【作者】 沈丽；

【导师】 赵志模； 王进军； 罗林明；

【作者基本信息】 西南大学 ， 植物保护， 2008， 博士

【摘要】 四川是我国小麦条锈病菌(Puccinia striiformis Westend f.sp.tritci Eriks.)的主要越夏区之一,也是我国小麦条锈菌最重要的冬繁区。小麦条锈菌白越夏区随高空气流传播到盆地冬繁区,经冬、春季大量繁殖并向外传播,成为我国其它麦区的重要春季菌源,由此可见四川在我国小麦条锈病大区循环中所处的重要地位。小麦条锈菌在四川既能越冬,也能越夏.特别是小麦在川西北不同海拔高度的垂直种植,导致病菌能顺利完成越夏、越冬和周年循环,有利于新小种的产生、保存和发展,使川西北成为我国小麦条锈菌易变区和新小种策源地之一。纵观小麦条锈菌生理小种监测历史,四川条锈菌生理小种的变异不但对当地条锈病的发生影响重大,而且对全国条锈病的发生也产生了深远的影响。控制四川小麦条锈病的流行危害,不仅能确保当地小麦的安全生产,还能降低外传菌源,减轻我国主要麦区的春季防治压力。研究四川小麦条锈病的流行规律可为病害的分区治理和大区协同治理提供依据;研究品种抗锈性和条锈菌生理小种动态变化可为预测病害流行和菌源地治理提供依据;研究病害的生态控制可为小麦条锈病的可持续控制提供技术支撑。尽管上个世纪八、九十年代曾对四川省小麦条锈病流行规律进行过研究,但受全球气候变暖、耕作制度和品种布局变化等的影响,病害流行规律发生了较大变化。近10年来四川小麦条锈病流行出现了秋苗病害始见期提早、流行期加长、危害损失趋重等新特点,有必要重新对其进行系统研究。本文在实地调查的基础上,利用GIS技术对全省132个小麦主产县(市、区)1987～2006年小麦条锈病发生情况进行了系统分析。结果表明,四川省小麦条锈病流行区域可划分为川西北越夏区、川西南越夏及冬繁区、盆地冬繁区和川东南春季流行区。GIS软件分析发现,病菌孢子在四川盆地内的传播路径为:沿岷江、涪江、沱江和嘉陵江等4条河流自北向南、自西向东传播。通过相关资料研究明确了影响四川小麦条锈病春季流行程度的主要因素有三个:品种抗锈性、冬季菌源量(发生面积)和冬、春季的气候条件。小麦条锈病已成为影响四川小麦安全生产的最重要病害。近年来小麦条锈病在四川连年大发生,究其原因,最主要和最直接的是大面积生产上应用的小麦品种抗锈性丧失。本研究根据对28个不同毒性谱的小麦条锈菌菌系的反应,并结合品种系谱分析,研究了58份四川省重要小麦品种、育种材料和抗源品种所具有的抗条锈基因。结果表明,Yr1、Yr2、Yr3、Yr5、Yr7、Yr9、Yr10、Yr24、YrVir1-2、YrAlba和YrSu等11个基因以单基因或基因组合的形式分布在42个供试品种中,其中携带Yr2基因的品种最多,有11个;携带Yr10基因的品种次之,有9个;14个品种抗所有供试小麦条锈菌菌系,可能具有Yr5或者Yr24基因;10个品种具有未知抗病基因或基因组合。相关资料和数据分析显示,四川小麦品种抗锈性现状为:新审定品种区试抗性水平有较大提高,但新品种一经大面积推广后抗锈性衰退现象十分严重,大面积种植的小麦品种抗锈性水平仍不容乐观。进行小麦条锈病菌越夏区和流行区的生理小种监测,掌握病菌群体组成结构和动态变化,对于预测病害的发生和流行,以及制定防治策略等都具有十分重要的意义,还可为抗病品种选育、品种布局、轮换等提供科学依据,为研究四川省小麦品种与条锈病菌互作在群体水平上的演替变化规律提供系统资料。小麦条锈菌生理小种监测结果显示,1996-2000年间,条中31号出现频率占第一位,但呈逐年下降趋势。自2001年起,条中32号出现频率超过了条中31,成为优势小种。具有较强致病力的Hybrid46和水源11两大致病类群内部虽发生着急剧分化,但两大致病类群所占比例自1997年以来一直稳定在80%以上,尤其是近两年竟高达99%以上,成为绝对的优势种群。近年来,对Hybrid46(含抗性基因Yr3b、4b)具毒性的致病类型出现频率逐年下降,而对水源11类群(含抗性基因YrSu)出现频率逐渐上升,其中条中33(Su-14)类型出现频率近年来上升明显,尤其是在2007年更高达18%,仅次于条中32,成为第2位流行小种。表现在毒力频率上,四川小麦条锈病菌群体除对Yr3b+4b毒力频率逐年上升外,尤其是对YrSu的毒力频率上升明显,且高于对Yr3b+4b的毒力频率,2007年达到100%。本研究还在三个不同生态区域对小麦与蚕豆间作对病害的控制作用进行了试验。结果表明,小麦与蚕豆间作对小麦条锈病和蚕豆叶斑病具有较好的控制作用,对小麦条锈病的相对控制效果可达31.3%～82.3%,对蚕豆叶斑病的相对控制效果为9.9%～26.4%。另外,作者通过对6个不同抗性水平的小麦品种进行不同组合的随机等量混播,系统调查了各品种净作田和多品种混播田小麦条锈病的病情发展动态。试验表明,4个或6个品种混播能有效推迟条锈病发病期,延缓发病速率,降低发病程度,并且具有较好的稳产作用。将高感品种铭贤169、川农10号、慢锈品种川麦107、生产上表现中抗的品种绵阳31、川麦37、川育18和目前大面积仍然表现高抗的川麦36单播,将川麦107、川育18、绵阳31和川麦36四组份等比混合播种(混Ⅰ),将川麦107、川育18、绵阳31、川麦37、川农10号和川麦36六组分等比混合播种(混Ⅱ),将一属Su-12致病类型、对川麦36具毒性的田间突变株接种上述品种或混播组合并连续继代繁殖9代后,病菌在各品种上的毒性均增强,其中川麦36和绵阳31上病菌分别演化为强毒性的条中32和条中33(即Su-14);抗病品种川麦36对其毒性突变具有定向选择作用,所检测的各代次夏孢子对其具稳定毒性,但此毒性在其他品种上继代繁殖9代后的部分菌株中会丧失,病菌在川麦36上连续继代繁殖6代后,毒性高于其他品种或混播组合上繁殖的菌株;在含有绵阳31、川麦36的四组份混播组合上,病菌继代繁殖9代后的毒性虽有所增强,但对鉴别寄主的毒性弱于条中32和33;而在含有上述两个品种的六组分混播组合上,病菌连续继代繁殖3代后的毒性就较弱于绵阳11和川麦36单播处理上继代繁殖相同代次的条锈病菌,继代繁殖9代后,病菌对川麦36毒性丧失,表明多组分混播不利于病菌毒性的增强。利用对四川小麦条锈病菌株具有AFLP多态性的引物,对各世代收集孢子基因组DNA限制性内切酶进行预扩和选扩,没有发现各品种和组合继代繁殖代次上条锈病菌具有AFLP多态性,由此可排除病菌毒性变异由机械混杂引起的可能性。更多还原

【Abstract】 Sichuan is considered as the inoculum sources of(Puccinia striiformis Westend f.sp.tritci Eriks.) in autumn and the main region where the inoculum can multiply continuosly in the whole winter.The inoculums spreading from oversummering areas with upper air can reproduce large number of uredia in winter-reproductive area in Sichuan basin through the whole seasons of winter and spring,which spread abroad to other winter wheat growing areas as the main sources of inoculums in the spring. Consequently,Sichuan has been considered as the hotspots for the disease epidemic circle and the disease management in China.The control of wheat stripe rust in Sichuan can protect the local wheat production and alleviate control pressures in other witer wheat growing areas.The inoculum of P.striiformis f.sp.can oversummer and also overwinter in Northwest Sichuan area,where susceptible wheat varieties were on mountains of different altitudes so the pathogen cycles between the wheat plants as well as volunteer seedlings at different altitudes with the help of wind.This area is also the refuge for the new races of the pathogen to develop.Therefore,wheat stripe rust usually occurred severely in the autumn,new physiological races of pathogen usually emerged firstly and the resistance of wheat varieties was liable to change in Northweat Sichuan. From the development history of physiological races of P.striiformis f.sp.tritici,we can see that the variance of pathogen in Sichuan affected the occurrence of wheat stripe rust greatly in local and other wheat growing areas in China.To study the epidemiology of the disease,the change of physiological races,the change of the resistance of wheat varieties and ecological control are of great importance to the forcast of the disease and sustainable control of the disease.Although great efforts had been paid to the epidemiological survey of the disease in Sichuan in the past 20 years,epidemiology of the disease had changed due to the global warming and changes in cultivation system and variety distribution.The time of disease emergence on the autumn seedlings of wheat had become earlier than ten years ago and longer epidemic period and higher severity of the disease had been observed in the whole growing seasons.The data collected from 132 counties were analyzed using GIS technology in order to reveal the epidemic characters of the disease and dispersal routes of the pathogen.The results indicated that Sichuan province could be divided into four epidemic zones of wheat stripe rust based on the ecological conditions,climate characters,disease occurrence and spreading as well as the systems of wheat production. i.e.,over-summer area in Northwestern Sichuan,over-summer and winter-reproductive area in Southwestern Sichuan,winter-reproductive area in Sichuan basin and spring epidemic area in South-east Sichuan.Pathogen inoculum of stripe rust could be spread by four dispersal ways along Min River,Fu River,Tuo River and Jialing River in the direction from north to south and from west to east in Sichuan province.The relative data analyzed showed that the resistance in wheat varieties,the incidence occurrence areas in winter,and climate factors in the winter and spring were the three major factors to affect the severity of the disease epidemics in the spring.Seedlings of 58 wheat cultivars and elite breeding lines were inoculated with 28 selected different isolates of P.striiformis f.sp.tritici to postulate the stripe rust resistance genes.The results showed that Yr1、Yr2、Yr3、Yr5、Yr7、Yr9、Yr10、Yr24、YrVir1-2、YrAlba and YrSu were detected in 42 wheat cultivars and beeding lines,either alone or in combination.Yr2,the most common gene,presented in 11 cultivars,while Yr10 in 9 cultivars.14 wheat cultivars were resistant to all the 28 isolates of Puccinia striiforms f.sp.tritici and may contain the Yr24 genes.10 wheat cultivars contained unkown genes or their combinations.Study on physiological races in Sichuan province showed that CY31 was the most dominant race during 1996～2000.Since 2001,occurrence frequency of CY32 exceeded CY31 and CY32 had become the most dominant race.Segregation in the Hybrid46 and Suweon 11 pathotype groups became more obviously.Occurrence frequency of the two pathotype groups with strong pathogenecity and wide virulence spectrum kept stable about 80%since 1997,especially in the past two years up to 99% in 2006 and 2007.Occurrence frequency of Hybrid46 pathotypes delined in the recent years whereas that of Suweon 11 ascended.Among Suweon 11 pathotype group, occurrence frequency of Su-14(CY33) rose obviously in the recent years,which had become the second dominant physiological race in 2007(18%).Virulence frequnency of pathogen colony to Yr3b+4b ascended year after year,especially to YrSu obviously. Virulence frequency to YrSu had up to 100%in 2007,being higer than that to Yr3b+4b.Intercropping and cultivar mixtures could increase species diversity which would keep ecological system stable and increase the system’s functions.To study ecological control of wheat strip rust by intercropping of wheat and faba bean,field studies were conducted at 3 locations representing different ecological regions.The results showed that wheat strip rust was controlled by 31.4%～82.3%and the leaf spot of faba bean was controlled by 9.9%～26.4%by wheat and fababean intercropping.Wheat stripe rust dynamic developments of all-planting and mixed-planting had been systematically investigated in this study by taking different mixed-planting combinations among 6 wheat varieties(Chuannong 10,Mianyang 31,Chuannai 107,Chuanmai 37,Chuanyu 16 and Chuanyu 18)with different resistance levels.The results of this experiment showed that planting of four or six variety mixtures with different resistant level can delay the occurrence of wheat stripe rust,slow the speed of disease and decline the damage of disease as well as stabilize yield of wheats.Highly susceptible wheat varieties Mingxian 169 and Chuannong 10,slow-rusting variety Chuanmai 107,moderately resistant varieties Chuanyu 18,Chuanmai 37, Mianyang 31,and highly resistant variety Chuanmai 36 were sown in pot individually or in mixture and inoculated with a field sporadic virulent mutant to Chuanmai 36, which was belonged to pathotype Su-12 for consecutive propagation of the uredia.After 9 consecutive generations,uredia from each variety or variety mixtures were found to be virulent to larger numbers of Chinese physiologic race differential varieties.While uredia collected from Chuanmai 36 were found to be stably virulent to Chuanmai 36, such virulence was lost in the uredia from some varieties after 9 generations.Uredia collected from Chuanmai 36 and Mianyang 31 after 9 consecutive generation was identified as CY32 and Su-14(CY33),respectively to the most dominant race in Sicuan province.The number of compatible differential varieties to the uredia after 6 and 9 consecutive generations on Chuanmai 36 were also found to be higer than other that on other varieties and variety mixtures.The virulence of uredia in terms of the number of compatible differential varieties from 4 variety mixture containing Mianyang 31, Chuanmai 36.Chuanyu 18 and Chuanmai 107.was weaker than that of Mianyang 31 and Chuanmai 36 after 9 consecutive generations,whereas the virulence of the uredia from the mixture with 2 additional varieties.Chuanmai 37 and Chuannong 10.had been than that from Chuanmai 36 and Mianyang 31 since 6th consecutive generation.The uredia from the latter mixture after 9 consecutive generation failed to infect Chuanmai 36,suggesting the deleterious effects of variety mixture on the virulence enhancement of the pathogen.The primers which have been proved to demonstrate the AFLP of genomic DNA of P.striiformis f.sp.tritici in Sichuan failed to detect such polymorphism among the uredia collected from different varieties after 3,6 and 9 consecutive generations of propagation.更多还原