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1977～1979连续三年在河南省浚县玉米小斑病严重流行地区进行试验。三年来均按相同的田间设计进行。采用中等感病品种洛阳白马牙,在自然发病条件下,间隔不同时期喷施敌菌灵保护叶面,人为地造成不同程度发病,至流行终止期,各处理间有显著不同的病情差別。产量差异亦极显著。将三年试验结果用多元协方差分析,推导出二组经验回归方程:(?)=27.82-0.1368X_1-0.1435X_2……(1)及(?)=23.48-0.1368X_1-0.1435X_2……(2)此处(?)为理论产量,X_1、X_2分别为灌浆期和乳熟期的病情指数,而减产率(L%)则为:L(%)=(1-(?)/a)×100,此处a为回归方程中的常数项。据分析,当玉米生育期(6月下旬至9月中旬)雨量较大,为300～365毫米,灌浆至乳熟期(8月下旬至9月上旬)雨日较少、为3～6时,玉米产量较高,此种情况下,应选用常数值较大的(1)式;当玉米生育期雨量较小、为160毫米左右,灌浆至乳熟期雨日较多、为15日左右时,玉米产量较低,此种情况下,宜选用常数值较小的(2)式。
1977 ~ 1979 for three consecutive years in Henan Junxian maize small spot severe endemic areas for testing. Three years have been the same field design. The middle-susceptible breed Luoyang Baimaya tooth was sprayed with paecilomyces sp. At different periods of time under natural disease conditions, artificially causing different degrees of disease, reaching the termination of epidemic phase, with significant differences in disease conditions among the treatments. Yield differences are also significant. The results of three years using multivariate analysis of covariance, derived two sets of empirical regression equation: (?) = 27.82-0.1368X_1-0.1435X_2 (1) and (?) = 23.48-0.1368X_1-0.1435X_2 2) where (?) Is the theoretical yield, X_1 and X_2 are the disease index of grain filling stage and milking stage, respectively, while the yield reduction rate (L%) is: L (%) = × 100, where a is the constant term in the regression equation. According to the analysis, when the corn growing period (from late June to mid-September) is relatively large, the rainfall is 300-365 mm. The rainfall from the filling stage to the milky ripening stage (late August to early September) is less from 3 to 6 , The corn yield is higher, in this case, the formula (1) with larger constant value should be used. When the rainfall during the growing period of corn is relatively small, about 160 mm, the rainy days from filling to milky maturity are more on the 15th When the corn yield is lower, in this case, the smaller constant (2) should be used.