【作者】 张晓春；

【导师】 李华荣；

【作者基本信息】 西南农业大学 ， 植物病理学， 2002， 硕士

【摘要】 丝核菌（Rhizoctonia）是一类自然界广泛存在的植物病原真菌，类群极为庞大，且丝核菌常以菌丝融合群引发植物病害，造成多种植物的严重病害，带来巨大的经济损失。杀菌剂对丝核菌菌丝融合群引发病害的作用特性及防治效果研究极少，目前国内仅对AG₁-IA亚群中来源不同的菌株间对不同药剂的敏感性进行了测定，而不同的丝核菌菌丝融合群对杀菌剂敏感性的研究尚未见正式报道。重庆是丝核菌菌丝融合群引发病害较重的地区，为了有效防治和控制这类病害，本文用“纸碟法”和“液培法”两种不同的离体培养方法，就12类丝核菌菌丝融合群（AG-2-1、AG-3、AG-4、AG-A、AG-C₁、AG-D、AG-E、AG-F、AG-K、226、290、BM₉）对目前市售的常用于防治立枯病、纹枯病的7种常用杀菌剂（多菌灵、甲基托布津、退菌特、增效敌克松、可杀得2000、井岗霉素、百菌清）进行室内敏感性测定，并观测丝核菌菌丝融合群的培养性状，搞清不同的菌丝融合群对药剂的敏感性，为生产上选择防治丝核菌引发病害的药剂、制定防治策略提供重要的参考依据。 先根据资料确定培养温度，再根据试验结果选择“纸碟法”的培养时间为48h，“液培法”的培养时间为72h。 在Excel上将抑制率作反正弦转换后，采用SPSS10.0 for Windows分析软件，进行各处理间抑制率的差异显著性检验（Duncan法）。 主要研究结果如下： 1．丝核菌菌丝融合群类型 不同菌丝融合群间在菌丝生长速度、菌核颜色和形状及其结构和大小、菌落颜色、表面绒毛的多少、分布、菌落气生菌丝的多少以及培养基的颜色等方面都具有明显的差异，而融合群内的这些方面却具有较大的相似性。通过对培养性状的观测，发现AG-A和AG-C₁的菌落、菌核的特征特性和培养基颜色等完全一致，而其余11类之间的培养性状存在着较明显的差异。因此专门对AG-A和AG-C₁进行配对培养，在显微镜下观察到其菌丝发生融合、菌丝间相互吸引和融合细胞逐渐坏死。可得出结论：有两个（AG-A和AG-C₁）是种内群（Instrapecific group，ISG）。 2．不同杀菌剂对菌丝融合群的抑制作用 井岗霉素、增效敌克松对12类菌丝融合群都具有良好的抑菌效果，其中增效敌克松的抑制作用最佳。7种杀菌剂对226均具有良好的抑制作用。 多菌灵对AG＊、AG(、AGot具有良好的抑菌作用，可用于防治这些菌群引发的水稻、玉米、高粱、谷子、大豆、芥菜、甜菜、菠菜、魔芋、茶、云杉、落叶松、人参、大麻等作物病害。 甲基托布津能有效抑制AG4、AG－A的生长，可作为生产上选择有效药剂来防治由它们引发的玉米、水稻、辣椒、马铃薯、茄子、豌豆、油菜、白菜、胡萝卜、瓜类、甜菜、养麦、杉类、柏木、谷子等作物病害的重要参考依据。也可用于防治小麦纹枯病（主要由AG－D引发的）。 退菌特对AG－K具有良好抑制作用，可作为生产上选择有效药剂来防治由AG－K引发的谷子、花生、草萄、菊花、甜菜、胡萝卜、茵香、唐葛蒲等作物病害的重要参考依据。 百菌清对AG－2－l、290具有良好的抑菌效果，可用于防治由AG－2－l引发的小麦、甘蓝、油菜、白菜、小枣等作物病害。 可杀得对12类菌群的抑制作用较差。 总之，在防治菌丝融合群引发的病害，应综合考虑杀菌剂对融合群的作用效果和引起病害的主导菌丝融合群，如防治小麦纹枯病（60O／以上是由于 AG．D的致病作用），可选择井岗霉素、退菌特和甲基托布津；在防治水稻立枯病、纹枯病时（主要是AG－4、AG．l引发的），可选择退菌特、增效敌克松、井岗霉素。在防治马铃薯、辣椒、甘蓝等作物等的黑藉病、网斑病、叶枯病、立枯病（主要由AGl引发）时可选择井岗霉素。 菌丝融合群在有井岗霉素的培养基上菌丝生长速度相对较慢，并在显徽镜下观察到了分支菌丝的畸形。其防治机理是对能引发纹枯病的丝核菌菌丝融合群产生畸形致使分支菌丝无法侵入。3．杀菌剂不同防治浓度对菌丝融合群抑制率的差异 7种杀菌剂的3种浓度之间对12类菌丝融合群的抑制作用表现出一定的差异性，总的趋势基本是一致的：随着浓度的增加，对菌丝融合群的抑制效果增强，即高浓度＞中浓度＞低浓度。因此，在田间防治这口类菌群引发的病害且病害发生较重时，最好使用杀菌剂施药说明的高浓度。在井岗霉素防治AG〕引发病害时应选择中浓度。更多还原

【Abstract】 Rhizoctonia Kuhn is kind of fungus with wide distribution and can infest many plants. It is a very large group, often result in series plant diseases by anastomosis group (AG) and cause large economic loss. Currently, there is little information available on the characteristics of the fungicides and control effect to the AG in the literature. In China, the susceptibility of different strains belong to the AG1-IA intraspecific group (ISG) to different fungicides were studied, while there is no information on the susceptibility of other AG to different fungicides. Chongqing is a serious AG infested area. In order to manage this kind of disease effectively, this paper studied the susceptibility of 12 anastomosis group (AG-2-1 s AG-3, AG-4, AG-A, AG-C1, AG-D, AG-E, AG-F, AG-K, R. solani, 290, BM9) to 7 fungicides (carbendazim, thiophanate-methyl, thiram, fenaminosulf, kocide 2000, Jingangmycin, and chlorothalonil) which commonly used to control the soreshin, and sheath blight in the laboratory by culture in vitro method of "paper dish method" and "fluid culture method". The culture characteristics of AG and the susceptibility of different strains to the same fungicide were investigated. All of these information could provide very important theory basis to the screening and changing of fungicide\ rotation and popularization of resistant crops and making of manage strategy.According to the information in the literature, the culture temperature was determined, and then according to the result, the culture time of "paper dish method’ was 48h, and ’fluid culture method’ was 72h.The statistical analyses of the data were performed on the computer using statistical software such as Excel and SPSS 10.0 for Windows. The percentage data was transformed to arcsin-square-root value before multiple range test was performed.The major results are as follows:1. The classification of anastomosis group (AG)The result showed that there is significant difference in the following aspects among different anastomosis groups. These including the growing velocity of hyphae, the color\ shape\ structure and size of the mycelitha, the color of the colony, number and distribution of the surfance villus, the number of the hypha, and the color of the culture medium, and so on. Based on the culture characteristics, it was found that the characteristics of colony, hyphae and the color of culture medium are completely same between AG-A and AG-C1, however, the others are different from each other. So the AG-A and AG-C1 were specially studied and the following conclusion was achieved: the two groups (AG-A and AG-C1) are intraspecific group (ISG).2. The inhibition of different fungicides to the AGsBoth Jingangmycin and fenaminosulf have good inhibition effects on 12 AGs, and the effect of fenaminosulf is the best. All 7 tested fungicides have effective inhibition to R. solani.Carbendazim has the effective inhibiting effects on AG-E> AG-CK AG-A. it might be used to control those diseases infested by the three AGs for paddy, maize, Chinese sorghum, millet, soybean, leaf mustard, beet, spinach, tea, dragon spruce, larch, ginseng, hemp, and so on.Thiophanate-methyl can effectively inhibit the growth of AG-4 and AG-A. It might be used as the important theory basis of choosing the fungicides to control those diseases infested by these two groups for maize, paddy, hot pepper, potato, eggplant, pea, rape, cabbage, carrot, beet, buckwheat, cypress, millet, and so on. It could also be used to control sharp eye spot of wheat which is mainly caused by AG-D.Thiram can effectively inhibit the growth of AG-K, this result might be as a theoretical basis to select fungicide to control the crop diseases caused by AG-K on millet, peanut, strawberry, chrysamthemum, beet, carrot, fennel, and so on.Chlorothalonil can effectively inhibit the growth of AG-2-1 and 290. It might be used to control the crop diseases caused by these two groups on wheat, wild cabbage, rape, cabbage, jujube, and so on.The inhibition effects of Kocide to 12 AGs更多还原