per ear for the shaded sample, a difference of 3.125 kernels between the two samples. Before calibration, the average kernel dry weight per ear was 1.1376 g for the unshaded sample and 0.9899 g for the shaded sample, representing a 12.9860% decrease in kernel dry weight under the shaded sample. After calibration, the average kernel count per ear for the unshaded sample was adjusted to 35.6667, while the average kernel dry weight under the shaded sample was 4.2482% lower. The pre-calibration results were affected by the difference in kernel count and did not accurately reflect the actual impact. After calibration, the error was reduced, more accurately reflecting the effect of shaded sample on kernel dry weight, demonstrating that the calibrated sampling method is more accurate.

[0064] Conventional sampling, conducted 35 days after flowering, revealed an average kernel count of 39.75 kernels per ear in the unshaded treatment and 36.5 kernels per ear in the shaded substalk, a difference of 3.25 kernels. The average kernel dry weight per ear was 1.5675 g in the unshaded treatment and 1.23 g in the shaded substalk. Before calibration, the average kernel dry weight per ear was reduced by 21.5311% in the shaded treatment. After calibration, the average kernel count per ear in the unshaded treatment was adjusted to 36.6667, while the average kernel dry weight per ear in the shaded treatment was reduced by 15.7534%. Similarly, before calibration, the results were significantly biased by the difference in kernel count per ear. After calibration, the sampling method effectively controlled the error, resulting in analytical results that were closer to reality.

[0065] Verification of the shade sampling method for Shiyou 17's lower stems:

[0066] As shown in Table 6, 14 days after flowering, the average number of grains per ear in conventional sampling without shading treatment was 36.4 grains, while that in the shading treatment under the stem of the ear was 36.8 grains, with a difference of 0.4 grains, which is a small difference. According to the present invention, samples with a difference of less than 1.5 grains per ear are not calibrated.

[0067] At 21 days after flowering, conventional sampling revealed an average grain count of 35.125 grains per ear in the unshaded treatment, compared to 38 grains in the shaded treatment, a difference of 2.875 grains. The average dry weight of grains per ear in the unshaded treatment was 0.8473g, while that in the shaded treatment was 0.9363g. Before calibration, the average grain dry weight per ear in the shaded treatment was 8.9083% higher than in the unshaded treatment. After calibration, the average grain count per ear in the unshaded treatment was adjusted to 38 grains, and the calculated average grain dry weight per ear in the shaded treatment increased by 1.5271%, a significant increase from the 8.9083% increase. This indicates that conventional sampling, influenced by the grain count per ear, was inaccurate, and the calibrated sampling method was more accurate.

[0068] At 28 days and 35 days after flowering, the average number of grains per ear in conventional sampling without shading treatment was 38.8333 and 36.1429 respectively, while that in sampling with shading treatment under the stem of the ear was 40 and 36.75 respectively, which differed from the number of grains per ear in the unshaded treatment by 1.1667 and 0.6071 respectively. The difference in the number of grains per ear was within 1.5 grains, which was a valid sampling and no calibration was performed.

[0069] Verification of the shade sampling method for Jimai 22 ear stems:

[0070] Table 6 shows that at 14 days after flowering, the average number of grains per ear in the conventional sampling of the unshaded treatment was 33.2, while that in the treatment with shading the stems beneath the ears was 27, a difference of 6.2 grains. The average dry weight of grains per ear in the unshaded treatment was 0.3536 g, while that in the treatment with shading the stems beneath the ears was 0.3105 g. Before calibration, the average dry weight of grains in the shaded treatment decreased by 10.5600%. After calibration, it increased by 0.6483% compared to the unshaded treatment. The change before and after calibration is significant, and calibration can more accurately reflect the effects of shading.

[0071] At 21 days after flowering, conventional sampling revealed an average kernel count of 35.625 kernels per ear in the unshaded treatment, compared with 29.7500 kernels in the shaded area, a difference of 5.875 kernels. The average kernel dry weight per ear in the unshaded area was 0.7739 g, while that in the shaded area was 0.5659 g. Before calibration, the average kernel dry weight in the shaded area was 26.8701% lower. After calibration, the average kernel count per ear in the unshaded area was adjusted to 31 kernels. The recalculated average kernel dry weight in the shaded area was 14.0552% lower than in the unshaded area, a significant change indicating that the calibrated sampling method is more accurate.

[0072] At 28 days after flowering, conventional sampling revealed an average kernel count of 32 kernels per ear in the unshaded treatment and 36 kernels in the shaded treatment, a difference of 4 kernels. The average kernel dry weight per ear was 0.9522g in the unshaded treatment and 0.7703g in the shaded treatment. Before calibration, the average kernel dry weight per ear in the shaded treatment was 19.1031% lower than in the unshaded treatment. After calibration, the average kernel count per ear in the unshaded treatment was adjusted to 35.5 kernels. The recalculated average kernel dry weight per ear in the shaded treatment was 29.4888% lower, a significant change.

[0073] At 35 days after flowering, conventional sampling revealed an average grain count of 35 grains per ear in the unshaded sample and 28 grains per ear in the shaded sample, a difference of 7 grains between the two samples. The average dry weight of grains per ear was 1.3938g in the unshaded sample and 1.01g in the shaded sample. Before calibration, the average grain dry weight per ear in the shaded sample was 27.5336% lower. After calibration, the average grain count per ear in the unshaded sample was adjusted to 29 grains, while the average grain dry weight per ear in the shaded sample decreased by 14.4068%, a significant change that validated the calibrated sampling method's effectiveness in reducing sampling error.

[0074] Table 6

[0075]

[0076]

[0077]

Claims

1. A sampling method for wheat shading stress test during the grain filling period, characterized in that: The following steps are involved: S1. Select wheat of the same variety and mark a group of main stem ears with consistent growth on the day of flowering of the wheat variety; S2. Divide the marked main stem ears into an experimental group and a control group, shade the main stem ears of the experimental group after flowering, and grow the main stem ears of the control group under natural conditions; S3. From the wheat filling stage to the maturity stage, sampling was performed at intervals on the main stems and ears of the experimental group and the control group, and agronomic traits of each main stem and ear were recorded, wherein the agronomic traits included grain number and dry weight; S4. The main stem ears sampled from the experimental group were shaded samples for the shade stress test. The average number of grains per ear of the shaded samples was used as the reference number. All main stem ears in the control group whose number of grains per ear was close to the reference number were selected as unshaded samples for the shade stress test. The difference between the average number of grains per ear of the selected unshaded samples and the reference number was in the range of (-1.5 to 1.5).

2. A wheat filling period shade stress test sampling method according to claim 1, characterized in that: In step S2, the main stem ears of the test group are shaded 3 days after flowering.

3. The wheat filling period shade stress test sampling method according to claim 1, characterized in that: In step S2, the shading treatment includes flag leaf shading treatment and ear stem shading treatment. The main stem ears in the test group are divided into two parts, one part of the main stem ears is subjected to flag leaf shading treatment, and the other part of the main stem ears is subjected to ear stem shading treatment.

4. The wheat filling period shade stress test sampling method according to claim 1, characterized in that: In step S3, the agronomic trait indicators also include ear length and fresh weight.

5. A wheat filling period shade stress test sampling method according to claim 4, characterized in that: In step S3, the grains in each treated main stem ear are divided into strong grains and weak grains, and the number, fresh weight and dry weight of the strong grains and weak grains in each main stem ear are recorded respectively.

6. A wheat filling period shade stress test sampling method according to claim 5, characterized in that: The first and second grains in the spikelet of the main stem spike are recorded as strong grains, and the third and fourth grains are recorded as weak grains.

7. The sampling method for wheat shading stress test during the grain filling period according to claim 1, characterized in that: In step S3, the main stem ears of the experimental group and the control group are sampled at 14 days, 21 days, 28 days and 35 days after flowering respectively.

8. The sampling method for wheat shading stress test during the grain filling period according to claim 1, characterized in that: In step S3, the number of ears sampled in the control group is greater than the number of ears sampled in each test group.

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