花后弱光逆境对弱筋小麦产量构成因素和籽粒品质影响的模拟模型

Quantifying the Effects of Low Level of Radiation After Anthesis on Yield Components and Grain Quality of Weak Gluten Wheat

【目的】建立花后弱光逆境对弱筋小麦产量构成因素和籽粒品质影响的模拟模型,为弱光天气事件对优质弱筋小麦生产的灾损评估提供模型工具。【方法】以弱筋小麦品种扬麦15号为试材,通过设定花后3个光照强度(光照强度分别为自然光强的50%、34%和16%)和4个弱光持续时间(2 d、4 d、6 d和8 d)的遮阴处理试验,模拟连阴雨天气诱发的弱光逆境对弱筋小麦产量构成因素和籽粒品质的影响。在定量分析弱光逆境对弱筋小麦产量构成因素和氮素累积影响的基础上,确定其与籽粒品质指标的函数关系,将这些函数关系与笔者前期建立的弱光对小麦干物质生产影响模拟模型相结合,建立花后弱光逆境对弱筋小麦产量构成因素和籽粒品质影响的模拟模型,并使用独立试验数据对模型进行检验。【结果】确定了花后对弱筋小麦每穗结实粒数和籽粒氮含量产生显著影响的临界弱光阈值和持续时间。模型检验结果表明,模型对每穗结实粒数、千粒重、籽粒容重、面粉降落数值、籽粒粗蛋白含量和面粉湿面筋含量的模拟值与实测值基于1﹕1线的决定系数(R2)分别为0.89、0.75、0.72、0.73、0.93、0.84,相对均方根差(rRMSE)分别为2.86%、3.41%、1.01%、2.50%、2.64%、5.05%。【结论】本研究建立的模型能够较为准确地模拟花后不同强度和持续时间弱光逆境对弱筋小麦产量构成因素和籽粒品质的影响,模型的建立为评估全球气候变化背景下弱光天气事件对优质弱筋小麦生产的不利影响提供了模型工具。

[ Objective ] The objective of this study is to develop a model for predicting the effects of low level of radiation on yield components and grain quality of wheat so as to quantitatively assess the impacts of low level of radiation on wheat crop production. [ Method ]Field experiments with weak gluten winter wheat （Triticum aestivum L. cv Yangmai 15） were conducted during three growing seasons. Shading treatments with three levels of radiation intensity （50%, 34% and 16% of natural radiation） and four durations （2 d, 4 d, 6 d and 8 d） after anthesis in the three growing seasons were designed to simulate the low level of radiation caused by cloudy or rainy weather conditions. Based on the experimental data, the impacts of low level of radiation on yield components and grain nitrogen accumulation, and their relations with grain quality traits were quantitatively analyzed and the corresponding functions were determined. These functions were then integrated into the simulation model of wheat crop biomass production and under low levels of radiation weather conditions developed in a previous study, to develop a dynamic model for predicting the effects of low level of radiation after anthesis on the yield components and grain quality of weak gluten wheat. Independent experimental data were used to validate the model. [Result] The critical daily total photosynthetically active radiation （PAR） and duration were determined for keeping normal levels of grain number per spike and grain nitrogen content based on the experimental data. Model validation results showed that the determination coefficient （R2） between the predicted and measured values of grain number per spike, thousand grain weight, test weight, falling number, protein content and wet gluten content were 0.89, 0.75, 0.72, 0.73, 0.93 and 0.84, respectively, and the corresponding relative root mean squared errors （rRMSE） were 2.86%, 3.41%, 1.01%, 2.50%, 2.64% and 5.05%, respectively. [Conclusion] The model developed in this study gave satisfactory predictions of the effects of low level of radiation after anthesis on yield components and grain quality of weak gluten wheat, hence, can be used for assessing the impacts of low level of radiation caused by cloudy or rainy weather conditions on weak gluten wheat production.