利用减数分裂期成株电离辐射选育小麦—大赖草易位系的研究

采用６００１１２５Ｒ剂量的６０Ｃｏγ射线对小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）大赖草（Ｌｅｙｍｕｓｒａｃｅｍｏｓｕｓ（Ｌａｍ．）Ｔｚｖｅｌ．）Ｌｒ．７单体异附加系在减数分裂期进行成株辐射处理,经过Ｍ１代根尖细胞有丝分裂中期（ＲＴＣ,Ｍ期）染色体ＧｉｅｍｓａＣ分带粗筛,Ｍ２代ＲＴＣＭ期染色体Ｃ分带和荧光原位杂交鉴定,选育出２个小麦大赖草Ｌｒ．７异易位系。其中Ｔ０２易位系是由Ｌｒ．７染色体绝大部分与一小片段小麦染色体接在一起组成的易位类型（ＴＬｒ．７·Ｌｒ．７Ｗ）;Ｔ０８的易位染色体由小麦４ＡＬ和大赖草Ｌｒ．７某臂组成。     

将大赖草种质转移给普通小麦的研究：VI.端体异附加系的选育与鉴定

利用根尖细胞有丝分裂中期染色体计数,花粉母细胞减数分裂中期１（ＰＭＣ ＭＩ）染色体构型分析仪及Ｃ－分带,从普通小麦中国春与大赖草（ＬｅｙｍｕｓｒａｃｅｍｏｓｕｓＬａｍ．）杂种回交后代中,选育出两个端二体异附加系９５Ｇ０９,９５Ｇ１１和一个添加了一对大赖草第１４号染色体和另一对端体的双重异附加系９５Ｇ３０２（２ｎ＝４４＋２ｔ）,它们的ＰＭＣ ＭＩ染色体配对构型分别为０．２１个单价体（其中０．１６个端     

将大赖草种质转移给普通小麦的研究：Ⅶ.一个普通小麦—大赖草等臂？…

通过花粉母细胞减数分裂中期Ｉ染色体配对构型分析ＧｉｅｍｓａＣ－分带,从普通小麦－大赖草第７条染色体二体异附加系自交后代中选育并鉴定出了９３Ｇ５１－９和９３Ｇ５２－８２个等臂染色体异附加系,该异附加系在花粉母细胞减数分裂中期Ｉ,其等臂染色体自身两臂配对频率高,染色体易发生断裂,且又携带有较抗赤霉病的基因,是向小麦转移大赖草赤霉病抗性基因的有用中间材料。     

将大赖草种转移给普通小麦的研究Ⅵ.端体异附加系的选育与鉴定

利用根尖细胞有丝分裂中期染色体计数、花粉母细胞减数分裂中期Ｉ（ＰＭＣＭＩ）染色体构型分析以及Ｃ－分带,从普通小麦中国春与大赖草（ＬｅｙｍｕｓｒａｃｅｍｏｓｕｓＬａｍ．）杂种回交后代中,选育出两个端二体异附加系９５Ｇ０９．９５Ｇ１１和一个添加了一时大赖草第１４号染色体和另一对端体的双重异附加系９５Ｇ３０２（２ｎ＝４４＋２ｔ）,它们的ＰＭＣＭＩ染色体配对构型分别为０．２１个单价体（其中０．１６个端体单价体）、１９．５７个环状二价体＋２．３２个棒状二价体（其中０．９２个由两端体配对构成）,１．５２个单价体（１．４４个端体单价体）＋１８．０７个环状二价体＋３．１７个棒状二价体（０．２８个由两端体配对构成）,１．０３个单价体（０．７２个端体单价体）＋１８．８９个环状二价体＋３．６１个棒状二价体（０．６４个由两端体配对构成）。运用单花滴注技术对这些材料在活体和离体条件下进行赤霉病人工接种鉴定,结果表明：９５Ｇ３０２的抗性与抗赤霉病对照品种苏麦３号相仿;９５Ｇ１１的抗性高于苏麦３号,明显高于亲本品种中国春。还对端体附加系的利用以及有效、快捷地转移赤霉病抗性基因进行了讨论。     

将大赖划种质转移给普通小麦的研究

大赖草比抗病品种“苏麦３号”更抗小麦赤霉病。经离体和活体赤霉病抗生单花滴注鉴定和有丝分裂中期及减数分裂中期Ｉ的Ｃ－分带分析,选育出添加了１对第２染色体的抗赤霉病异附加系,其４４条染色体在ＭＩ配成０．１２－０．４０１＋２１．７０－２１．９３Ⅱ＋０．０１－０．０４Ⅳ。经Ｃ－分带和生物素记的染色体组ＤＮＡ作探针的分子原位杂交分析证实分析证实添加的１对我源染色全在ＭＩ配成二价体,在细胞学上已基本稳定。     

将大赖草种质转移给普通小麦的研究──Ⅲ．抗赤霉病异附加系选育

大赖草比抗病品种“苏麦３号”更抗小麦赤霉病。经离体和活体赤霉病抗性单花滴注鉴定和有丝分裂中期及减数分裂中期Ⅰ的Ｃ－分带分析,选育出添加了１对第２染色体的抗赤霉病异附加系,其４４条染色体在ＭＩ配成０．１２—０．４０ⅠＩ＋２１．７０—２１．９３Ⅱ＋０．０１—０．０４Ⅳ。经Ｃ－分带和生物素标记的染色体组ＤＮＡ作探针的分子原位杂交分析证实添加的１对外源染色体在ＭＩ配成二价体,在细胞学上已基本稳定。     

同胞质普通小麦—纤毛鹅观草附加系D和端体异附加系tBL的选育

用普通小麦－纤毛鹅观草双倍体与普通小麦中国春连续回交两次,然后连续自交,通过形态观察、根细胞染色体计数,花粉母细胞减数分裂中期Ｉ染色体配对分析及染色体Ｃ－分型,在ＢＣ２Ｆ２和ＢＣ２Ｆ３群体中,分别筛选到一个端二体异附加系９４Ｋ２２７和一个二体异附加系９４Ｋ２８０,其中Ｃ－分带显示９４２２７添加的是纤毛鹅鸡草染色体Ｂ的一对长壁９４Ｋ２８０添加的是纤毛鹅观草的一对染色体Ｄ。     

同胞质普通小麦-纤毛鹅观草异附加系D和端体异附加系tBL的选育

用普通小麦－纤毛鹅观草双倍体与普通小麦中国春连续回交两次,然后连续自交,通过形态观察、根尖细胞染色体计数、花粉母细胞减数分裂中期Ｉ染色体配对分析及染色体Ｃ－分带,在ＢＣ２Ｆ２和ＢＣ２Ｆ３群体中,分别筛选到一个端二体异附加系９４Ｋ２２７和一个二体异附加系９４Ｋ２８０,其中Ｃ－分带显示９４Ｋ２２７添加的是纤毛鹅观草染色体Ｂ的一对长臂,９４Ｋ２８０添加的是纤毛鹅观草的一对染色体Ｄ。     

利用荧光原位杂交技术检测导入普通小麦的大赖草染色质

利用以大赖草基因组ＤＮＡ为探针的荧光原位杂交技术对导入普通小麦的大赖草染色质进行检测。结果：９１）根尖体中花粉母细胞时期均可用于检测大赖草染色质。间期核中杂交信号点数与所含大赖草染色体数目之间的对应关系依染色体显强Ｃ－带末端数不同而不同;（２）利用荧光原位杂交,从普通小麦－大赖草单体异附加系的减数分裂前植株＾６０Ｃｏ－γ射线辐射后代中检测到一批大赖草端着丝粒染色体和小麦－大赖草染色体易位等结构变异     

导入小麦的外源染色体片段的准确鉴定及外源抗性基因的稳定性分析

用抗白粉病的普通小麦一簇毛麦６ＶＳ／６ＡＬ易位系与普通小麦品种扬麦５号、普通小麦一簇毛麦６Ｖ代换系和中国春６Ａ双端二体以及６Ｖ代换系和６Ａ双端二体配制了４个测交组合,分析了这４个杂交组合Ｆ１ＰＭＣ’ｓＭＩＣ－分带的减数分裂构型。在（６ＶＳ／６ＡＬ易位系×扬麦５号）和（６ＶＳ／６ＡＬ易位系×６Ｖ代换系）的Ｆ１ＰＭＣ’ｓＭＩ,分别观察到由易位染色体与６Ａ染色体和６Ｖ染色体配对形成的具有特定Ｃ－分带带型的棒状二价体,杂种中的棒状二价体数目高于各自亲本中的棒状二价体数。在（易位系×Ｃ．Ｓ．ｄ．ｄ．ｔ６Ａ）Ｆ１中,在８７．９％的ＰＭＣ中观察到由易位染色体长臂与６ＡＬ端体配对形成的异形二价体（ｔｌ”）。而在（６Ｖ代换系×Ｃ．Ｓ．ｄ．ｄ．ｔ６Ａ）Ｆ１中,９６．６８％的ＰＭＣ具有两个单价端体（ｔ’,ｔ’）。该结果进一步证实易位涉及簇毛麦染色体６ＶＳ和小麦染色体６ＡＬ,易位断点靠近着丝粒。在减数分裂中,易位染色体的正常配对和分离,保证了６ＶＳ上白粉病抗性基因Ｐｍ２１的正常传递,为这一新抗源在小麦育种中的应用奠定了细胞学基础。     

Development of Triticum aestivum Leymus racemosus Translocation Lines by Irradiating Adult Plants at Meiosis

Two alien translocation lines referring to chromosome Lr. 7 of Leymus racemosus (lam.) Tzvel. were produced from M2 of Triticum aestivum-L, racemosus Lr. 7 monosomic addition lines irradiated with 60Co- γ rays of 600-1125R does shortly before meiosis. Among them, T02 was identified to contain largely-alien, partly-wheat translocation chromosomes, T08 contains a centric fusion translocation chromosome of TLr. 7S (L?) ·4AL on the basis of Giemasa C-banding and fluorescent in situ hybridization (FISH).     

Cytogenetic and molecular identification of three Triticum aestivum-Leymus racemosus translocation addition lines

Chromosome 2C from Aegilops cylindrica has the ability to induce chromosome breakage in common wheat （Tritivum aestivum）. In the BC1F3 generation of the T. aestivum cv. Chinese Spring and a hybrid between T. aestivum-Leymus racemosus Lr.7 addition line and T. aestivum-Ae, cylindrica 2C addition line, three disomic translocation addition lines （2n = 44） were selected by mitotic chromosome C-banding and genomic in situ hybridization. We further characterized these T. aestivum-L, racemosus translocation addition lines, NAU636, NAU637 and NAU638, by chromosome C-banding, in situ hybridization using the A- and D-genome-specific bacterial artificial chromosome （BAC） clones 676D4 and 9M13; plasmids pAsl and pSc119.2, and 45S rDNA; as well as genomic DNA of L. racemosus as probes, in combination with double ditelosomic test cross and SSR marker analysis. The translocation chromosomes were designated as T3AS-Lr7S, T6BS-Lr7S, and T5DS-Lr7L. The translocation line T3AS-Lr7S was highly resistant to Fusarium head blight and will be useful germplasm for resistance breeding.     

Development of Triticum aestivum-Leymus racemosus translocation lines using gametocidal chromosomes

Maan[1] and Endo[2] et al. first reported that some chromosomes from Ae. longgissima, Ae. sharonensis and Ae. triuncialis showed preferential transmission when introduced into wheat background. The mechanism for this phenomenon rests with the fact that contrary to the normal fertility of gametes with these chromosomes, chromosome structural aberrations occur seriously in the gametes without these chromosomes, causing less compatibility in selective fertilization and resulting in semi-sterilit…     

Fluorescence in situ Hybridization and Southern Blot Analyses on Leymus racemosus and Related Species

Fluorescence in situ hybridization (FISH) was carried out in somatic cells of racemosus (lam.) Tzvel. and Thinopyrum junceum ( Savul. & Rayss) A. Love using Th. bessarabicum ( Savul. & Rayss) A. Love genomic DNA as probe. Fourteen pairs of chromosomes in L. racemosus gave positive signal, and only seven of fourteen pairs of chromosomes in Th. junceum showed signal. In FISH probed with PHv62, the chromosomes in Th. bessarabicum and L. racemosus hybridized with PHv62, whereas Th. Bessarabicum showed positive signal in four pairs of chromosomes, and the latter in thirteen pairs of chromosomes. No positive signal was observed in chromosomes of Psathyrostachys juncea (Fisch.) Nevski and Th. junceum. The results of Southern hybridization probed with PHv62 were similar to those of in situ hybridization. Twelve alien chromosome lines of T. aestivum-L, racemosus were detected by PHv62 probing. In most of the alien chromosome lines, PHv62 hybridized in fragment of Leymus chromosomes, except for the line containing chromosomes 5Lr # 1 and 1 1Lr # 1. It is inferred that Th. bessarabicum may involve in the formation of species. Non the less, significant changes have occurred during the evolution of Leymus genomes.     

Development of Wheat-alien Lines with Added Leymus racemosus Chromosomes and 6VS/6AL Translocation Chromosomes

By chromosome C-banding and bi-color fluorescence in situ hybridization (FISH) using digoxigenin-labelled total genomic DNA of Leymus racemosus (Lam.) Tzvel. and biotinylated total genomic DNA of Haynaldia villosa (L.) Schur as probes, three wheat-alien lines with L. racemosus Lr.7 addition and H.　villosa 6VS/6AL translocated chromosomes, and eight lines with L.　racemosus Lr.14 addition and H.villosa 6VS/6AL translocated chromosomes were respectively identified from DALr.7×T6VS/6AL (93G51-4×P64) and DALr.14×T6VS/6AL （94G15×P64）F2 or F3 hybrids. Fluorescein-isothiocyanate-conjugated avidin and rhodamine-conjugated sheep anti-digoxigenin Fab fragment were used in bi-color FISH detection. The chromosomes of L.racemosus and 6VS fragment of H.　villosa were simultaneously detected by their red and green fluorescence. Powdery mildew and scab resistance were also evaluated. The result showed that the obtained plants had high resistance to these two diseases. The potential usage of bi-color FISH in identifying chromatin of L.racemosus and H.villosa was discussed.     

Development of Triticum aestivum-Leymus racemosus translocation lines using gametocidal chromosomes

Specific chromosomes of certain Aegilops species introduced into wheat genome background may often facilitate chromosome breakage and refusion, and finally result in a variety of chromosome restructuring. Such a phenomenon is commonly called gametocidal effect of the chromosomes. The chromosome 2C of Ae. cylindrica is one of such chromosomes. In the present study, scab resistant wheat-L. racemosus addition lines involving chromosomes Lr.2 and Lr.7 were crossed to wheat-Ae. cylindrica disomic addition line Add2C. Then F₁ hybrids were subsequently backcrossed with wheat cv “Chinese Spring”. BC₁ plants with chromosome structural aberration were identified by C-banding. In the self-pollinated progenies of these plants, three translocation lines were developed and characterized by mitotic and meiotic analysis combined with C-banding and fluorescent in situ hybridization (FISH) using biotin-labeled genomic DNA of L. racemosus as probe. Some other putative translocation lines to be further characterized were also found. The practicability and efficiency of the translocation between wheat and alien chromosomes induced by gametocidal chromosomes, as well as the potential use of the developed alien translocation lines were also discussed.     

Development of <Emphasis Type="Italic">Triticum aestivum-Leymus racemosus</Emphasis> translocation lines using gametocidal chromosomes

Specific chromosomes of certain Aegilops species introduced into wheat genome background may often facilitate chromosome breakage and refusion, and finally result in a variety of chromosome restructuring. Such a phenomenon is commonly called gametocidal effect of the chromosomes. The chromosome 2C of Ae. cylindrica is one of such chromosomes. In the present study, scab resistant wheat-L. racemosus addition lines involving chromosomes Lr.2 and Lr.7 were crossed to wheat-Ae. cylindrica disomic addition line Add2C. Then F₁ hybrids were subsequently backcrossed with wheat cv “Chinese Spring”. BC₁ plants with chromosome structural aberration were identified by C-banding. In the self-pollinated progenies of these plants, three translocation lines were developed and characterized by mitotic and meiotic analysis combined with C-banding and fluorescent in situ hybridization (FISH) using biotin-labeled genomic DNA of L. racemosus as probe. Some other putative translocation lines to be further characterized were also found. The practicability and efficiency of the translocation between wheat and alien chromosomes induced by gametocidal chromosomes, as well as the potential use of the developed alien translocation lines were also discussed.     

Induction of small-segment-translocation between wheat and rye chromosomes

A new approach to produce wheat-rye translocation, based on the genetic instability caused by monosomic addition of rye chromosome in wheat, is described. 1 283 plants from the selfed progenies of monosomic addition lines with single chromosome of inbred rye line R12 and complete chromosome complement of wheat cultivar Mianyang 11 were cytologically analyzed on a plant-by-plant basis by the improved C-banding technique. 63 of the plants, with 2n = 42, were found containing wheat-rye translocation or substitution, with a frequency of 4. 91% . Compared with the wheat parent, other 32 plants with 2n = 42 exhibited obvious phenotypic variation, but their com-ponent of rye chromosome could not be detected using the C-banding technique. In situ hybridization with a biotin-la-beled DNA probe was used to detect rye chromatin and to determine the insertion sites of rye segments in the wheat chromosomes. In 20 out of the 32 variant wheat plants, small segments of rye chromosomes were found being inserted into dif     

应用原位杂交技术对小麦—黑麦代换系间杂交的细胞遗传研究

应用原位杂交技术结合染色体组型分析方法,对两个小麦-黑麦异源双代换系5R/5A和6R/6A杂交后代的遗传进行了研究,探讨同祖染色体配对的可能性并获得小麦-黑麦易位系。实验中对杂种F1代植株减数分裂各时期的花粉母细胞染色体行为进行分析,结果发现有22.91%的花粉母细胞中黑麦染色体与小麦染色体发生同祖配对。F2代通过C-分带、原位杂交鉴定,在45株中检测到9株易位,易位频率为20%,是目前报道易位频率最高的。染色体易位有的来源于同祖配对交换,有的来源于单价体错分裂或断裂的重建。     

Development and characterization of wheat- Leymus racemosus translocation lines with resistance to Fusarium Head Blight

Wheat scab (Fusarium Head Blight, FHB) is a destructive disease in the warm and humid wheat-growing areas of the world. Finding diverse sources of FHB resistance is critical for genetic diversity of resistance for wheat breeding programs. Leymus racemosus is a wild perennial relative of wheat and is highly resistant to FHB. Three wheat- L. racemosus disomic addition (DA) lines DA5Lr#1, DA7Lr#1 and DALr.7 resistant to FHB were used to develop wheat- L.racemosus translocation lines through irradiation and gametocidal gene-induced chromosome breakage. A total of nine wheat-alien translocation lines with wheat scab resistance were identified by chromosome C-banding, GISH, telosomic pairing and RFLP analyses. In line NAU614, the long arm of 5Lr#1 was translocated to wheat chromosome 6B. Four lines, NAU601, NAU615, NAU617, and NAU635, had a part of the short arm of 7Lr#1 transferred to different wheat chromosomes. Four other lines, NAU611, NAU634, NAU633, and NAU618, contained translocations involving Leymus chromosome Lr.7 and different wheat chromosomes. The resistance level of the translocation lines with a single alien chromosome segment was higher than the susceptible wheat parent Chinese Spring but lower than the alien resistant parent L. racemosus. At least three resistance genes in L. racemosus were identified. One was located on chromosome Lr.7, and two could be assigned to the long arm of 5Lr#1 and the short arm of 7Lr#1.