【作者】 向鲲鹏；

【导师】 文成敬；

【作者基本信息】 四川农业大学 ， 植物病理学， 2008， 硕士

【摘要】 从雅安郊区西瓜地采集典型发病植株,剪取茎蔓病组织,采用组织分离法分离鉴定得到病原菌尖孢镰刀菌西瓜专化型（Fusarium oxysporum f.sp.niveum（E.F.Smith）Synder etHansen）菌株。病原菌生物学特性研究结果表明,病菌菌丝生长的适宜条件是:光照、PDA和燕麦培养基、25℃～30℃、PH5～8,且供试的营养中以蔗糖为最佳碳源,尿素为最佳氮源;适合产孢子的条件是:光照、查彼和PDA培养基、30℃～35℃、PH5～6,蔗糖为最佳碳源,硝酸钾为最佳氮源;适合分生孢子萌发的条件是:光照、25℃～35℃、PH5～8。温度,光照和PH是影响病菌生长和产孢以及孢子萌发的重要因素,故选3因素、3水平的L₉（3³）来安排正交实验。试验结果表明:30℃、PH5、交替光的条件组合为尖孢镰刀菌西瓜专化型菌丝生长和产孢的最佳条件。同时病菌对供试药剂敏感性实验表明:烯唑醇对病菌的毒力最强,EC₅₀为4.7976ug.ml^-1,甲基托布津、百菌清及多菌灵次之,EC₅₀分别为81.444lug.ml^-1、82.487ug.ml^-1、152.852ug.ml^-1,714.5950ug.ml^-1的三唑酮对病菌的毒力较差。从雅安郊区不同生态土壤中分离得到41株木霉,并以这41株木霉作为生防菌株筛选的出发菌株。通过对41个木霉菌株的生长速度、对峙培养、非挥发性代谢产物和挥发性代谢产物的抑菌作用测定,筛选出T1、T3、T4、T24四个具有较强生防潜能的木霉菌株,经鉴定T1、T4为桔绿木霉Trichoderma citrinoviride;T3、T24为黄绿木霉Trichodermaaureoviride。用筛选出的生防活性好的木霉菌株T1、T3、T4、T24之麦麸砂土培养物做进一步的室内盆栽防病试验,结果表明:供试菌株T1、T3的防病效果显著,防效依次为64.60%、74.95%,明显高于多菌灵的58.50%的防效,较好地控制了西瓜枯萎病的发生。然而菌株T4的防效低于多菌灵,仅为50.25%,但T4处理的病指仍大大低于对照的68.58%。有意义的是,当T4与土壤杀菌剂联合应用时（T4+PCNB）,其防效为56.00%,与多菌灵相当。木霉与杀菌剂联合应用可以减少杀菌剂的使用量。更多还原

【Abstract】 (Fusarium oxysporum f.sp.niveum（E.F.Smith）Synder etHansen) was isolated from the infected caudexes of watermelon in suburb of Ya-an,Sichuan.The culture optimum conditions for hyphal growth of pathogen were light,PDA or OA medium,25℃to 30℃,PH5 to 8.And the optimal carbon source was sucrose and nitrogen source was urea.The optimum conditions for spore sporulation were light,PDA or Czapek cultures,30℃to 35℃,PH5 to 6.The optimal carbon for sporulation was sucrose and nitrogen sourcee was nitre as well as the optimum conditions for conidiophore germination were light,25℃to 35℃,PH5 to 8.Temperature,illumination and PH were the most important factors on hyphal growth rate and spore sporulation of Fusarium oxysporum f.sp.niveum.The orthogonal test of three factors i.e.temperature,illumination and PH was designed.The result showed that the best conditions combination of hyphal growth rate and spore sporulation were 30℃,PH5,Alternate light.Virulence test of several pesticides to the pathogen showed that EC₅₀ 4.7976ug.ml^-1 of diniconazole against pathogen was best.triophanate-methyl、chlorothalonil and carbendazim subsequently and its EC₅₀ respectively was 81.4441ug.ml^-1,82.487ug.ml^-1, 152.852ug.ml^-1,effected of 714.5950ug.ml-1 of triadimefon on pathogen was weak.41 strains of Trichoderma.spp were isolated from the different ecotypic soil in surburb of Ya-an and Those strais were used in the screening experiment of biocontrol strains.4 strains,named T1,T3,T4 and T24 respectively,that possessed stronger potential ability for plant disease biocontrol,were chosed according to the hyphal growth rate,dual culture on PDA plates,effects of volatile and non-volatile metabolites.T1 and T4 was identified as T.citrinoviride;T3 and T24 was T.aureoviride.T1,T3,T4,T24 were selected for pot experiment.The result of pot experiment showed that the efficacies of solid culture of T1 and T3 against watermelon Fusarium Wilt were 64.60%,74.95%,respectively,that were better than those of carbendazim（58.50%）. However,the efficacies of isolate T4 was only 50.25%,lower than those of the solid culture,but lower than disease exponential of comparison.it is significance that effect of T4 combines soil bactericide were 56.00%,as same as carbendazim.Trichoderma combines bactericide can reduce dosages of antiseptics.更多还原