小麦-黑麦1BL/1RS易位系7-1抗纹枯病的分子细胞学鉴定

黑麦(Secale cereale)是小麦(Triticum aestivum)的重要三级基因源,具有小麦改良所需要的多种优良性状。为丰富小麦杂交育种新的种质资源,利用墨西哥黑麦(2n=2x=14,RR)与普通优质小麦W770B(2n=6x=42,AABBDD)杂交,经过多年筛选,选出若干优良性状的衍生系,在小麦五叶期时用PDA培养基培养的带纹枯病菌的牙签,接菌到小麦芽鞘内,温室内培养,5周后鉴定纹枯病发病等级,计算病情指数,为了结果的准确性,经过多次牙签法鉴定,筛选出病情指数为PI=32.8%的抗病衍生系7-1。为明确衍生系7-1的遗传成分,本研究综合采用形态学、细胞遗传学、基因组原位杂交(genomic in situ hybridization,GISH)、特异序列扩增(sequence characterized amplified region,SCAR)分子标记、简单重复序列(simple sequence repeat,SSR)分子标记和醇溶蛋白分析。对7-1的根尖细胞和花粉母细胞的细胞遗传学观察表明7-1染色体结构和数目稳定2n=42=21Ⅸ;以黑麦DNA为探针的GISH分析观察表明7-1含有两个黑麦染色体臂;黑麦基因组SCAR标记分析表明,D15和P13LF/R能够在黑麦和7-1中扩增出黑麦特异条带,黑麦1RS SCAR标记分析表明,ω-sec-p1/ω-sec-p2、ω-sec-p3/ω-sec-p4和IB-267能够在黑麦和7-1中扩增出黑麦目的条带,说明7-1具有黑麦1RS染色体;筛选小麦每条染色体长短臂上的多对引物,在7-1中只有1BS上的引物Xgwm264和Xgwm11未能扩增出相应条带,其余染色体上的引物均扩增出了条带,说明7-1中缺失了小麦1BS染色体;醇溶蛋白分析表明7-1中扩增出了1RS黑麦碱条带,由此证实了小麦染色体1BS被黑麦染色体1RS所替换,该材料为小麦-黑麦1BL/1RS易位系。本研究中7-1为抗纹枯病的1BL/1RS易位系,为小麦纹枯病抗病育种提供了新的种质资源,拓宽了小麦育种材料。     

含抗白粉病新基因普通小麦-黑麦1R二体异附加系的遗传学鉴定

黑麦（Secale cereale）含有丰富的优良基因,在小麦遗传改良中具有重要利用价值。为了鉴定普通小麦（Triticum aestivum）与奥地利黑麦杂交后代选育的抗白粉病品系N9436-1的黑麦遗传物质,对其进行了细胞学、基因组原位杂交、Giemsa-C分带、SCAR（sequence characterized amplified region）标记以及酸性聚丙烯酰胺凝胶电泳(A-PAGE)分析。结果表明,N9436-1形态学和细胞学稳定,2n=44=22Ⅱ,对白粉病免疫,携带奥地利黑麦的多小穗性状。以奥地利黑麦总基因组DNA为探针的原位杂交结果及Giemsa C-分带显示,N9436-1含有2条奥地利黑麦的1R染色体, SCAR标记鉴定及A-PAGE分析进一步证实N9436-1携带有黑麦遗传物质,表明N9436-1携带的抗白粉病基因不同于Pm8和Pm17,是新的抗白粉病基因,可作为白粉病抗源用于小麦抗病育种。     

小麦-顶芒山羊草2M染色体系的鉴定与评价

为了研究小麦-顶芒山羊草新种质材料的染色体组构成及开发其在育种中的利用价值,本研究利用分子标记和荧光原位杂交对小麦-顶芒山羊草杂交新种质进行鉴定,并通过小麦主要病害生理小种接种和农艺性状调查等方法对鉴定的材料进行综合评价。分子标记和原位杂交结果显示,所鉴定材料分别为小麦-顶芒山羊草2M附加系、2M(2D)代换系、2AS-2ML.2MS易位系和2DS-2ML.2MS易位系;抗病性鉴定结果表明,含2M染色体的材料均高抗小麦条锈病,其小麦亲本则高感条锈病,表明2M染色体上可能含有抗条锈病新基因;农艺性状调查分析结果表明,2M染色质导入小麦,可影响其小穗数、穗粒数和穗粒重等产量性状。因此,在创制和利用抗条锈病的小麦-顶芒山羊草2M染色体小片段易位系时,应加强对上述农艺性状的考察,并利用当前主栽品种进行回交改良。本研究鉴定出的抗条锈病小麦-顶芒山羊草2M染色体系丰富了小麦抗病基因库,为小麦育种提供了新抗源。     

间套复种小麦—早优504的选育

本文以八倍体小偃麦中５为远缘亲本材料，通过远缘杂交，染色体工程与常规育种技术相结合的方法，选育出一个适合间套复种的小麦新品种－早优５０４。该品种具有特早熟、矮秆、株型紧凑、叶片上挺、抗病、优质、高产等优良性状。     

抗条锈病的小麦-非洲黑麦异代换系的分子细胞学鉴定

黑麦属(Secale)物种是改良小麦条锈病抗性的优良供体,为发掘和利用黑麦属野生种非洲黑麦(S.africanum)所携带的优异抗小麦条锈病基因,本研究在硬粒小麦(Triticum durum)-非洲黑麦双二倍体(基因组为AABBRaRa)和小麦(T.aestivum)杂交的高代材料中发现了一个免疫条锈病的株系HH41.HH41的体细胞染色体数目为2n=42.用小麦D基因组特异重复序列pAsl和秦岭黑麦(S.cereale)基因组总DNA作为探针的顺序原位杂交分析表明,HH41中一对小麦6D染色体被一对非洲黑麦6Ra染色体所代换.利用开发的基于表达序列标签的6R/6Ra特异分子标记也证实了HH41缺少6D特征带,具有6Ra特征带,是6Ra(6D)代换系.条锈菌生理小种(Puccinia striiformis Eriks.f sp.tritici)接种鉴定结果表明其抗条锈病性源自6Ra染色体.本研究还综合利用分子细胞学证据将来自非洲黑麦的6Ra染色体与栽培黑麦的6R染色体的多态性进行了比较,证实了6R(6D)代换系HH41是一种具有古老野生黑麦优异抗性的特殊珍贵材料,是创造异易位系、实现外源基因转移和改良小麦的重要资源.     

间套复种小麦--早优504的选育

本文以八倍体小偃麦中₅为远缘亲本材料，通过远缘杂交，染色体工程与常规育种技术相结合的方法，选育出一个适合间套复种的小麦新品种--早优504。该品种具有特早熟、矮秆、株型紧凑、叶片上挺、抗病、优质、高产等优良性状。     

14份小麦种质资源抗麦长管蚜遗传多样性的SSR分析

利用SSR分子标记在分子水平探讨小麦种质资源抗麦长管蚜的遗传多样性,为高效节本型和环境友好型的抗蚜育种的研究和利用提供理论依据和技术支持。结果表明：在小麦的A、B和D 3组同源染色体组上的175对SSR分子标记鉴定出了有多态性的32对引物,其中在D同源组中小麦抗蚜性的遗传多样性较高,同时在21对染色体中7D染色体上遗传...     

DNA分子标记技术及其在小麦育种及遗传研究中的应用

本文介绍了几种常用的DNA分子标记,如RFLP、RAPD、AFLP、SSR、STS、SNP等,并简要综述了分子标记技术在小麦遗传育种研究中的应用现状,包括基因标记与定位、遗传图谱构建、外源染色体鉴定与标记、种质资源鉴定和辅助育种等。     

利用黑麦基因组特异PCR标记鉴别小麦K型雄性不育保持系

选用９１个小麦品种和黑麦，小黑麦系各一个，利用黑麦基因组散布重复序列ＰＣＲ标记，检测普通小麦遗传背景下的１Ｂ／１Ｒ易位和黑麦染色体片段，探讨鉴别小麦Ｋ型雄性不育保持系的可行性。     

水稻与异科植物月见草远缘杂交研究初报

本文报道通过水稻（品种通育211）与柳叶菜科植物—-月见草进行远缘杂交,其后代出现了大量、明显的性状变异。 通过系谱选育,获得了一批在形态、生育期和多个农艺性状上有育种价值的水稻新种质。对代表性变异材料及其水稻受体亲本和供体月见草进行了AFLP分子标记分析。结果表明,月见草的花粉介入确使受体水稻材料中在DNA分子水平产生了大量的变异。文中对远缘杂交行之有效的新方法---复态导入法的特点及效应等问题进行了讨论。     

Transfer of leaf rust and stripe rust resistance from <Emphasis Type="Italic">Aegilops umbellulata</Emphasis> Zhuk. to bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Aegilops umbellulata acc. 3732, an excellent source of resistance to major wheat diseases, was used for transferring leaf rust and stripe rust resistance to cultivated wheat. An amphiploid between Ae. umbellulata acc. 3732 and Triticum durum cv. WH890 was crossed with cv. Chinese Spring Ph ^I to induce homoeologous pairing between Ae. umbellulata and wheat chromosomes. The F₁ was crossed to the susceptible Triticum aestivum cv. ‘WL711’ and leaf rust and stripe rust resistant plants were selected among the backcross progenies. Homozygous lines were selected and screened against six Puccinia triticina and four Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both rust pathogens at the adult plant stage. Genomic in situ hybridization in some of the selected introgression lines detected two lines with complete Ae. umbellulata chromosomes. Depending on the rust reactions and allelism tests, the introgression lines could be classified into two groups, comprising of lines with seedling leaf rust resistance gene Lr9 and with new seedling leaf rust and stripe rust resistance genes. Inheritance studies detected an additional adult plant leaf rust resistance gene in one of the introgression lines. A minimum of three putatively new genes—two for leaf rust resistance (LrU1 and LrU2) and one for stripe rust resistance (YrU1) have been introgressed into wheat from Ae. umbellulata. Two lines with no apparent linkage drag have been identified. These lines could serve as sources of resistance to leaf rust and stripe rust in breeding programs.     

Characterization of a new T2DS.2DL-?R translocation triticale ZH-1 with multiple resistances to diseases

In the present study, we report on a new triticale (×Triticosecale Wittm.) ZH-1, derived from the progeny of common wheat (Triticum aestivum L.) cv. MY15?×?Chinese Weining rye (Secale cereale L.). ZH-1, exhibiting shorter plant height and higher tillering ability compared to MY15, is immune to both powdery mildew and stripe rust and has stable fertility. Genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH) and C-banding revealed that the chromosome composition of triticale ZH-1 was 14 A-genome (1A-7A), 12 B-genome (1B-2B, 4B-7B), 12 R-genome (1R, 3R-7R), chromosomes 6D and T2DS.2DL-?R. Moreover, the PCR results of PLUG and EST-SSR markers also strongly supported the above stated chromosome composition of triticale ZH-1. In addition, the physical mapping of chromosome T2DS.2DL-?R showed a minute chromosomal fragment derived from rye was attached at the distal end of 2DL. The new triticale ZH-1 could be a valuable source for wheat improvement, especially for resistance to disease.     

Genome and rye chromosome distribution in tricepiro “Don René INTA”, a synthetic forage

The tricepiro “Don René INTA” is an artificial hybrid with 2n?=?42 chromosomes, including 14 rye (RR) and 28 wheat (AABB) chromosomes, with introgression of Thinopyrum ponticum (Podp.) Barkw. et Dewey on chromosome 6A. The aim of this work was to study the spatial distribution of the genomes and chromosomes of rye and wheat in metaphase cells from the root tip of this hybrid. The rye chromosomes were recognized by genome in situ hybridization using total genomic DNA as a probe of rye and wheat DNA as the blocking agent. Two points were determined in each cell: one representing the genomic mean distance of rye chromosomes (G_RMD) and the other the genomic mean distance of wheat chromosomes (G_WMD). The distance between the rye chromosomes and G_RMD and G_WMD showed no statistically significant difference, thus indicating that there would be no differential spatial domains for both genomes. The fluorescence in situ hybridization analysis of rye chromosomes using the pSc119.2 probe suggested that all chromosome pairs present somatic association in mitotic metaphase.     

Chromosomal distribution and genetic expression of Lophopyrum elongatum (Host) A. Löve genes for adult plant resistance to stripe rust in wheat background

A set of wheat cv. Chinese Spring (CS)-Lophopyrum elongatum addition and substitution lines has been analyzed for its potential to offer new sources of stripe rust resistance for wheat. The adult plants of these lines, together with CS-L. elongatum amphiploid and CS, were inoculated by new physiological races CYR-30 and CYR-31 of stripe rust in China. The resistance investigation indicated that chromosome 7E1 of L. elongatum was responsible for the adult resistance in CS background. Moreover, the expression of the adults plant resistance derived from chromosome 7E1 in wheat background was dependent on the wheat genotype. In addition, the different rust resistance and glutenin composition were observed in 2 CS-L. elongatum amphiploids, indicating the genetic diversity existed in different origins of L. elongatum.     

Testing of rye-specific markers located on 1RS chromosome and distribution of 1AL.RS and 1BL.RS translocations in Turkish wheat (Triticumaestivum L., T.durum Desf.) varieties and landraces

Rye (Secale cereale L.) is a valuable source for alien chromosome translocations in wheat breeding, due to its capability to grow and sustain under harsh environmental conditions. Wheat germplasm with 1AL.1RS and 1BL.1RS wheat-rye chromosome translocations have been used worldwide by breeders. Determining 1AL.1RS and 1BL.1RS translocations in wheat is therefore of important practical value for wheat improvement. In this study, nine rye-specific markers detecting the rye chromosome 1RS in wheat background were evaluated. The markers PAWS5/S6, SCM9 and O-SEC5′-A/O-SEC3′-R amplified specific bands associated with 1AL.1RS and 1BL.1RS translocations. These three markers therefore provide a quick and reliable tool to identify and to discriminate these two wheat-rye translocations in wheat background. Six out of nine rye specific markers were subsequently used to determine the frequency of these translocations in commonly grown bread and durum wheat cultivars from Turkey. One hundred seven wheat cultivars and landraces were molecularly screened. Among them, only 4% (‘Seri-82’, ‘Yıldız-98’, ‘Tahirova’, and ‘Osmaniyem’) harbor the 1BL.1RS translocation whereas the 1AL.1RS translocation was not found. The information provided here will contribute to the creation of new Turkish wheat populations with a larger genetic diversity necessary for future requirements.     

Evaluation of Genetic Diversity Among Bulgarian Winter Wheat (Triticum aestivum L.) Varieties During the Period 1925–2003 Using Microsatellites

Simple sequence repeats (SSRs) were used to study the genetic diversity within old and modern Bulgarian winter wheat (Triticum aestivum L.) varieties released in 20th century. A set of 91 varieties were screened by 19 wheat microsatellite markers (WMS), covering 17 wheat chromosomes, and one secalin-specific marker for rye chromosome arm 1RS. A total of 136 allelic variants were detected at 22 loci, ranging from 2 to 11, with an average of 6.8 alleles per marker. For 7 markers, null alleles were detected. The occurrence of rare alleles (frequency <2%) was observed for 13 markers. The polymorphism information content (PIC) values of the markers ranged from 0.10 (WMS0165 on 4AS) to 0.81 (WMS0437 on 7DL) with an average of 0.51. Approximately 74% of the varieties, mostly non-commercial, showed heterogeneity, with an average level of 10.1%. For the majority of markers, the relative frequencies of alleles varied considerably among different groups of varieties, revealing the effects of different selection between breeding centres. Some alleles, present in old genotypes, were lost, and new alleles have been introduced into modern varieties. Genetic diversity values over different periods of release were high, starting at 0.64 for varieties developed before 1960 to reach 0.71 in 1990s, revealing no declining trends in the diversity due to breeding activity. The cluster analysis discriminated all varieties (except for two) and revealed distinct groups of old and modern varieties, released from the main breeding centres in Northern, Southern and Western Bulgaria.     

小麦苗期耐低氮基因型的筛选与评价

氮是作物吸收的第一大必需营养元素, 对作物生长发育具有不可替代的作用。大量研究表明, 不同基因型小麦对氮的吸收利用能力不同, 培育氮高效小麦品种是提高氮利用效率的根本途径, 而发掘耐低氮小麦种质资源是小麦氮高效育种的基础。为此, 本研究以30 个小麦-冰草远缘杂交的高代品系, 1 个小麦-黑麦远缘杂交的T1BL·1RS 易位系, 2 个"小偃54"×"京411"重组自交系群体中的品系, 以及13 个生产上的主栽品种为试验材料, 通过低氮胁迫和正常供氮2 个处理的苗期水培试验, 进行了耐低氮基因型的筛选与评价。方差分析显示, 13 个氮效率相关性状在2 种氮水平之间及各小麦基因型之间的差异均达到显著或极显著水平。主成分分析显示, 前3 个主成分累积贡献率达到81.2%, 已包含了大部分信息, 能够基本反映整体状况。其中, 相对茎叶吸氮量、相对植株吸氮量、相对根冠比、相对茎叶干重、相对植株干重、相对茎叶氮利用效率、相对根含氮量在3 个主成分中占较大的比重。综合评价结果显示, 在33 个小麦远缘杂交品系中08B41 得分最高, 为1.60,为最耐低氮的品系; 13 个主栽品中"科农9204"得分最高, 为2.10, 为耐低氮的品种。聚类分析显示, 46 份基因型小麦可划分为3 大类: 耐低氮型(15 份)、中间型(22 份)和低氮敏感型(9 份)。筛选出08B41、XJ19-1、08B8、08B10、08B13、08B25、WR9603、08B2、08B5 共9 份耐低氮远缘杂交高代品系, 及"科农9204"、"邯7086"、"河农827"、"石麦18"、"石4185"、"石新733"共6 份耐低氮主栽品种。这些耐低氮的基因型可作为小麦营养高效育种的种质资源, 本文并对小麦近缘种属在小麦营养高效遗传改良中的作用进行了讨论。     

Molecular characterization of <Emphasis Type="Italic">Triticum militinae</Emphasis> derived introgression lines carrying leaf rust resistance

Triticum militinae Zhuk. et Migusch. belongs to timopheevii [Triticum timopheevii (Zhuk.) Zhuk.] group of wheats with 2n = 4x = 28 chromosomes and genome formula A^tA^tGG. Triticum militinae Zhuk. et Migusch. is known to carry resistance to fungal diseases including rusts and powdery mildew. Genes from timopheevii wheat can be incorporated into cultivated wheat by either direct hybridization or through development of amphiploids. Three T. militinae derived introgression lines (ILs) Triticum Militinae Derivative (TMD) 6-4, TMD7-5 and TMD11-5 were selected for the current study based on cytological stability. All three ILs showed resistance against wide spectrum of Indian pathotypes of leaf rust. More than 1200 SSR markers were used for genotyping of ILs and parental lines. The ILs showed variable and multiple introgressions in different chromosomes of A, B and D genome of wheat. The introgression points were distributed mostly in the distal regions though significant introgressions were also observed in proximal regions of some chromosomes. The extent of introgression in ILs TMD6-4, TMD7-5 and TMD11-5 was 2.8, 8.3 and 8.6% respectively. The set of ‘informative markers’ in the Molecularly Tagged Chromosome Regions (MTCR) of T. militinae origin can also be used in future for tagging of genes associated with traits of economic importance apart from leaf rust resistance. The transferability of Triticum aestivum L. SSR markers to T. militinae was 96.4% for A genome, 95.8% for B genome and 84.3% for D genome. Transferability of wheat SSR markers to T. militinae can be used in preparing genetic maps in timopheevii group of wheats.     

小麦抗叶锈病基因Lr2c的SSR标记

选取抗叶锈病基因位于2D染色体上的TcLr2c等7个小麦（Triticum aestivum）近等基因系、感病亲本Thatcher及215株TcLr2c与Thatcher杂交F2代为材料,研究抗叶锈病基因Lr2c SSR分子标记。从筛选的29对位于小麦2D染色体的SSR引物中获得4对能够揭示Lr2c多态性的分子标记,通过215株TcLr2c × Thatcher F2群体验证,结果表明Xgwm261和Xgwm296与Lr2c紧密连锁,其距目的基因的遗传距离分别为1.9和3.6 cM,可用于小麦抗叶锈病分子辅助育种。