DON毒素作为小麦赤霉病损失率评估及防治指标的研究

Study on the control index of wheat dead blight caused by Gibberella zeae

本文通过自然发病调查和人工接种方法,对小麦赤霉病发病程度与产量损失率的关系,以及小麦赤霉病发病程度与病粒中脱氧雪腐镰刀菌烯醇(DON)毒素浓度的关系进行了研究,并对制定小麦赤霉病的化学防治指标进行了探讨,为指导大田防治提供依据。结果表明:小麦赤霉病发生程度和DON浓度呈极显著的正相关关系。小麦赤霉病病粒率(FDK)(X)与DON毒素浓度(Y)的关系式分别是Y=16.4+1.39X(R^2=0.75,P<0.001)和Y=-9.99+1.76X(R^2=0.77,P<0.001)。小麦赤霉病造成小麦产量减少,根据小麦赤霉病产量损失率制订的防治指标为小麦乳熟期的病情指数2.4-8.7%,或者是FDK 2.8-7.5%。小麦赤霉病产生的DON毒素污染小麦,造成小麦价格下降,根据小麦赤霉病DON造成小麦价格损失,小麦赤霉病的防治指标是乳熟期病情指数0.4-3.2%,或者是FDK 0.6%-3.1%。说明小麦赤霉病含有DON毒素引进小麦价格下降造成的损失大于其产量下降的损失。小麦赤霉病含有DON毒素造成其损失增大,改变了小麦赤霉病化学防治指标。简要表述该研究的意义。

Wheat head blight （ WHB） is caused by Gibberella zeae （ Schwein. ） Petch, also known by the name of its anamorph Fusarium graminearum Schwabe. In order to provide scientific basis for the control of wheat head blight, establish its control index based on deoxynivalenol （ DON） concentration under natural and inoculated conditions, the correlationship among the percentage of Fusarium damage kernel （ FDK ） , WHB disease severity and toxin DON in wheat grain were studied. The results indicated that the percentage of FDK and toxin DON concentration had significantly positive correlation. The formula between the percentage of FDK（X） and the DON content （Y） were observed with Y=16. 4＋1. 39X （R2 =0. 75, P〈0. 001） and Y= -9. 99 ＋1. 76X（R2 =0. 77,P〈0. 001）, respectively. The chemical control index was also discussed. According to the yield losses, the economic threshold of FDK for different varieties of wheats were 2. 8 -7. 5%, while the economic threshold of disease index were 2 . 4-8. 7% （ Table 4 ） . Based on the DON toxin content in the wheat grain, the economic threshold of DON/FDK （1mg/kg） for different wheat varieties were＆amp;nbsp;0 . 6-3 . 1 while the economic threshold of disease index were 0. 4-3. 2%.