黄淮海冬小麦春季低温灾害等级指标构建

Indicator Construction of Spring Low-temperature Disaster Affecting Winter Wheat of Huang-Huai-Hai Based on Meta-analysis

  • 摘要: 为了明确黄淮海冬小麦春季低温胁迫与产量及其构成因素的定量关系, 基于减产率构建小时尺度低温灾害等级指标。通过检索及筛选的34篇试验文献中的1924组试验组数据和对照组数据, 采用Meta分析方法分析黄淮海地区返青期、拔节期、孕穗期和抽穗-开花期低温胁迫对小麦产量及其构成因素的影响, 以过程最低温度、积冷量为判识因子, 根据约登指数确定减产率为0、10%和30%的临界阈值, 构建并验证低温灾害等级指标。结果表明: 冬小麦产量及其构成因素受低温胁迫过程低温强度和持续时间共同影响, 因所处发育阶段不同存在差异。按照减产率(0, 10%、(10%, 30%和(30%, 100%为分级标准, 分别以过程最低温度和过程积冷量为判识因子构建并验证低温灾害等级指标, 过程积冷量指标在不同发育期的判识准确率均高于过程最低温度指标。因此, 基于过程低温强度和持续时间的综合影响构建的判识因子能更好地表征冬小麦遭受低温灾害的严重程度。

     

    Abstract: The low temperature disaster in spring is one of the main agro-meteorological disasters affecting the yield and quality of winter wheat by affecting the development process and physiological function, resulting in yield reduction. In order to clarify the quantitative relationship between spring low temperature stress and winter wheat yield and its components in Huang-Huai-Hai Region, an indicator is constructed based on yield reduction rate. Based on 1924 sets of experimental data and control data in 34 retrieved literatures, effects of low temperature stress on wheat yield and its components at green-up stage, jointing stage, booting stage and heading-flowering stage are analyzed by Meta-analysis. Using the minimum temperature and accumulated cold of the process as identification factors, the critical thresholds of 0, 10% and 30% of yield reduction rate are determined by using the Youden's Index to establish and verify the low temperature disaster grade indicator. Results show that the yield and its components of winter wheat are jointly affected by the intensity and duration of low temperature to different extent in different developmental stages. The yield and all its components decrease significantly under low temperature stress, and the sensitivity of panicle number per plant and grain number per panicle to low temperature stress is greater than that of thousand kernel weight. The low temperature disaster grade indicators are constructed according to the yield reduction rate of (0, 10%, (10%, 30%, (30%, 100%. Taking the minimum temperature (unit: ℃) of the process as identification factor, ranges for low temperature disaster grade (Ⅰ, Ⅱ, Ⅲ) during the green-up stage are -5.0, -2.0), -8.5, -5.0), <-8.5; during the jointing period, they are -1.0, 3.0), -2.5, -1.0), <-2.5; during the booting stage, they are 1.1, 5.1), -3.0, 1.1), <-3.0. With the accumulated cold (unit: ℃·h) of the process as identification factor: Indicators during the green-up stage are -216.1, -72.0), -360.0, -216.1), <-360.0; during the jointing stage, they are -41.0, -1.2), -66.0, -41.0), <-66.0; during the booting stage, they are -101.6, -16.8), -169.3, -101.6), <-169.3; during the heading to flowering period, they are -38.5, -19.6), -93.8, -38.5), <-93.8. The accuracy of the indicator constructed with process accumulated cold volume is higher than that of process minimum temperature in all growth stages, indicating that the identification factor (accumulated cold of the process) based on the comprehensive influence of low temperature intensity and duration of the process could better characterize the severity of winter wheat suffering from low temperature disaster.

     

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