【作者】 石志琦；

【导师】 叶钟音；

【作者基本信息】 南京农业大学 ， 植物病理学， 1999， 硕士

【摘要】 油菜菌核病是危害油菜生产最严重的病害，我国多年来一直使用苯并咪唑类杀菌剂防治该病害。但是在浙江、江苏和湖北等省田间出现了油菜菌核病菌对苯并咪唑类杀菌剂的抗药性问题。本文针对这一生产实际问题，以三唑酮、福美双、丙环唑、乙霉威、速克灵、菌核净、烯唑醇对油菜菌核病菌（Sclerotinion sclerotiorum）对多菌灵的抗性突变体和田间敏感菌株进行离体药剂筛选和活体治疗试验。结果表明三唑酮、烯唑醇、菌核净和速克灵对S.sclerotiorum的离体活性较高，而活体治疗作用以菌核净，丙环唑，烯唑醇和速克灵效果较好，均大于70％以上，活体保护作用以速克灵，菌核净和丙环唑为好。在单剂筛选的基础上，本研究选择不同作用机制的三种单剂茵核净+福美双+三唑酮复配以治理S.sclerotiorum对苯并咪唑类杀菌剂的抗药性。各单剂之间的互作率随配比的不同而表现为增效或拮抗作用，选用增效作用为1.88的配比进行混配。以有效成分为24.8％的混配剂（暂名thob）进行田间小区试验，当用量为2700g/hm~2，田间相对防效为80.9％比25％多菌灵4500g/hm~2的防效40.3％高出一倍以上。这一结果表明24.8％Thob复配剂在田间对S.sclerotiorum对苯并咪唑类的抗性菌株同样有效。 在确定thob复配剂对油菜菌核病田间防效优良后，对其主要成分菌核净进行抗性风险评估。研究证明利用药剂筛选和95%致死剂量的紫外诱导均获得S.sclerotiorum对菌核净和其正交互抗性药剂速克灵的高、中、低不同抗性水平的突变体。但各抗性突变体在菌丝生长方面与敏感菌株无显著差异，产菌核能力不如野生敏感菌株。中抗和高抗抗性突变体对1％和8％葡萄糖更敏感，而低抗菌株对渗透压不敏感。100％的敏感亲本均能致病，而只有85.7％的抗性突变体能致病。抗性突变体和敏感茵菌丝片段液于盛花期喷雾接种，油菜收割前从茎杆里回收菌核进行抗性测定，没有回收到抗性突变体的菌核。这一结果表明抗性突变体在田间产菌核能力很弱或不形成菌核。因此对S.sclerotiorum来说，菌核净为中等抗性风险的杀菌剂。 初步的抗性机制研究表明，在与药剂接触后抗性突变体与敏感菌株相比能在更短的时间里渗出更多的电解质。抗性突变体苯并氨酸解氨酶（PAL）活性比敏感亲本菌株高出1倍以上，当用不同浓度菌核净处理或饥饿处理时，抗性突变体和敏感亲本菌株PAL活性均上升，但抗性突变体的酶活始终高于敏感亲本菌株。更多还原

【Abstract】 The research on how to manage the resistance of Sclertinia sclerotiorum to carbendazim occurred in some regions of Jiangsu, Hubei and Zhejiang provinces. The sensitivity test of S.sclerotiorum to triadimefon, dimethachlon, diniconazole, procymidone and propiconazole had the better effects in vifro as well as the good therapy effect in viva. While diethofencarb had the better effect to resistance- carbendazim isolates. The mixture thob of diniethachlon+thiram+triadimefon with synergistic biological response (SR1 .88) was used for field plot test. At the dosage of 2700glhm2of 24.8%a.i. thob, it had treatment effect up to 80.9% compared with its respective components. 25%MBC was used at the rate of 4500g/hxn2 had only got the effectiveness with 40.3%. The resistance risk of dimethachlon, the main component of the thob was evaluated. Dimethachlon resistant mutants were obtained at 2.4 X I 0~桰 o-~ frequency when its mycelia pieces were irradiated with 95% lethal dosage UV- ray in PDA medium. The mutants were still able to grow regularly on the PDA medium amend with 5-10 ~1 g/ml (LR),I0-50 j.?gImI (MR),100 ii g/ml (HR)dimethachlon. All the mutants had positive cross resistant to procymidone of DCF. The capacity of linal growth of mycelium of mutants on PDA medium exhibited no difference from their parents, though the dry-weight of mycelia of mutants was lower. 85.7% of mutants had pathogenicity while 100% parent isolates did. Mutants had the weaker capacity of produce sclerotium generation than that of those wild sensitive isolates. None of resistant sclerotia of mutants was monitored after mycelia piece suspection of mutants mixtureed with wild sensitive isolates which were sprayed during the period of full bloom of the rape. These results showed mutants had lower fitness than wild sensitive isolates. Procymidone caused less electrolyte leakage of the sensitive cultures isolate than that of resistant strains. The change of cell membrane permeability of the 4 sensitivity isolate was smaller than that of the resistant isolate. The activity of PAL of mutant MN6I was high than that of parent isolate PNO61 in the situation of nutrient deficieny or in the 5 u glint or 20+ p. glint dimethachlon treatment solution.更多还原