【作者】 何敦春；

【导师】 谢联辉； 程兆榜； 王林萍；

【作者基本信息】 福建农林大学 ， 植保经济学， 2016， 博士

【摘要】 水稻对世界粮食安全至关重要,水稻病毒病是制约稻谷产量主要因素之一。历史上水稻条纹病毒(Rice stripe virus,RSV)所致的水稻条纹叶枯病多次持续暴发流行并造成严重损失,2000年代在中国、日本、韩国等再次流行,特别是在中国江苏省,当地生产者、政府、科技者都高度重视并全力防控,但该病仍持续流行10多年。这种情况对分析和揭示RSV病害流行规律十分有利,也很必要。为此,我们在RSV病害流行初期即设立系统田(病害不防控)作为大田(病害防控)的对照来调查系统田和大田的灰飞虱、病害发生动态、人为和气候因素,据此用多年多点区域性(2002-2012年,江苏省8个县)的数据来定量分析病害流行规律和防控效果,以填补RSV等水稻病毒研究的空白,旨在为高效经济和生态型控制持续流行的虫传植物病毒病奠定理论基础和提供方法,为植物病害防控提供具普遍性意义的思路和模式,在研究和生产上产生引领性的影响。RSV病害流行及防控的研究是一项复杂的系统工程,其中供定量分析用的可能影响指标(因子)筛选是首要工作。我们在研究中借助植保系统工程、等级全息建模的理论,结合文献分析、专家访谈法,确立水稻条纹叶枯病流行的可能影响指标(因子)体系,即病害的严重度、发病率,灰飞虱的虫量、带毒率、带毒虫量,气候因素的温度、降雨,人为因素的耕作生产安排、品种布局、防控方式等。这些因子间的互作左右病害流行,它们的归类对病害监控研究能提供更为清晰的思路和视角。为此我们运用系统理论的二阶观察法(自然和人为),运用斯皮尔曼(spearman)相关分析等统计学方法对试验、调查所取得的大数据进行系统、深入的整理、分类、归纳和统计分析,探讨自然因子与人为因子间的关系以及它们如何对病害流行起作用?起什么作用?研究主要结果表明:1)灰飞虱带毒率是水稻条纹叶枯病流行的关键指示因子,回归方程ln(y·100)=4.2-0.1861/x(式中y是预期的病害严重度,x是越冬代灰飞虱的带毒率)可用作病害预测预报。2)上年病害流行是新一轮病毒侵染源,主要毒源来自本地,农药使用量与灰飞虱控制效果不相关。3)在单年双熟制中小麦、水稻生产的时间安排与病害流行相关,“麦套稻”为下年灰飞虱带毒率保持创造条件,在茬口上保障下年毒源;“稻套麦”影响水稻感病期与灰飞虱高效传毒期的吻合度,促使毒源成为初侵染源。4)水稻品种区域整体抗性水平与病害严重度、下年越冬代灰飞虱带毒率逆相关,但流行期内抗性水平一直不高,难以抑制病害流行。5)RSV病害流行监测与防控:通过监测带毒率并根据RSV病害预测报回归方程,确定病害流行风险等级(如1,2,3,4),总体上根据谢联辉院士首倡的“抗(水稻品种抗性)、避(避开灰飞虱传毒高峰期)、除(根除越冬毒源)、治(杀虫、RSV)”四字原则,制定不同风险管理策略:当风险级别为1时可种植任何品种包括高感品种;当级别为2时尽量选用抗性水平较高的品种或合理安排区域布局;当级别为3时可尽量选用抗性水平较高的品种并采取避字;当级别为4时以除毒源为主避为辅。水稻条纹叶枯病流行风险(自然和人为)和管理(硬科学和软科学)的二阶观察都是必要的。由于“抗(寄主植物在单植株和种群两个层次防御病原生物侵染的抵抗力)、避(避开病原生物繁殖高峰期和关键期)、除(根除侵染源)、治(杀病原生物和/或介体)”四字原则对于植物病害防控具有普遍性和广适性意义,所以我们从植物病害生态高度在技术层面(硬科学)探讨植物病害防控的问题、挑战和未来,进一步拓展和完善以四字原则为核心的植物病害生态防控理论和技术体系;在社会经济层面(软科学)研究植物病害防控管理,提出在社会、经济、生态层面通过综合的经济评估、信息流管理和供需关系调控,从根本上引导和驱动植物病害防控可持续性发展,完善植病经济学理论和实践体系。更多还原

【Abstract】 Rice stripe disease caused by Rice stripe virus(RSV)is one of the most important diseases in East Asia,causing great grain loss thereby threatening rice production and global food security.The disease has caused several major epidemics in many countries including Japan,China,South Korea,North Korea and the Ukraine.The resurgence disease induced greater damage compared to its pre-2000 outbreaks,especially in Jiangsu Province,China.To control the disease epidemics from 2001,an abundance of labor,material and financial resources were input in Jiangsu Province.However,the disease epidemics still last more than 10 years.Unlike studies of RSV epidemics in the 1960-1970s,in the current experiments co-incident with the current upsurge in RSV,we established a set of sprayed and unsprayed fields in 8 counties in Jiangsu Province where disease,RSV,its vector insect(Laodelphax striatellus,small brown planthopper,SBPH),climatic conditions and human factors were monitored between 2002 and 2012.Disease data gathered from both sprayed and unsprayed fields over a 10-year period of epidemics were evaluated by statistic methods such as Spearman correlation to determine key biotic and abiotic factors driving epidemics of the disease in parallel with the data of vector,climatic and human factors with an objective to develop a lower cost,more effective and ecologically friendly approach for managing RSV and other plant disease.The result is expected to lead the development of theory and practice of plant disease managment.Disease severity of RSV was positively correlated with viruliferous rate of the vector but not with the population density of the insect,suggesting that,the proportion of vectors infected by the virus rather than the absolute number,plays an important role in RSV epidemics and could be used for disease forecasting.This result also suggests that viruliferous rate could be a good indicator of RSV disease epidemics and management such that the equation In(y·100)=4.2-0.1861/x,[where y is the expected disease severity and x is the viruliferous rate of overwintering SBPH]could be used for disease forecasting.The finding of a positive correlation of disease severity and viruliferous rate among years suggests that local infection is likely the main source of primary inoculum of RSV.Of the two main climatic factors,temperature plays a more important role than rainfall in RSV epidemics.In unsprayed and sprayed fields,rice stripe disease severity in any given year was correlated with the time gap between wheat sowing and rice harvest in preceding year and between rice sowing and wheat harvest in current year,suggesting that,the time arrangement of wheat and rice production is related to the disease epidemic.The time gap between wheat sowing and rice harvest was correlated with viruliferous rate but not with the total and viruliferous population density of the overwintering and first generation of SBPH in following year.These results suggest that the rotation system of rice and wheat cteated the environment to maintain SBPH viruliferous rate in wheat field and then turned to the primary inoculum of RSV from wheat to rice.The finding of a negative correlation between the total rice resistant level in every county and disease severity of current year,and overwintering SBPH viruliferous rate of following year suggest that lower rice resistance plays a role in higher SBPH viruliferous rate of following year which resulted in the following RSV epidemics.Compared with the rice resistance,the cropping system adjustment of rice and wheat may reduce the RSV epidemic degree gradually at the late-stage.Future plant disease management including rice stripe disease should aim to strengthen food security for a stable society while simultaneously safeguarding the health of associated ecosystems and reducing dependency on natural resources.To achieve these multiple functionalities,sustainable plant disease management should place emphases on rational adaptation of resistance,avoidance,elimination and remediation strategies individually and collectively,guided by traits of specific host-pathogen associations using evolutionary ecology principles to create environmental(biotic and abiotic)conditions favorable for host growth and development while adverse to pathogen reproduction and evolution.Plant disease management plays an important role in food security,economic improvement and social stability.However,the technologies available are often limited as a result of conflicting interests between producers and society,a lack of understanding of economic thresholds,and the complex interactions among ecology,productivity and profitability.A comprehensive evaluation of economic,societal and ecological effects with technologies and production demands as main components should be used to guide approaches for sustainable disease management that aim to mitigate crop loss while maintaining functional farm ecologies and biodiversity.Consequently,there should be an increased emphasis on technology development,public education and information exchange among governments,researchers,producers and consumers to broaden the options for disease management in the future.更多还原