欠量灌溉供水率胁迫强度与玉米产量的规律分析

Study on the Theoretical Model of Watering Ratio and Drought Resistance under Proportional Irrigation of Maize

【目的】研究和建立供水率与抗旱性的理论关系模型,为欠量灌溉玉米抗旱性精准鉴定提供理论依据。【方法】2017~2019年选择12个杂交种,设置6个水分梯度的欠量胁迫处理,各处理区全程灌水8次,出苗水均为675 m^(3)/hm^(2),其余的7次灌水量按照100%、80%、60%、40%、20%和0%比例减少,以形成不同的干旱胁迫强度;在缺次灌溉模型的基础上等价变换和推导,建立欠量灌溉模型,并对模型进行验证。【结果】供水率与玉米抗旱性关系的理论模型γ=Φ^(k)/(Φ^(k)+Φ_(h)^(k)),该模型能描述玉米杂交种的抗旱系数(γ)随供水率(Φ)变化的幂饱和曲线。12个玉米杂交种的抗旱系数计算值与实际测定值间的相关系数为0.973~0.995(平均0.987),达到了极显著水平(P_(0.01)=0.917);模型拟合得出的残差预测偏差RPD值为3.914~9.485,均大于3.0,拟合效果良好。【结论】建立的欠量供水率与玉米抗旱性的模型可用于玉米抗旱性的精准鉴定;其中,半产供水率Φ_(h)和水分敏感系数k均具有明确的生物学意义,是玉米抗旱性的两个重要指标,2者数值均小的品种具有相对稳定的抗旱性。

【Objective】To research and establish a theoretical model of the relationship between watering ratio and drought resistance in the hope of providing a theoretical basis for accurate identification of drought resistance under the condition of proportional irrigation of corn.【Methods】From 2017 to 2019,12 hybrids were treated with 6 water gradients under the condition of reducing the proportion of irrigation.Each treatment area was irrigated 8 times in the whole process.The watering for emergence was 675 m^(3)/hm^(2),and the water for the remaining 7 times was reduced according to the proportion of 100%,80%,60%,40%,20%and 0%to form different drought stress intensity.Based on the equivalent transformation and derivation of the lack irrigation model,the proportional of irrigation model was established.The model was validated with the results of 3 years of experiments.【Results】A theoretical model of the relationship between water supply rate and corn drought resistance was established,and the model wasγ=Φ^(k)(Φ^(k)+Φ_(h)^(k)),which could describe maize hybrid in nonlinear power exponential saturation curve drought resistant coefficient(γ)changing with watering ratio(Φ).After being fitted and verified,the correlation coefficient between the predicted value and the actual value of 12 corn hybrids was 0.973-0.995(mean 0.987),and the fitting reached an extremely significant level(P<0.01,0.917).The RPD value of residual prediction deviation fitted by the model was 3.914-9.485,which was greater than 3.0,which meant the model was a good fitting.【Conclusion】The model of watering ratio and drought resistance of maize hybrid can be used in the precise identification of maize drought resistance under proportional irrigation.The parameters,half-yield watering ratio(Φ_(h))and water sensitive coefficient(k)have definite biological significance,which are two important indexes of maize drought resistance.Maize varieties with small values of two parameters have relatively stable drought resistance.