| 摘要: |
| 【目的】明确福建省鲜食玉米大斑病田间病情与玉米产量损失的关系，为福建省鲜食玉米大斑病的合理防控提供理论依据。【方法】在玉米大斑病自然发病条件下，利用不同施药次数人为造成田间不同病情梯度，建立病情指数与玉米产量损失率模型，制定适合福建省鲜食玉米大斑病的经济阈值。同样条件下，以病情指数与产量损失率模型推算不同抗性玉米品种科学用药时期和次数，制定鲜食玉米品种抗性分级标准。【结果】采用逐步回归分析建立了玉米大斑病全部叶片病情指数与种植天数的回归方程。玉米产量损失率与玉米大斑病全部叶和功能叶病情指数均呈显著正相关关系，建立了基于玉米全部叶和功能叶病情指数与产量损失率的模型。在用药次数依次为1，2，3和4次条件下，基于全部叶病情指数乳熟期（R3）玉米大斑病经济阈值分别是14.63，17.88，18.72和22.06，基于功能叶病情指数分别是7.74，10.43，12.24和16.80。基于建立的回归方程、经济阈值及玉米籽粒建成期（R2）功能叶病情指数（DI），建议玉米品种抗性分级标准为：DI≤15为抗病（R），15＜DI≤30为中抗（MR），30＜DI≤45为中感（MS），DI＞45为感病（S）。【结论】建立了福建省鲜食玉米大斑病田间病情消长动态理论模型和病情指数与产量损失率的模型，制定了玉米大斑病的经济阈值和不同玉米品种对大斑病的抗性分级标准。 |
| 关键词: 鲜食玉米 玉米大斑病 为害损失 经济阈值 抗性分级标准 福建省 |
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| 基金项目:国家重点研发计划项目（2018YFD0200706）；福建省属公益类科研院所专项（2018R1025-1）；福建省农业科学院植物保护创新团队项目（STIT2017-1-8） |
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| Economic threshold of northern corn leaf blight and classification standard for resistance on fresh corn |
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DAI Yuli,GAN Lin,TENG Zhenyong,et al
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| Abstract: |
| 【Objective】This study determined the relationship between field disease index and damage losses on fresh corn caused by northern corn leaf blight (NCLB) to provide basis for reasonable control of NCLB on fresh corn in Fujian.【Method】The model of disease index and percentage of yield loss was established and economic thresholds suitable for NCLB on fresh corn in Fujian were determined through spraying different times of fungicide to artificially cause different grades of disease under NCLB natural occurrence conditions.The model was used to calculate periods and frequencies of fungicide application on corn varieties with different resistance under same conditions,and the classification standard for resistance was established.【Result】The regression equation between disease index and grown days was established by stepwise regression analysis.There was a significant positive correlation between percentage of yield loss and disease index of all leaves on each plant or functional leaves.The model of disease index and percentage of yield loss was established based on disease severity of all leaves on each plant and functional leaves.The economic thresholds of NCLB were 14.63,17.88,18.72 and 22.06 based on disease index of all leaves on each plant,and were 7.74,10.43,12.24 and 16.80 based on disease index of functional leaves at milk stage (R3) of fresh corn when fungicide application frequencies were 1,2,3 and 4,respectively.According to the established regression equation,economic threshold and disease index (DI) of functional leaves at blister stage (R2) of fresh corn,the classification standard for resistance to NCLB was in the order of ≤15,1545,and the varieties were evaluated as “R”,“MR”,“MS” and “S”,respectively.【Conclusion】The dynamics of NCLB on fresh corn under field conditions in Fujian and the model of disease index and percentage of yield loss were established,and the economic thresholds of NCLB and the classification standard of resistance for different corn varieties were formulated. |
| Key words: fresh corn northern corn leaf blight damage losses economic threshold classification standard of resistance Fujian province |
