大豆灰斑病流行强度预测模型研究

Study on the forecasting model of epidemic intensity of Cercospora sojina

大豆灰斑病是一个多循环病害,叶、荚病情田间流行曲线均呈“S”型,Y^1=C/1+ea-bX公式进行曲线方程拟合,拟合方程均达到显著水平。根据荚病指(x)与病粒率(y)的相关建立了荚病指与病粒率的直线回归方程,感病品种Y=3.2+0.8890X,抗病品种Y=1.223+0.7669X。根据病粒率与气象因子的相关关系建立了早熟品种和中晚熟品种灰斑病粒率预测多元回归方程,早熟品种Y^1(%)=-0.38-0.3889X1+0.7726X2+0.7070X3,中晚熟品种Y^2(%)=-7.08-6.37×10-2X1+1.405X2+2.694X3。预测方程在一个农场运行结果,预测病粒率与实际调查的病粒率十分接近。

The gray speck of soybean is a poly cyclic disease, and the epidemic curve of infected leaf and pod discovered “S” model. The spora from diseased leaf was an infective source of pod, and the logistic period of infected leaves was longer than that of pods, which was about 10 days. The equation of linear regression was completed based on the coefficiency of disease index of pods （x） with percentage of infected seeds （y） which was Y1 = 3.2 ＋ 0. 8890X for susceptible variety, and Y2 = 1. 223 ＋ 0. 7669X for resistant variety. The multivariate equation used to forecast percent of infected seeds of early and mid - late varieties on the meteoregical condition with diseased seeds, which was Y1 （ % ） = - 0.38 - 0. 3889X1 ＋ 0. 7726X2 ＋ 0. 7070X3 for early varieties and Y2 （ % ） = - 7.08 - 6.37×10^-2X1 ＋ 1. 405X2 ＋ 2. 694X3 for mid - late varieties. The equation was used to forecast the percent of infected seeds of gray speck soybean in a farm, the forecasted percent was close to the percent of diseased seeds observed.