八倍体小黑麦(Triticale)与六倍体小黑麦杂交若干问题的探讨

本工作以改进八倍体小黑麦与六倍体小黑麦的经济性状为目的,对60个杂交组合 F_1的田间出苗率、结实率、杂种后代的性状分离、新类型的形成以及细胞遗传的若干问题进行了探讨,观察到 F_1田间出苗率、结实率以八倍体为母本的杂交组合显著好于以六倍体为母本的杂交组合。由于杂种是普通小麦、硬粒小麦、黑麦三个物种种质的再度组     

六倍体小黑麦种质资源遗传多样性分析

利用RAPD标记对10份六倍体小黑麦、1份普通小麦和1份黑麦种质资源遗传多样性进行了分析,19个RAPD引物中,有10个引物(52.63%)可扩增出清晰且具多态性的条带。10个引物共产生385条DNA片段,其中384条具有多态性,多态性比率为99.74%,不同引物扩增带数变幅为8~71条,平均为38.5条,扩增产物的片段大小为298~3 054 bp,材料间的遗传距离变化范围在0.724~0.833之间。对12份供试材料的遗传关系进行聚类分析,在平均GD值0.77水平上可将12份供试材料分为3类。研究结果为将六倍体小黑麦的优良基因导入到普通小麦中提供了理论依据。     

普通小麦品种间以及与六倍体小黑麦种间杂种F1农艺性状的遗传分析

为给杂交选育优良小麦品种提供基础,本研究以普通小麦品种晋农190为父本,分别与9个普通小麦品种、7个六倍体小黑麦品种为母本配置杂交组合,对杂种F1代的农艺性状进行分析,发现除了无芒对有芒为显性之外,其余农艺性状均表现为数量遗传,F1代表现为超亲遗传或介于双亲之间。六倍体小黑麦的灰绿色叶片或茎秆、穗长长和红色不饱满的籽粒在杂种F1代显现,可作为鉴别真假杂种的典型性状。     

六倍体小黑麦基于农艺性状和品质性状的多样性分析

为明确从国际玉米小麦改良中心(CIMMYT)引进的111份六倍体小黑麦的遗传多样性特点,为其有效利用提供参考依据,对其农艺性状和品质性状特点进行了多样性分析。结果表明：6个农艺性状的平均变异系数为16.94%,平均多样性指数是1.96,小穗数/穗、穗长和千粒重的多样性指数均高于2.00;10个品质性状的平均变异系数为8.60%,平均多样性指数是1.94,吸水率、面团稳定时间的多样性指数均高于2.00。结论：111份六倍体小黑麦的农艺性状和品质性状表现出较大的差异,具有较丰富的多样性。     

利用小麦与黑麦远缘杂交创造麦类种质资源

目前小麦与黑麦杂交研究主要分两大方面:一是培育异源多倍体(八倍体小黑麦或六倍体小黑麦)新物种。另一方面是选育具有某些黑麦优良特性或双亲特性的麦类新种质资源。我们工作重点是后者。也就是期望能有目的、有计划地进行染色体或染色体片断的附加(Addition)、代换(Substitution)和易位(Trans location),从而达到定向改     

小麦–华山新麦草异代换系DH2322的分子细胞遗传学鉴定

利用分子标记、细胞学、基因组原位杂交(GISH)等技术,结合田间农艺性状调查,对小麦–华山新麦草七倍体材料H8911与硬粒小麦D4286杂交F4代分离群体中株系DH2322进行了综合鉴定。华山新麦草基因组特异SCAR标记鉴定表明,DH2322含有华山新麦草遗传物质;细胞遗传学观察显示,DH2322染色体构型为2n=42=21 II;有丝分裂和花粉母细胞减数分裂中期I基因组原位杂交(GISH)鉴定表明,DH2322的染色体由40条小麦染色体和2条华山新麦草Ns染色体构成,且2条Ns染色体能完全配对为一个二价体;SSR和STS分子标记分析表明,DH2322缺失小麦D基因组的2D染色体,而含有华山新麦草的2Ns染色体;农艺性状分析结果表明,DH2322具有双亲的形态学特征,结实性好,穗长和穗粒数显著大于亲本。     

Rht12导入八倍体小黑麦及其对小黑麦株高、单株分禁数和种子饱满度的影响

Rht12是位于5A染色体上的显性矮秆基因。用带有该基因的普通小麦Bezostaya1, Mercia作矮源与八倍体小黑麦杂交、回交,经自交和染色体数镜检及田间、室内选择,将Rht12基因导入八倍体小黑麦,获得了染色体数56的矮秆八倍体小黑麦株。在八倍体小黑麦遗传背景下,基因型纯合(Rht12 Rht12)时降秆能力约为41.2%,杂合(Rht12rht12)     

八倍体小黑麦与普通小麦杂交的细胞遗传

八倍体小黑麦与普通小麦杂交,后代可以出现亲本类型八倍体小黑麦、普通小麦和普通小麦附加黑麦染色体异附加系与异代换系,对改进八倍体小黑麦的株高、熟期、结实率、籽粒饱满度有一定的效果,也可以选育抗病、耐旱较亲本增产的普通小麦新品种。细胞学观察结果:F₁染色体基本型为21_Ⅱ+7_Ⅰ,F相似文献   

Rht12导入八倍体小黑麦及其对小黑麦株高、单株分蘖数和种子饱满度的影响

Rht12是位于5A染色体上的显性矮秆基因.用带有该基因的普通小麦Bezostaya 1、Mercia作矮源与八倍体小黑麦杂交、回交,经自交和染色体数镜检及田间、室内选择,将Rht12基因导入八倍体小黑麦,获得了染色体数56的矮秆八倍体小黑麦株.在八倍体小黑麦遗传背景下,基因型纯合(Rht12Rht12)时降秆能力约为41.2%,杂合(Rht12rht12)时约为31.0%.小黑麦遗传背景对该基因有修饰作用.该基因增强了八倍体小黑麦的分蘖力,延迟了熟期,对籽粒饱满度有不利影响,尚需继续回交和选择.     

硬粒小麦-长穗偃麦草附加系、代换系和易位系的创制

通过小麦与长穗偃麦草远缘杂交创制附加系、代换系及易位系是小麦遗传改良中利用长穗偃麦草优良基因的重要途径。本研究将长穗偃麦草特异分子标记、染色体计数、基因组原位杂交(GISH)及非变性原位杂交(ND-FISH)等多种方法相结合,对硬粒小麦Langdon(AABB)与小偃麦8801(AABBEE)的杂交后代群体进行分子细胞学鉴定,创制出硬粒小麦-长穗偃麦草3E、6E染色体双体附加系Du-DA3E和Du-DA6E,硬粒小麦-长穗偃麦草1E(1B)染色体双体代换系Du-DS1E(1B)以及硬粒小麦-长穗偃麦草1AS-1EL染色体易位系Du-T1AS·1EL。创制的4个种质中长穗偃麦草染色体均能稳定遗传,这不仅增加了硬粒小麦-长穗偃麦草附加系和代换系的类型,还为后续利用长穂偃麦草优良基因改良小麦提供了特殊种质资源。     

Wheat Substitutions in Hexaploid Triticale*

Crosses between octoploid and hexaploid triticales have been made m breeding programs for several years, From an analysis of the progeny of such crosses where selections for an octoploid-like phenotype had been made, it was established that 149 out of 150 lines were hexaploid in chromosome number, C-banding and in situ hybridization demonstrated that all but five of the 62 lines analyzed in detail contained visible chromosomes or segments from the D genome. Only four lines had D-genome chromosome replacing rye chromosomes. All of the remaining 53 D-genome substitutions involved the replacing of wheat chromosomes from either the A or B genomes. This establishes the ease with which D-genome genes can be placed into triticale without the loss of rye chromosomes.     

Screening for zinc efficiency among wheat relatives and their utilisation for alien gene transfer

Genetic diversity for micronutrient efficiency among the most highly adapted and advanced hexaploid and tetraploid wheat cultivars in the world is limited compared with alien species of wheat or rye. Therefore, screening for zinc efficiency was conducted in greenhouse experiments under controlled conditions, and in field trials. Different varieties of hexaploid wheat, hexaploid oats and diploid rye, together with hexaploid and octoploid triticales, wheat-Agropyron, wheat-Aegilops and several wheat-alien chromosome addition series were studied. Considerable differences in zinc efficiency were found between wheat and its relatives. Individual chromosomes of Secale, Agropyron and Haynaldia were found to carry major genes for this character. The transfer of alien chromosome segments was effective, demonstrated using several wheat-rye translocation lines. Alien genetic information was clearly expressed in the wheat genetic background. Further experimental introgressions by chromosome manipulation and marker-aided selection may efficiently contribute to wheat improvement in marginal soils. This revised version was published online in August 2006 with corrections to the Cover Date.     

Spontaneous wheat/rye translocations from female meiotic products of hybrids between octoploid triticale and wheat

Summary Heptaploid hybrids between octoploid triticale and wheat were backcrossed as female parents with wheat to examine the rye chromosome distribution in the resultant progenies using genomic in situ hybridization (GISH). One hundred and one backcross (BC) seeds were examined and whole rye chromosome additions and substitutions, wheat/rye centric and noncentric translocations and rye telocentric chromosomes were detected. Dicentric wheat/rye translocated chromosomes were also observed. Comparisons were made with previous results on the rye chromosome distribution from male gametes of the same cross and differences were found, where in the female derived population a deficit of plants with more than two rye chromosomes was apparent relative to the anther derived population.     

Analysis of spaced-plant and micro-plot performance for yield-related traits in octoploid and hexaploid primary triticales

Summary Twenty-nine primary triticales (x Triticosecale Wittmack), derived from homozygous, uniform wheat and rye inbreds, were evaluated (i) to assess wheat, rye and interaction effects for yield-related characters, (ii) to estimate correlations between these characters, and (iii) to investigate the possibility of predicting micro-plot performance from early spaced-plant tests. The triticales (12 octoploid, 17 hexaploid) were tested under space-planting and in micro-plots in three-replicate, randomized block designs in 1983 and 1984, respectively. In general, hexaploid triticales performed significantly better than octoploids. Strong wheat and wheat x rye interaction effects were found, making it difficult to predict the performance of primary triticales from their constituent parental genotypes. At both ploidy levels under space-planting kernel weight per spike showed significant positive correlations with spikelets per spike, kernels per spikelet, and 1000-kernel weight. No significant associations were detected between spaced-plant and micro-plot performance for octoploids, indicating severe disorders at this ploidy level. In hexaploid triticales spikes per plant, kernel weight per spike, and kernels per spikelet observed in spaced-plants appeared to be useful indicators of grain yield in micro-plots.     

Chromosomal location of factors affecting content and composition of non-starch polysaccharides in wheat-rye addition lines

Summary Content of dietary fibre (DF) as well as content and composition of non-starch polysaccharides (NSP) were evaluated in disomic wheat-rye addition lines and octoploid triticale compared to their parental species — wheat (Grana) and rye (Dakowskie Zote). Large variation in the contents of NSP and DF were observed in the wheat-rye addition lines, especially in the soluble fractions. The double addition of rye chromosomes led to important transgression effects on content and composition of DF in wheat grain. Chromosomes 2R and 5R increased SDF content above the rye level, whereas the 3RS arm decreased SDF content below the wheat level. The octoploid triticale demonstrated the highest content of total arabinoxylan (AX), exceeding that of rye, while the double addition of chromosomes 4R, 6R and 6RL had an impact on high expression, comparable to that of rye content of total AX in wheat grain. Chromosomes 2R and 5R notably increased the proportion of soluble non-cellulosic glucose in the NSP fraction, in contrast to the rest of wheat-rye addition lines, octoploid triticale, wheat and rye, where AX was found to be predominant among NSP constituents. The effects of single chromosome pairs on content and composition of NSP proved to be higher than the effect of the whole rye genome in octoploid triticale. The most remarkable effect, especially considering the direction of changes, was of a 3R chromosome short arm addition. The obtained data might be of interest in breeding rye or triticale with lower viscous AX content as well as rich in soluble non-starch glucose polymers, regarded as a corrective factor in modern diseases.Abbreviations AX arabinoxylan - CV coefficient of variation - DF dietary fibre - IDF insoluble dietary fibre - NSP non-starch polysaccharides - SDF soluble dietary fibre - TDF total dietary fibre - TFA trifluoroacetic acid     

Cytogenetic Study of a Trigeneric (Triticale × Trileymus) Hybrid

Summary In this study a new trigeneric hybrid involving species from the Triticum, Secale and Leymus was produced by crossing octoploid triticale (Jinsong49) with octoploid tritileymus (950059). The chromosome constitution of the parental amphiploid, trigeneric hybrid and its progenies were studied. Genomic in situ hybridization (GISH) analysis showed that Jinsong49 and 950059 had 44 wheat chromosomes, and 12 rye chromosomes, 12 L. mollis chromosomes respectively. The mean meiotic configuration of trigeneric hybrid F₁ was 13.17 I + 20.82 II + 0.37 III + 0.02 IV. GISH results indicated the trigeneric hybrid F₁ had 6 rye chromosomes and 6 Leymus chromosomes. In the selfed derivatives of the trigeneric hybrids, while the number of selfed generation increased, the mean number of chromosomes tends to decrease gradually and slowly. GISH results revealed that most plant tested in the progeny population had 8–12 rye chromosomes, and no Leymus chromosomes were detected. The results indicated that rye chromosomes can be preferentially transmitted in the progenies of trigeneric hybrid than Leymus chromosomes.     

Confirmation of a 1A/1R Wheat-Rye Chromosome Translocation in the Wheat Variety 'Amigo'

Differential chromosome staining by using the Giemsa C- banding technique and test crosses have revealed rye chroma tin in the hexaploid wheat variety ‘Amigo’ which resulted from wheat crosses with the octoploid triticale ‘Gaucho’. The results demonstrated a pair of translocated wheat chromosomes involving the short arm of rye chromosome 1R and the long arm of the homoeologous wheat chromosome 1A (1Aq/1Rp translocation). The localization of the translocation breakpoint is supposed 10 be within the centromeric region.     

The Use of Monosomic Rye Addition Lines for Transferring Rye Chromatin into Bread Wheat

Hybrid plants with 21 pairs of wheat chromosomes and with a haploid rye genome were produced by backcrossing a primary octoploid triticale with its parental hexaploid wheat. Upon a second backcrossing or selfing, the rye chromosomes were eliminated rapidly. Added rye chromosomes, in varying numbers, affected the transmission rate of wheat chromosomes significantly. Loss of wheat chromosomes ranging from 0.06 to 0.35 per plant in different populations was observed. In these plants a remarkably high incidence of wheat/rye and rye/rye translocations occurred. Translocations were identified by using the C-banding technique. Among 837 analyzed plants 64 wheat/rye and 256 rye/rye translocations were identified. In different generations of backcrossing or selfing the frequency of wheat/rye translocations varied between 4.23 % and 14.67 %. All 14 rye chromosome arms were involved in translocations but with different frequencies. BC₁F₃ plants with homozygous wheat/rye translocations were isolated The results indicate that monosomic wheat/rye addition lines may be directly used as an effective means to transfer genetic material from rye into bread wheat.     

Chromosome Constitution of Hexaploid Triticale Lines in the Recent International Yield Trials*

Lines of hexaploid triticale included in the 11th and 12th Eucarpia Triticale Yield Nurseries and the 18th and 19th International Triticale Yield Nurseries were karyotyped using C-banding. A new chromosome substitution, 6D(6A), was identified in both spring and winter triticales. It is likely that the substitution first appeared in the progenies of octoploid × hexaploid triticale hybrids at CIMMYT and within a few years spread to about one-fourth of spring materials. The 2D(2R) substitution appeared in winter triticales, probably by introgression from spring lines from CIMMYT.