3E附加系与2C附加系杂交后代的细胞学鉴定

为了创造小麦-长穗偃麦草染色体易位系,将‘中国春’-长穗偃麦草3E二体附加系与‘中国春’-柱穗山羊草2C二体附加系进行了正反交、F1代自交和回交,利用细胞遗传学等方法对杂种后代进行了鉴定。以‘中国春’-长穗偃麦草3E二体附加系为母本的杂交组合,其杂交当代结实率平均为37.3%,而以‘中国春’-杀配子染色体2C二体附加系为母本的杂交组合,其平均结实率为28.19%,二者差异显著(P0.05)。杂种F1代自交结实率平均为31.45%,用"中国春"-长穗偃麦草3E二体附加系为父本的F1代回交结实率为38.82%,二者差异显著(P0.05)。在杂交后代有丝分裂和减数分裂中观察到了染色体畸变现象,说明杀配子染色体2C在配子的形成过程中起作用。这些研究结果为进一步创制小麦-长穗偃麦草3E染色体易位系奠定了基础。     

八倍体小偃麦和硬粒小麦杂交后代的染色体组成分析

在小麦育种工作中,因长穗偃麦草、中间偃麦草和四倍体硬粒小麦等小麦近缘种属含有许多重要的功能基因,育种家经常应用远缘杂交创制小麦育种中间材料。本研究应用FISH、GISH、Mc-GISH技术检测了八倍体小偃麦和四倍体硬粒小麦杂交的后代材料,结果表明:山农20和四倍体硬粒小麦的杂交后代中,D组染色体显著优先于十倍体长穗偃麦草染色体传递到子代中;中3和中4与四倍体硬粒小麦的杂交后代中,D组和中间偃麦草染色体从1～14条随机传递到子代中;所有材料中仅从山农20和四倍体硬粒小麦的杂交后代中筛选出3份稳定的代换系,对其中的2576-1代换系进一步分析证明,是十倍体长穗偃麦草染色体代换了1D染色体并确定该材料抗条锈病,可以作为育种材料,也为异源新种质的创制奠定了基础。     

长穗偃麦草1E附加系与杀配子染色体2C附加系杂交后代的细胞学及形态学分析

长穗偃麦草是小麦的野生近缘种属,具有抗寒、抗旱、抗病等优异性状。为了利用长穗偃麦草的优异基因,将‘中国春’-长穗偃麦草1E二体附加系与‘中国春’-柱穗山羊草2C二体附加系杂交、自交和回交,观察其后代的细胞学和形态学特性。结果表明,在杂交后代有丝分裂和减数分裂中观察到了染色体畸变现象;统计F1代自交结实率,发现与亲本相比,这些杂种后代的结实率明显降低;杂种后代的穗型发生了分离,除正常穗型外还观察到了密穗型,说明杀配子染色体2C可以诱导染色体畸变并对结实率和穗型均有一定的影响。本研究为进一步创制小麦-长穗偃麦草1E染色体易位系和缺失系奠定了基础。     

小麦-长穗偃麦草3E二体附加系与小麦-杀配子染色体2C二体附加系杂交后代的细胞学鉴定

为了创造小麦-长穗偃麦草染色体易位系,本研究将“中国春”-长穗偃麦草3E二体附加系与“中国春”-柱穗山羊草2C二体附加系进行了正反交、F1代自交和回交,利用细胞遗传学等方法对杂种后代进行了鉴定。以“中国春”-长穗偃麦草3E二体附加系为母本的杂交组合,其杂交当代结实率平均为37.3%,而以“中国春”-杀配子染色体2C二体附加系为母本的杂交组合,其平均结实率为28.19%,二者差异显著（P<0.05）。杂种F1代自交结实率平均为31.45%,用“中国春”-长穗偃麦草3E二体附加系为父本的F1代回交结实率为38.82%,二者差异显著（P<0.05）。在杂交后代有丝分裂和减数分裂中观察到了染色体畸变现象,说明杀配子染色体2C在配子的形成过程中起作用。这些研究结果为进一步创制小麦-长穗偃麦草3E染色体易位系奠定了基础。     

小麦-偃麦草杂种后代及小麦种质资源对纹枯病的抗性

为鉴定小麦-偃麦草杂种后代以及我国小麦品种和育种中间品系对纹枯病的抗性,并且解析偃麦草染色体与纹枯病抗性的关系,在徐州和南京两个试点,采用田间病圃法对321份普通小麦品种或品系和56份小麦-偃麦草杂种后代材料进行了纹枯病抗性鉴定。在徐州试点没有发现高抗纹枯病的种质,但是有52份材料表现中抗反应型,包括34份普通小麦材料,其中萧农8506-1、小偃81、冀植4001、农大195、徐州8913和京东3066A-3的相对抗病指数高于0.7。在南京试点,全部普通小麦材料都不抗纹枯病,只有5份小麦-偃麦草种质表现中抗反应型。部分小麦-偃麦草种质的病情指数不但显著低于感病对照品种苏麦3号和扬麦158,而且还低于抗病对照品种安农8455和宁麦9号,如小麦-中间偃麦草4Ai#2或4Ai#2S附加系、代换系和易位系材料TA3513、TA3516、TA3517和TA3519及小麦-长穗偃麦草第4部分同源群染色体代换系SS767,说明中间偃麦草4Ai#2染色体和长穗偃麦草4J染色体可能与纹枯病病情指数降低有关。基因组原位杂交分析结果表明,4Ai#2染色体属中间偃麦草的J^s基因组,而长穗偃麦草与纹枯病抗性相关的第4部分同源群染色体属J基因组。虽然纹枯病与眼斑病的发病部位和症状非常相似,但抗眼斑病基因Pch1 (Madsen)和Pch2 (Cappelle-Desprez)对纹枯病无效。     

小麦-十倍体长穗偃麦草抗白粉病新种质的鉴定与分析

十倍体长穗偃麦草是普通小麦遗传改良的重要材料。对从十倍体长穗偃麦草与普通小麦衍生后代中选育的2个株系(10-1-3-1和10-1-3-2)进行形态学和分子细胞学检测。结果表明:在田间自然发病条件下,10-1-3-1高抗白粉病,而10-1-3-2高感白粉病;二者根尖细胞染色体数均为2n=42,基因组原位杂交表明10-1-3-1的一对染色体短臂被长穗偃麦草遗传物质所替换,而10-1-3-2没有明显的杂交信号;利用长穗偃麦草E基因组的特异引物p Le UCD2对2个株系及其亲本进行PCR检测,发现10-1-3-1扩增出长穗偃麦草特异DNA条带,进一步证明其含有长穗偃麦草的遗传物质;269(96.1%)对SSR和EST-SSR引物在2个株系间表现单态扩增,表明这两个材料的遗传组成基本一致。以上结果表明,10-1-3-1是一个小麦-十倍体长穗偃麦草易位系,可以作为小麦抗病改良的亲本材料。本研究为小麦抗白粉病育种提供新的种质资源,有助于育种方面的深入探讨与利用。     

中国春-长穗偃麦草异代换系、异附加系的氮营养性状

为从小麦近缘植物长穗偃麦草中寻找氮高效基因,在高、低氮2个水平下,以中国春-长穗偃麦草二体异附加系和二体异代换系为试材,对其氮素利用特性进行了鉴定和遗传分析。结果表明:5E附加系氮素生理利用效率在低氮处理下极显著高于对照中国春,5E代换系氮素生理利用效率在高氮处理下显著高于对照中国春,4E代换系氮素总累积量和籽粒氮累积量在高、低氮处理下均显著高于对照中国春,表明5E和4E染色体可能分别携有促进氮素生理利用效率和促进氮素吸收转运的高效基因,长穗偃麦草5E和4E染色体可以作为提高小麦氮营养特性的有益基因资源。     

小偃麦异代换系抗病基因的鉴定及其SSR分子标记

小偃麦山农87074-557是小麦一长穗偃麦草双体异代换系,它保留了偃麦草的许多优良特性,是小麦抗病育种和遗传改良的基础材料.本文利用接种鉴定法对山农87074-557的抗病性进行鉴定表明:其对白粉病和条锈病均表现免疫,其抗性基因来源于长穗偃麦草,且其白粉病和条锈病抗性均分别受1对显性基因控制.在592对小麦SSR引物中寻找到1个标记Xgwm344120/150与白粉病抗性基因和条锈病抗性基因连锁,推测白粉病抗性基因可能为新基因,条锈病抗性基因可能不同于已定位的抗小麦条锈病基因.     

普通小麦背景中长穗偃麦草[Lophopyrum elongatum(Host) A. Lve]E染色体组的RGAP特异标记

利用已知植物抗病基因编码氨基酸保守区域NBS-LRR(核苷酸结合位点-富亮氨酸区域)设计了42个简并引物组合,运用抗病基因类似物多态性(resistance gene analog polymorphism,RGAP)分子标记技术,对中国春、中国春-长穗偃麦草双二倍体及其附加系和代换系基因组DNA进行PCR扩增。结果表明,共有38对引物组合获得扩增产物,其中35对在普通小麦中国春、中国春-长穗偃麦草双二倍体中能扩增出多态性,平均每个引物组合扩增出38.5个片段。在普通小麦背景下,共获得275条长穗偃麦草E基因组多态性谱带,占扩增总谱带数的17.44%,揭示出在普通小麦背景下E基因组和普通小麦A、B、D基因组间的高丰度遗传变异。另外,利用RGAP分子标记技术,构建了一套完整的长穗偃麦草1E~7E染色体的特异RGAP标记。为小麦背景中长穗偃麦草外源遗传物质的快速检测提供了新途径。     

小麦-中间偃麦草2A/6St代换系014-459的分子细胞遗传学鉴定

中间偃麦草是小麦遗传改良的有用资源,育成了大量的小麦-中间偃麦草附加系、代换系及部分双二倍体。中4是小麦-中间偃麦草部分双二倍体,很方便与普通小麦杂交并被广泛用于小麦的遗传改良。014-459是中4与普通小麦杂交后代,具有一些特殊特性,材料014-459与一些普通小麦杂交,无论正反交,其F1表现为不育,而与另一些普通小麦的杂交F1表现为可育,此外,材料014-459粗蛋白和湿面筋含量很高。基于014-459的这些特性,猜测其可能具有中间偃麦草染色体片段,为此对014-459进行了细胞学鉴定。FISH和GISH以及PLUG标记分析用来分析材料014-459的染色体组成情况。连续的FISH和GISH试验证实小麦-中间偃麦草部分双二部体中4与小麦杂交后代品系014-459的1对小麦2A染色体被来自中间偃麦草的1对St染色体代换, PLUG标记分析证实这1对St染色体属于第6同源群,可能来自中间偃麦草的St染色体被代换进小麦中造成了材料014-459的一些特性。对品系014-459的分子细胞遗传学鉴定对促进中间偃麦草6St染色体在小麦中利用及小麦品质改良有积极作用。     

Analysis of wheat-Thinopyrum intermedium derivatives with BYDV-resistance

Chromosome compositions of seven lines, derived from hybrids between a wheat cultivar and the wheat-Thinopyrum intermedium addition line Z6, with barley yellow dwarf virus (BYDV) resistance, were determined by genomic in situ hybridization, cytogenetic and SSR assays. The results showed that line N522 was a disomic addition line, lines N420 and N439 were 2Ai-2(2B) chromosome substitution lines, lines N431 and N452 were 2Ai-2(2D) chromosome substitution lines, line N523 was a 2Ai-2S(2D) ditelosomic substitution line, and line N530 was a double ditelosomic line with the mitotic chromosome number of 2n = 40 + 4t. One pair of telosomes in line N530 lacked several proximal SSR markers of chromosome 2AS, but possessed certain terminal markers, which were consistent with an acrocentric structure, and the other pair of chromosome arms were presumably 2Ai-2S telosomes with BYDV-resistance. These wheat-Th. intermedium lines provide useful genetic resources for developing alien chromosome translocation lines.     

Identification of wheat–Thinopyrum intermedium 2Ai-2 ditelosomic addition and substitution lines with resistance to barley yellow dwarf virus

Among the regenerated plants derived from immature hybrid embryos of wheat–Thinopyrum intermedium disomic addition line Z6 × common wheat variety ‘Zhong8601’, a plant with a telocentric chromosome and barley yellow dwarf virus (BYDV) resistance was obtained. The telocentric chromosome paired with an entire Thinopyrum chromosome to form a heteromorphic bivalent at meiotic metaphase I. Genomic in situ hybridization showed that the telosome originated from Th. intermedium. Two ditelosomic additions and one disomic substitution were identified among the offspring of the plant. Two random amplified polymorphic DNA molecular markers were identified among 150 random primers used to detect the different arms of the alien chromosome. These might be useful for developing translocation lines with BYDV resistance.     

普通小麦-簇毛麦易位系T4VS·4VL-4AL的选育与鉴定

利用染色体C-分带和基因组原位杂交分析,从普通小麦-簇毛麦4V染色体二体异附加系（DA4V）与普通小麦农林26-离果山羊草3C染色体二体异附加系（DA3C）杂种后代中选育出小麦-簇毛麦纯合易位系T4VS·4VL-4AL。SSR和RFLP标记分析表明,该易位染色体包括4VS、4VL近着丝粒部分区段和4AL顶端区段;该易位系具有良好的细胞学稳定性,结实正常,为杀配子染色体诱发形成的补偿型易位;易位系T4VS·4VL-4AL高抗梭条花叶病,是小麦抗病育种新种质。     

Molecular cytogenetic identification of wheat-Elymus tsukushiense introgression lines

Elymus tsukushiense Honda (syn. Roegneria kamoji C. Koch) (2n = 6x = 42, S^tsS^tsH^tsH^tsY^tsY^ts) is a hexaploid species, distantly related to bread wheat Triticum aestivum L. em Thell (2n = 6x = 42, AABBDD). Apart from the delineation of evolutionary relationships, this species is a potential source of resistance to scab, a devastating disease of wheat caused by Fusarium graminearum Schw. A standard C-banded karyotype was established identifying all 21 chromosome pairs of E. tsukushiense. By using C-banding and genomic in situ hybridization analyses, three wheat-E. tsukushiense chromosome addition lines, one ditelosomic addition line, and one disomic substitution line were identified in BC₂ progenies from wheat × E. tsukushiense hybrids. Twenty DNA markers specific for the seven homoeologous groups of the Triticeae were used to determine the homoeology of the added E. tsukushiense chromosomes. The E. tsukushiense chromosomes in the addition lines NAU702, NAU703, and NAU701 were identified as belonging to homoeologous groups 1, 3, and 5, and thus, were designated as 1Ets#1, 3Ets#1, and 5Ets#1, respectively. NAU751 was identified as a disomic substitution line with chromosome 3A of wheat replaced by chromosome 3Ets#1. Line NAU702 has a high level of resistance to scab and will be used in chromosomal engineering and development of improved wheat germplasm for scab resistance breeding. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and identification of wheat–Haynaldia villosa T6DL.6VS chromosome translocation lines conferring resistance to powdery mildew

Three lines conferring resistance to powdery mildew, Pm97033, Pm97034 and Pm97035, were developed from the cross of Triticum durum-Haynaldia villosa amphidiploid TH3 and wheat cv.'Wan7107' via backcrosses, immature embryo and anther culture. Genomic in situ hybridization analysis showed that these lines were disomic translocation lines. Cytogenetic analysis indicated that the F1 plants of crosses between the three translocation lines and 'Wan7107' and crosses between the three translocation lines and substitution line 6V(6D) formed 21 bivalents at meiotic metaphase I. Aneuploid analysis with 'Chinese Spring' double ditelocentric stocks indicated that the translocated chromosomes were related to chromosome 6D. Biochemical and restriction fragment-length polymorphism (RFLP) analyses showed that the translocation lines lacked a specific band of 6VL of H. villosa compared with the substitution and addition lines but possessed specific markers on the short arm of the 6V chromosome of H. villosa. The three translocation lines lacked specific biochemical loci and RFLP markers located on chromosome 6DS. The results confirmed that Pm97033, Pm97034 and Pm97035 were T6DL.6VS translocation lines.     

Development of dominant nuclear male-sterile lines with a blue seed marker in durum and common wheat

In order to develop genie male‐sterile lines with a blue seed marker, male‐sterile plants, controlled by a dominant nuclear gene Ms2, were used as female parents against a 4E disomic addition line ‘Xiaoyan Lanli’(2n= 44, AABBDD+4EII) as the male parent to produce monosomic addition lines with blue seed. Male‐sterile plants from the monosomic addition lines were pollinated with durum wheat for several generations and in 1989 a male‐sterile line with the blue grain gene and the male‐sterile gene Ms2 on the same additional chromosome was detected and named line 89‐2343. Using this line, the blue seed marker was successfully added to a short male‐sterile line containing Ms2 and Rht10. The segregation ratios of male sterility and seed colour as well as the chromosome figurations of different plants indicated that the blue grain genes, Ms2 and Rht10 were located on the same additional chromosome. Cytological analysis showed that the blue marker male‐sterile lines in durum wheat and common wheat were monosomic with an additional chromosome 4E. The inheritance ratio for blue seed male‐sterile plants and white seed male‐fertile plants was 19.7% and 80.3%, respectively, in common wheat. The potential for using blue marker sterile lines in population improvement and hybrid production is discussed.