小麦纹枯病病情消长与气象因子研究

AN INVESTIGATION OF THE RELATIONSHIP BETWEEN WHEAT SHEATH BLIGHT DEVELOPMENT AND CLIMICAL FACTORS

小麦苗期接种小麦纹枯病菌(Rhizoctonia cerealis),观察其病情消长动态,并结合气象因素作相关:通径和回归分析。结果表明,相对湿度对病斑的垂直扩展无实质性影响。影响病斑垂直扩展(y_v)的主导气象因子是气温(x_1),其次为雨量(X_2)再次为雨日(X_3)。其回归模型为:y_v=0.0190(±0.0053)X_1+0.0108(±0.0036)X_2-0.0312(±0.0121)

In 1984-1986,during the two seasons of winter wheat growing,by way of artificially inoculating the sclerotia of Rhizoctonia cerealis to seedling wheat hills in experimental plots arranged in cement a trough containing sterilized soil in which sterilized wheat seeds were sown,systematic observations of sheath blight incidence and development were made in Southwest Agricultural University.Local climatical,including average air temperature for 10 days,relative humidity,rainfall,and days of rain recorded in the same period when this experiment was earried out,were used to dynamically study their relation with the disease development in terms of statistical analysis.The results suggest that the dominant factor that influences the vertical spreading of disease lesions on wheat culm is air temperature, followed by rainfall and then days of rain.There is no substantial effect of air relative hu- midity on the development of this disease.The model showing this relationship is obtained by stepwise regression analysis: Yv=0.0190(±0.0053)X1+0.0108(±0.0036)X2-0.0312(±0.0121)X3 Where Yv respresents the rate of vertical spreading of the disease(em/day),X1 aver- age air temperature of 10 days during the period of wheat development,X2 rainfall in 10 days,X3 rain days for a 10-day period.