【作者】 牛晓科；

【导师】 崔建州； 冉隆贤；

【作者基本信息】 河北农业大学 ， 森林保护， 2009， 硕士

【摘要】 灰枣红点软腐病是2005年至今在河南新郑灰枣产区大面积发生的一种严重危害灰枣的新病害,这种病害不仅影响果实的正常生长,降低了果实的商品价值,而且所有病果完全失去食用价值。为了降低灰枣红点软腐病对河南省灰枣的危害,本文系统研究了灰枣红点软腐病的病原,并进行了化学药剂及生防菌的筛选,主要结果如下:1本文对灰枣红点软腐病在河南省新郑枣产区的危害和发病特点进行了调查与研究,以形态学特征为基础并结合核糖体DNA-ITS序列对病原菌进行分析鉴定。结果表明:菌落初期气生菌丝为白色,5～6 d后变为灰色,两周后变为黑色,菌丝发达,绒毛状;分生孢子器球形,长196.9μm,宽213.3μm;分生孢子纺锤形,单胞,无色,长15～20μm,宽4.5～6.5μm;分生孢子梗帚状。分离菌株NXK核糖体DNA-ITS序列与葡萄座腔菌的同源性达到99.87 %,仅有2个碱基的差异,从而将灰枣红点软腐病的病原鉴定为葡萄座腔菌(Botryosphaeria dothidea)。2采用多种促进葡萄座腔菌产孢的方法,对其产孢速度及产孢量进行研究。结果表明,B. dothidea在25℃下,CMA培养基上产孢速度最快,产孢量最大。3采用生长速率法观测14种杀菌剂的抑菌效果,并对抑制菌丝生长效果较好的药剂采用梯度稀释法进行稀释,进行菌丝生长抑制试验,利用POLO软件计算其毒力指标,求出EC50。结果表明:炭疽福美、多菌灵、代森锰锌对菌丝抑制效果最好,与其他药剂间均达到极显著差异,抑菌率都在99%以上,EC50分别为6.633 mg/L,0.326 mg/L和27.978 mg/L。4采用孢子萌发法对10种菌丝生长抑制率在90%以上的杀菌剂进行筛选,得到2种抑制效果好的药剂。并采用梯度稀释法对2种药剂进行毒力测定,利用POLO软件计算其毒力指标,求出EC50。结果表明:25%除菌通WP、25%酷乐咪鲜胺EC对孢子萌发抑制作用最强。对孢子萌发的抑制率均为100%,EC50分别为15.305 mg/L和50.158 mg/L。5田间试验表明,5种自配方复合药剂都有一定的防治效果,与CK都达到了极显著差异,其中喷施3号配方枣果的发病率与喷施其他配方的枣果发病率之间都达到了极显著差异,发病率最低,为35.5%,其次是4号配方,发病率为44.5%,其余几个配方发病率都在70%左右,防治效果较差。6以灰枣红点软腐病菌(B.dothidea)为指示菌,采用平板对峙法筛选对灰枣红点软腐病菌有拮抗效果的生防菌株,结果表明龟裂链霉菌(CN124)拮抗效果最好,抑菌率达97.52%。并且以龟裂链霉菌菌株CN124为试材,采用单因子试验与均匀试验相结合的方法,通过均匀设计回归分析,筛选出菌株CN124最佳发酵培养基配方。其最佳配方为:淀粉11.67%,玉米粉2.69%,(NH4)2SO4 0.22%,CaCO3 0%,NaCl 0.03%。更多还原

【Abstract】 Fruit soft rot disease of Ziziphus jujuba was a new disease which had widely distributed and caused great damage in Xin zheng, Henan Province since 2005. It affected the normal growth of fruit and reduced the commercial value. Furthermore, all the infected fruits were not edible at all. To reduce the loss caused by soft rot disease of Ziziphus jujuba, the pathogen was isolated and identified. Several kinds of fungicides and antagonistic bacteria were also screened in this study. The main results were summarized as follows:1 The occurrence, symptom characteristics and pathogen identification of soft rot disease of Ziziphus jujuba were studied, which widely occurred in xinzheng jujube areas of Henan province. Pathogens were identified by traditional morphological characteristics and ribosome DNA-ITS sequence analysis. The results showed that the villous aerial mycelium was white in the early germination, turned gray after 5 ~ 6 d and black after two weeks, which grew luxuriantly; Pycnidium was flask-shaped, 196.9×213.3μm; Conidium was spindle and colorless with a single spore, 15~20×4.5~6.5μm; Conidiophore was fastigiate. The homology of ribosome DNA-ITS sequence between strain NXK and Botryosphaeria dothidea reached to 99.87 %, with only 2 bp difference, and the pathogen of soft rot disease of Ziziphus jujuba was identified as B. dothidea.2 To promote the sporulation speed and quantity of B. dothidea, some facilitative methods were used in this research. The results showed that B. dothidea had the fastest and largest amount of conidia on the CMA sporulation medium, and the optimum temperature was at 25℃.3 The bacteriostatic effects of 14 fungicides were observed using the growth rate method. The fungicides which have good inhibitory effect were diluted by gradient dilution for carrying out the inhibitory experiments on the growth of mycelium. Toxicity index and EC50 were calculated by POLO software. The results showed that the inhibitory effects of anthrax fukumi, carbendazim and mancozeb were the best,and the correlation between the three fungicides and others was significant. The rate of the three bacteriostasis was more than 99%, and EC50 were 6.633 mg/L, 0.326 mg/L and 27.978 mg/L, respectivly.4 Screening of 10 fungicides whose inhibition rate was up to 90% by spore germination method was conducted and 2 effective fungicides were obtained. Toxicity of the 2 fungicides was tested by gradient dilution. The toxicity index and EC50 was calculated with POLO software. The results showed that the inhibitory effect of 25% sterilization Tong WP, 25% Prochloraz EC were the best,and the correlation between the three fungicides and others were significant. The inhibition rates of the three bacteriostasis were 100%, and EC50 were 15.305 mg/L, and 50.158 mg/L, respectively.5 The results of field test showed that 5 kinds of self-prescription pharmaceutical compound had a certain effect on soft rot disease of Ziziphus jujuba, which had reached a very significant difference compared with the control. The incidence rate of soft rot disease of Ziziphus jujuba treated by the 3rd formula was 35.5%, the lowest one which reached a significant difference compared with other treatments. Followed by the 3rd formula was the 4th, whose incidence rate was 44.5%, and the rest were less effective with incidence rate at about 70%.6 The antagonistic microbes were selected by plates assay, using B. dothidea as an indicator strain. The results indicated that the antagonistic strain CN124, belonging to Streptomyces rimosus, had the best biocontrol effect, and the bacteriostasis rate reached to 97.52%. The fermentation medium of the highest rates of S.rimosus CN124 for B. dothidea was selected using single-factor test combined with the evenness test through the regression analysis. The results showed that the components of optimum medium was starch 11.67%, corn flour 2.69%, (NH4)2SO4 0.22%, CaCO3 0%, and NaCl 0.03%.更多还原