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Regulatory of Exogenous Melatonin on Floret Development and Carbon Nutrient Metabolism in Winter Wheat Under Drought Stress ZHANG Rong, LIU LinRu, FU KaiXia, WU ZiJun, SONG YiFan, WANG LuYuan, HOU GeGe, HE Li, FENG Wei, DUAN JianZhao, WANG YongHua, GUO TianCai Scientia Agricultura Sinica    2024, 57 (23): 4644-4657.   DOI: 10.3864/j.issn.0578-1752.2024.23.006 Abstract （187）   HTML （12）    PDF （1512KB）（673）       Knowledge map    Save 【Objective】 This study aimed to clarify the regulatory effects of exogenous melatonin on floret development and carbon nutrient metabolism in winter wheat under drought stress. 【Method】 Two soil water conditions (drought stress treatment: D, and normal moisture treatment: W) were set up using multi-spike variety Yumai 49-198 and large-spike variety Zhoumai 22 as experimental wheat materials, with foliar spraying 100 μmol·L-1 exogenous melatonin (MT) and clear water control (CK) before the peak of floret degradation (about 20 days after jointing) in 2021-2023, focusing on the effects of exogenous melatonin on the number and morphological characteristics of floret development, SPAD value, net photosynthetic rate, sucrose content and its metabolic enzyme activities of top spread leaves, and yield component factors of winter wheat under drought stress. 【Result】 The drought stress led to an increase in floret degradation and abortion in wheat, while spraying exogenous melatonin could effectively reduce floret degradation and abortion, and increase number of fertile florets of the two varieties, but could not completely counteract the negative effect of drought stress; exogenous melatonin also showed positive regulatory effect on normal water treatments of the two varieties. Spraying exogenous melatonin could effectively increase SPAD value, net photosynthetic rate, carbon metabolism- related enzyme activities of top spread leaves and spike sucrose content of the two varieties under drought stress and normal water treatment, and the increase range was higher in drought treatment than in normal water treatment; exogenous melatonin decreased sucrose content of stem and leaf organs of both varieties under drought stress, but the opposite was true under normal water treatment. Spraying exogenous melatonin significantly increased grain number per spike of two varieties under two moisture treatments, compared with no-spraying MT treatment, the grain number per spike of Yumai 49-198 with spraying MT treatment increased by 19.12% (D) and 6.65% (W), respectively; the grain number per spike of Zhoumai 22 with spraying MT treatment increased by 21.57% (D) and 8.73% (W), respectively; spraying MT showed some regulation effect on spike number and thousand grain weight of the two varieties under the same water treatment, but did not reach a significant level. Compared the differences between two varieties, the regulatory effect of spraying melatonin was overall higher in the large-spike variety Zhoumai 22 than in the multiple-spike variety Yumai 49-198. 【Conclusion】 Spraying exogenous melatonin before the peak of floret degradation could effectively increase the SPAD value, net photosynthetic rate, and carbon metabolism-related enzyme activities of top spread leaves in wheat, and promote synthesis of photosynthesis products and the distribution and transportation of sucrose from stem and leaf nutrient organs to spike organ, which could provide sufficient nutrient security for the development of florets to increase number of fertile florets, thereby increasing grain number per spike, and the regulating effect on the large-spike variety of Zhoumai 22 was more pronounced. The results of this study provided the theoretical basis and technical support for increasing grain number per spike, stabilizing yield and reducing disaster under drought stress through the application of exogenous melatonin. Table and Figures | Reference | Related Articles | Metrics

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Regulation Effects of Line-Spacing Expansion and Row-Spacing Shrinkage on Dry Matter and Nutrient Accumulation and Transport of Summer Maize Under High Plant Density SHI DeYang, LI YanHong, WANG FeiFei, XIA DeJun, JIAO YanLin, SUN NiNa, ZHAO Jian Scientia Agricultura Sinica    2024, 57 (23): 4658-4672.   DOI: 10.3864/j.issn.0578-1752.2024.23.007 Abstract （165）   HTML （16）    PDF （681KB）（140）       Knowledge map    Save 【Objective】 The aim of this study was to explore the effect of line-spacing expansion and row-spacing shrinkage on maize yield, dry matter and nutrient accumulation and transport under high-density planting conditions, and to clarify the optimal allocations of row-spacing, so as to provide the theoretical basis for the further increase of grain yield in Huang-Huai-Hai summer maize region.【Method】 For two consecutive maize growing seasons in 2019-2020, under the planting density of 82 500 plants/hm2, a field comparison experiment was conducted with 5 equidistant row, including 60 cm (B1), 65 cm (B2), 70 cm (B3), 75 cm (B4) and 80 cm (B5), and 2 summer maize varieties, including Denghai 518 (DH518) and Denghai 605 (DH605). The effects of line-spacing expansion and row-spacing shrinkage on maize yield and its constituent factors, dry matter accumulation, distribution and transport, nutrient absorption and transport were studied, and the correlation between dry matter accumulation, nutrient absorption and yield was analyzed too. 【Result】 The increase of the yield of summer maize showed a trend of increasing first and then decreasing, reaching the extreme value under B4. In the 2-year experiment, the yields of DH518 and DH605 under B4 treatment increased by 9.59% and 13.18% on average compared with B1 treatment, respectively. The analysis of yield components showed that the yield of summer maize was affected mainly by the number of grains per ear, the grain number per spike of DH518 and DH605 increased by 8.30% and 11.1% under B4 treatment compared with B1 treatment, respectively. Line-spacing expansion and row-spacing shrinkage significantly affected the dry matter accumulation of maize plants after silking (R1), and the increase of trailing distance showed a trend of first increasing and then decreasing, which reached the maximum value under B4 treatment. Logistic regression equation was used to fit the growth curve, and it was found that the maximum dry matter accumulation rate of DH518 and DH605 under B4 treatment increased by 13.6% and 16.3% than that under B1 treatment, respectively, and the average growth rate increased by 15.9% and 17.5%, respectively. Appropriate increase of planting row spacing could improve dry matter accumulation after R1, and dry matter transfered from vegetative organs to grain before R1. The accumulation of N, P and K in the two varieties increased first and then decreased. The N, P and K accumulation of DH518 in R1 and physiological maturity (R6) were increased by 5.2%-25.2%, 9.8%-43.5%, 3.5%-26.1% and 6.3%-29.0%, 9.6%-49.9%, and 8.5%-31.0% compared with B1 treatment, respectively; DH605 increased by 6.0%-17.4%, 5.7%-28.9%, 5.2%-19.1% and 7.6%-28.4%, 8.7%-46.5%, and 6.6%-25.7%, respectively. The increase of row spacing significantly increased the volume of transshipment of N, P and K in the 2 varieties, and reached the extreme value under B4 treatment. The volume of transshipment of N, P and K in DH518 and DH605 under B4 treatment increased by 19.9%, 39.3%, 23.3% and 14.6%, 30.8%, 24.9% compared with B1 treatment, respectively. The correlation analysis of above-ground dry matter accumulation and N, P, K accumulation and yield in R1 and R6 showed that the dry matter accumulation and N, P, and K accumulation were significantly positively correlated with grain yield.【Conclusion】 Under high density planting conditions, line-spacing expansion and row-spacing shrinkage improved the maximum and average dry matter growth rate of DH518 and DH605, and promoted nutrient translocation amount and contribution rate of accumulation nutrients after the R1 stage, synergistically, thus increased maize yield and fertilizer utilization. Considering yield, accumulation and transport of dry matter and nutrients, 75 cm equal row spacing was beneficial to yield under the planting condition of 82 500 plants /hm2 in Huang-Huai-Hai summer maize region. Table and Figures | Reference | Related Articles | Metrics

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Effects of Late Sowing on Yield, Quality, Photosynthetic Source Succession and Loadability Characteristics of Rape LI Fei, XIONG Cai, GU JiaJia, CAO Xin, WANG ShanShan, HU Wei, ZHOU ZhiGuo, CHEN BingLin Scientia Agricultura Sinica    2024, 57 (23): 4673-4685.   DOI: 10.3864/j.issn.0578-1752.2024.23.008 Abstract （157）   HTML （10）    PDF （633KB）（102）       Knowledge map    Save 【Objective】 This study aimed to explore the regulation mechanism of late sowing on succession of photosynthetic sources (leaf and silique shell), source loadability, yield and quality in rape. 【Method】 The experiment was conducted in the Dafeng District, Yancheng city of Jiangsu Province, and Nanjing of Jiangsu Province in 2022-2023. The main factors sowing dates were set up at 6 levels, October 17th (SD1), October 23rd (SD2), October 29th (SD3), November 4th (SD4), November 10th (SD5), and November 16th (SD6), and the secondary factors were two conventional varieties: Nannongyou 4 (strong cold resistance) and Zheyou 51 (medium cold resistance). The effects of different sowing dates on dynamic change characteristics of leaf area index (LAI), pod area index (PAI) and source succession, source loadability and rape yield and quality were investigated. 【Result】 (1) The later the sowing dates, the younger the pre-winter seedling age, and the lower the overwintering survival rate. The latest safe date of late-sowing rapeseed in the lower reaches of Yangtze River was the end of October, and the pre-winter seedling age was more than 5 leaves. The sowing date was postponed to November, the leaf age of rape decreased to 1.2-3.6 leaves, and the average overwintering survival rate was less than 30%. The average overwintering rate of Nannongyou 4 in November was 30.9%, which was 14.5% higher than that of Zheyou 51. (2) During the latest safe sowing period, the yield of rapeseed decreased significantly with the delay of sowing dates, and the decrease of plant silique number and 1000-seed weight were the most direct factors causing the decrease of oilseed yield. With the delay of sowing date, compared with SD1, the yield of SD2 and SD3 decreased by 9.6% and 29.0%, the number of plant silique number decreased by 6.1% and 23.9%, and the 1000-seed weight decreased by 4.4% and 6.5%, respectively. The average content of fat and protein in Nannongyou 4 was 42.9% and 25%, which in Zheyou 51 was 47.9% and 22.7%, respectively. (3) With the delay of sowing dates, the maximum LAI and PAI of rape decreased significantly, the slow growth rate before LAI reaching the peak and the fast decline rate after LAI reaching the peak both decreased, and the rapid growth rate of PAI slowed down. The later the sowing dates, the earlier the LAI and PAI succession points (the lower the effective accumulated temperature), and the lower the LAI and PAI succession points (the lower the LAI and PAI succession point). The photosynthetic source and source succession dynamic characteristic values of Nannongyou 4 were generally better than those of Zheyou 51. (4) With the delay of sowing date, the leaf area decreased faster than the seeds yield and pod area, caused the leaf loadability gradually increased, while the silique loadability gradually decreased. Insufficient leaf source and seeds sink were the main reasons for the yield reduction of late sowing. The leaf and shell loadability of Nannongyou 4 was both higher than that of Zheyou 51.【Conclusion】 Within the latest safe sowing period of rapeseed in the lower reaches of Yangtze River, it was advisable to select cold-resistant, high-yield and high-oil varieties with suitable photosynthetic source succession point and high source load, to reduce yield loss caused by late sowing. Table and Figures | Reference | Related Articles | Metrics

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Effects of Sowing Date Adjustment on Yield and Quality of Winter Wheat and Summer Maize in Northern Area of North China ZHAO HuaRong, ZHOU GuangSheng, QI Yue, GENG JinJian, TIAN XiaoLi Scientia Agricultura Sinica    2024, 57 (15): 2964-2985.   DOI: 10.3864/j.issn.0578-1752.2024.15.005 Abstract （581）   HTML （38）    PDF （698KB）（2172）       Knowledge map    Save 【Objective】Based on the field staging experiments, this study revealed the different responses of winter wheat and summer maize sowing date adjustments in growth and development, photosynthetic physiological characteristics, grain filling, yield formation and quality to climate warming in northern area of North China, providing scientific basis for agricultural production measures to cope with climate change in North China Plain.【Method】Different sowing date experiments of winter wheat and summer maize have been conducted at Hebei Gucheng Agricultural Meteorology National Observation and Research Station in northern area of North China from 2017 to 2023, which were set up in four sowing dates, including 10 d early sowing, 10 d late sowing, 20 d late sowing, and control. The growth process, above-ground dry matter accumulation and distribution, photosynthetic characteristics of leaves, grain filling rate, yield agronomic traits, and grain nutrients of winter wheat and summer maize were observed. 【Result】 The whole growth period of winter wheat was shortened with the delay of sowing date, mainly because of the shortening of seedling stage before winter. There was a parabolic relationship between the whole growth period and sowing date of summer maize. The seedling stage was shortened by 1.3 d, and the flowering stage and grain formation-filling stage were extended by 1.5 d and 1.6 d for every 10 d delay of sowing date. The grain filling characteristics of winter wheat and summer maize were not sensitive to sowing date adjustments, and the grain filling rate of summer maize was little different during different sowing dates, but the grain formation period, the filling end date and the peak date were successively delayed due to the delay of sowing date, and the duration of filling days was shortened by 4.0 d for every 10 d delay of sowing date. Under the background of warm autumn and winter in northern wheat region, the sowing duration of winter wheat was extended, while its influence on the yield was obviously weakened. The delay of sowing date with the increase of sowing seed amount would result in yield increase slightly. The yield of summer maize decreased significantly with the delay of sowing date, and the decline rate of theoretical yield was 1 381.50 kg·hm-2 for every 10 d delay of sowing date, but the yield of winter wheat and summer maize showed a jumping decease for 20 d late sowing. The grain distribution rate increased by 1.67% for winter wheat, decreased by 1.57% for summer maize with every 10 d delay of sowing date. As a result, the harvest index increased by 0.017 for winter wheat, and decreased by 0.016 for summer maize with every 10 d delay of sowing date. The leaf photosynthetic rates (Pn) of winter wheat and summer maize were also different in response to sowing date, they were similar for winter wheat during different sowing dates, while decreased by 1.21 μmol·m-2·s-1 for summer maize for every 10 d delay after sowing date. Sowing date adjustments had no significant effects on grain quality of winter wheat and summer maize in northern area of North China. 【Conclusion】Extending suitable sowing date range and sowing date delay of winter wheat in North China Plain were positive and effective measures to adapt to climate warming. The early sowing of summer maize in North China Plain might avoid the negative effects of high temperature and heat damage, and would promote the increase of yield. Table and Figures | Reference | Related Articles | Metrics

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The Related Driving Factors of Water Use Efficiency and Its Prediction Model Construction in Winter Wheat GAO ChenKai, LIU ShuiMiao, LI YuMing, ZHAO ZhiHeng, SHAO Jing, YU HaoLin, WU PengNian, WANG YanLi, GUAN XiaoKang, WANG TongChao, WEN PengFei Scientia Agricultura Sinica    2024, 57 (7): 1281-1294.   DOI: 10.3864/j.issn.0578-1752.2024.07.006 Abstract （286）   HTML （20）    PDF （686KB）（1005）       Knowledge map    Save 【Objective】The water use efficiency can comprehensively reflect the growth suitability and energy conversion efficiency of winter wheat. The driving factors of winter wheat in response to standardized water use efficiency (WP*) at different growth stages were screened and explored, and the WP* prediction model of related driving factors was constructed, which was of great significance for the monitoring of water use efficiency and efficient use of water resources in winter wheat in the Huang-Huai-Hai Plain.【Method】Three water treatments were set up, including water deficit treatments (W1:35 mm, and W2:48 mm) and control treatment (W3: 68 mm), and the canopy temperature parameters, physiological indexes and standardized WP* of winter wheat at the jointing, booting and filling stages were measured. Stepwise regression and pathway analysis were used to screen the main driving factors in response to WP* changes at each growth stage, the relationship between WP* and related drivers was explored, and finally the partial least squares regression (PLSR) and support vector machine (SVM) methods were used to construct a driver-based WP* prediction model in each growth stage. 【Result】 Compared with W3, the canopy temperature parameters, physiological indexes and WP* of winter wheat under the water deficit treatments showed significant differences. Based on the stepwise regression method, the main driving factors in response to WP* at each growth stage were screened, and the sensitivity of each driving factor in response to WP* was ranked by pathway analysis, that is, maximum temperature difference (MTD), stomatal conductance (Gs), leaf water content (LWC) and POD were selected at the jointing stage; canopy relative temperature difference (CRTD), equivalent water thickness (EWT), soluble sugar content (SSC) and crop water stress index (CWSI) were selected at the booting stage; SSC, standard deviation of canopy temperature (CTSD), LWC and Gs were selected at the filling stage. Finally, the driver-based WP* prediction model for each growth stage was construct by using PLSR and SVM. Among them, the prediction model of WP* at booting stage constructed by SVM had the best accuracy, with R2cal (R2val), RMSEcal (RMSEval) and nRMSEcal (nRMSEval) of 0.945 (0.926), 0.533 g·m-2 (0.580 g·m-2) and 2.844% (3.075%), respectively. 【Conclusion】 By screening the relevant driving factors of WP* at each growth stage of winter wheat and constructing a prediction model of winter wheat water use efficiency, this paper provided a theoretical basis for accurate monitoring and management of winter wheat moisture in the Huang-Huai-Hai Plain. Table and Figures | Reference | Related Articles | Metrics

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Nitrogen Fertilizer Postponing Application Benefits Wheat-Maize Intercropping by Reducing Soil Evaporation and Improving Water Use Efficiency REN Qiang, XU Ke, FAN ZhiLong, YIN Wen, FAN Hong, HE Wei, HU FaLong, CHAI Qiang Scientia Agricultura Sinica    2024, 57 (7): 1295-1307.   DOI: 10.3864/j.issn.0578-1752.2024.07.007 Abstract （232）   HTML （32）    PDF （590KB）（597）       Knowledge map    Save 【Objective】Aiming at the problem of insufficient excavation of the potential of efficient water utilization of wheat-maize intercropping in the oasis irrigation area, which restricted the stable development of multi-maturing cultivation, this study was intended to provide the theoretical basis for the creation of a model of efficient water utilization of wheat-maize intercropping in the oasis irrigation area by investigating the effects of different nitrogen fertilizer postponing application on water consumption characteristics and water utilization of wheat-maize intercropping.【Method】The experiment was carried out in the oasis agricultural comprehensive experimental station of Gansu Agricultural University from 2020 to 2021. Three planting patterns of wheat-maize intercropping, monocropping wheat and monocropping maize were set up. Four treatments application systems were set up for maize: no nitrogen application (N0), 20% nitrogen fertilizer postponing (N1), 10% nitrogen fertilizer postponing (N2), and traditional nitrogen fertilizer without postponing (N3). The total nitrogen application rates of intercropping maize and monocropping maize were 210 and 360 kg·hm-2, respectively. The effects of different planting systems and nitrogen fertilizer postponing ratios on soil evaporation, water consumption characteristics and water use of wheat and maize were studied.【Result】During wheat and maize independent growth stage, the intercropping tree evaporation was greater than that of monocropping, the intercropping wheat tree evaporation increased 15.9%-16.7% than that of monocropping wheat, and the intercropping maize tree evaporation increased 5.4%-14.7% than that of monocropping maize, while wheat and maize symbiosis of intercropping tree evaporation compared with the monocropping weighted reduction of 4.6%-6.1%; the total amount of evaporation during the whole life cycle tree performance: wheat maize in the intercropping mode, intertree evaporation was reduced by 6.5% in the 20% N fertilization setback treatment compared with N3, and intertree evaporation in the wheat belt increased by 12.6%-17.3% compared with that in the maize belt, which was the main source of intertree evaporation in the intercropping system. In the intercropping system, water consumption was 34.3 and 18.9 mm lower than that of traditional N application under the 20% and 10% N fertilizer setback treatments, respectively, but the difference between E/ET and traditional N application was not significant. The seed yield of intercropping system was increased by 21.1%-39.0% compared with the weighted average of monocrop, and the seed yield of intercropping system with 20% N fertilizer setback treatment was increased by 28.8% compared with the traditional N application, among which the intercropped wheat and intercropped maize with 20% N fertilizer setback treatments were increased by 24.3% and 30.8%, respectively, compared with the traditional application of N. The water consumption during the whole growth period under intercropping system with 20% and 10% N fertilizer setback treatment was decreased by 34.3 and 18.9 mm that under traditional application of N, respectively. The E/ET of intercropping system with 20% N fertilization was increased by 20% than that under the traditional N application. The water use efficiency of intercropping planting pattern nitrogen fertilizer setback treatment was significantly increased by 15.0% and 12.3% than that under the weighted average of monocrops; among which the nitrogen fertilizer setback 20% treatment was increased by 35.9% compared with the traditional nitrogen application, and the nitrogen fertilizer setback 10% treatment was increased by 19.3% compared with the traditional nitrogen application.【Conclusion】The wheat-maize intercropping pattern combined with 20% nitrogen fertilizer postponing could reduce soil evaporation and water consumption during the whole growth period, and increase yield and water productivity, which was a nitrogen application system that could be used for high-yield and high-efficiency production of wheat-maize intercropping in oasis irrigation areas. Table and Figures | Reference | Related Articles | Metrics

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Differences in Physicochemical Characteristics and Eating Quality Between High Taste Northern Japonica Rice and Southern Semi- Glutinous Japonica Rice Varieties in China ZHU DaWei, ZHENG Xin, YU Jing, MOU RenXiang, CHEN MingXue, SHAO YaFang, ZHANG LinPing Scientia Agricultura Sinica    2024, 57 (3): 469-483.   DOI: 10.3864/j.issn.0578-1752.2024.03.004 Abstract （238）   HTML （27）    PDF （782KB）（443）       Knowledge map    Save 【Objective】Clarifying the differences of physicochemical characteristics and sensory taste qualities between northern japonica and southern semi-glutinous high eating quality japonica rice varieties in China is of great significance to the cultivation of high eating quality japonica rice. 【Method】In this study, representative northern japonica varieties and southern semi-glutinous japonica varieties were used as materials, Japanese Koshihikari rice was used as a control to systematically analyze the differences in appearance quality, starch fine structure, protein components, pasting properties of rice flour, cooked-rice texture, and sensory taste qualities of the two categories of japonica rice. 【Result】Although the three northern japonica varieties and the three southern semi-glutinous japonica varieties had high similar sensory taste values, they had significant differences of starch fine structure, protein components, pasting characteristics, and cooked-rice texture. For cooked rice sensory taste, three high taste northern japonica varieties showed better palatability (96-98 points), and three southern semi-glutinous japonica varieties showed better cold rice texture (92-100 points). For physicochemical characteristics, the three northern japonica varieties showed higher apparent amylose content (17.6%-19.6%), lower crude protein, gliadin and glutenin content. The three southern semi-glutinous japonica varieties showed lower apparent amylose content (8.5%-10.5%) and higher gliadin and glutenin content. For starch fine structure, the amylose content and amylose/amylopectin ratio of the three southern semi-glutinous japonica rice varieties were low (54.7% and 55.6% lower on average, respectively), and they had similar amylopectin chain length distribution. In addition, the ratio of amylose short chain to long chain in Nanjing 46 and Ningxiangjing 9 was higher than that in Wuyoudao 4 and Tianlongyou 619 (43.2% higher on average). As a result, the rice flour of southern semi-glutinous japonica varieties had higher pasting temperature, peak viscosity, breakdown value, and lower setback viscosity, and the cooked rice had higher stickiness, less hardness and elasticity. 【Conclusion】Taste quality is a synergy of multiple factors of cooked rice, such as appearance, taste and cold rice texture. Appropriate protein components and amylose ratio are the key factors affecting pasting characteristics of rice flour and sensory taste of rice. In this study, the high eating quality northern japonica varieties had lower pasting temperatures, moderate hardness, and better elasticity, while the high eating quality southern semi-glutinous japonica varieties exhibited higher breakdown value, and the cooked rice had higher viscosity and better appearance. Table and Figures | Reference | Related Articles | Metrics

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A VSURF-CA Based Hyperspectral Disease Index Estimation Model of Wheat Stripe Rust MEI GuangYuan, LI Rong, MEI Xin, CHEN RiQiang, FAN YiGuang, CHENG JinPeng, FENG ZiHeng, TAO Ting, ZHAO Qian, ZHAO PeiQin, YANG XiaoDong Scientia Agricultura Sinica    2024, 57 (3): 484-499.   DOI: 10.3864/j.issn.0578-1752.2024.03.005 Abstract （273）   HTML （21）    PDF （1134KB）（341）       Knowledge map    Save 【Objective】Stripe rust is a serious threat to the growth and yield of wheat. Accurate monitoring and diagnostic assessment are fundamental prerequisites for effective prevention and control of stripe rust. The objective of this study is to construct a wheat stripe rust estimation model using remote sensing technology, enable the rapid and precise estimation of the disease index (DI), and to provide technical support for precise prevention and control.【Method】The hyperspectral data of wheat at different growth stages (heading period, grain-filling period, and maturity period) were acquired through the ASD spectrometer. Initially, the variable selection using random forests (VSURF) method, combined with correlation analysis (CA), was applied to select characteristic bands from the original spectrum (OR) and the first-order differential spectrum (FD). Subsequently, the random forest (RF) algorithm was utilized to compare modeling results of characteristic bands from different datasets, identifying the feature set with the most effective model. Further, models such as partial least squares regression (PLSR), extreme gradient boosting (XGBoost), and back-propagation neural network (BPNN) were employed to compare the modeling effects of different feature sets within various algorithms. This comprehensive analysis aimed to determine the optimal estimation model for wheat stripe rust DI across the entire growth period. Simultaneously, to validate the effectiveness of the feature set across different growth stages, the feature set was used to rebuild models during each of the three distinct growth periods.【Result】The comparative analysis of model effects revealed that the VSURF-CA-FD feature set (537 nm in the green range and 821, 846 nm in the near-infrared range) demonstrated the most effective estimation within the RF model, achieving an R2 value of 0.89 and an RMSE of 12.34. These feature bands also exhibited precision in models constructed with other algorithms, including XGBoost (R2: 0.87, RMSE: 13.15), BPNN (R2: 0.84, RMSE: 15.19), and PLSR (R2: 0.69, RMSE: 20.92). For models constructed during different growth stages, the early growth stage (heading period) exhibited an R2 value of 0.54, RMSE of 1.29, and NRMSE of 0.21, meeting the requirements for disease estimation. In the middle growth stage (grain-filling period), the model performed well with an R2 of 0.66, RMSE of 12.24, and NRMSE of 0.21. In the late growth stage (maturity period), the model’s effectiveness surpassed that of the previous two stages, with an R2 of 0.75, RMSE of 10.77, and NRMSE of 0.15.【Conclusion】Utilizing characteristic bands selected through the VSURF-CA method, an RF model with excellent estimation accuracy for wheat stripe rust DI can be established. The research outcomes will provide valuable insights and methodologies for predicting early and mid-stage stripe rust DI. Table and Figures | Reference | Related Articles | Metrics

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Effects of Planting Density and Row Spacing Configuration on Sugar Accumulation and Lodging Performance of Wheat Stem Under Rainfall Harvesting Planting Mode QIN Feng, WANG XiaoFei, WU Zhen, HU YiBo, WANG XiaoQin, ZHANG JiaWei, CAI Tie Scientia Agricultura Sinica    2024, 57 (1): 65-79.   DOI: 10.3864/j.issn.0578-1752.2024.01.006 Abstract （278）   HTML （34）    PDF （2529KB）（526）       Knowledge map    Save 【Objective】The aim of this study was to analyze the effects of different planting densities and row spacing configurations on stem carbohydrate accumulation and lodging resistance of wheat under ridge-furrow rainfall harvesting planting mode, and to clarify the reasonable density and row spacing of wheat under ridge-furrow rainfall harvesting planting mode, so as to provide a theoretical basis for further stabilizing and increasing wheat yield. 【Method】Xinong 979 was the main wheat cultivar in the arid area of north China, which was used as the experimental material. In 2019-2021, two planting densities (low density: 1.8 million plants per hm2; high density: 2.25 million plants per hm2) and two row spacing (equal row spacing: 20 cm; non-equal spacing: 12.5 cm:35 cm:12.5 cm) treatments were set in the rainfall harvesting planting mode. The effects of different densities and row spacing on photosynthetic rate of middle and lower leaves in wheat plants, content of stem non-structural carbohydrates and structural carbohydrates, stem breaking moment and lodging index, and grain yield were analyzed. 【Result】The net photosynthetic rate (Pn) of the middle and lower leaves (the third leaf, the fourth leaf and the fifth leaf) in wheat plants, the content of non-structural carbohydrates (glucose, fructose, sucrose) and structural carbohydrates (hemicellulose, cellulose) in the second internode at the base of stem, and the stem breaking moment were significantly decreased with the increase of planting density in the rainfall harvesting planting mode, but the stem lodging index increased significantly. However, under high-density planting condition, non-equal row spacing treatment could significantly change all plant indexes. Compared with high planting density + equal spacing treatment, the Pn of the third leaf, the fourth leaf and the fifth leaf in plants increased significantly, with increases of 7.7%-16.5%, 5.3%-37.7% and 11.9%-24.9%, respectively; the content of glucose, fructose and sucrose in stems increased by 9.8%-15.0%, 8.8%-27.4% and 8.2%-41.1%, respectively; the content of hemicellulose and cellulose increased by 4.5%-19.8%, 5.9%-31.2%, respectively; the stem breaking moment increased by 4.8%-17.3%, the stem lodging index decreased by 10.9%-25.9%, while wheat yield was significantly increased by 13.5%-15.2%. Correlation analysis showed that, the content of glucose, fructose and sucrose in the basal internode of wheat stem were positively correlated with the content of hemicellulose and cellulose. Non-structural carbohydrates and structural carbohydrates in wheat stem were positively correlated with Pn of middle and lower leaves as well as stem breaking moment, however, they were negatively correlated with lodging index. 【Conclusion】Under the rainfall harvesting planting mode, adjusting population spatial distribution by non-equal row spacing could effectively increase photosynthetic rate of middle and lower leaves of wheat plants, promote the synthesis and accumulation of sugar substances in stems, and enhance the lodging resistance of wheat stem, furthermore, reduce the lodging incidence of wheat and improve grain yield. Table and Figures | Reference | Related Articles | Metrics

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Prediction of Water Content of Winter Wheat Plant Based on Comprehensive Index Synergetic Optimization GAO ChenKai, LIU ShuiMiao, LI YuMing, WU PengNian, WANG YanLi, LIU ChangShuo, QIAO YiBo, GUAN XiaoKang, WANG TongChao, WEN PengFei Scientia Agricultura Sinica    2023, 56 (22): 4403-4416.   DOI: 10.3864/j.issn.0578-1752.2023.22.004 Abstract （317）   HTML （14）    PDF （1467KB）（363）       Knowledge map    Save 【Objective】To find a more comprehensive and accurate method to monitor the water deficit and to provide a theoretical basis for drought relief of winter wheat, the present study was conducted to construct an inversion model of plant water content (PWC) at different growth stages based on three comprehensive indexes, namely, canopy temperature, morphology and physiology indexes of winter wheat.【Method】The winter wheat was studied by setting up three water treatments (water deficit treatment W1: 35 mm, water deficit treatment W2: 48 mm, and control treatment W3: 68 mm) and two wheat varieties (general drought resistant variety Luomai 22 and weak drought resistant variety Zhoumai 27). Canopy temperature parameters (canopy temperature standard deviation (CTSD) and crop water stress index (CWSI)), morphological indicators (plant height, stem diameter, aboveground biomass, and leaf aera index (LAI)) and physiological indicators (stomatal conductance, transpiration rate, and photosynthetic rate) of winter wheat were obtained at jointing, booting, and filling stages, respectively. Comprehensive temperature parameter indicators (CTPI), comprehensive growth indicators (CGI) and comprehensive physiological indicators (CPI) based on the average weight principle were constructed. The correlation between PWC and comprehensive indicators was analyzed, and multiple linear regression (MLR), partial least squares recurrence (PLSR) and support vector machine (SVM) methods were used to construct the PWC inversion model based on comprehensive indicators according to the growth period.【Result】The canopy temperature parameters, morphology and physiological indexes of winter wheat at different growth stages showed significant differences between water deficit treatments (W1, W2) and control treatment (W3) (P<0.05). Comprehensive indicators (CTPI, CGI and CPI) at booting and filling stages have a significant correlation with PWC, with correlation coefficients (r) of -0.70 (-0.78), 0.84 (0.80) and 0.83 (0.76), respectively. Using MLR, PLSR and SVM methods, the PWC inversion prediction model based on comprehensive indicators (CTPI, CGI and CPI) has high prediction accuracy, among which the PWC model built by SVM is the best, R2cal (R2val), RMSEcal (RMSEval), and nRMSEcal (nRMSEval) were 0.878 (0.815), 2.06% (2.37%), and 3.10% (3.33%), respectively.【Conclusion】The SVM-PWC model based on the comprehensive indicators CTPI, CGI and CPI can well predict the water deficit of winter wheat at different growth stages, and provide theoretical basis for drought prevention and drought resistance of winter wheat in the Huang-Huai-Hai Plain. Table and Figures | Reference | Related Articles | Metrics

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Effect of Light Intensity on Leaf Hydraulic Conductivity and Vein Traits of Soybean at Seedling Stage GAO Jing, CHEN JiYu, TAN XianMing, WU YuShan, YANG WenYu, YANG Feng Scientia Agricultura Sinica    2023, 56 (22): 4417-4427.   DOI: 10.3864/j.issn.0578-1752.2023.22.005 Abstract （304）   HTML （22）    PDF （2132KB）（394）       Knowledge map    Save 【Objective】The objective of this study is to explore the effects of light intensity on leaf hydraulic conductivity, photosynthetic traits, and water potential in soybean seedlings, analyze the adaptive mechanisms of leaf vein traits in response to varying light intensities, and to provide theoretical support for enhancing future light energy utilization in soybean.【Method】Two soybean varieties, Nandou 12 (shade-tolerant) and Guixia 7 (shade-sensitive), were cultivated and placed in growth chambers. The plants were exposed to varying light conditions, including high light intensity (HL) at (424.47±12.32) µmol·m-²·s-¹, medium light intensity (ML) at (162.52±20.31) µmol·m-²·s-¹, and low light intensity (LL) at (93.93±9.87) µmol·m-²·s-¹. After a 20-day treatment period, the impacts of different light intensities on hydraulic conductivity, photosynthetic parameters, leaf water potential, and leaf vein traits in the seedling leaves of soybean were examined.【Result】Compared with HL treatment, the leaf hydraulic conductivity of Nandou 12 and Guixia 7 under LL treatment was significantly decreased, and the leaf hydraulic conductivity of Nandou 12 under the three treatments was significantly higher than that of Guixia 7 under the three treatments. Compared with HL treatment, the leaf hydraulic conductivity of Nandu 12 under ML and LL treatments decreased by 7.56% and 21.24%, stomatal conductance decreased by 43.96% and 58.89%, and net photosynthetic rate decreased by 29.44% and 46.49%, respectively. Similarly, the leaf hydraulic conductivity of Guixia 7 under the ML and LL treatments decreased by 42.16% and 23.71%, stomatal conductance decreased by 54.55% and 45.79%, and net photosynthetic rate decreased by 37.03% and 42.06%, respectively. Additionally, no statistically significant differences were observed in the leaf water potential of both soybean varieties across the various treatments. Notably, leaf hydraulic conductivity and stomatal conductance of soybean exhibited a highly significant positive correlation (P<0.01) under the three light intensity treatments. As the light intensity decreased, a positive correlation was observed between leaf hydraulic conductivity and net photosynthetic rate (P<0.05) as well as stomatal conductance (P<0.01). Conversely, there was a noticeable decrease in the minor leaf vein density and the area of xylem conduits in major and minor veins under the ML and LL treatments for both soybean varieties. In the case of the minor leaf vein density and the area of xylem conduits in major veins, Nandou 12 exhibited significantly higher values than Guixia 7 under the ML and LL treatments. The major leaf vein density of Nandou 12 remained relatively stable across treatments, while that of Guixia 7 experienced a significant reduction of 11.4% and 15.0% under the ML and LL treatments compared to the HL treatment. Furthermore, a decrease in light intensity had a notable effect on increasing the distance between leaf veins and stomata. Specifically, under the ML and LL treatments, the distance from veins to stomata increased by 21.33% and 60.01% for Nandou 12 and by 31.50% and 53.59% for Guixia 7 in comparison to the HL treatment. The correlation analyses revealed significant positive correlations (P<0.05) between the hydraulic conductivity of soybean leaves and the density of minor leaf veins, the area of xylem conduits in major and minor veins. Conversely, a significant negative correlation (P<0.01) was observed between hydraulic conductivity and the distance from veins to stomata.【Conclusion】Light intensity exerts an influence on the leaf hydraulic conductivity by modulating the leaf vein structure of soybean. Under low light conditions, there is a reduction in leaf hydraulic conductivity in soybean; however, the coordination between leaf hydraulic conductivity and stomatal conductance is maintained to establish equilibrium between leaf water supply and demand as light intensity diminishes. The presence of a higher vein density under low light serves to abbreviate the distance required for water transport, thereby enhancing leaf water supply capacity. Consequently, this facilitates CO2 diffusion and photosynthesis, representing an additional strategy employed by shade-tolerant soybean to acclimate to low-light environments. Table and Figures | Reference | Related Articles | Metrics

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Potato Tuber Skin Roughness Classification Analysis Based on Image Characteristics Recognition TANG ZhenSan, YUAN JianLong, KANG LiangHe, CHENG LiXiang, LÜ Tai, YANG Chen, ZHANG Feng Scientia Agricultura Sinica    2023, 56 (22): 4428-4440.   DOI: 10.3864/j.issn.0578-1752.2023.22.006 Abstract （270）   HTML （22）    PDF （3392KB）（662）       Knowledge map    Save 【Objective】The classification analysis of potato tuber skin roughness could provide the non-destructive testing methods for tuber appearance quality traits, which would establish the theoretical and practical base for the objective evaluation of tuber quality and high-throughput screening varieties.【Method】Seventy-nine potato varieties (lines) were selected as materials, and the images of tuber skin with and without bud-eyes were taken by camera. The tuber skin images were preprocessed using MATLAB R2016a software. Eight materials were randomly selected to compare the effect of image graying, enhancement and denoising using the correlation function indicators. The image characteristic parameters, angular second moment (ASM), entropy (ENT), contrast (CON) and correlation (COR) were extracted using the gray level co-occurrence matrix (GLCM), and the suitable distance (d) of GLCM were determined. The differences in two types of tuber skin image feature parameters were compared, and the set of tuber skin image features with less difference was selected for statistical analysis and classification recognition. The support vector machine (SVM) and backpropagation neural network (BPNN) models were constructed for tuber skin roughness classification, and the evaluation indexes of model grading accuracy were accuracy, precision, recall and harmonic mean, respectively. 【Result】The texture structure of tuber skin image after grayscale processing using the weighted average method was clear, and the evaluation value of image clarity was 2.5698±0.5959, which was significantly higher than that of the mean method (1.8035±0.4856) and the maximum method (1.0535±0.4088). The gray scale range of tuber skin image after histogram equalization enhancement was expanded from 100-200 to 0-200, which made the gray distribution wider. The salt noise denoising effect of tuber skin images using the median filter under 3×3 sliding windows was obvious, and the peak signal-to-noise ratio (PSNR) was maximum (28.6250±3.9784 Bp), which was significantly higher than that under 3×3 and 5×5 windows. Two types of tuber skin image feature parameters extracted by GLCM (d=4) were significantly different, and the set of tuber skin image features (without bud-eyes) with less difference was selected for statistical analysis and classification recognition. The results indicated that the variation coefficient of these parameters was varied significantly. The variation coefficient of contrast was the largest (0.40), followed by the angular second moment (0.24) and correlation (0.23), and the variation coefficient of entropy was the smallest (0.18). Using the feature set as the input variable of tuber skin classification model, the overall classification performance of SVM was higher than BP neural network, and the accuracy reached 87.5%. Especially, the prediction accuracy and recognizability of SVM for smooth and heavy hemp skins was the highest. The accuracy reached 100%, the recall reached 85.7% and 100%, and the harmonic mean reached 100% and 92.3%, respectively. 【Conclusion】The combination of the image processing techniques presented in this study and the GLCM extracted texture feature parameters could effectively characterize potato tuber skin roughness variations. The tuber skin roughness grading based on machine vision could be achieved by constructing SVM classification model, and the accuracy reached 87.5%. Table and Figures | Reference | Related Articles | Metrics

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Effects of Straw Mulching and Nitrogen Application on the Improvement of Wheat Root Architecture and the Absorption and Utilization of H+ and NO3- in Hilly Dry Land AI DaiLong, LEI Fang, ZOU QiaoSheng, HE Peng, YANG HongKun, FAN GaoQiong Scientia Agricultura Sinica    2023, 56 (21): 4192-4207.   DOI: 10.3864/j.issn.0578-1752.2023.21.005 Abstract （265）   HTML （14）    PDF （1392KB）（200）       Knowledge map    Save 【Objective】In order to further study the root architecture and root tip nitrogen transport process of wheat after straw mulching in the wheat-maize rotation system in the dry land of southwest China, and to elucidate the physiological basis of straw mulching and nitrogen application to promote the efficient absorption and utilization of wheat nitrogen.【Method】The experiment was a two-factor split plot experiment of straw mulching (SM: straw mulching; NSM: no straw mulching) and nitrogen application (N0: 0; N1: 120 kg·hm-2), which was conducted at Sichuan Renshou Modern Agricultural Test Station from 2020-2022. The effects of straw mulching and nitrogen application on soil physicochemical properties, wheat root architecture, nitrogen absorption in root tips, plant biomass and aboveground nitrogen accumulation and utilization were analyzed according to the current situation that soil drought inhibited root elongation in dry land of southwest hills, resulting in low wheat biomass and nutrient use efficiency.【Result】The soil nitrate nitrogen content of straw mulching treatment increased by 43.1% and 30.8%, and the ammonium nitrogen content increased by 21.8% and 18.8%, respectively, in 2020-2021 and 2021-2022 compared with the no straw mulching treatment. Straw mulching increased the root length, root surface area, and root volume of the 0-10 cm soil layer at jointing stage, booting stage and anthesis stage of wheat, and nitrogen application significantly increased the 0-10 cm soil root length, root surface area and root volume. In addition, straw mulching and nitrogen application could significantly increase the absorption rate and net absorption rate of H+ and NO3- at the root tips of wheat, and reduce the H+ efflux rate at the root tips of 0-20 cm soil layer. Straw mulching and nitrogen application significantly increased the activities of nitrate reductase and glutamine synthetase in roots, and the nitrogen accumulation and biomass in the aboveground part of wheat increased by 25.8% and 35.8% on average, respectively, in two years. H+ absorption rate, NO3- absorption rate, nitrate reductase activity, glutamine synthetase activity, and nitrogen accumulation were positively correlated with root length, root surface area and root volume of 0-10 cm soil layer (P<0.05).【Conclusion】In the southwest hilly dry land wheat-maize rotation system, maize straw mulching and nitrogen application can increase the content of inorganic nitrogen in the soil during the wheat season, the root distribution in the soil surface and the absorption rate of H+ and NO3- at the root tips, promote nitrogen uptake and root tip nitrogen transport, and then promote aboveground nitrogen assimilation and accumulation; Under the conditions of this experiment, straw mulching combined with 120 kg N·hm-2 is a green production mode suitable for high yield and high nitrogen use efficiency in Sichuan hilly dry land. Table and Figures | Reference | Related Articles | Metrics

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Investigation on the Effects of Climate Change on the Growth and Yield of Different Maturity Winter Wheat Varieties in Northern China Based on the APSIM Model SHI XinRui, HAN BaiShu, WANG ZiQian, ZHANG YuanLing, LI Ping, ZONG YuZheng, ZHANG DongSheng, GAO ZhiQiang, HAO XingYu Scientia Agricultura Sinica    2023, 56 (19): 3772-3787.   DOI: 10.3864/j.issn.0578-1752.2023.19.006 Abstract （358）   HTML （18）    PDF （615KB）（1885）       Knowledge map    Save 【Objective】This study aims to clarify the impacts of climate change on the growth, development and yield of winter wheat of different maturity, so as to provide a theoretical basis for the sustainable production of wheat under future climate change. 【Method】The data about growth of two winter wheat varieties of Liangxing 99 (late-maturing) and Zhongke 2011 (early-maturing), soil, and meteorology, which were observed under different temperatures and [CO2] treatments in the open top chamber in 2017-2020, were used to calibrate and validate the APSIM (agricultural production systems simulator) model. Then the verified model was used to simulate winter wheat yield, yield composition and phenology dates under different future climate conditions (RCP 4.5 and RCP 8.5) with a baseline period of 1986-2005. And the impacts of climate change and extreme high temperature on the production potential of different maturity winter wheat varieties were analyzed. 【Result】The APSIM model was able to well simulate the phenology, yield and biomass under different air temperature and [CO2] treatments since the simulated and measured values of R2 were higher than 0.614 and the values of nRMSE were all lower than 10.6%. However, the simulation result of leaf area index (LAI) was relatively poor. For the long-term simulation results, under different climate conditions, the days from sowing to jointing were shorter than the baseline for two wheat varieties. The shortened days of early-maturing variety were smaller than those of late-maturing variety. There was no obvious change in the days from jointing to maturity between the two varieties. The yield and potential yield of the two wheat varieties were higher under the future RCP conditions than under the baseline period. The yield and potential yield were the highest under the RCP 8.5 condition in 2100s. The yield and potential yield of early-maturing variety were more remarkably increased than those of late-maturing variety. Compared with the baseline, the LAI values of the two wheat varieties increased in the early growth stage. Then, the LAI of the late-maturing variety decreased obviously in the late growth stage, while the LAI of the early-maturing variety had no obvious difference. The aboveground biomass of the two wheat varieties both increased, and the early-maturing variety increased more remarkably than the late-maturing variety. Under different RCP conditions, extreme high temperature had negative impacts on the yield and 1 000-grain weight of the two varieties of winter wheat. Extreme high temperature at flowering stage had the greatest impact on 1 000-grain weight. Compared with the normal years, the 1 000-grain weight and yield of late-maturing variety decreased obviously in extreme-high-temperature years under the RCP 8.5 condition in 2100s, while the grain number also decreased slightly. Under different RCP conditions, compared with the normal years, extreme high temperature obviously reduced the 1 000-grain weight of early-maturing variety but slightly increased the grain numbers. Thus, yield reduction of early-maturing wheat variety in extreme high temperature years was not obvious. 【Conclusion】Early-maturing variety of winter wheat will be more adaptable to future climate change. Thus, breeding of wheat varieties to adapt to climate change is one of the effective measures to cope with future climate change. Table and Figures | Reference | Related Articles | Metrics

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Influence of Future Climate Change on the Climate Suitability of Potato Cultivation in China ZHANG ZhiLiang, HE ZhiHao, RU XiaoYa, JIANG TengCong, HE YingBin, FENG Hao, YU Qiang, HE JianQiang Scientia Agricultura Sinica    2023, 56 (18): 3530-3542.   DOI: 10.3864/j.issn.0578-1752.2023.18.004 Abstract （436）   HTML （44）    PDF （5463KB）（2386）       Knowledge map    Save 【Objective】As the fourth staple food crop in China, potato suitability evaluation is of great significance to ensure national food security. Based on climate data, this study constructed an integrated species distribution model to predict the climate suitable area of potato in China in the future, and provided an important scientific reference for optimizing potato planting in China.【Method】In this study, the future climate data derived from six different global climate models (GCMs) were used to drive an ensemble of five different species distribution models (SDMs) to simulate the temporal and spatial distribution characteristics of climate suitable areas of potato cultivation in China in the historical (1970-2000) and four future (2021-2040, 2041-2060, 2061-2080, and 2081-2100) periods under four greenhouse gas emission scenarios (ssp126, ssp245, ssp370, and ssp585). 【Result】 (1) The precipitation in the wettest month, the highest temperature in the warmest month, and the average temperature in the coldest quarter were the main meteorological factors that affected the climate suitability of potato in China, with their contribution rates of 54.7%, 21.4% and 18.1%, respectively. (2) In four scenarios of greenhouse gas emission, the prediction results of various suitable areas were basically the same, showing the similar trends that the areas of suitable and low suitable would become larger, while the area of high suitable would become smaller. Only in Hainan, Tibet, Xinjiang and some other regions, the climate was not suitable for potato planting. The suitable potato planting areas (including both suitable and high suitable) exceed 50% in all cases. (3) In the future, the low suitable and suitable areas for potato planting will increase greatly, while the high suitable areas will decrease. The order of areas of different suitable grades would remain: suitable areas>low suitable areas>high suitable areas. (4) With the increase of greenhouse gas emission level, the high suitable area in China would be greatly reduced. For spatial distribution, the high suitable areas were mainly in Northeast China, Gansu, western Xinjiang, and some parts of southwest China. From the perspective of time, the future climate change would greatly affect the northwest of Shaanxi, the middle and lower reaches of the Yangtze River, the central and western Inner Mongolia and other regions. The climate suitability of potato planting would obviously decrease. 【Conclusion】In this study, the integrated species distribution models were constructed to predict the temporal and spatial distribution characteristics of potato climate suitable areas in the future. Northeast, Gansu, Southwest and other regions of China could be the main potato planting areas, while Xinjiang and other regions could be the main development areas. The rest regions should be given priority to the development of other staple crops and cash crops according to local conditions. Table and Figures | Reference | Related Articles | Metrics

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Effect of Nitrogen Application Rate and Planting Density on the Lodging Resistance and Grain Yield of Two Winter Wheat Varieties MU HaiMeng, SUN LiFang, WANG ZhuangZhuang, WANG Yu, SONG YiFan, ZHANG Rong, DUAN JianZhao, XIE YingXin, KANG GuoZhang, WANG YongHua, GUO TianCai Scientia Agricultura Sinica    2023, 56 (15): 2863-2879.   DOI: 10.3864/j.issn.0578-1752.2023.15.003 Abstract （369）   HTML （19）    PDF （1133KB）（408）       Knowledge map    Save 【Objective】 To investigate the interactions between genotype, nitrogen application rate and planting density on the regulation of wheat lodging resistance and grain yield, so as to identify the optimal combination of nitrogen-density that matches the biological characteristics of varieties. The results provide theoretical basis and technical support for stable and abundant winter wheat yield and resistant strain cultivation. 【Method】 A split-split plot field experiment was conducted in Jiaozuo, Henan Province, China, for two consecutive years from 2020 to 2022. Two wheat varieties Xinhuamai 818 and Xinmai 26 with different lodging resistance were selected in the main plots. The nitrogen fertilizer application rates were used as split-plots, and five levels were set: no N application (N0), 180 kg·hm-2 (N1), 240 kg·hm-2 (N2), 300 kg·hm-2 (N3) and 360 kg·hm-2 (N4), the planting densities were used as split-split plots, and three levels were set: 2.25 million plants/hm2 (D1), 3.75 million plants/hm2 (D2) and 5.25 million plants/hm2 (D3). The study focused on analyzing the effects of the three-factor combination of variety, nitrogen application and planting density on the anatomical structure of wheat culms, field lodging rate and yield. 【Result】 The results showed that nitrogen application rate and planting density significantly regulated the vascular bundle structure of both wheat varieties. The number and area of big vascular bundles and the ratio of number and area of big and small vascular bundles were significantly and positively correlated with culm wall thickness and culm breaking strength, while the area of small vascular bundles was significantly and negatively correlated with culm wall thickness. Compared with Xinmai 26, Xinhuamai 818 had more big vascular bundles and larger area, while the number of small vascular bundles was equal and the area was smaller. This may be the anatomical basis for the superiority of Xinhua 818 over Xinmai 26 in terms of lodging resistance. Under the same planting density, the number and area of big vascular bundles of both wheat varieties showed a trend of increasing and then decreasing with the increase of nitrogen application rate, with the largest number and area of big vascular bundles in N3 treatment. The average increase of number and area of big vascular bundles of Xinhuamai 818 and Xinmai 26 under N3 treatment compared with the minimum treatment were 14.61%, 15.80% and 16.18%, 20.10% respectively. The number and area of small vascular bundles showed similar changes. Under the same level of nitrogen application rate, the number and area of big vascular bundles of both varieties were the largest in the low density D1 treatment. Compared with the minimum value of high density D3, the average increase in the number and area of big vascular bundles of Xinhuamai 818 and Xinmai 26 under D1 treatment were 6.14%, 5.20% and 8.95%, 11.42%, respectively.【Conclusion】 Nitrogen-density control combination D1N2 with 240 kg·hm-2 and planting density of 2.25 million plants/hm2 can optimize the vascular bundle structure, coordinate the development of big and small vascular bundles. Specifically, the number and area of big vascular bundles and the number ratio and area ratio of two vascular bundles were increased in this treatment. The combination can also increase the thickness of the culm wall between the basal nodes and improve the breaking strength of the plant. These changes realize the synchronous improvement of lodging resistance and yield of wheat. We think this treatment can be used as a suitable nitrogen-density combination pattern for high-yielding and efficient cultivation of winter wheat in high-yielding irrigation areas in northern Henan. Table and Figures | Reference | Related Articles | Metrics

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Effects of Tassel Sizes on Post-Flowering Dry Matter Accumulation and Yield of Different Maize Varieties Under High Temperature Stress During Pollination MU XinYuan, LÜ ShanShan, LU LiangTao, LIU TianXue, LI ShuYan, XUE ChangYing, WANG HongWei, ZHAO Xia, XIA LaiKun, TANG BaoJun Scientia Agricultura Sinica    2023, 56 (15): 2880-2894.   DOI: 10.3864/j.issn.0578-1752.2023.15.004 Abstract （312）   HTML （22）    PDF （2160KB）（422）       Knowledge map    Save 【Objective】 High temperature stress is one of the most critical meteorological disaster factors that restrict the high and stable yield of maize. This study explored the effect of tassel sizes on yield of different maize varieties under high temperature stress during pollination, so as to provide the theoretical basis and reference for stress-resistant cultivation and high temperature resistance breeding of maize. 【Method】 This study was conducted by plot experiment in a greenhouse with two maize varieties as the experimental materials, Xundan 20 (XD20) and Nonghua 101 (NH101), from 2020 to 2021. The effect of tassel sizes on dry matter accumulation, distribution and yield of maize under high temperature stress during pollination was investigated by setting the tassel branch removal treatment at tasseling stage. 【Result】 The results of two years showed that high temperature stress during pollination had little effect on tassel length, branch number, spikelet number and flowering dynamics of male and female. However, high temperature stress resulted in the decrease of dry matter accumulation capacity and distribution ratio to ear, which affected the growth and development of ear, resulting in the significant decrease of cob length and diameter, the significant decrease of grain number per ear, the decrease of proportion of matter accumulation to grain after anthesis, and the significant decrease of yield. Under high temperature stress, the decrease of ear length of NH101 was less than that of XD20, but the decrease of grain number per row, grain number per ear and the proportion of matter accumulation to grain after anthesis was higher than that of XD20, resulting in the decrease of yield of NH101 more than that of XD20, and the yield of XD20 and NH101 decreased by 12.32% and 25.00% respectively. XD20 is more resistant to heat than NH101. The tassel branch removal treatment significantly reduced the number of tassel branch and spikelet of XD20 and NH101 by 58.57%, 42.91% and 57.30%, 41.34%, respectively, but had little effect on the flowering dynamics of male and female. Under the two temperature conditions, the tassel branch removal treatment promoted the growth of ear, increased the grain number per ear, increased the proportion of matter accumulation to grain after anthesis, and thus increased the yield. Among them, the yield increase of XD20 under high temperature conditions was the largest. Compared with normal tassel branch treatment, tassel branch removal treatment increased the yield of XD20 and NH101 by 2.76% and 4.37% under normal temperature conditions, while increased by 12.47% and 5.75% under high temperature conditions, respectively. 【Conclusion】 High temperature stress during pollination has little effect on the growth and development of tassel, but it caused irreversible damage to the growth and development of ear, reduced the number of grains per ear, limited the distribution of photosynthate to grains after anthesis, and significantly reduced the yield. Under high temperature conditions, properly reducing the number of branches in tassel can promote the growth and development of ear, increase the number of grains per ear, promote the accumulation of matter to grains after anthesis, and increase the yield. In addition, the yield increase of the large tassel-type variety XD20 was higher than that of the small tassel-type variety NH101. Table and Figures | Reference | Related Articles | Metrics

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Yield-Increasing Effects Under Plastic Film Mulching of Potato in China Based on Meta-Analysis XU JuZhen, ZHANG MengLu, HE WenQing, SUI Peng, CHEN YuanQuan, CUI JiXiao Scientia Agricultura Sinica    2023, 56 (15): 2895-2906.   DOI: 10.3864/j.issn.0578-1752.2023.15.005 Abstract （295）   HTML （11）    PDF （601KB）（478）       Knowledge map    Save 【Objective】 Plastic mulching film (PMF) has various effects, including improving soil temperature, moisture retention, and weed inhibition. It is an efficient and simple technical measure to alleviate the limitations of potato production. Based on publication data, this study quantified the effect of PMF on potato yield and water use efficiency (WUE), and further analyzed the influencing factors to provide a reference for sustainable potato production. 【Method】 Based on a meta-analysis of 291 field experiments on PMF of potato production in China from 1981 to 2021, published in Web of Science and CNKI databases, including four regions, Northern single farming area (NSFA), Southwest mixed farming area (SWMFA), South winter farming area (SWFA), and Central plains second farming area (CPSFA). Meta-analysis was used to quantify the effects of PMF on potato yield and WUE. The study examined the effects of PFM on potato yield and WUE from various perspective, including the regions, natural conditions (average annual precipitation, soil bulk density, and soil organic matter content), and different management conditions (potassium fertilizer application rate, planting density, mulching color, and mulching method). 【Result】 Compared with no mulching, PMF increased potato yield and WUE by 24.9% and 28.3% respectively. The effects of PMF on yield and WUE varied among different regions: NSFA (27.2%), SWFA (23.6%), SWMFA (18.1%) and CPSFA (10.1%). However, WUE was only significantly improved in the NSFA (29.1%). The response of yield and WUE to PMF varied among different regions and was influenced by natural conditions and management conditions. The response of yield to PMF varied among different regions under different natural condition. Planting density and mulching method had consistent effect in all regions, with the best yield increase achieved with low planting density and ridge. In the NSFA, PMF significantly improved WUE under low average annual precipitation, relatively low soil organic matter content, low soil bulk density and fertilizer application rate, medium planting density, black mulching color, and ridge. 【Conclusion】 PMF had been widely used in China and the results showed it increased potato yield. The yield increase varied among different regions and was in the following order: NSFA, SWFA, SWMFA, and CPSFA. PMF only improved WUE in the NSFA. PMF performed better on yield increase under natural condition of low average annual precipitation, poor soil fertility, and loose soil, as well as under management conditions of relatively low fertilization level, relatively low planting density, black mulching, and ridge. In the NSFA, the conditions required for achieving optimal yield increase and WUE increase using PFM were comparable. Table and Figures | Reference | Related Articles | Metrics

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Study on Adaptability of Spring Wheat Yield to Water and Nitrogen Reduction Under Wide-Width Uniform Sowing and Conventional Strip Sowing in Oasis Irrigated Regions CHEN GuiPing, CHENG Hui, FAN Hong, FAN ZhiLong, HU FaLong, YIN Wen Scientia Agricultura Sinica    2023, 56 (13): 2461-2473.   DOI: 10.3864/j.issn.0578-1752.2023.13.003 Abstract （305）   HTML （40）    PDF （590KB）（157）       Knowledge map    Save 【Objective】Water shortage and high fertilizer input have become the dominant factors restraining spring wheat production in arid oasis irrigated areas. It is urgent to study the technology of the effects of water and nitrogen reduction in different planting modes on dry matter accumulation and yield formation of spring wheat, so as to provide a theoretical and practical basis for efficient production of spring wheat with water and fertilizer saving. 【Method】A field experiment with split-split plot was conducted at arid oasis irrigated areas from 2020 to 2021. Two planting modes, including wide-width uniform sowing (W) and conventional strip sowing (C), were designed, with two irrigation levels on local conventional irrigation (I2, 2 400 m3·hm-2) and local conventional irrigation reduced by 20% (I1, 1 920 m3·hm-2), and three levels of nitrogen fertilizer at a local conventional nitrogen (N3, 225 kg·hm-2), local conventional nitrogen reduced by 20% (N2, 180 kg·hm-2), and local conventional nitrogen reduced by 40% (N1, 135 kg·hm-2). The adaptability of spring wheat yield to water and nitrogen reduction under wide-width uniform sowing and conventional strip sowing was studied. 【Result】Compared wtih conventional strip sowing, the wide-width uniform sowing increased the maximum dry matter growth rate (Vmax), average dry matter growth rate (Vmean), and dry matter accumulation rate after booting stage of spring wheat, and delayed the time of emergence of the highest dry matter growth rate (Tm). Compared with conventional strip sowing with conventional irrigation and nitrogen levels, the Vmax and Vmean values of spring wheat under the wide-width uniform sowing were increased by 13.0%-23.4% and 11.0%-16.9%, respectively, and Tm was delayed by 3.3-3.7 days with the treatment on the reduction of 20% for water and nitrogen, so the growth and development dynamics of spring wheat could be effectively regulated by wide-width uniform sowing. The wide-width uniform sowing had greater grain and biomass yields by 11.0%-17.3% and 4.3%-9.6%, respectively, and the greater harvest index by 6.3%-6.9%, than conventional strip sowing. Furthermore, the grain and biomass yields were 16.0%-22.5% and 5.6%-13.2%, and harvest index was 8.2%-10.9% greater under wide-width uniform sowing with the reduction of 20% in water and nitrogen than those under the conventional strip sowing with conventional irrigation and nitrogen levels. There was no significant difference in grain and biomass yields, and harvest index of spring wheat was found between the reduction 20% of water and nitrogen, and the reduction of 20% irrigation and conventional nitrogen application under wide-width uniform sowing. The increase of spring wheat yield was mainly attributed to the synergistic of grains per ear and 1000-grain weight, which were increased by 3.9%-7.1% and 18.4%-22.7%, respectively, compared with conventional strip sowing with conventional irrigation and nitrogen application, and the 1000-grain weight increased by a greater extent. Path analysis showed that the reduction 20% of water and nitrogen in wide-width uniform sowing enhanced grain yield mainly through increasing harvest index and 1000-grain weight. 【Conclusion】 The wide-width uniform sowing could realize the simultaneous reduction 20% of water and nitrogen in spring wheat production, which was a feasible measure to save water and nitrogen for stable and high yield of spring wheat in oasis irrigation areas. Table and Figures | Reference | Related Articles | Metrics

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Integrating Multi-Source Gaofen Images and Object-Based Methods for Crop Type Identification in South China WANG JiaYue, CAI ZhiWen, WANG WenJing, WEI HaoDong, WANG Cong, LI ZeXuan, LI XiuNi, HU Qiong Scientia Agricultura Sinica    2023, 56 (13): 2474-2490.   DOI: 10.3864/j.issn.0578-1752.2023.13.004 Abstract （377）   HTML （32）    PDF （12012KB）（205）       Knowledge map    Save 【Objective】 Due to frequent cloudy and rainy weather, it is challenging to map crop types over South China with fragmented agricultural landscapes. The Gaofen (GF) series satellites developed by China have high spatial-temporal resolution and good image quality. This study exploited the spatial and temporal advantages of multi-source GF images for fine crop classification in heterogeneous agricultural areas with frequent clouds and rain. 【Method】This study characterized the spatial geometry of agricultural fields based on GF-2 data with high spatial resolution, and cooperated with the encrypted observations from GF-1 and GF-6 time series to fully characterize the spectral seasonal variations of crops. By constructing three-dimensional classification features of spectrum-time-space, the crop classification based on random forest classifier were conducted, and the importance scores of different features were calculated. Furthermore, several classification scenarios were set based on different satellite combinations and different classification units, for further analyzing the performances of integrating different GF datasets on crop type mapping. 【Result】The overall accuracy of synergistic GF-1, GF-2 and GF-6 by object-oriented crop classification was 95.49% with Kappa of 0.94 in Qianjiang city; the overall accuracy in Zaoyang city was 93.78% with Kappa of 0.92. The accuracy of crop classification by integrating GF-2 and GF-6 was higher than that by GF-2 and GF-1. In addition, the object-oriented crop classification based on GF-2 outperformed the pixel-oriented one, in which the overall accuracy improved by 1.4% and 1.32% in Qianjiang and Zaoyang, respectively. Compared with the spectral and spatial features of GF-1 and GF-2, the GF-6 spectral bands had the largest contribution to crop type identification, and the cumulative importance score accounted for 82% (Qianjiang) and 77% (Zaoyang) of all spectral bands. Among them, the four new spectral bands of GF-6, namely, red-edge I band (B5), red-edge Ⅱ band (B6), purple band (B7) and yellow band (B8), accounted for 47% (Qianjiang) and 33% (Zaoyang) of all spectral bands for crop type identification. 【Conclusion】Integrating multi-source GF images by taking advantages of their spectral, spatial and temporal features could not only alleviate the "mixed pixel" problem caused by the fragmented agricultural landscape, but also reduce the uncertainty of crop type identification in cloudy and rainy areas, providing great potential for accurate crop mapping in South China. Table and Figures | Reference | Related Articles | Metrics

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Optimization of Dryland Wheat Grain Growth Model Parameters Based on an Improved Shuffled Frog Leaping Algorithm CUI WeiNan, NIE ZhiGang, LI Guang, WANG Jun Scientia Agricultura Sinica    2023, 56 (12): 2274-2287.   DOI: 10.3864/j.issn.0578-1752.2023.12.004 Abstract （245）   HTML （15）    PDF （614KB）（2001）       Knowledge map    Save 【Objective】As the core decision module for intelligent agricultural production, the accurate simulation of the crop model depends on efficient and accurate optimization of the model parameters. In order to improve the efficiency of tuning parameters and enhance the performance and accuracy of the crop model, this study optimized the single objective parameters of the dryland spring wheat grain growth sub-model by improving the optimization algorithm, so as to provide a reference for the adaptation study of dryland spring wheat in the loess hilly region of northwestern China, to expand the application of the model, and to facilitate the model to better guide agricultural production.【Method】Based on a field experiment in Anjiapo Village, Fengxiang Town, Anding District, Dingxi City, Gansu Province, from 2015 to 2021, this study combined weather data and yearbook yield data from 1970 to 2021, further optimized six parameters of dryland wheat grain growth stage using roulette selection strategy based on the global communication and local depth search of traditional shuffled frog leaping algorithm (SFLA), carried out error calculation and comparison between measured and simulated yield values before and after algorithm improvement, and tested the APSIM-Wheat model.【Result】(1) At the same number of iterations, the traditional shuffled frog leaping algorithm converged around 200 times, while the improved shuffled frog leaping algorithm converged around 100 times. (2) The optimized parameters for the dryland spring wheat grain growth stage were: the grain number per gram stem was 26.0; the potential rate of grain filling from flowering to start of grain filling period was 0.00119 grain/d; the potential rate of grain filling during grain filling period was 0.00174 grain/d; the potential rate of grain filling under N limitation was 6.20×10-5 g grain/d; the minimum rate of grain filling under N limitation was 1.90×10-5 g grain/d; the maximum grain dry weight per plant was 0.0437 g. (3) The wheat yield was simulated using the parameter values optimized by the traditional shuffled frog leaping algorithm and the parameter values optimized by the improved shuffled frog leaping algorithm, respectively. After parameter optimization, the root mean square error (RMSE) between the measured and simulated yield values decreased from 363.22 kg·hm-2 to 57.85 kg·hm-2, and the normalized root mean square error (NRMSE) decreased from 21.78% to 3.47%.【Conclusion】Compared with the traditional shuffled frog leaping algorithm, the improved shuffled frog leaping algorithm increased the diversity of populations and subpopulations, converged quickly, and improved the optimization efficiency and accuracy, so the optimized results conformed to the growth and development process of dryland spring wheat with higher applicability, which significantly improved the performance of the APSIM-Wheat model in the loess hilly agricultural area of northwestern China. Table and Figures | Reference | Related Articles | Metrics

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Analysis of Common Characteristics of Widely Adaptation Wheat Cultivars LÜ LiHua, HAN JiangWei, ZHANG JingTing, DONG ZhiQiang, MENG Jian, JIA XiuLing Scientia Agricultura Sinica    2023, 56 (11): 2064-2077.   DOI: 10.3864/j.issn.0578-1752.2023.11.003 Abstract （323）   HTML （26）    PDF （614KB）（2043）       Knowledge map    Save 【Objective】 The objective of this study was to provide simple detection indicators for the screening of stress resistant and widely adapted cultivars under the background of frequent meteorological disasters in the North HuangHuaiHai Plain, through to screen drought resistant, heat-resistant and cold resistant winter wheat cultivars, and to clarify the yield composition, plant type structure and physiological characteristics of stress resistant and widely suitable cultivars.【Method】A field and a greenhouse experiments (experiment 1 and experiment 2, respectively) were carried out in Gaocheng of Hebei province from Autumn 2017 to Summer 2020, and using 16 winter wheat cultivars as experimental material. For experiment 1, three treatments were set up, i.e., 0 irrigation, 1 irrigation (jointing) and 2 irrigation (jointing and flowering). For experiment 2, two treatments were set up at the late stage of filling, i.e., normal temperature treatment (CK) and warming temperature treatment. At the same time, the cold resistance test was conducted using the natural low temperature in the spring of 2018 and 2020. The stress resistance evaluation index, yield formation index, plant type structure index and leaf physiological index were determined.【Result】Five winter wheat cultivars were screened out by comprehensively considering yield, drought resistance index, yield heat sensitivity index and grade of freeze injury, and these cultivars included Jimai 23, Shannong 30, Jimai 325, Jimai 22 and Pinyu 8012. These cultivars had strong drought, heat and cold resistance, and had high and stable yield. By analyzing the correlation between yield and yield formation index, plant type index and leaf physiological index, it was found that 1000-grain weight, harvest index and biomass production were positively correlated with yield; the width of flag leaf, stem diameter and spike length were significantly or extremely significantly positively correlated with yield, while angle of stem and flag leaf was significantly negatively correlated with yield; relative chlorophyll value (SPAD value) and relative water content of flag leaf were positively correlated with yield, and the canopy temperature was negatively correlated with yield. Compared with other cultivars, the 1000-grain weight, harvest index and biomass production of the stress resistant cultivars increased by 12.9%, 5.2% and 3.4%, respectively. For stress resistant wheat cultivars, the width of flag leaf, angle of stem and flag leaf, diameter of basal stem, ear length and plant height were (16.2 ± 0.4) mm, (18.2 ± 3.2)°, (4.0 ± 0.3) mm, (7.5 ± 0.14) cm and (80.3 ± 1.3) cm, respectively. Compared with other cultivars, the SPAD value and relative water content in flag leaves of these five cultivars increased by 9.8% and 4.2% respectively, and the canopy temperature decreased by 1.9 ℃ at the late stage of filling.【Conclusion】The optimized plant type of the stress resistant wheat cultivars, namely “compact in the upper part and flat in the lower part”, was defined. The quantitative indexes were put forward, including width of flag leaf, angle of stem and flag leaf, diameter of basal stem and ear length; the physiological characteristics were put forward, including higher leaf SPAD value and relative water content of flag, and lower canopy temperature; the yield characteristics were identified, including higher 1000-grain weight, harvest index and biomass production. Table and Figures | Reference | Related Articles | Metrics

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Effects of Ridge and Furrow Planting Patterns on Crop Productivity and Soil Nitrate-N Accumulation in Dryland Summer Maize and Winter Wheat Rotation System WU JinZhi, HUANG XiuLi, HOU YuanQuan, TIAN WenZhong, LI JunHong, ZHANG Jie, LI Fang, LÜ JunJie, YAO YuQing, FU GuoZhan, HUANG Ming, LI YouJun Scientia Agricultura Sinica    2023, 56 (11): 2078-2091.   DOI: 10.3864/j.issn.0578-1752.2023.11.004 Abstract （291）   HTML （23）    PDF （1602KB）（508）       Knowledge map    Save 【Objective】The aim of the present study was to discuss the effects of different ridge and furrow planting patterns on crop productivity, soil properties and soil nitrate-N accumulation, and thus provided a scientific basis for improving soil fertility, increasing crop yield and water use efficiency, and alleviating environmental risks in summer maize-winter wheat rotation system (namely maize-wheat) in dryland.【Method】A study was carried out at the Luoyang Dry Farming Experimental of the Chinese Academy of Agricultural Sciences based on the long-term field experiment initiated in 2004. The experiment included five treatments: permanent ridge and furrow and 6 row wheat planted in ridge (6RPRF), ridge and furrow in each year and other managements kept with 6RPRE (6REYRF), permanent ridge and furrow and 4 row wheat planted in ridge (4RPRF), ridge and furrow in each year and other managements kept with 4RPRF (4REYRF), and conventional flat planting pattern according to the local farmer (CF). The effects of different treatments on the grain yield, water use efficiency of summer maize, winter wheat and the annual in 2015-2021, and the bulk density, nutrient content and enzyme activity in the 0-40 cm soil layer at harvest of summer maize in 2020, and the nitrate-N accumulation in the 0-380 cm soil profile at harvest of winter wheat in 2019-2020 was investigated. 【Result】 Compared with CF, the four ridge and furrow planting patterns improved grain yield in summer maize, winter wheat, and all year by 8.6%-32.1%, 12.5%-25.6%, and 11.3%-29.6%, respectively, and water use efficiency by 8.6%-31.4%, 12.5%-31.1% and 12.8%-30.3%, respectively, averaged across the 6 experimental years from 2015 to 2021. They also significantly decreased the soil bulk density by 7.3%-11.3% in 0-5 cm soil layer and by 4.9%-11.5% in 20-40 cm soil layer, respectively, increased the average content of organic matter by 6.0%-19.8%, total nitrogen by 80.8%-100.0%, available phosphors by 28.5%-80.9%, available potassium by 58.5%-141.2%, urease activity by 24.0%-46.9% in 0-40 cm soil layer, as well as increasing the nitrate-N accumulation by 38.8%-116.0% in 0-100 cm soil layer. Among the four ridge and furrow treatments, 4RPRF had the best productivity and the function of improving root layer but decreasing the sub-layer nitrate-N accumulation, in which the nitrate-N accumulation was significantly increased by 38.7% in the 0-100 cm soil layer but significantly decreased by 15.0% in 200-380 cm soil layer with the total amount in 0-380 cm soil layer maintaining at CF level. Compared with ridge and furrow in each year (EYRF), the 6 year average grain yield in summer maize and all year in permanent ridge and furrow (PRF) treatments were increased by 10.55% and 9.10%, respectively, as well as the WUE in summer maize under 6 rows wheat planted in ridge (6R) pattern, in winter wheat under 4 rows wheat planted in ridge (4R) pattern and in all year were increased by 21.08%, 15.06% and 8.23%, respectively. The soil nutrient content under PRF increased in surface layer but decreased in subsoil layer, and the nitrate nitrate-N accumulation decreased by 4.9%-30.2%, compared with EYRF. Compared with 6R pattern, 4R pattern increased the grain yield in summer maize and in all year by 9.9% and 6.8%, as well as the WUE by 7.4%, 16.5% and 6.7%, respectively, in summer maize under EYRF, in winter wheat under PRF and in all year, averaged across the 6 experimental years. Compared with 6R pattern, 4R pattern had a tendency to improve soil properties, but the effect varied with different indexes, ridge raising patterns and soil layer.【Conclusion】4RPRF could not only reduce soil bulk density and increase soil organic matter, total nitrogen and available potassium contents, but also increase the grain yield and water use efficiency in summer maize, winter wheat and all year under most conditions, and also effectively reduce the nitrate-N accumulation in 200-380 cm soil layer. Therefore, 4RPRF was an alternative planting pattern to achieve high yield, high efficiency and environmentally friendly in dryland summer maize-winter wheat rotation system. Table and Figures | Reference | Related Articles | Metrics

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Effect of Phytochlorin Iron on Stress Tolerance to Waterlogging in Wheat CHU YanMeng, MAO YingChao, CAI Jian, ZHOU Qin, DAI TingBo, WANG Xiao, JIANG Dong Scientia Agricultura Sinica    2023, 56 (10): 1848-1858.   DOI: 10.3864/j.issn.0578-1752.2023.10.003 Abstract （481）   HTML （38）    PDF （509KB）（257）       Knowledge map    Save 【Objective】Waterlogging stress is one of the main limiting factors for wheat production, especially in the middle and lower reaches of the Yangtze River in China. Improving the waterlogging tolerance of wheat is an important goal to achieve stable and increased yield in this region. In this study, by exploring the suitable use period and concentration of phytochlorin iron, its role in improving waterlogging stress tolerance was further evaluated mainly from the perspectives of plant photosynthesis and plant antioxidant capacity. The research results could provide the theoretical and technical support for waterlogging-resistant cultivation of wheat.【Method】Using Yangmai 16 as material, three concentrations (0.0875, 0.126, and 0.194 mmol·L-1) of phytochlorin iron were set at anthesis and grain filling stages to screen the appropriate period and concentration for achieving a significant increase in wheat yield. Based on this, the effect of phytochlorin iron on wheat tolerance to waterlogging stress at anthesis stage was further evaluated.【Result】Compared with control, treatment with a concentration of 0.126 mmol·L-1 phytochlorin iron at anthesis stage (A2) could significantly increase wheat grain yield by increasing the grain weight. Waterlogging stress at anthesis stage significantly reduced the chlorophyll content, net photosynthesis rate, and post-flowering dry matter accumulation and translocation to grain, resulting in grain yield reduction. However, compared with non-spraying treatment, AW2 treatment showed a higher photosynthetic pigment content, photosystem II stability, net photosynthetic rate. Meantime, the raised activities of antioxidant enzymes, reduced O2- production rate and H2O2 content, which showed correspondence with the reduced accumulation of malondialdehyde content, thus alleviated the damage of cell membrane lipid peroxidation and the yield reduction caused by waterlogging stress.【Conclusion】Spraying a concentration of 0.126 mmol·L-1 phytochlorin iron at anthesis stage could significantly increase wheat yield. Phytochlorin iron could alleviate the plant senescence, reduce damage to PSII, enhance the activity of antioxidant enzymes, reduce the damage of cell membrane lipid peroxidation, maintain higher photosynthetic rate, reduce the degree of yield reduction, and enhance wheat tolerance to waterlogging stress. Table and Figures | Reference | Related Articles | Metrics

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Effects of Changing Normal and Extreme Climate States on Maize Meteorological Yield in Northeast China ZHANG WenJing, ZHAO Jin, CUI WenQian, LI ManYao, LI E, GONG XiaoYa, YANG XiaoGuang Scientia Agricultura Sinica    2023, 56 (10): 1859-1870.   DOI: 10.3864/j.issn.0578-1752.2023.10.004 Abstract （466）   HTML （42）    PDF （2016KB）（277）       Knowledge map    Save 【Objective】Northeast China is the main grain production base in China, which has been significantly affected by climate change in recent years. It was of great significance to understand the impact of normal and extreme climate states changes on crop yield in Northeast China for regional crop production and national food security.【Method】In this study, the maize in Northeast China was used as research object, and the main climate factors affecting maize yield were screened to analyze the effects of normal and extreme climate states changes on maize yield in 81 counties in Northeast China from 1980 to 2018.【Result】(1) The average temperature, growing degree-days (GDD), and heat degree-days (HDD) during the maize growth period showed an increasing trend, and the rising rates were 0.34 ℃·(10 a)-1, 47.07 ℃·d·(10 a)-1, and 5.15 ℃·d·(10 a)-1, respectively. The precipitation showed a decreasing trend, with the rate of 7.0 mm·(10 a)-1; the average temperature, GDD, and HDD increased from northeast to southwest, while the precipitation increased from northwest to southeast. (2) The meteorological yield of maize in Northeast China showed an increasing trend from 1980 to 1999, with a rate of 80.93 kg·hm-2·a-1, while it showed a decreasing trend of 46.25 kg·hm-2·a-1 from 2000 to 2018. In terms of spatial distribution, it showed an increasing trend from the middle to the surrounding areas. The area with high yield was concentrated in the eastern part of Heilongjiang. The change of Liaoning was the most stable, and the fluctuation range was stable in the middle area. (3) By the multiple linear regression model, HDD contributed the most to meteorological yield from 1980 to 2018, and the effect was negative, which meant extreme high temperature had the greatest impact on maize yield in Northeast China and caused maize yield reduction; GDD had a positive effect, that is, the average temperature increased maize yield, and the greater GDD, the more yield increased; the precipitation had a negative effect; the interaction between temperature and precipitation had a positive impact on maize yield in Northeast China.【Conclusion】Normal and extreme climate states changes and its impact on maize meteorological yield in Northeast China from 1980 to 2018 were as follow: the normal and extreme temperature showed an overall increasing trend, while the normal precipitation showed a decreasing trend. Extreme high temperatures and normal precipitation led to a decrease in maize yield, but the average temperature increased maize yield, and the extreme high temperature had the greatest impact. In the future, it was necessary to make full use of the average temperature state and minimize the harm caused by extreme high temperature to ensure a high-stable maize production. Table and Figures | Reference | Related Articles | Metrics

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Meta-Analysis of Yield Effects and Influencing Factors of Cover Crops on Main Grain Crops in China MA JiaYu, WANG Tao, LIU XiaoLi, WANG Li, ZHANG XueCheng, WANG WenTao, KONG FanSheng, HUANG XueJun, WANG ZiYi, WANG YanDong, ZHEN WenChao Scientia Agricultura Sinica    2023, 56 (10): 1871-1880.   DOI: 10.3864/j.issn.0578-1752.2023.10.005 Abstract （567）   HTML （49）    PDF （2214KB）（420）       Knowledge map    Save 【Objective】The objective of this study was to clarify the effect of cover cropping on the yield of main grain crops in China, and to investigate the significant influencing factors, so as to provide a scientific basis for the promotion and application of cover crops in China.【Method】A Meta-analysis including data from 903 pairwise observations from 137 publications from 1980 to 2022 was conducted to elucidate the effect of “fallow” versus “cover cropping” on yield of main grain crops. Meta regression was also conducted to explore the factors influencing the effect of cover crops on grain crops yield.【Result】Under cover crops, grain crop yields increased significantly by 12.2% compared to fallow, with wheat, rice and maize yields increasing significantly by 9.5%, 11.9%, and 19.6%, respectively. In addition, grain crop yields increased by 9.5% and 12.4% for winter and summer cover crops, respectively. Among the different types of cover crops, leguminous cover crops increased grain crop yields by 12.9% (February orchid 14.2%, Chinese milk vetch 11.8%, vetch 9.5%, pea 7.8%, soybean 7.4%), while cruciferous and gramineous cover crops increased grain crop yields by 9.3% and 8.3% (rape 7.0%, ryegrass 7.9%), respectively. However, compared with pure stands, cover crop mixtures more markedly increased grain crop yield by 17.3%. Furthermore, cover cropping years and sunshine hours significantly increased the effect of cover crops. High precipitation and temperature increased the effect of cover crops at high latitudes, while high precipitation and temperature decreased the effect of cover crops at low latitudes.【Conclusion】During the fallow period, cover crops mixtures contribute to increase grain crops yields, reduce surface exposure and make full use of solar, thermal, water and soil resources, especially during the northern summer and southern winter. Table and Figures | Reference | Related Articles | Metrics

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Effects of Increasing Density on the Granule Size Distribution and Viscosity Parameters of Endosperm Starch in Spring Maize Kernel LU MengLi, ZHANG YaTing, REN Hong, WANG TuJin, HAN YiMing, LI WenYang, LI CongFeng Scientia Agricultura Sinica    2023, 56 (9): 1646-1657.   DOI: 10.3864/j.issn.0578-1752.2023.09.003 Abstract （337）   HTML （56）    PDF （574KB）（206）       Knowledge map    Save 【Objective】Dense planting is one of the main measures to improve the high yield cultivation of maize, and density has a significant effect on the formation of maize starch. Therefore, this study analyzed the granule size distribution and viscosity parameters of different types of spring maize kernels under different increasing density conditions for improving the quality of maize starch. 【Method】 The field experiments were conducted at the Gongzhuling experimental base in Jilin province in 2019 and 2020. In the present experiments, eight main maize varieties in Northeast China, such as Xianyu 335, Zhengdan 958 and Nonghua 101, etc, were selected as experimental materials, and two planting densities of 67 500 and 97 500 plants/hm2 were set. The granule size distribution and viscosity parameters of starch in different treatments were measured by diffraction particle size analyzer and viscosity analyzer, and the relative quality of maize was measured by near-infrared analyzer, and the correlation analysis was conducted to clarify the effects of increasing density on the granule size distribution and viscosity parameters of endosperm starch in spring maize.【Result】The results showed that with the increase of planting density, maize grain yield and starch content increased significantly, and the increase of density significantly increased the volume, surface area and number percentage of large (>17 μm) starch granules, while the opposite trend was observed in the volume, surface area and number percentage of small (<3 μm) starch granules. It could be seen that with the increase of planting density, the volume and number percentage of small starch granules in maize kernels decreased significantly, and the volume and number percentage of large starch granules increased, indicating that increasing density was beneficial to the increase of the volume ratio of large starch granules, that is, increasing density promoted the accumulation of starch and increased the number of large starch granules and the formation of individual volume. At the same time, it was found that the peak viscosity, trough viscosity, breakdown and final viscosity of maize starch were significantly increased after increasing density. The results of correlation analysis showed that the starch content, yield and viscosity parameters of maize grain were negatively correlated with the volume percentage of small starch granules, significantly or extremely significantly negatively correlated with the volume percentage of medium (3-17 μm) starch granules, and significantly or extremely significantly positively correlated with large (>17 μm) starch granules.【Conclusion】Increasing planting density could increase maize grain yield, starch content and its viscosity parameters by mainly affecting the granule size distribution of endosperm starch, namely increasing the proportion of large starch granules and reducing the proportion of small and medium-sized ones. Table and Figures | Reference | Related Articles | Metrics

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Effects of Squares and Bolls Abscission on Photosynthate Accumulation and Its Strength as an Auxiliary Source of Cotton Sympodial Leaves KAN JiaQiang, LIU Yu, ZHOU ZhiGuo, CHEN BingLin, ZHAO WenQing, HU Wei, HU ShaoHong, CHEN Yang, WANG YouHua Scientia Agricultura Sinica    2023, 56 (9): 1658-1669.   DOI: 10.3864/j.issn.0578-1752.2023.09.004 Abstract （316）   HTML （32）    PDF （1181KB）（144）       Knowledge map    Save 【Objective】The abscission rate of squares and bolls is often more than 60%, and the sympodial leaves after squares and bolls shedding are often used as “auxiliary sources” to play an important role in the development of adjacent bolls. In order to enrich the “source-sink” regulation theory and provide theoretical basis for the regulation of cotton yield compensatory development, the activity changing characters of the “auxiliary sources” was explored after the shedding of their squares or bolls.【Method】In this study, two sowing dates (May 10 and June 1, 2021) of Zhongmian 425 were used to carry out a field experiment at the Pailou Experimental Station of Nanjing Agricultural University in Nanjing, Jiangsu province (118° 50′ E, 32° 02′ N). Under the conditions of fruiting branch phloem blocking, the changes of related indicators of leaf source capacity, such as cotton sympodial leaves morphological characteristics, gas exchange parameters, carbon and nitrogen substances and endogenous hormone content, were studied after defruiting (isolate the “source-sink” system on the first node at the fourth, fifth or sixth fruiting branches by chemical blocked the phloem, and then simulated the boll abscission condition by manual remove the bud or young bolls of the system).【Result】(1) The defruiting treatment significantly increased the content of fructose, sucrose, starch and cellulose in sympodial leaves, but significantly decreased the glucose content. With the extension of time, the increase of starch was the largest at 1 day after treatment (DAT), while that of cellulose was significantly larger at 3 DAT and that of sucrose, cellulose and starch was relatively larger at 5 DAT. (2) After treatment, carbohydrates accumulated more in the form of non-reducing sugars; photosynthates were more distributed to starch; polysaccharides/oligosaccharides decreased at first and then increased; while the C/N of sympodial leaves increased at first and then decreased. (3) The defruiting treatment significantly decreased the net photosynthetic rate and chlorophyll content of sympodial leaves. (4) The sympodial leaves showed purplish red locally, and compared with the control, the anthocyanin content increased by about 2 times. (5) After treatment, the content of ABA, JA, SA in sympodial leaves significantly increased compared with the control, and the content of IAA increased at first and then decreased, while the content of GA3 was significantly lower than the control. (6) The dynamic balance of endogenous hormones in sympodial leaves changed after treatment: ABA/IAA and JA/IAA decreased at first and then increased, while ABA/GA3 and JA/GA3 increased continuously. 【Conclusion】After squares and bolls shedding, the forms of sugar accumulation and distribution as well as endogenous hormone signals in sympodial leaves changed significantly and had a significant effect on source capacity. In a short period of time (1-3 days), the overall content of sugars in sympodial leaves increased, especially the accumulation of non-reducing sugars, and the source capacity strengthen rapidly. However, with the passage of time, the enhancement of source capacity diminished, and the leaves had a tendency of senescence, while chlorophyll degradation accelerated. That was, after abscission, the “auxiliary source” function of the sympodial leaves increased rapidly in a short period of time (about 3 days), then decreased rapidly, and made limited contribution to the development of the adjacent bolls in the later stage. Table and Figures | Reference | Related Articles | Metrics

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Monitoring Wheat Lodging Based on UAV Multi-Spectral Image Feature Fusion WEI YongKang, YANG TianCong, ZANG ShaoLong, HE Li, DUAN JianZhao, XIE YingXin, WANG ChenYang, FENG Wei Scientia Agricultura Sinica    2023, 56 (9): 1670-1685.   DOI: 10.3864/j.issn.0578-1752.2023.09.005 Abstract （427）   HTML （32）    PDF （6071KB）（257）       Knowledge map    Save 【Objective】The wheat lodging seriously affected the process of photosynthesis and maturity, which led to the reduction of yield and quality. In order to obtain lodging information quickly and accurately, UAV ability of remotely monitoring wheat lodging was evaluated, and a wheat lodging monitoring model was built, so as to provide a technical support for disaster assessment, insurance claims and post-disaster remediation.【Method】Five original multispectral band images, including red, green, blue, red-edge and near-infrared, were acquired by near-ground UAV. The wheat canopy image with flying height of 50 m was preprocessed to obtain digital orthophoto map (DOM) and digital surface model (DSM) with a resolution of 1.85 (cm/pixel), three types of feature information were extracted, namely spectral features, height features, and texture features. Support Vector Machine (SVM) and Random Forest (RF) were used to compare the lodging classification of six different feature set combinations, and accuracy (Acc), precision (Pre), recall (Re) and harmonic mean (F1) were used to determine the best feature combination and classifier. At the same time, three different feature set screening methods (Lasso algorithm, random forest recursive algorithm RF-RFE and Boruta algorithm) were used to comprehensively evaluate the optimized feature subset, and to establish an appropriate evaluation method for lodging classification.【Result】The results showed that the single feature spectrum and texture as well as their combinations had poor classification and evaluation results for wheat lodging, and the “salt and pepper phenomenon” was serious. On this basis, the classification accuracy of DSM information fusion was significantly improved. The random forest classifier was used to combine spectral features, texture features and height features, and the classification accuracy of wheat lodging identification reached 91.48%. In order to reduce the number of feature set variables, three feature optimization methods were adopted. Compared with the full feature set, Lasso algorithm and the RF-RFE algorithm, the optimized feature subset based on the Boruta algorithm had higher classification accuracy and better overall stability. From the perspective of the mean value of the three feature combinations containing DSM, the overall classification accuracy and Kappa coefficient were improved by 0.17% and 0.01 (full feature set), 2.45% and 0.05 (Lasso), 2.87% and 0.05 (RF-RFE), respectively. Among them, spectrum-texture-DSM was the best, with the overall classification accuracy of 92.82% and Kappa coefficient of 0.86.【Conclusion】The study showed that the Boruta algorithm could effectively optimize the number of feature subsets of the spectrum-texture-DSM combination, allow fewer feature parameters to participate in the classification, and obtain higher classification accuracy. Meanwhile, a multi-feature combination-Boruta-RFC technology model was established for accurately monitoring wheat lodging, which provided a reference for wheat disaster assessment and the formulation of remediation measures. Table and Figures | Reference | Related Articles | Metrics

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Study on the Dynamics of Root Length Density in Soil Layers of Single Plant Wheat Under Controlled Seed-to-Seed Distance SUN QiBin, WANG JianNan, LI YiNian, HE RuiYin, DING QiShuo Scientia Agricultura Sinica    2023, 56 (8): 1456-1470.   DOI: 10.3864/j.issn.0578-1752.2023.08.003 Abstract （410）   HTML （57）    PDF （4264KB）（311）       Knowledge map    Save 【Objective】In order to quantify the influence of seed-to-seed distance on wheat root development in soil layers under single seed precision sowing, an integrated technique combining root architecture digitizer and MATLAB simulation was developed to quantify wheat root length density (RLD) and relative root length density (NRLD), as well as related models in each soil layer in the field.【Method】Ningmai 13 was used as experiment marital and the seed was sown with single seed precision sowing method in no-till paddy soil. The experiment was carried out in 2020 and 2021, respectively. Five treatments (JT1.5, JT3, JT4.5, JT6.7, and JT9) with row spacing of 1.5, 3.0, 4.5, 6.7 and 9.0 cm were introduced for field stand control. RLD was analyzed with combined technologies, i.e. root architecture digitizer and 3D root system architecture reconstruction with Pro-E, supplemented with MATLAB simulation, which facilitated fine segmentation and analysis of the rhizosphere dynamics under soil space voxel resolution of 3 mm3, and this further results quantified RLD distribution dynamics and the development of NRLD models along soil layers.【Result】The post-paddy wheat RLD decreased gradually along the soil layers under different treatments. As much as 95% of the root system was confined within the top soil layer in 0-9 cm, below which, root length decreased rapidly. The wheat root expansion area of a single plant first increased along the soil layers and then decreased. Root expansion started from the seed site as its central point, and revealed an obvious directional and constraining effects induced by the soil environment. With the increase of seed-to-seed distance, wheat RLD experienced first an increasing and then a decreasing trend, and the maximum value of which was found at JT4.5. The expansion area of wheat RLD increased with the increased seed-to-seed distance, and the maximum value of which was 22 972 mm2. Either the too high or the too low density stand was found adversely impacts the efficiency of root configuration. Only the most suitable sowing density led to the best 3D distribution of wheat root system, which has been considered as the primary mechanism for efficient utilization of soil spatial resources. The NRLD distribution within 0-20 cm soil layers satisfied both cubic polynomial and exponential models well (R2>0.99, RMSE<0.1), but when considered the field state root system architecture, it was found that the exponential model was more realistic and fit the field wheat RLD the best along the soil layers.【Conclusion】An integrated technique combining root architecture digitizer and MATLAB simulation was developed to quantify wheat RLD and NRLD in the field, which satisfactorily illustrated the influence of seed-to-seed distance on RLD and NRLD along the soil layers. The results showed that the proposed method could be applicable for studies of wheat precision cultivation, precise water and fertilizer management, root configuration regulation and so on in the future. Table and Figures | Reference | Related Articles | Metrics

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Mepiquat Chloride Increases the Cry1Ac Protein Content Through Regulating Carbon and Amino Acid Metabolism of Bt Cotton Under High Temperature and Drought Stress XING YuTong, TENG YongKang, WU TianFan, LIU YuanYuan, CHEN Yuan, CHEN Yuan, CHEN DeHua, ZHANG Xiang Scientia Agricultura Sinica    2023, 56 (8): 1471-1483.   DOI: 10.3864/j.issn.0578-1752.2023.08.004 Abstract （339）   HTML （30）    PDF （1190KB）（174）       Knowledge map    Save 【Objective】The effects of mepiquat chloride (DPC) on the insecticidal protein contents in Bt (Bacillus thuringiensis) cotton shell under high temperature and drought stress were investigated to provide a theoretical reference for the Bt cotton breeding as well as high-yield and high-efficiency cotton cultivation.【Method】The study was undertaken on the Bt cotton cultivar Sikang 3 during the 2020 and 2021 growing seasons at the Yangzhou University Farm, Yangzhou, China. The potted cotton plants were exposed to high temperature and drought stress, and 20 mg·L-1 DPC and water (CK) were sprayed to cotton plants. Seven days after treatment, the insecticidal protein content, α-ketoglutarate content, pyruvic acid content, glutamate synthase activity, glutamic oxaloacetic transaminase activity, soluble protein content, free amino acid content in boll shell were analyzed, and the transcriptome sequencing was performed. DESeq was used for differential gene analysis. The GO and KEGG pathway databases were used to analyze the differentially expressed genes involved in regulating the insecticidal protein content through DPC.【Result】Compared with the water treatment (CK), the insecticidal protein contents under DPC treatment increased by 4.7%-11.9%. In terms of carbon metabolism, the contents of α-ketoglutarate and pyruvic acid were increased by 46%-57% and 25%-29%, respectively. In terms of amino acid metabolism, the activities of glutamate synthase and glutamic oxaloacetic transaminase, and the contents of soluble protein and free amino acid were increased by 32%-44%, 30%-40%, and 28%, 22%-27%, respectively. The transcriptome analysis revealed that there were 7 542 upregulation genes and 10 449 downregulation genes for DPC vs water. The GO and KEGG analysis showed that the differentially expressed genes were mainly involved in biological process such as amino acid metabolism and carbon metabolism. The genes coding 6-phosphofructokinase, pyruvate kinase, glutamic pyruvate transaminase, pyruvate dehydrogenase, citrate synthase, isocitrate dehydrogenase, 2-oxoglutarate dehydrogenase, glutamate synthase, 1-pyrroline-5-carboxylate dehydrogenase, glutamic oxaloacetic transaminase, amino-acid N-acetyltransferase, and acetylornithine deacetylase were all significantly up-regulated. 【Conclusion】 Under the stress of high temperature and drought, the DPC treatment increased the contents of α-ketoglutarate and pyruvic acid, and improved the synthesis ability of aspartic acid, glutamic acid, pyruvate and arginine, then enhanced the insecticidal protein contents in boll shell by regulating the carbon and amino acid metabolism. Table and Figures | Reference | Related Articles | Metrics

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Effect of Post-Anthesis Shading Stress on Eating Quality of Indica Rice in Chengdu Plain ZHU YouYun, ZENG YuLing, LI Bo, YUAN YuJie, ZHOU Xing, LI QiuPing, HE ChenYan, CHEN Yong, WANG Li, CHENG Hong, ZHOU Wei, TAO YouFeng, LEI XiaoLong, REN WanJun, DENG Fei Scientia Agricultura Sinica    2023, 56 (3): 430-440.   DOI: 10.3864/j.issn.0578-1752.2023.03.003 Abstract （389）   HTML （48）    PDF （545KB）（208）       Knowledge map    Save 【Objective】 The aim of this study was to clarify the effect of post-anthesis shading stress on the eating quality of indica rice in Chengdu Plain, so as to provide the theoretical and practical basis for the selecting of shade-tolerant rice varieties in low light rice region. 【Method】 Field light control experiments were conducted in 2019 and 2020 in Wenjiang, Sichuan by using indica rice varieties with different amylose contents as materials. The effect of shading stress on eating quality of rice was studied by measuring the components and RVA spectrum values of rice, as well as the texture properties and eating quality of cooked rice. 【Result】(1)Shading stress significantly decreased amylose, amylopectin, and total starch contents of rice, but significantly increased the contents of protein and fat. (2)Shading stress significantly decreased the peak viscosity and breakdown of rice, while increased the pasting temperature and setback. (3)Shading stress also significantly increased the hardness of cooked rice, but decreased the stickiness and elasticity, which contributed to a significant reduction in the comprehensive score of cooked rice by decreasing both appearance and taste. (4)The results of principal component analysis showed that the rice components, RVA spectrum values, and texture properties could explain 81.2% of the total variation of eating quality of cooked rice. The comprehensive score of rice was significantly and positively correlated with the amylose, starch content, peak viscosity, breakdown, elasticity and stickiness, but negatively related to the protein and fat contents. 【Conclusion】 The protein and fat contents possessed greater influence on the eating quality of cooked rice than that of amylose and starch contents under shading stress. The shading stress leaded to significant variations in starch, protein, and fat components in rice, which contributed to a decrease in peak viscosity and breakdown, but an increase in pasting temperature and setback. And then, those variations contributed to the significantly decrease in eating quality of cooked rice by increasing the hardness, but decreasing both stickiness and elasticity of cooked rice. Table and Figures | Reference | Related Articles | Metrics

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Effects of Different Nitrogen Gradients on Yield and Nitrogen Uptake of Hybrid Seed Maize in Northwest China LIU Dan, AN YuLi, TAO XiaoXiao, WANG XiaoZhong, LÜ DianQiu, GUO YanJun, CHEN XinPing, ZHANG WuShuai Scientia Agricultura Sinica    2023, 56 (3): 441-452.   DOI: 10.3864/j.issn.0578-1752.2023.03.004 Abstract （453）   HTML （53）    PDF （603KB）（218）       Knowledge map    Save 【Objective】The law of nitrogen uptake and accumulation of maize in seed production in China is unclear. In view of this, the responses of biomass accumulation, yield formation, and the nitrogen uptake to nitrogen supply were studied in order to provide the theoretical basis for green and efficient hybrid maize seed production. 【Method】 Taking the parent varieties combination of large area seed production as the experimental material, the on-site experiment was carried out from 2019 to 2020. A completely random block design was applied to study the effects of different nitrogen gradients on parental biomass, grain yield and nitrogen uptake and accumulation of maize seed production. Four nitrogen gradients were set up as basal fertilizer control (CK), 168, 240 and 320 kg N·hm-2, respectively. 【Result】The accumulation of parental biomass of hybrid maize seed production increased with the increase of nitrogen gradients. The yield of maize seed production increased at first and then remained stable with the increase of nitrogen gradients. N240 treatment achieved higher yield, nitrogen use efficiency and grain nitrogen concentration at the same time, which were consistent in the two years. The yield under N168 treatment was higher than that under N240 treatment in the second year, but the nitrogen concentration was lower than that under N240 treatment. The nitrogen concentration of the whole plant of female parent straw and male parent was higher in high nitrogen gradient treatment than that in low nitrogen gradient treatment. The critical nitrogen concentration of maximum biomass of female parent at filling stage was 15.08 g·kg-1, and there was a linear correlation between female parent biomass and nitrogen concentration at harvest stage. The post-silking biomass of each topdressing nitrogen fertilizer treatment was higher than that of pre-silking stages in two years, and increased with the increase of nitrogen gradients. The change rule of post-silking nitrogen uptake ratio with nitrogen gradients was consistent with the biomass. There was no significant difference in yield level, biomass accumulation, and nitrogen uptake between N320 treatment and N240 treatment. Under the premise of comprehensive consideration of yield and hybrid seed quality, N240 could be regarded as the recommended nitrogen application rate for hybrid maize seed production in this region. 【Conclusion】 The optimal nitrogen application rate could increase yield and nitrogen use efficiency by regulating the ratio of nitrogen uptake for maize parents in pre- and post-silking in seed maize production. This study revealed that optimizing nitrogen application rate to stabilize nitrogen uptake in the pre-silking stage and ensure nitrogen supply after anthesis was the key to achieve high yield and nitrogen use efficiency of seed maize, and provided a theoretical basis for sustainable production of hybrid seed maize. Table and Figures | Reference | Related Articles | Metrics

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Effect of Phosphorus Application on Physiological Parameters and Antioxidant Capacity in Alfalfa Leaves ZHAO JianTao, YANG KaiXin, WANG XuZhe, MA ChunHui, ZHANG QianBing Scientia Agricultura Sinica    2023, 56 (3): 453-465.   DOI: 10.3864/j.issn.0578-1752.2023.03.005 Abstract （417）   HTML （56）    PDF （1486KB）（173）       Knowledge map    Save 【Objective】The aim of this study was to investigate the effects on nutrient uptake, photosynthetic pigment content, stomatal aperture and antioxidant system of alfalfa leaves after three consecutive years of phosphorus fertilizer application, so as to provide scientific fertilization methods for efficient production of alfalfa.【Method】Field trials were conducted at the forage experiment station of Shihezi University in Xinjiang from 2019 to 2021. ‘WL366HQ’ alfalfa was used as the test material, and four fertilizer treatments in the experiment included 0 (CK), 50 (Low P, LP), 100 (Middle P, MP), and 150 (High P, HP) kg·hm-2. Samples were taken at the first flowering of alfalfa to determine the hay yield, nitrogen and phosphorus content, pigment content, stomatal opening, antioxidant enzyme activity, and oxidizing substances of leaves.【Result】The nitrogen and phosphorus content, photosynthetic pigment content and stomatal aperture of leaves of alfalfa increased significantly (P<0.05) after 3 years of continuous phosphorus fertilization, with the highest nitrogen and phosphorus content under MP treatment (54.74 and 2.99 g·kg-1, respectively), the highest chlorophyll a and chlorophyll b content under MP, and the highest carotenoid content under LP or MP, and the lowest in CK. The stomatal aperture was the highest under MP and significantly higher than that under CK (P<0.05). Therefore, phosphorus fertilizer had different effects on the morphological and physiological characteristics of alfalfa leaves, and MP treatment significantly affected the photosynthetic and physiological characteristics of alfalfa leaves (P<0.05). Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities were the highest under MP, with the value of 162.55, 406.40 and 147.13 U·g-1, respectively, and were significantly higher than those under CK (P<0.05). The malondialdehyde (MDA), hydrogen peroxide (H2O2) and proline (Pro) content were the lowest under MP, at 2.38 and 1.04 μmol·g-1 and 56.85 μg·g-1, respectively. According to the Pearson correlation analysis, the total N and P contents of alfalfa leaves showed significant positive correlation (P<0.05) with chlorophyll content, carotenoid content, stomatal aperture, SOD activity and POD activity, and significant negative correlation (P<0.05) with MDA and H2O2 content. The overall evaluation showed that the principal component scores of phosphorus application treatments were ranked as MP>HP>LP>CK. 【Conclusion】 The reasonable application of phosphorus fertilizer increased the nutritional characteristics and photosynthetic physiological characteristics of alfalfa leaves, thus avoiding the stressful effects brought by other environmental factors, enhancing the adaptive capacity of alfalfa, and making it better adapted to external environmental changes. Considering the leaf morphology, photosynthetic physiological characteristics and antioxidant enzymes and oxidizing substances of alfalfa, the phosphorus application rate of 100 kg·hm-2 was suitable under this experiment. Table and Figures | Reference | Related Articles | Metrics

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Effects of Rhizosphere Oxygen Environment on Phosphorus Uptake of Rice Seedlings and Its Physiological Mechanisms in Hydroponic Condition XIAO DeShun, XU ChunMei, WANG DanYing, ZHANG XiuFu, CHEN Song, CHU Guang, LIU YuanHui Scientia Agricultura Sinica    2023, 56 (2): 236-248.   DOI: 10.3864/j.issn.0578-1752.2023.02.003 Abstract （491）   HTML （42）    PDF （575KB）（215）       Knowledge map    Save 【Objective】This study was conducted to research the effect of rhizosphere oxygen environment on the phosphorus uptake of rice seedlings and its physiological mechanisms, so as to provide a theoretical basis for the new cultivation measures to promote the absorption and utilization of phosphorus uptake of rice. 【Method】Two varieties, including Zhenshan 97B and Miyang 46, were cultured in nutrient solution with different oxygen content (DOC) levels (medium oxygen: DOC 2.5-3.5 mg·L-1, high oxygen: DOC>6.0 mg·L-1, continuous bubbling with atmospheric air, and normal conditions as CK) controlled by on-line dissolved oxygen meter. After different oxygen treatments, the rice seedling growth (biomass, root morphological structure), root physiology (root activity, phosphorus absorption kinetics, phosphatase activity, root secretion of organic acids, citric acid, etc.), and phosphorus absorption and accumulation were measured and analyzed. 【Result】 (1) The medium oxygen treatment significantly promoted the occurrence and growth of tillers, and increased the biomass, root shoot ratio, phosphorus content and accumulation of the two tested varieties; The high oxygen treatment reduced the plant height and shoot biomass, but had no significant effect on root biomass. (2) Compared with the control, the total root length, surface area and total volume of root were significantly increased, and the average root diameter were significantly decreased after the medium oxygen treatment, while the high oxygen treatment was opposite to the medium. The medium and high oxygen treatment could promote the secretion of organic acids (the total amount of organic acids, oxalic acid, tartaric acid, and citric acid content increased), and increase the activity of acid phosphatase in leaves and roots. However, compared with high oxygen, the medium oxygen treatment significantly enhanced the activity of roots, optimized the kinetic parameters of phosphorus absorption, increased Imax, and decreased Km and Cmin. (3) The results of correlation analysis showed that the phosphorus accumulation and aboveground phosphorus content were significantly positively correlated with root morphology (total root length, root surface area, average diameter and total volume of root), root activity, absorption kinetic parameters Imax, the content of oxalic acid and tartaric acid, and negatively correlated with phosphorus absorption kinetic parameters Km and Cmin. The root phosphorus content of root was significantly positively correlated with root acid phosphatase, root activity, total organic acid and oxalic acid content, but not significantly with other indexes. 【Conclusion】The moderate increase of dissolved oxygen concentration (medium oxygen treatment) could improve the activity of acid phosphatase in leaves and roots, root activity, the root secretion content of oxalic acid, tartaric acid and citric acid, optimize the root morphological structure (increase the root surface area) and phosphorus uptake kinetics of rice seedlings so as to increase phosphorus content and accumulation of rice. Therefore, the selecting appropriate cultivation measures could change the rhizosphere oxygen environment and improve the ability of phosphorus absorption of rice in field planting. Table and Figures | Reference | Related Articles | Metrics

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Effects of Direct Seeding Cultivation Method on Growth Stage, Lodging Resistance and Yield Benefit of Double-Cropping Early Rice ZHANG XiaoLi, TAO Wei, GAO GuoQing, CHEN Lei, GUO Hui, ZHANG Hua, TANG MaoYan, LIANG TianFeng Scientia Agricultura Sinica    2023, 56 (2): 249-263.   DOI: 10.3864/j.issn.0578-1752.2023.02.004 Abstract （491）   HTML （46）    PDF （775KB）（192）       Knowledge map    Save 【Objective】The objective of this study was to investigate the effects of direct seeding cultivation on the growth period, lodging resistance, yield and economic benefits of different rice varieties, in order to provide a theoretical basis for the application and promotion of mechanized direct seeding rice. 【Method】 For the early rice in 2020 and 2021, the conventional rice varieties with a large area in Guangxi production, including Guiyu 9, Guiyu 11, Guiyefeng, Guangliangxiang 2, and hybrid rice Y Liangyou 1, were used as test materials. In the field, using the traditional manual transplanting as a control, the field was accurately direct seeding. A split plot design was used in this experiment with planting method as the main plot, with rice varieties as the split plot, and set up three replications. The length of the growth period was observed, the morphology of main stem and the characteristics of the basal stem, as well as the lodging indicators such as breaking resistance, bending moment and lodging index, were calculated, the yield and yield components were measured at the maturity stage, and the cost and economic benefits were calculated too. 【Result】(1) The growth period of direct seeding was shortened by about 2-6 days, which was mainly reflected in the period from sowing to the beginning of young spike. (2) The lodging resistance of direct seeding rice was relatively poor, and its plant height, center of gravity height and panicle dry weight were lower than that of transplanted rice; The stem thickness, wall thickness, fresh weight and dry weight of its N2 stem were also lower than that of transplanted rice, and the length of the stem of direct seeding rice was higher than that of transplanted rice, which might be the main reason for the weak lodging resistance of the direct rice. (3) Among the varieties tested, the actual yields of the remaining four rice varieties were lower than those of transplanted under direct-seeded cultivation, except for Yliangyou1. For varieties with relatively short growth period in the test materials, the yield under direct seeding conditions is significantly lower than that of transplanting, while for varieties with relatively long growth period, the yield difference between planting methods is not significant, among the yield components, the increase in the number of grains per panicle and the seed setting rate were the main factors for increasing the yield of direct seeding rice. (4) From the analysis of economic benefits, among the varieties tested, Guiyu 11, which had a shorter growth period, had a significantly lower yield and economic benefit in direct seeding method, and the economic benefits of direct seeding rice of the remaining four varieties were higher than those of transplanted rice; The main reason for this was that direct seeding rice saved labor costs in seedling and transplanting link. 【Conclusion】At present, it was an urgent to develop a light and simple production model of rice with the main goal of preserving area and increasing efficiency. Compared with transplanted rice, direct seeding rice had obvious advantages, such as shortening the growth period and reducing production costs. There was a certain risk of lodging, for the yield was easily affected by variety characteristics and environmental factors. Therefore, the lodging-resistant varieties with medium maturity, reasonable stem length at the base, thick stems and thick stem walls could be selected in the direct seeding cultivation of early rice. In cultivation management, the proportion of ear fertilizer should be appropriately increased to compensate for insufficient number of grains per panicle and seed setting rate could improve the yield of direct seeding rice. Table and Figures | Reference | Related Articles | Metrics

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Effects of Sowing Date on Yield of Double Cropping Rice and Utilization Efficiency of Light and Heat Energy in Hunan Province ZHANG Wei, YAN LingLing, FU ZhiQiang, XU Ying, GUO HuiJuan, ZHOU MengYao, LONG Pan Scientia Agricultura Sinica    2023, 56 (1): 31-45.   DOI: 10.3864/j.issn.0578-1752.2023.01.003 Abstract （457）   HTML （42）    PDF （532KB）（234）       Knowledge map    Save 【Objective】By comparing the effects of different sowing dates on yield of double cropping rice and utilization efficiency of light and heat energy, and analyzing the sensitivity of different varieties to sowing date and light and heat resource efficiency, the best sowing date was investigated, which was conducive to double-cropping rice yield and resource utilization efficiency in Hunan province. 【Method】Using the main double-cropping rice varieties approved in Hunan province, the main double-cropping rice producing area, as the test materials, three sowing dates for early and late rice were set up for field experiments from 2018 to 2019. The rice growth period, yield and yield components as well as meteorological data were analyzed to compare the yield and the utilization efficiency of light and heat resources of each variety under different sowing dates. 【Result】With the delay of the sowing date, the early and late rice shortened the growth period by shortening the days of the sowing-ear start stage, while the yield of early rice showed an increasing trend. Late-maturing rice responded faster to late sowing than middle-maturing late rice; In 2018, with the delay of sowing date, the heat energy utilization rate of early rice decreased by 2.73% and 4.45% respectively, the light energy utilization rate decreased by 1.28% and -1.77% respectively, the heat energy utilization rate of late rice decreased by -2.64% and 8.15% respectively, and the light energy utilization rate decreased by 2.14% and 13.25% respectively. In 2019, with the postponement of sowing date, the heat energy utilization rate of early rice increased by 0.36% and 10.36% respectively, and the light energy utilization rate increased by 1.53% and 12.52% respectively. The heat energy utilization rate of late rice decreased by -0.72% and 6.09% respectively, and the light energy utilization rate decreased by 0.58% and 6.21% respectively. 【Conclusion】The sowing date had a significant impact on the utilization efficiency of light and heat resources of double-cropping rice. It was appropriate to delay the sowing date of early rice and advance the sowing date of late rice to improve the efficiency of light and heat resources. The comprehensive efficiency of the combination of the second sowing date of early rice+the second sowing date of late rice for double cropping rice is higher, and the combination of late-maturing early rice and medium-maturing late rice combination had higher comprehensive efficiency. Table and Figures | Reference | Related Articles | Metrics

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Effects of Meteorological Factors on Quality of Late Japonica Rice During Late Season Grain Filling Stage Under ‘Early Indica and Late Japonica’ Cultivation Pattern in Southern China FENG XiangQian, YIN Min, WANG MengJia, MA HengYu, CHU Guang, LIU YuanHui, XU ChunMei, ZHANG XiuFu, ZHANG YunBo, WANG DanYing, CHEN Song Scientia Agricultura Sinica    2023, 56 (1): 46-63.   DOI: 10.3864/j.issn.0578-1752.2023.01.004 Abstract （414）   HTML （45）    PDF （1180KB）（221）       Knowledge map    Save 【Objective】The responses of the rice grain qualities to the climate factors during the grain filling period were studied to facilitate the variety screening and the agronomic practices optimization for japonica rice during the late rice season in southern rice region in China. 【Method】 To evaluate the effects of different climate factors during the grain filling period on the qualities of late japonica rice, the field experiment was conducted in Fuyang and Wenzhou, Zhejiang province, in 2018, using three late indica rice as control varieties and 20 japonica rice (including 10 inbred japonica rice, 3 japonica hybrids and 7 indica-japonica hybrids) as evaluating varieties. 【Result】(1) Based on the results of clustering with grain qualities, the late indica rice varieties were classified as an unique category due to its highest aspect ratio (3.18) and high amylose content (19.40%). Compared with the late indica rice, the most of hybrid varieties had greater brown rice rate (4.31%-5.28%), milled rice rate (6.51%-9.33%), head rice rate (25.83%- 28.34%), gel consistency (1.81%-4.27%), alkali spreading value (11.62%-50.85%), and tasted value (2.31%-2.85%), with lower amylose content (20.98%-28.14%) and protein content (1.16%-14.85%), showing obvious improvement of rice quality. Whereas, the rice quality performance response to late season were differentiated within inbred japonica varieties, and some inbred japonica rice varieties originating from southern Jiangsu and Jiaxing (4 varieties) were similar to the those in the hybrid-japonica category, while the rest inbred japonica varieties from Jiangsu and Shanghai (6 varieties) belonged to another category due to their relatively poor rice quality performances (high chalkiness, chalky grain rate and protein content) in the late season. (2) The rice grain qualities were closely related to climate factors during grain filling period of late rice season. The stage of 10-20 days after full heading was identified as the sensitive period of climate factors on rice qualities. The brown rice rate was negatively correlated with daily solar radiation (R: -0.40--0.19, P<0.05) and daily temperature difference (R: -0.45--0.28, P<0.05), and positively correlated with daily minimum temperature (R: 0.24-0.53, P<0.05) and precipitation (R: 0.38-0.45, P<0.05). The chalkiness rate and chalkiness grain rate were significantly increased with the rainfall and night temperature (R: -0.37--0.16, P<0.05; R: -0.43--0.12, P<0.05), resulting in reducing rice appearance quality. Meanwhile, the rainfall and night temperature were negatively correlated with rice tasted value (R: -0.37--0.16, P<0.05; R: -0.43--0.12, P<0.05). The daily maximum temperature at grain filling stage was positively correlated with rice tasted value (R=0.37, P<0.05), while the daily minimum temperature was positively correlated with rice protein content (R=0.19, P<0.05), chalkiness (R=0.16, P<0.05), and chalkiness grain percentage (R=0.12, P<0.05). 【Conclusion】 The stage of 10-20 days after full heading was the key period for affecting rice grain quality by climate factor, and the improvement of rice qualities for late japonica varieties in southern rice region should focus on the integration of high-quality japonica genes with an indica gene of local adaptation, and the choice of hybrid rice (including indica-japonica hybrids and japonica hybrids) was more reliable and convenient than inbred japonica rice. The breeding of inbred japonica varieties should consider their ecological adaptability in combined with local climatic conditions. Table and Figures | Reference | Related Articles | Metrics

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Effects of Ethylene-Chlormequat-Potassium on Root Morphological Construction and Yield of Summer Maize with Different Nitrogen Application Rates FANG MengYing, LU Lin, WANG QingYan, DONG XueRui, YAN Peng, DONG ZhiQiang Scientia Agricultura Sinica    2022, 55 (24): 4808-4822.   DOI: 10.3864/j.issn.0578-1752.2022.24.003 Abstract （391）   HTML （41）    PDF （1735KB）（174）       Knowledge map    Save 【Objective】 Root is an important organ for maize to obtain water and nutrients, and a developed root structure is the key to maximum maize yield potential, which is currently an important issue to be solved in maize cultivation research. Ethylene- chlormequat-potassium and nitrogen application can affect the development of the maize root system. The aim of this study was clarify the effects of ethylene-chlormequat-potassium on the construction of summer maize root morphology and yield under different nitrogen application rates, so as to provide the theoretical and technical basis for the improvement of high yield and efficient cultivation management and rational fertilization of maize. 【Method】In 2019 and 2020, the field experiments were carried out in Daliudian village, Yanjiao town, Langfang city, Hebei province, and Shunyi Experimental Base, Chinese Academy of Agricultural Sciences, Shunyi district, Beijing, respectively, using maize single cross Yudan 9953 as experimental material. A split-zone experimental design was used, with the ethylene-chlormequat-potassium treatment (ECK) and the clear water control (CK) as the main zones, and the six nitrogen levels of 0 (N0), 96 (N96), 132 (N132), 168 (N168), 204 (N204) and 240 kg·hm-2 (N240) as the secondary zones, aiming to analyze the effects of ECK on root morphology and yield of summer maize at different nitrogen application rates. 【Result】The nitrogen application significantly increased root dry weight, number of aerial roots, root length, root surface area and root volume. Compared with no nitrogen application, root dry weight, the number of aerial roots, root length, root surface area and root volume increased by 15.0%-25.2%, 31.7%-71.7%, 15.5%-30.8%, 19.0%-40.9% and 28.8%-54.0% on average with different nitrogen application rates, respectively. Compared with CK, ECK treatment increased root dry weight, number of root layers, number of roots in 1 to 2 layers and the number of aerial roots in summer maize with different nitrogen application rates by 10.4%-17.0%, 5.8%-12.6%, 10.8%-33.9% and 12.5%-79.6%, respectively; On the construction of root morphology, compared with CK, ECK treatment significantly increased the total root length, root surface area and root volume of summer maize with different nitrogen application rates by 7.5%-21.0%, 8.4%-29.3% and 14.3%-38.8%, respectively, and the root length with root diameter > 1.0 mm was significantly increased at medium and high nitrogen levels (N≥N204). Compared with CK, ECK treatment had no significant effect on summer maize yield per unit area in 2019 and 2020 under N0-N168, but significantly increased summer maize yield in 2019 and 2020 under N204 and N240, which increased by an average of 6.3% with N204 and 3.2% with N240. Correlation analysis showed that kernel number, 1000-kernel weight, root length, root surface area and root volume were positively correlated with summer maize yield, and the correlation coefficient between yield and root length was the highest. 【Conclusion】ECK and nitrogen could synergistically promote maize root development and increase summer maize yield under high nitrogen conditions. In the current study, spraying ECK at the V6 growth stage combined with 204 kg·hm-2 N fertilizer was a suitable cultivation technique and N fertilizer management practice for high-yielding summer maize in the Beijing-Tianjin area. Table and Figures | Reference | Related Articles | Metrics

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SPAD Value Inversion of Cotton Leaves Based on Satellite-UAV Spectral Fusion WANG ShuTing, KONG YuGuang, ZHANG Zan, CHEN HongYan, LIU Peng Scientia Agricultura Sinica    2022, 55 (24): 4823-4839.   DOI: 10.3864/j.issn.0578-1752.2022.24.004 Abstract （348）   HTML （28）    PDF （3452KB）（134）       Knowledge map    Save 【Objective】The aim of this study was to improve the inversion accuracy of chlorophyll content in cotton leaves, and to grasp its spatial distribution characteristics in Xiajin county, Shandong province. 【Method】Taking Xiajin county, Dezhou city, Shandong province as the study area and Dalizhuang cotton field in Xiajin county as the test area, the relative value of chlorophyll content (SPAD value) in cotton leaves in the experimental area was measured by SPAD (soil and plant analyzer development), and obtained the near earth multispectral image of unmanned aerial vehicle (UAV) and Sentinel-2A MSI (MSI) satellite image in the study area in the same period; Then, based on the spectral reflectance of UAV and MSI satellite images, the optimal spectral parameters were constructed and selected, and the inversion model of SPAD value was established by multiple linear regression (MLR); Finally, the quadratic polynomial fitting method was used to fuse the optimal spectral parameters corresponding to UAV and Sentinel-2A MSI. By comparing and analyzing the model effects before and after fusion, the inversion model was optimized, and the SPAD value inversion of the study area was realized. 【Result】(REG-R)/(REG+R), R/G, Cl(red edge) and NDVI could be the optimal spectral parameters of SPAD value. The precision of cotton leaf SPAD inversion model based on UAV near ground image was better than that based on satellite image; After quadratic polynomial fitting, the calibration R2 was increased by 0.015-0.057, and RMSE was decreased by 0.457-0.638, while the validation R2 was increased by 0.040-0.085, RMSE was decreased by 0.387-0.397, and RPD was increased by 0.020-0.139. The fused spectral parameters based on Sentinel-2A MSI image were input to the inversion model based on UAV data (Fused MSI-ModUAV), the high inversion accuracy of SPAD value in cotton leaves could be obtained, with the model calibration R2 up to 0.672, RMSE of 3.982, validation R2 up to 0.713, RMSE of 3.859, and RPD of 1.685. Based on the above model, two inversion prediction maps of different scales were obtained. The SPAD value of cotton leaves in the test area showed the distribution trend of high in the south and low in the north, and the study area showed the distribution trend of low in the middle and high around, which were consistent with the field situation and showed the model had a good prediction effect. 【Conclusion】Therefore, the fusion of UAV and satellite image data by using quadratic polynomial fitting method could better realize the quantitative inversion of regional high-precision crop growth indicators. The research results could enrich the theory and technology of multi-source remote sensing fusion, and provide the technical reference and data support for cotton growth monitoring and precision production. Table and Figures | Reference | Related Articles | Metrics

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