玉米粗缩病病情严重度分级标准及病情指数与产量损失率关系的研究

The Relations of the Disease Grading Criterion,Disease Index and the Yield Loss Caused by Maize Rough Dwarf Disease

通过对农大108、郑单958和德玉18等3个玉米品种感染玉米粗缩病后株高与单株产量的测定，按病株相对健株株高的比值推导出了玉米粗缩病严重度分级标准，即病株相对健株株高的比依次为1，4／5，2／3，1／2，1／3，其对应病株的病级分别是0，1，2，3，4级；明确了0—4级玉米粗缩病病情严重度分级标准与产量损失的关系，即0，1，2，3，4级病株，产量损失率依次为0.25％，50％，75％和100％。利用该分级标准对10个生产品种的玉米粗缩病病情进行调查，构建了回归方程Y=-0．253＋1．02X。利用16个生产品种对方程进行检验，检验准确率为：理论产量损失率与实际产量损失率没有显著差异。应用此方程，可预测玉米粗缩病导致的产量损失。

Maize rough dwarf disease caused by Rice black-streaked dwarf virus （RBSDV） is one of the most important diseases on maize production in North China. Studies were carried out to measure and calculate each of the healthy and infected plant height and the yield of 1003 plants of 3 cuhivars. The result showed that disease severity was closely correlated to the plant height and yield. When diseased plant heights were 1,4/5,2/3,1/2,1/3 of the healthy plant, disease severities were graded from 0,1,2,3 to 4 ; and the yield losses ranged from 0 %, 25 %, 50 %, 75 % to 100 % respectively. By analyzing the data of disease index and yield loss from 10 cuhivars with SSPS, a regression equation was established, which is Y = -0.253 ＋ 1.02X （ Y： yield loss; X： disease index）. The equation was validated with the data from 16 cuhivars. The result supported the feasibility of the equation to predict the yield loss caused by maize rough dwarf disease in production.