【作者】 刘建霞；

【导师】 畅志坚；

【作者基本信息】 山西大学 ， 作物遗传育种， 2008， 硕士

【摘要】 小麦白粉病是我国乃至世界广大麦区常见的重要病害,自20世纪70年代后期以来,随着半矮秆品种的推广、栽培水平的提高和水肥条件的改善,我国的小麦白粉病由局部地区发生向全国扩展蔓延,特别是随着含抗病基因Pm8的1B/1R易位系衍生品种及其它抗源抗性的丧失,主栽品种对白粉病的抗性普遍较差,多个新的生理小种已成为优势小种并开始流行。据统计,在我国小麦白粉病的发生面积由1981年的290万公顷增加到1996年的1200万公顷,从而对小麦生产构成新的威胁。培育和推广抗病品种是防治小麦重要病害的主要手段,从小麦近缘植物种属导入新的抗病基因则是实现抗源多样化进而防止或延缓抗性丧失的有效途径。中间偃麦草和十倍体长穗偃麦草蕴藏着许多对小麦遗传改良极其有用的基因资源,是应用于小麦育种最为成功的两个多年生野生近缘植物。为导入其抗病基因,山西省农科院作物遗传研究所以感病的高产、优质小麦品种（系）为受体,八倍体小偃麦为供体,采用六·八杂交方式,育成一批丰产性好、品质优良、兼抗白粉病、条锈病等多种病害的小麦新品系,它们是优良的小麦抗病育种亲本材料。本研究采用常规遗传分析方法和分子标记技术,以分别衍生于中间偃麦草和十倍体长穗偃麦草的多抗性新品系CH5026和CH7034为材料,开展了小麦白粉病的抗性鉴定、抗性遗传分析及抗病基因的SSR标记定位,获得以下研究结果:1:CH5026是衍生于普通小麦—中间偃麦草（Th.intermedium）的八倍体小偃麦“TAI7045”的抗病新品系,它兼抗小麦的白粉病和条锈病,其系谱来源为“76216穗96/TAI7045//京411”。温室抗性评价的结果显示,无论是苗期还是成株期CH5026对白粉病菌系E09均表现为免疫,且具有与其抗性供体TAI7045及TAI7045的野生亲本中间偃麦草相似的白粉病抗性,而CH5026和TAI7045的小麦亲本均为中、高感,表明存在于CH5026的白粉病抗性来自中间偃麦草。为进一步明确其白粉病抗性的遗传规律,用高感品种（系）晋太170、CH5065分别与CH5026杂交、回交,将其F₁、F₂、BC₁、F₃,代群体及其双亲分别在太原温室用白粉病E09菌系的15号生理小种接种,并按单株调查其抗感分离之比。结果表明:F₁对白粉病的感染分别为0或0;级。F₂、BC₁代的群体中,其抗感分离分别符合3R:1S和1R:1S;而且在F₃代的株系中,全抗:抗感分离:全感为1:2:1。说明衍生于TAI7045的抗病品系CH5026对白粉病的抗性受1对显性核基因控制。使用分离群体分组分析法（BAS）和SSR标记技术,发现小麦微卫星标记Xwmc41和Xgwm539与抗病基因连锁,遗传距离为14.8cM和7.9cM,将小麦抗白粉病新基因MlCH5026定位于染色体2DL上。2:CH7034是衍生于普通小麦—长穗偃麦草（Th.ponticum）的八倍体小偃麦“小偃7430”的多抗性新种质材料,兼抗小麦的白粉病和条锈病,通过普通小麦与八倍体小偃麦“小偃7430”杂交、回交选育而成,系谱来源为“京411/小偃7430//中8601”。为明确其白粉病抗性的遗传机制及抗性基因的染色体位置,用小麦高感品系“SY95-71”与CH7034杂交,所获F₁、F₂及其双亲在温室用白粉病E09菌系的15号小种接种,对CH7034的白粉病抗性进行鉴定和遗传分析。结果表明,无论是苗期还是成株期,CH7034对白粉病菌均表现为免疫,且具有与其抗性供体小偃7430及野生亲本长穗偃麦草相似的白粉病抗性,F₁代抗病反应型为0或0;级,F₂代抗感分离比符合3R:1S,说明CH7034抗性受显性单基因控制。用307对小麦微卫星引物对一个148株的F₂群体进行分析,发现小麦微卫星标记Xgwm311与抗病基因连锁,遗传距离为12.4cM。用中国春缺-四体和双端体材料进一步验证与抗病相关的片段位于2A染色体的长臂上,进而将CH7034所含的抗白粉病基因定位于小麦的2AL上。更多还原

【Abstract】 Powdery mildew,caused by Blumeria graminis f.sp.tritici.is an important disease of wheat(Triticum aestivum)worldwide.Since the late 1970s.powdery mildew has gadually spread in China as a consequence of changing crop practices such as irrigation, increased nitrogen fertilization,and the use of semi-dwarf cultivars.Especially during 1980s-1990s,mainly due to the wide employment of 1B/1R translocations contained the single gene Pm8 and their derivatives in wheat breeding programs,the high frequency of virulence to Pm8 in Chinese B.graminis f.sp.tritici populations has remained stable at about 94%,resulting in the wheat area affected by powdery mildew increased to 12.0 million ha in 1996 from 2.9 million ha in 1981.Resistant wheat cultivars remain the most cost efficient and effective means for powdery mildew control,while the introgression of alien resistance gone from relatives of wheat is one of the efficient ways to deal with a ’short live" problem of monogenic resistance.Among the Thinopyrum species,the hexaploid Th.intermedium(2n = 6x = 42, JJ~SS) and decaploid Th.ponticum(2n = 10x = 70,JJJJ~sJ~s) are two of the most important perennial Triticeae species in wheat improvement.The wheat-Thinopyrum partial amphiploids and their derivatives have been widely used in wheat breeding programs throughout the world,as a valuable source of multiple disease and mite resistance for increasing genetic diversity available to wheat breeders.In 1992,the inter-genus hybridization between wheat and Thinopyrum programs at Institute of Crop Genetics of Shanxi Academy of Agricultural Sciences initiated a program of the introgression of Thinopyrum-derived alien resistance genes for powdery mildew and yellow rust,crossing susceptible wheat cultivars with resistant wheat-Thinopyrum partial amphiploids as donor parents.To date a lot of derived lines have been developed with multi-resistance genes incorporated from Th.intermedium and Th.ponticum.The objectives of this study are:1) To determine the inheritance of resistance to powdery mildew and identify the number of resistance genes in the germplasm lines CH5026 and CH7034:and 2) To identify chromosomal location of the resistance genes introgressed from Th.intermedium and Th. ponticum using SSR markers,which would be helpful in employing new resistance genes, especially for pyramidal complexes containing several resistance genes. 1:CH5026,a wheat breeding line developed by backcrossing a partial wheat-Th. intermedium amphiploid TAI7045 with susceptible wheat cultivar,exhibits the resistance to both powdery mildew(Pro) and yellow rust.Greenhouse evaluation of resistance reactions at seedling and adult stage showed that CH5026 had Pm-resistance similar to its donor TAI7045 and Th.intermedium,whereas the wheat parents of both CH5026 and TAI7045 were susceptible,indicating that the Pm-resistance gene present in CH5026 derived from Th.intermedium,the grass parent of TAI7045.To investigate the inheritance mode of its Pro-resistance,CH5026 was crossed with the susceptible(S) cv.Jintai 170 and line CH5065.Parents and the resulted F1 plants,F2 and BC1 populations,and F2-derived F3(F2:3) lines were tested with mixed powdery mildew races,including Egt isolate E09, in the greenhouse.The F2 populations from two crosses segregated in a ratio of 3R:1S. and the BC1 population from a backcross of CH 5026(R) / Jintai170(S) // Jintai170(S) in a ratio of 1R:1S.The F2:3 lines from CH5026(R)×CH5065(S) exhibited a segregation pattern of 1(all R):2 segregating:1(all S).According to disease ratings of parents,and the F1,F2,and BC1 generations,and the F3 lines,the Pm-resistance in CH5026 was conferred by a single dominant gene.Using bulked segregant analysis(BAS),a CH5026(R)×CH5065(S) F2 population consisting of 161 individuals was screened with 349 wheat microsatellite(SSR) primer pairs to detect molecular markers linked to gene responsible for powdery mildew resistance.The results indicated that the microsatellite primer Xwmc41 and Xgwm539 on chromosomal arm 2DL was linked with the resistance gene,with the genetic distance 14.8 cM and 7.9cM2:Wheat germplasm line CH7034,developed by backcrossing a wheat-Th,ponticum partial amphiploid Xiaoyan7430 with susceptible wheat cultivars,was found to be resistant to both powdery mildew(Pm) and yellow rust.To determine the inheritance and chromosomal location of powdery mildew resistance gene,CH7034 was crossed with a susceptive wheat cultivar SY95-71.The seedling and adult tests of F1,F2 progeny plus parents were inoculated with Egt isolate E09 in greenhouse.F1 plants were consistent with their resistant parent CH7034 and resistant to Pro.In the F2 populations,the observed phenotypic classes for powdery mildew reaction satisfactorily fitted a 3R:1S segregation ratio,suggesting that the powdery mildew resistance in CH7034 was genetically controlled by a single dominant gene.Using bulked segregation analysis(BSA),a total of 148 F2 plants from the cross CH7034(R)/SY95-71(S) was screened with 307 wheat microsatellite(SSR) primer pairs to detect molecular markers linked to Pm resistance gene. The microsatellite marker linked to Pm resistance gene position were conformed using Chinese Spring nullitetrasomic and ditelosomic lines.The results indicated that the Pm resistance gene present in CH7034 was linked to microsatellite marker Xgwm311-2A with the genetic distance of 12.4cM and mapped to chromosome 2AL.更多还原