Molecular Cytogenetic Identification of a Wheat-Thinopyron intermedium （Host） Barkworth ＆ DR Dewey Partial Amphiploid Resistant to Powdery Mildew

Wide cross and molecular cytogenetic methods were used to transfer the powdery mildew resistance gene from Thinopyron intermedium(Host) Barkworth & DR Dewey to wheat. Among the progeny of crossing common wheat (Triticum aestivum L.) Yannong 15 with Th. intermedium, a partial amphiploid E990256, with resistance to powdery mildew, was developed. It had 56 chromosomes and could form 28 bivalents in pollen mother cells at metaphase I of meiosis. Resistance verification by race 15 at the seedling stage and by mixed strains of Erysiphales gramnis DC. f. sp. tritici Em. Marchal at the adult stage showed it was immune to powdery mildew at both stages. Gene postulation via 21 isolates of E. gramnis f. sp. tritici and 29 differential hosts showed it was nearly immune to all the isolates used, and its resistance pattern was different from all the mildew resistance genes used, which indicated it probably contained a new resistance gene to powdery mildew. Biochemical verification showed it might convey different Th. intermedium chromosomes from those of the wheat- Th. intermedium partial amphiploids Zhong 1–5. Genomic in situ hybridization analysis by using St genomic DNA as the probe showed E990256 contained a recombination genome of St and E.

Molecular Cytogenetic Characterization and Stem Rust Resistance of Five Wheat-Thinopyrum ponticum Partial Amphiploids

Partial amphiploids created by crossing common wheat （Triticum aestivum L.） and Thinopyrum ponticum （Podp.） Barkworth ＆ D. R. Dewey are important intermediates in wheat breeding because of their resistance to major wheat diseases. In this study, we examined the chromosome compositions of five Xiaoyan-series wheat-Th, ponticum partial amphiploids （Xiaoyan 68, Xiaoyan 693, Xiaoyan 784, Xiaoyan 7430, and Xiaoyan 7631） using GISH, multicolor-GISH, and multicolor-FISH. We found several chromosome changes in these lines. For example, wheat chromosomes 1B and 2B were added in Xiaoyan 68 and Xiaoyan 7430, respectively, while wheat chromosome 6B was eliminated from Xiaoyan 693 and Xiaoyan 7631. Chromosome rearrangements were also detected in these amphiploids, including an interspecific translocation involving chromosome 4D and some intergenomic translocations, such as A--B and A--D translocations, among wheat genomes. Analysis of the Th. ponticum chromosomes in the amphiploids showed that some lines shared the same alien chromosomes. We also evaluated these partial amphiploids for resistance to nine races of stem rust, including TTKSK （commonly known as Ug99）. Three lines, Xiaoyan 68, Xiaoyan 784, and Xiaoyan 7430, exhibited excellent resistance to all nine races, and could therefore be valuable sources of stem rust resistance in wheat breeding.

Chromosomal Constitutions and Reactions to Powdery Mildew and Stripe Rust of Four Novel Wheat-Thinopyrum intermedium Partial Amphiploids

As a staple food crop for one-third of the world＇s population, common wheat （Triticum aestivum L., 2n = 6x = 42, AABBDD） plays an important role in humans＇ food security. However, the genetic variation of cultivated wheat has been dramatically narrowed by genetic erosion under the modem cultivation system, resulting in vulnerability to biotic and abiotic stresses （Jiang et al., 1994; Friebe et al., 1996）. The wild relatives of wheat represent a large reservoir of superior genes, and transferring these alien genes to modem cultivars through chromosome engineering is a successful method of broadening the genetic diversity of wheat （Chen et al., 2003;

Variation in Chromosome Constitution of the Xiaoyan Series Partial Amphiploids and Its Relationship to Stripe Rust and Stem Rust Resistance

The wild relatives of wheat （Triticum aestivum L.） contain tremendous amounts of potentially useful genes and represent a promising source of genetic diversity for wheat improvement （Bommineni and Jauhar, 1997）. Thinopyrum ponticum （Popd.） Barkworth and D. R. Dewey [syn. Agropyron elongatum （Host） P. Beauv., Elytrigia pontica （Podp.） Holub, Lophopy- rum ponticum （Podp.） A. L6ve] （2n = 10x = 70）, has high crossability with various Triticum species. Numerous studies have shown that Th. ponticum carries many potentially valu- able resistance genes against biotic and abiotic stresses （Shannon, 1978; Cox, 1991; Zheng et al., 2014a,b）. Transferring the useful genes from Th. ponticum to common wheat through chromosome engineering had been a successful way to enhance the resistance of wheat to pests and diseases （Sharma et al., 1989; McIntosh, 1991）.

应用分子原位杂交技术解析小麦-天兰冰草部分双二倍体──远中2号的染色体构成

为分析普通小麦（Ｔｒｉｔｉｃｕｍａｅｓｔｉｖｕｍ）－天兰冰草（Ａｇｒｏｐｙｒｏｎｉｎｔｅｒｍｅｄｉｕｍ）部分双二倍体──远中２号（２ｎ＝５４）的染色体构成，用生物素（ｂｉｏｔｉｎ－１６－ｄＵＴＰ）标记天兰冰草染色体组ＤＮＡ作为探针，以普通小麦品种中国春染色体组ＤＮＡ为封闭ＤＮＡ（ｂｌｏｃｋｉｎｇＤＮＡ），与远中２号的有丝分裂中期染色体ＤＮＡ进行了分子原位杂交。证明远中２号除具有普通小麦的２１对染色体外，附加了１对小麦－天兰冰草易位染色体（即天兰冰草染色体片段易位到小麦染色体的两臂端部）、５对天兰冰草染色体。说明小麦－天兰冰草部分双二倍体在形成过程中染色体行为是比较复杂的，不仅可能产生小麦－天兰冰草染色体间易位，而且小麦染色体也可能与天兰冰草染色体的３种染色休组染色体共同参与组建新的染色体组附加到小麦中去。

小麦—中间偃麦草抗条锈衍生系的分子细胞遗传学研究

应用缺体回交法 ,以部分阿勃缺体为母本 ,中 4为父本 ,培育出 1个对目前条锈病优势小种和新小种高抗至免疫的小麦—中间偃麦草衍生系 N90 2 5 - 3 - 3 - 2 - 1 - 1。研究表明 ,该选系在形态学和细胞学上已经基本稳定 ,染色体构型为 2 n=42 =2 1″,抗病性来自中间偃麦草(Thinopyron intermedium)。以中间偃麦草 DNA为探针 ,对 N90 2 5 - 3 - 3 - 2 - 1 - 1进行基因组原位杂交分析结果证明 ,它为小麦—中间偃麦草异代换

源于中间偃麦草的小麦新品系CH5026白粉病抗性的遗传

CH5026是衍生于八倍体小偃麦TAI7045的抗病新品系,它兼抗小麦的白粉病和条锈病。温室抗性评价结果显示,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,且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和CH5065分别与CH5026杂交、回交,将其F1,F2,BC1,F3群体及其双亲分别在太原温室用白粉病15号小种的E09菌系接种,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的群体中,其抗感分离分别符合3R∶1S和1R∶1S;而且在F3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。

小偃麦部分双二倍体及其异附加系异源染色体的GISH分析

应用ＴＩＳＨ对小偃麦部分双二倍体ＴＡＦ４６（２ｎ＝８ｘ＝５６）及其衍生的６个二体异附加系的中间偃麦草染色体组种类进行了分析、鉴定。以拟鹅冠草（Ｐｓ．ｓｔｒｉｇｏｓａ）ＤＮＡ为探针的分析结果表明，ＴＡＦ４６所含有的中间偃麦草染色体组为合成染色体组，即６条Ｓｔ组染色体和８条Ｅ组染色体。在其衍生的二体异附加系中，Ｌ４和Ｌ７含有Ｓｔ组染色体，Ｌ１、Ｌ２、Ｌ３、Ｌ５含有Ｅ组染色体。ＴＡＦ４６所含有的中间偃麦草染色体的部分同源群依次为ＩＥ（Ｌ３）、２Ｓｔ（Ｌ６）、３Ｅ（Ｌ２）、４Ｓｔ（Ｌ４）、５Ｅ（Ｌ５）、６Ｓｔ（Ｌ７）、７Ｅ（Ｌ１）。

小麦与彭梯卡偃麦草杂种及其衍生后代的细胞遗传学研究──Ⅱ．来自小麦和彭梯卡（长穗）偃麦草及中间偃麦草杂种后代11个八倍体小偃麦的比较研究

利用染色体配对分析和酯酶及种子醇溶蛋白电泳分析研究了我国育成的１１个八倍体小偃麦，结果表明：（ａ）来源于小麦和中间偃麦草杂交后代的６个部分双二倍体中，中１和中２的偃麦草染色体组不同于中３、中４、中５和小偃７８８２９的偃麦草染色体组；（ｂ）来源于小麦和长穗偃麦草杂交后代的５个部分双二倍体中，小偃７８４的偃麦草染色体组不同于小偃６９３和小偃７６３１中的偃麦草染色体组，表明在长穗偃麦草中有两个互不相同又不同于小麦的染色体组Ｅ和Ｆ，而小偃７４３０和小偃６８中的偃麦草染色体组很可能是Ｅ和Ｆ染色体组的重组体；（ｃ）小偃７８４中的长穗偃麦草染色体组和中５及小偃７８８２９中的中间偃麦草染色体组基本相同，而中２的中间偃麦草染色体组不同于小偃６９３和小偃７６３１中的长穗偃麦草染色体组Ｆ，这意味着在长穗偃麦草和中间偃麦草中可能只有一个共同的染色体组Ｅ。部分双二倍体中酯酶及醇溶蛋白偃麦草染色体特征带的存在和发现，为这些染色体或其片段导入小麦后的鉴定提供了方便。

小偃麦衍生品系CH7086对白粉病抗性的遗传分析

CH7086是衍生于十倍体长穗偃麦草与普通小麦的八倍体"小偃7430"的小麦新品系,对小麦白粉病和条锈病均为免疫。为明确其白粉病抗性的遗传规律,用高感品种(系)绵阳11,晋太170,CH5241与CH7086杂交,将其F1,F2及其亲本分别在太原温室(用白粉病15号小种的E09菌系接种)进行了抗性基因的遗传分析。结果表明:F1对白粉病的感染为0级。F2群体中,白粉病抗感分离符合3R:1S,说明小偃麦衍生品系CH7086对白粉病的抗性受1对显性基因控制。

小麦种质资源SNTE0537与原始亲本叶表皮微观形貌特征的比较

为研究小麦桥梁种质资源SNTE0537及其原始亲本的叶表皮微观形貌特征的异同,利用扫描电子显微镜对从中间偃麦草与普通小麦品种烟农15远缘杂交后代中选育的小麦桥梁种质资源SNTE0537及其原始亲本进行了叶表皮电子显微形态学比较。结果表明,SNTE0537叶表皮微观形貌特征介于双亲之间,与其原始亲本有着比较明显的差异,叶表皮的微观形貌特征可以做为鉴别三个物种的依据。

小麦-中间偃麦草部分双二倍体种子贮存后遗传完整性研究

以不同收获年份的小麦-中间偃麦草部分双二倍体种子为试材,研究了室温保存条件下,种子活力变化与遗传完整性。结果表明,随贮存时间的延长,种子发芽率呈下降趋势,贮存11年、12年的种子基本失去活力,贮存7年的种子平均发芽率仅为13.36%。鉴定还发现,保存7年的小麦-中间偃麦草部分双二倍体中5根尖染色体畸变率高达35.09%。

一个新的小麦-中间偃麦草的部分双二倍体及其白粉病与条锈病的抗性鉴定研究

【目的】对一个新合成的小麦-中间偃麦草的部分双二倍体12-1179的染色体组成进行鉴定,并评价其对条锈及白粉病的抗病能力。【方法】采用GISH和FISH等细胞学技术鉴定12-1179的染色体结构,通过田间接种试验考察其抗病性。【结果】染色体计数表明品系12-1179的染色体数目为54到57,其中绝大多数植株包含56条染色体(78.57%)。在少量染色体数目为54或55的非整倍体12-1179植株中观察到一或两条端着丝粒染色体,包含56条染色体的12-1179植株中54.05%的花粉母细胞在减数分裂中期I能够形成28个二价体。统计分析发现,在2n=56的植株中,每个花粉母细胞平均形成27.26个二价体、1.33个单价体、0.01个三价体以及0.03个四价体。使用拟鹅观草DNA作为探针的GISH分析发现品系12-1179只包含12条中间偃麦草染色体,分别是3对St、2对Js和1对St-Js易位染色体。此外,使用寡核苷酸探针Oligo-p Sc119.2-1和Oligo-p Ta535-1的FISH分析表明12-1179的中间偃麦草第五同源群染色体被一对小麦5D替换。与此同时,在非整倍体12-1179中观察到的端着丝粒染色体都是小麦5DL。通过抗病性研究表明品系12-1179具有高度的抗条锈病与白粉病的特征。【结论】品系12-1179的外源复合染色体组成不仅包括不同的中间偃麦草染色体,而且还包括小麦染色体,不同于已有文献报道的小麦-中间偃麦草部分双二倍体,该品系是一个新的部分双二倍体。该品系在细胞遗传学水平上基本稳定,其抗病基因能够转移到小麦并在小麦育种中应用。