【作者】 田雪亮；

【导师】 杨家荣； 杨之为；

【作者基本信息】 西北农林科技大学 ， 植物病理学， 2004， 硕士

【摘要】 苹果黑星病是世界各苹果产区的重要病害，主要为害苹果叶片和果实，造成叶片早期脱落，降低树势；在果实表面形成疮痂状病斑，使果实畸形，降低其商品价值。该病虽属国内检疫性病害，但发病面积逐年扩大，严重威胁我国苹果生产。将苹果黑星病春季流行过程分解为苹果叶片生长、子囊孢子成熟、子囊孢子释放着落、子囊孢子萌发、子囊孢子侵染、病斑扩展6个过程。利用系统分析和模拟的方法描述苹果黑星病春季流行过程中各主要组分与环境条件主要是积温的关系，并分别建立子模型。采用1997－2003年，4月10日至7月10日日积温，建立逐日累累积温预测子模型，为其它模型提供积温数据。苹果叶片生长子模型、子囊孢子成熟子模型利用4月10为起点的积温预测逐日叶片面积、逐日平均叶龄、子囊孢子逐日成熟度。子囊孢子释放着落子模型采用黑盒处理，推测叶片上着落的子囊孢子数量。子囊孢子萌发子模型采用降雨日的逐时积温、降雨、日平均温度及叶面湿润时间预测子囊孢子产生附着胞的概率。子囊孢子有效侵染率子模型中以叶片平均叶龄为驱动变量，计算着落于叶片上的子囊孢子有效侵染率。病斑扩展子模型以积温为驱动变量，预测逐日病斑面积增长量、病斑数量增加量。按总体设计框图，以Windows XP为支持系统，采用可视化结构程序设计语言Delphi 7.0编写程序将各子模型有机的连接起来，组建成苹果黑星病春季流行模拟模型模型中以4月10日为起点的积温、4月10日后大于0.25mm降雨量为驱动变量，预测经一个潜育期后苹果黑星病的发病率，并确定最佳防治时期。初始菌原量，潜育期作为常量计入模型。通过对模型的灵敏度检测，结果发现降雨日期对苹果黑星病严重度的影响最敏感，但对单个苹果枝条上黑星病斑数目的影响相对迟钝。通过改变降雨日期和初侵染源数量模拟试验发现4月30日至5月20日之间的降雨引起的苹果黑星病发病率较高；初侵染菌量越多造成的发病率也越高。通过对苹果黑星病单个枝条上的病斑数目调查结果与SMEASS模型模拟结果进行测验卡平方，结果表明卡平方值为0.2309，对应的概率值为0.9725，说明SMEASS模型模拟的结果与田间实际调查结果一致。SMEASS模型结构基本合理，预测结果较理想，基本反映出陕西省苹果黑星病的春季流行规律，为苹果黑星病综合防治提供理论基础。更多还原

【Abstract】 Apple scab (Venturia inaequalis) is a serious disease of apples in temperate regions throughout the world, because the causal fungus can infect the leaves and fruits. Infected leaves may drop early resulting in weaken trees, Infected fruits may be blemished and deformed. Though apple scab is the internal quarantine disease, the disease was expanding to large areas and threatening to apple sustainable production in China.The epidemic process of apple scab in spring was divided into the six following parts: vegetative growth of apple leaves，maturity of ascospores, ascospores discharge and landing on apple leaves; germination of ascospores; infection of ascospores and expanding of lesions. The relation between environmental factors and the primary components of the epidemic process of apple scab in spring was described and sub-models were developed.Dates of Accumulative temperature (degree day) from 10th April to 10th July in 1997-2003 were used for developing degree-day accumulative model that provided other sub-models with data of degree-day accumulation. Areas and ages of leaves and probit of mature ascospores were calculated by Sub-model for vegetative growth of apple leaves and ascospores maturity. Numbers of ascospores landed on leaves were predicted by sub-model for discharge and landing of ascospores which were presumedly taken them as a ‘Black-box’. The probit of ascospores producing appresora was predicted by sub-model of ascospores germination with accumulative temperature (degree hour)、average temperature and duration of wetness. The efficiency of ascospores infection to leaves was calculated by sub-model for average ages of leaves. The daily increased area and the number of lesions were predicted by lesion expanding sub-model based on driving variant of accumulative temperature. According to the frame of collectivity design, SMEASS model was composed of sub-models that were coupled with visual structure programming language-Delphi 7.0 in operating system-windows XP. In order to confirm the best <WP=8>prevent and control period, the model was used to forecast incidence of apple scab throughout one incubation period with the aid of over 0.25 mm rainfall after 10th April and start point of accumulative temperature on 10th April. Incubation period and number of primary inoculum were a constant put into the model. Through the sensitivity determination of the model, it found that date of rainfall had the most sensitivity to influence on apple scab severity, but it had the less influence on numbers of apple scab lesions on the individual apple branch. According to the result of simulated test by changing rainfall and numbers of primary inoculum, it found that the incidence of apple scab which primary inoculum caused was relatively high in duration of the first rainfall from 30th April to 20th May. Compared the result from investigation of numbers of lesions on the single branch with the result of SMEASS model by Chi-square test, it indicated that the value of X2 was 0.2309, the corresponding probability value was 0.9725. The value of X2 showed that simulative result was consistent with one of field investigation.The structure of model that reflected the epidemic of apple scab in spring in Shanxi Province was basically reasonable and result of forecasting was desirable, and supplied a solid foundation of theory for integrated apple scab management.更多还原