【作者】 于舒怡；

【导师】 傅俊范；

【作者基本信息】 沈阳农业大学 ， 植物病理学， 2011， 博士

【摘要】 玉米是我国四大作物之一,具有重要的经济效益和社会效益。玉米病害一直是玉米生产的主要限制因素,其中玉米大斑病(Exserohilum turcicum (Pass.) Leonard et Suggs)、玉米灰斑病(Cercospora zeae-maydis Tehon & Daniels)和玉米纹枯病(Rhizoctonia solani Kuhn)是辽宁玉米生产的主要叶部病害,发生和危害呈逐年加重的趋势,给玉米生产造成重大损失。近年来,新型高产栽培模式和保护性耕作技术的推广,加大了玉米群体增产潜力的同时也对玉米病害流行产生了较大影响。为明晰不同生态区玉米大斑病、玉米灰斑病和玉米纹枯病发生动态和灾变规律,本研究对上述玉米病害的发生和流行动态进行了多年调查和监测,结合田间小区试验,明确了流行规律,并构建了田间自然发病条件下玉米主要叶部病害流行时间动态及预测模型。探索了新型栽培模式对玉米大斑病和玉米灰斑病流行动态的影响。明确了以玉米叶片衰老程度为评价玉米早衰的形态指标,并在此基础上明晰了玉米主要叶部病害对玉米早衰影响和玉米早衰对玉米产量性状的影响程度。主要研究结果如下。1.采用定量流行学研究方法分析了玉米大斑病和玉米灰斑病流行过程的重要组分。通过室内试验和田间小区调查,明确了玉米大斑病和玉米灰斑病菌侵染过程中分生孢子萌发、侵染概率、病斑扩展、病斑产孢和孢子飞散5个组分以及侵染循环中病原物的越冬场所、越冬途径和病害传播3个组分的定量关系,明晰了环境因素对玉米大斑病和玉米灰斑病流行过程中主要组分的影响,为研究上述玉米病害田间流行动态奠定了前期基础。2.系统监测了辽宁省不同生态区玉米叶部病害的多年发生流行动态情况。经田间调查发现,目前玉米大斑病、玉米灰斑病和玉米纹枯病已成为限制辽宁玉米生产的主要病害。三种玉米病害在辽宁省各生态区均有发生,但在不同地区和不同年份间其发生和流行程度却存在显著差异,其中玉米大斑病在沈阳、锦州和铁岭等辽宁冷凉区发生严重,玉米灰斑病在沈阳、大连和丹东辽宁湿润区发生严重,玉米纹枯病由丹东、大连等辽东、辽南湿润区常年严重发生变为目前在辽宁各地区均严重流行的趋势。3.首次构建了田间自然发病条件下玉米叶部病害流行的单年时间动态及预测模型。通过田间小区试验,应用SPSS 11.5统计软件进行对比分析,确认Logistic模型为最佳模型,分别构建了三个玉米叶部病害的6个流行时间动态及预测模型：(1)玉米大斑病田间流行时间动态模型Y=1/(4.2735×10-3+400.0084exp(-0.1334t))；(2)多气象因子玉米大斑病预测模型Y=1/(4.4115×10-4+(0.0614exp(0.1253t-0.2159x1-0.0052x2-0.0079x3)))；(3)玉米灰斑病田间流行时间动态模型Y=1/(7.8137×1015+0.0018exp(-0.3435t))；(4)多气象因子玉米灰斑病预测模型Y=1/(0.0018+(5.1956×1011exp(0.2498t+0.0687x1+0.0122x2+0.0090x3)))；(5)玉米纹枯病田间流行时间动态模型Y=1/(0.0125+29.4358exp(-0.0664t))；(6)多气象因子玉米纹枯病预测模型Y=1/(0.0100+(0.0614exp(0.1253t-0.2159 x1-0.0052x2-0.0079x3)))。4.首次构建了描述多年玉米纹枯病流行时间动态的周期性脉冲Logistic模型。与Logistic模型相比,脉冲Logistic模型可更直观、明确地反映年度间玉米纹枯病周期性流行动态,且符合该病发生的生物学意义。推导了不同年度间同一品种上玉米纹枯病最大病情存在较大差异,沈阳地区玉米纹枯病指数增长期为从玉米出苗至7月上旬,逻辑斯蒂增长期为从7月上旬到8月末或9月初,衰退期为从8月末或9月初到玉米生育后期。5.系统研究了不同新型栽培模式下玉米大斑病和玉米灰斑病流行时间动态情况。初步明确了秸秆覆盖免耕、平播和宽窄行3种栽培模式通过改变植株空间分布,同时也使玉米农田生态系统发生改变,进而对玉米大斑病和玉米灰斑病流行产生了明显影响。对比分析表明Logistic模型能够反映玉米大斑病和玉米灰斑病流行时间动态,并推导了各个流行时期。不同栽培模式下玉米大斑病的指数增长期不同,先后顺序是免耕、平播、常规、宽窄行,不同栽培模式下玉米灰斑病的指数增长期依次为：常规、平播、免耕、宽窄行,该时期也是最佳药剂防治时间。6.系统研究了不同栽培密度和播期下玉米大斑病流行动态情况。各栽培密度下玉米大斑病病情严重程度为：45000株/hm2>60000株/hm2>90000株/hm2>75000株/hm2,因此合理密植,有利于控制玉米大斑病的发生和流行。随着播期的推迟,玉米大斑病的流行程度明显增加,因此适时早播对控病和增产具有明显作用。经对比分析确认Logistic模型为不同栽培密度和播期下玉米大斑病的最佳模型,并推导了各个流行时期,为该病害的综合防治提供理论依据。7.通过对比分析,选择了以玉米整株叶片衰老程度作为玉米早衰评价体系的形态指标,并制定了玉米早衰的分级标准。人工接种试验发现玉米病害可加剧玉米早衰程度。不同玉米病害对玉米早衰的影响程度由大到小依次为：玉米纹枯病、玉米大斑病、玉米灰斑病、玉米弯孢菌叶斑病。随着接种时间推迟,玉米病害对玉米早衰的影响逐渐降低。玉米早衰对玉米产量性状中的百粒重显著降低,而对穗粗和穗行数没有显著影响。更多还原

【Abstract】 Maize is one of four major crops in China, and has remarkable economic and social benefits. Maize diseases have been main limited factor to production, of which northern leaf blight, gray leaf spot, and corn sheath blight are the major leaf diseases in corn production in Liaoning Province, because of the occurrence and harm of the diseases with a rising trend year by year, they cause great yield loss to maize production. With the development of new cultivation patterns and conservation tillage technology, the yield potential of maize population has been increased, and also the epidemics of maize diseases have been affected. In order to clear the occurrence dynamics northern leaf blight, gray leaf spot, and corn sheath blight in different ecological region, in this paper the occurrence and epidemic dynamics of the above diseases were investigated and monitored, combining with the field plot experiment, the epidemic regularity and constructed the dynamic and forecasting model of epidemic time of maize leaf diseases were defined. The effect of new cultivation patterns on epidemic dynamics of northern leaf blight and gray leaf spot and used the degree of ageing of leaves as morphological index for premature senescence. On this basis, the influence degree of maize leaf senescence, premature senility of maize and yield traits was cleared. The main results are as follows:1 The important component of epidemic process of northern leaf blight and gray leaf spot was analyzed by applying quantitative epidemiology. According to the results of laboratory test and field plot experiment, the quantitative relation between the five components (conidia germination, infection probability, spot expansion, sporulation and spores flying) of infection process of northern leaf blight and gray leaf spot and the three components (overwintering place, overwintering pathway and spread of diseases) of infection cycle were cleared and the effect of environmental factors on the main component of epidemic process of northern leaf blight and gray leaf spot, which laid previous foundation for studying on epidemic dynamics of northern leaf blight and gray leaf spot.2. The system monitoring of occurrence dynamics of the leaf diseases in different ecological region was carried out. From investigating, northern leaf blight, gray leaf spot, and corn sheath blight had become the main diseases which limited the production of corn. The three kind of maize diseases occurred in different region in Liaoning Province, but epidemic degree there were significant differences of occurrence and epidemic degree in different year and different area. For instance, northern leaf blight occurred seriously in cool area, such as Shenyang, Jinzhou and Tieling, gray leaf spot in Shenyang, Dandong and Dalian-humid area occurred seriously, and the trend of the occurrence of corn sheath blight in eastern and southern Liaoning province has changed into each region in Liaoning.3. The temporal dynamic and predictive models of maize leaf diseases under naturally infected condition were first constructed. According to field experiment, making analysis and comparison via SPSS11.5, logistic model was confirmed as the best one and respectively constructed six epidemic time and predictive models of three kinds of maize leaf diseases.(1) Temporal dynamic model of northern leaf blight:Y=1/(4.2735×10-3+400.0084exp(-0.1334t));(2) Multiple meteorological factors forecasting model of northern leaf blight:Y=1/ (4.4115×10-4+(0.0614exp(0.1253t-0.2159x1-0.0052x2-0.0079x3)));(3) Temporal dynamic model of gray leaf spot:Y=1/(7.8137×1015+0.0018exp(-0.3435t));(4) Multiple meteorological factors forecasting model of gray leaf spot:Y=1/(0.0018+5.1956×1011 exp(0.2498t+0.0687x1+0.0122x2+0.0090x3)));(5) Temporal dynamic model of corn sheath blight:Y=1/(0.0125+29.4358exp(-0.0664t));(6) Multiple meteorological factors forecasting model of corn sheath blight:Y=1/(0.0100+(0.0614exp(0.1253t-0.2159x1-0.0052x2-0.0079x3))).4. Impulsive logistic model with periodicity was first established. The model described epidemic dynamics of corn sheath blight among years. Impulsive logistic model with periodicity could more intuitively and definitely reflect the simulation on epidemics of corn sheath blight than logistic model among years, and also accorded to its biological significance. According to the impulsive logistic model, there were great differences in the max disease index among years, but there was little difference in the apparent infection rates. Logistic model deduced that exponential phase of corn sheath blight was from seeding stage to beginning July in Shenyang, the logistic phase was from beginning July to late August or early September, the decline phase was late August or early September to the end of corn grow stage.5. The epidemic temporal dynamic of northern leaf blight and gray leaf spot in new cultivation patterns were systematic studied in this paper. No-till with straw cover (NTSC), flat planting (FP), and wide-narrow row (WNR) changed plant spatial distribution, and also changed corn farmland ecosystem, and then significantly affect the epidemic dynamic of northern leaf blight and gray leaf spot. Through comparing and analyzing, Logistic model can well reflect the temporal dynamic of maize northern leaf blight and gray leaf spot in field by naturai infection. The exponential phases were different with different cultivation patterns. The sequence was NTSC, FP, CTM and WNR. The exponential phases were in order of CT, FP, NTSC, and WNR.The phase was also the best time to chemical control.6. Epidemic dynamic of northern leaf blight among different cultivation densities and sowing dates were definited. The disease severity among different cultivation densities were in sequence of 45000 plants/hm2>60000 plants/hm2>90000 plants/hm2>75000 plants/hm2, rational close planting was beneficial to control epidemic of northern leaf blight. Sowing date significantly affect epidemic of northern leaf blight. Early sowing in good time was significantly beneficial to the disease control and yield increase. Logistic model can well reflect the temporal dynamic of maize northern leaf blight among different cultivation densities and sowing dates by comparison analysis, deduced the different epidemic phases, and provided theoretical basis for the integrated control of northern leaf blight.7. Degree of whole maize leaf senescence was used as morphological index of maize senescence evaluation system by comparison analysis, and established classification standard of maize leaf senescence. Maize diseases obviously intensified maize senescence using artificial inoculation method. The influence degrees on maize senescence were in sequence of corn sheath blight, northern leaf blight, gray leaf spot, Curvalaria leaf spot. With the inoculation time delayed, the degree on maize senescence was gradually decreased.100-seed weight was decreased significantly after maize senescence, but ear diameter and kernel rows had no significant effects.更多还原