【作者】 郭世保；

【导师】 黄丽丽；

【作者基本信息】 西北农林科技大学 ， 植物病理学， 2012， 博士

【摘要】 小麦条锈病是我国小麦生产上危害最重、发生范围最广的病害。目前，我国小麦生产上使用的品种虽较多，但抗源单一的局面并未发生根本改变，因此，探索合理、经济、有效使用抗病品种和抗性资源的方法是小麦条锈病持续控制的关键。由于病原菌毒性变异导致小麦品种抗锈性不断丧失，成为目前抗病品种应用中最突出的问题，育种和品种更替速度难以跟上小种变异的速度。而频繁施用杀菌剂则使条锈病的防治成本不断增加，而且对环境造成严重的破坏作用。因此，如何解决品种抗病性丧失快、条锈菌生理小种变异快的问题是当前亟待解决的关键问题。品种混播技术简单，减少了对农药的使用程度，具有增产、稳产作用，近年来，利用品种混播技术控制病害的研究得到了较好的发展。因此，本研究选择抗锈性不同的品种，在田间(5个品种在安康，6个品种在宝鸡)分别设计品种单播及其组合的混播处理，比较条锈病的发生情况和产量差异；并采用TP-M13-SSR荧光标记技术分析自然发病条件下条锈菌群体的遗传多样性，研究多品种混播对条锈病的控制效果及其机理。本研究旨在寻找一条经济、持久的方法控制条锈病的危害，实现高产、稳产的目的。取得如下主要研究结果：1.对小麦条锈病的发生特点和品种混播中的条锈病流行过程进行了研究，结果表明，在品种混播群体中的病叶率、病情指数低于它在混播中各组分单播时的平均数。品种混播可明显降低条锈病的病叶率和病情指数的日增长率（r）；品种混播小区苗期发病中心较少，且发病中心的扩展速度明显受到抑制，在春季流行阶段病情指数显著降低；在混播的品种搭配上以绵阳31、绵阳25、绵阳98-351-15和绵农6号（R+R+MR+S）组合效果较好。2.研究了品种混播对小麦条锈病的控制效果和对产量的影响，结果表明，品种混播的病情指数和病情曲线下面积（AUDPC）都明显低于感病品种单播。2007年各品种混播处理的相对防效在14.29%~86.38%之间。其中，所有抗、感病品种混播处理的防效平均为72.60%，相对增产率平均为13.26%；2008年抗、感病品种混播处理的相对防效为平均为31.22%，相对增产率平均为8.21%。其中，以小偃22（S）、陕138（R）、西农889（R）3品种等比例混播和小偃22（S）、武农148（S）、秦农142（R）、西农889（R）4品种等比例混播效果较好。3.采用TP-M13-SSR技术分析自然发病条件下条锈菌群体的遗传多样性，结果显示，混播小区条锈菌群体遗传多样性比较丰富，处理之间存在明显的差异，感病品种单播和抗、感混播种群遗传多样性相对较高。品种混播的多态性位点数百分率(%)、Nei基因多样性指数（H）和Shannon’s信息指数(I)分别为91.30%，0.2860和0.4260，均高于单播小区，这可能就是品种混播能够持久控制病害的分子机理。4.对混播品种的抗性机制进行了研究，结果表明密度效应在三种效应中起的作用最大。从病害的发生过程看，密度效应从开始就发挥了较大的作用，中期加大，后期呈下降趋势；阻挡效应在病害发生初期不明显，后期才表现出来，在整个病害流行期间所起的作用显著小于密度效应；诱导抗性效应从病原菌的第二代即发挥作用，但并不显著，直到中后期诱导效应才发挥较大的作用。品种混播对小麦条锈病有较好的控制效果，品种多样化有利于条锈菌群体结构的稳定，可作为生态防病措施。更多还原

【Abstract】 Wheat stripe rust (yellow rust) is one of the most seriously diseases of wheat nationwidein China. Presently, There is no essentially change of the single resistant source though a largeamount of cultivars are growing in China. It is the key point that develop the reasonable,economic and effective approach of the use of cultivars and resistant sources. However, therapid development of the virulent races often circumvents the resistance in cultivars after theirrelease, which make the use of resistant cultivars a outstanding problem. Wheat resistancebreeding and cultivars alternation significantly follow behind the variation of races. Moreover,The excessive use of fungicide make the cost continuously increasing. And the environment isbadly damaged. It is very important subject that how to solve the problem of rapid breakdownof resistance and race variation.Recently, the use of clutivars mextures has made fruitful progress in wheat stripe rustmanagement, because cultivar mixtures require low technology and reduce the dependence onpesticides to increase or stabilize grain yields. Cultivars, with different resistance to pucciniastriiformis f. sp. tritici, are designed （5cultivar in Ankang area and6cultivars in Baoji area）for mono-cultivar treatments and multi-cultivars treatments while disease incidence, focinumbers and yield per plot were investigated. TP-M13-SSR technique was used to detectpopulation genetic diversity of P. striiformis f. sp. tritici in natural infested wheat inmono-cultivar and multi-cultivars plots. Thus, our objective of this research is to find aneconomic, sustainable measure for stripe rust control and achieve high stable yields. The mainresults are summarized as following:1) Occurrence of wheat stripe rust and developing process of stripe rust in differentcultivars mixture are studied, the results show that diseased leaf rate and disease index ofcultivar mictures are lower than the mean value of the pure stannd. Daily multiplication rateof wheat stripe rust is significantly decreased in cultivar mixtures; Disease foci of cultivarmixtures is less than those of the susceptible pure stand and expanding rate is also inhibited incultivar mixtures. Disease index is decreased in cultivar mixtures in spring. The cultivarmixtures, comprising Mianyang31(R), Mianyang35(R), Mianyang98-351-15(S) andMiannong6(MR),have beter mixture effect on disease control. 2) Control effect and yields of cultivar mixtures are studied, the results show that diseaseincidence and the area under the disease progress curve (AUDPC) of the cultivar mixtures aresignificantly lower than those of the susceptible pure stands. The relative efficacy of cultivarmixtures range from14.29%to86.38%during2007, among them relative efficacy of theresistant and susceptible mixtures(R and S mixtures) is72.60%, and the relative yield increaseis13.26%. The relative efficacy of the R and S mixtures is31.22%during2008, and therelative yield increase is8.21%. Two treatments of cultivar mixtures (mixed with equal ratioof each component) had the best efficacy, one is that of comprising culitvars of Xiaoyan22(S), Shan138(R) and Xinong889(R), another is that of comprising culitvars of Xiaoyan22(S), Wunong148(S), Qinnong142(R) and Xinong889(R).3) Population genetic diversity is investigated for the P. striiformis f. sp. tritici populationfrom different plots with TP-M13-SSR technique. The important conclusion is that P.striiformis f. sp. tritici populations are considerably diversity in plots of cultivar mixtures,while there are different between plots. Genetic diversity for the pathogen population from thesusceptable pure stand and the cultivar mixtures are much higher than that from the resistanpure stand. The polymorphic from cultivar mixtures, such as enetic diversity The percentage ofpolymorphic loci, the Nei’s gene diversity (H) and Shannon’s information index (I), are91.30%,0.2860and0.4260respectively. Those of the above are possibly genetic mechanism thatcultivar mixtures sustainably control stripe rust.4) The resistance mechanisms of cultivar mixtures is studied, results show that thedensity effect, as one of three effects, played the most important role. The density effectplayed a larger role from the beginning in disease process, Strengthen in the mid-up, andshowed the downtrend in the latter stage. Blocking effect is not obvious in the early stage ofdisease process, and it demonstrat in the late stage. Blocking effect is significantly less thandensity effect during the whole disease process. Induced resistance effects took the effectfrom the second generation of pathogens, but it didn’t play a greater role until medium-latestage of disease process.The diversifying cultivars in mixed-planting had good control effect to the wheat striperust, and the diversifying cultivars could maintain population stability of P. striiformis f. sp.Tritici, Which make cultivar mixtures is to be used as one of an ecological measures toprevent and control disease.更多还原