Distribution of the wheat–rye translocation 1RS.1BL among bread wheat varieties of Bulgaria

The distribution of the wheat–rye translocation 1RS.1BL was studied in 31 winter wheat varieties from Bulgaria. The presence of the translocation was verified in 17 varieties using chromosome N‐banding analysis, PAGE‐analysis of grain storage proteins and DNA‐marker analysis. The 1RS.1BL has been transmitted in 54% of varieties with a known source of the translocation in their pedigree.     

The 1BL/1RS chromosome translocation effect on yield characteristics in a Triticum aestivum L. cross

Comparisons involving 28 random F₂-derived F₆ wheat (Triticum aestivum L.) lines from the cross, ‘Nacozari’/‘Seri 82’, suggested that advanced derivatives with the 1BL/1RS chromosome translocation possess superior agronomic performance in both full and reduced irrigation conditions when compared with 1B derivatives. This performance advantage was attributed to high grain yield, above-ground biomass at maturity, grains/spike, 1000-grain weight and test weight. The 1BL/1RS lines were shorter with delayed flowering and maturity. The superiority of the 1BL/1RS translocation group on grains/m² was expressed only under the full irrigation environment. Higher harvest index, longer spike-length and grain-filling period were detected only under reduced irrigation conditions. A significant grain yield relationship with test weight was detected only among the 1BL/1RS genotypes, indicating that they possess heavier and plumper grains than the 1B genotypes.     

Agronomic performance of chromosomes 1B and T1BL.1RS near-isolines in the spring bread wheat Seri M82

The T1BL.1RS wheat (Triticum aestivum L.) - rye (Secale cereale L.) translocations have been of particular interest and are widely used in bread wheat breeding programs. The objective of this study was to determine the effect of the T1BL.1RS chromosome on grain yield and its components using 20 near-isolines of spring bread wheat cultivar ‘Seri M82’ (10 homozygous for chromosome 1B substitution and 10 homozygous for T1BL.1RS). The test lines have been produced by substituting the 1B chromosome in Seri M82 (T1BL.1RS, T1BL.1RS) through backrossing. Two field experiments were evaluated under optimum (five irrigations) and reduced (one irrigation) moisture conditions for two consecutive production cycles at the Mexican National Agricultural Research Institute, Ciudad Obregon, Sonora, Mexico. The presence of T1BL.1RS had a significant effect on grain yield, harvest index, grains/m², grains/spike, 1000-grain weight, test weight, flowering date and physiological maturity in both moisture conditions. The agronomic advantage of the 1B substitution lines on above-ground biomass yield at maturity, spikes/m²and grain-filling duration was expressed only under the optimum moisture condition. The presence of T1BL.1RS increased grain yield 1.6% and 11.3% for optimum and reduced moisture conditions, respectively. These results encourage further use of T1BL.1RS wheats in improving agronomic traits, especially for reduced irrigation or rainfed environments. This revised version was published online in August 2006 with corrections to the Cover Date.     

小麦-黑麦1RS/1BL新易位系的创制和分子细胞遗传学鉴定

利用普通小麦（Triticum aestivum L．）品种小偃6号与黑麦（Secale cereale L．）品种德国白粒杂交，选育出一批带有黑麦抗病性状的小偃6号类型种质材料。应用连续C-分带-基因组原位杂交（sequent C-banding-GISH）技术对上述材料进行染色体组成分析，筛选出2个小麦-黑麦1RS/1BL纯合易位系BC152-1-1和BC01-89-1。其中，BC152-1-1（2n=42）除含有1对1RS/1BL易位染色体外，未见其他染色体变异；BC01-89-1（2n=43）除含有1对1RS/1BL纯合易位染色体外，还附加1条两端缺失的3R染色体。高分子量麦谷蛋白亚基（HMW-GS）组成分析和品质分析结果表明，BC152-1-1和BC01-89-1不仅含有来自小偃6号的14＋15优质亚基，而且其蛋白质含量、湿面筋含量和SDS沉降值等品质性状都得到显著改良。     

Genetic, agronomic and quality comparisons of two 1AL.1RS. wheat-rye chromosomal translocations

The 1AL.1RS wheat-rye chromosomal translocation originally found in ‘Amigo’ wheat possesses resistance genes for stem rust, powdery mildew and greenbug biotypes B and C, but also has a negative effect on wheat processing quality. Recently, a second 1AL.1RS translocation carrying Gb6, a gene conferring resistance to greenbug biotypes B, C, E, G and I, was identified in the wheat germplasm line ‘GRS1201′. Protein analytical methods, and the DNA polymerase chain reaction were used to identify markers capable of differentiating the 1RS chromosome arms derived from ‘Amigo’ and ‘GRS1201′. The secalin proteins encoded by genes on 1RS chromosome arms differed in ‘Amigo’ and ‘GRS1201′. A 70 kDa secalin was found in the ‘Amigo’1AL.1RS, but did not occur in the ‘GRS1201’1AL.1RS. Polymorphisms detected by PCR primers derived from a family of moderately repetitive rye DNA sequences also differentiated the two translocations. When ‘GRS1201’was mated with a non-1RS wheat, no recombinants between 1RS markers were observed. In crosses between 1RS and non-1RS parents, both DNA markers and secalins would be useful as selectable markers for 1RS-derived greenbug resistance. Recombination between 1RS markers did occur when 1RS from ‘Amigo’ and 1RS from ‘GRS1201’were combined, but in such intermatings, the molecular markers described herein could still be used to develop a population enriched in lines carrying Gb6. No differences in grain yield or grain and flour quality characteristics were observed when lines carrying 1RS from ‘Amigo’ were compared with lines with 1RS from ‘GRS1201′. Hence, differences in secalin composition did not result in differential quality effects. When compared with sister lines with 1AL.1AS derived from the wheat cultivar ‘Redland’, lines with ‘GRS1201’had equal grain yield, but produced flours with significantly shorter mix times, weaker doughs, and lower sodium dodecyl sulphate sedimentation volumes.     

PCR-based markers for detection of different sources of 1AL.1RS and 1BL.1RS wheat–rye translocations in wheat background

The rye ( Secale cereale L.) chromosome arm 1RS is one of the most successfully used alien resources in wheat ( Triticum aestivum L.) improvement, and it is still being widely utilized by many breeding programmes. With increasing application of marker-assisted selection in wheat breeding, development of an efficient molecular marker system to monitor and track 1AL.1RS and 1BL.1RS wheat–rye translocations is of practical value. In this study, we systematically evaluated the utility of eight rye-specific molecular markers in detecting 1RS chromatins with different origins in diverse wheat genetic backgrounds. Two such markers, PAWS5/S6 and SCM9 were identified that were able to differentiate multiple sources of wheat–rye translocations involving 1RS. A duplex polymerase chain reaction (PCR) procedure was developed with two rye-specific markers PAWS5/S6 and RIS and tested in a set of representative wheat lines. The two rye-specific markers and the duplex PCR procedure established in this study provided a useful tool in marker-assisted selection of materials containing desirable 1RS chromatin in wheat breeding.     

Bread-making quality and yield performance of 1BL/1RS wheat isogenic lines

Isogenic lines were developed in order to assess the precise effects of the 1BL/1RS translocation on quality characteristics and agronomic traits. Results showed that the translocation has a detrimental effect on sodium dodecyl sulphate sedimentation volume, in any background. Yield was similar between translocated and non-translocated lines; however, lines carrying lBL/1RS showed a significant increase in grain weight, together with a decrease in spike number per plant.     

Segregation for isozymes and HMW glutenins in a doubled-haploid cross of winter wheat carrying 1BL.1RS and 5DL.5RS translocations from rye

The doubled haploid (DH) wheat line ‘dh 5841’ carrying two translocations from rye, 5DL.5RS and 1BL.1RS, has been crossed to the subline of wheat cultivar ‘Amadeus 7143’ with a 1BL.1RS translocation. The resulting F₁ hybrid IJ 98 with a heterozygous 5DL.5DS‐5DL.5RS chromosome pair has been used to produce doubled haploids. A total of 57 DH lines were obtained from plantlets regenerated in anther culture after successful colchicine treatment and seed set. These lines were identified regarding the constitution of chromosome 5D (5DL.5DS or 5DL.5RS) by means of isoenzyme marker analysis. Thirty DH lines possessed the 5DL.5DS chromosome, while the remaining 27 lines carried the 5DL.5RS translocation. For some of these lines, the 5DL.5RS chromosome was cytologically confirmed by C‐banding. Furthermore, the DH lines were evaluated for their high molecular weight glutenin subunit composition. All possible combinations for the four independent loci —Skdh, Glu‐Al, Glu‐B1 and Glu‐D1— were detected in only 57 DH lines and no segregation distortion was observed.     

Quality effect of wheat-rye (1R) translocation in 'Pavon 76'

A growing interest exists in using wheat for producing both hard and soft wheat products. It would be desirable if 1RS translocations in hard wheat could produce flour suitable for soft wheat products. The objective of this study was to test the effects of centric translocations of chromosome 1 from different rye sources for end‐use quality. The quality influences of the 1RS and 1RL translocations and 1R substitutions from different rye sources were studied in a set of hard spring wheat ‘Pavon 76’(CIMMYT) lines in three environments in Georgia. The protein concentration of the 1RL translocations was the highest while the 1RS translocations showed no difference in protein concentration compared with that of controls. The 1RS translocations increased alkaline water retention capacity while the 1RL translocations reduced it. T1DSAE1RL was preferred for soft wheat products over other genotypes.     

Genetic mapping of sequence-specific PCR-based markers on the short arm of the 1BL.1RS wheat-rye translocation

Wheat cultivars carrying the 1BL.1RStranslocation were crossed with newly synthesised octoploid triticale lines involving four rye genotypes having ο-secalin banding patterns different from each other and from that of the 1BL.1RS translocation. Homologous recombination was expected between the short arm of the 1R chromosomes of the rye genotypes and the 1RS arm of the 1BL.1RSwheat/rye translocation. Seven sequence-specific PCR-based markers:Xiag95, RMS13, Bmac0213, GPI, Xpsr960, 5Sand SCM9, and ο-secalinproteins were used to detect recombination events in the BC₁F₂ generation. Segregation analysis demonstrated that a barley SSR marker (Bmac0213) locus was present on the 1RS chromosome arm. Of 834plants tested in four different BC₁F₂ populations, 246individuals were found to carry recombined1BL.1RS translocation chromosomes. Genetic linkage analysis was performed on the eight markers in the four different mapping populations. The physical positions of the markers are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

About the origin of 1RS.1BL wheat-rye chromosome translocations from Germany

In order lo investigate the origin of two of the German 1RS. 1BL wheat-rye translocations used world-wide in breeding, a number of DNA probes were considered which (a) were critical for the short arm of the rye chromosome 1 R and (b) should show a specificity for the gene pool of Petkus rye. The DNA probe CDO580 was revealed as a specific one. (1) It clearly differentiated 1RS.1AL (‘Amigo’). 1RS.lBL (‘Salmon’) and 1RS.1DL (‘Gabo’) from the two German sources. (2) Both translocation wheats deriving from the Weihenstephan (Munich) and from the Salzmünde (Halle/S.) origin showed an identical DNA fragment which was typical for the gene pool of Petkus rye. It is supposed that both German sources have one progenitor in common.     

Importance of wheat-rye translocations for breeding modern cultivar of Triticum aestivum L.

Investigations of the world wheat genepool conducted by Ukraine's National Centre for Plant Genetic Resources produced information on the geographic origins and genetic background of numerous wheat lines possessing the 1BL/1RS wheat-rye translocation, 1B(R) substitution and 1AL/1RS translocation. Wheat-rye translocations can determine high productivity, adaptive possibilities, and disease and insect resistance in wheat. Data on 330 cultivars and lines carrying wheat-rye translocations and/or substitutions were analysed. Based on this information, wheats were classified according to continent and country of origin and year of release. This clarified how translocation sources of different genetic and geographic origins have been used in breeding programmes all over the world. This revised version was published online in August 2006 with corrections to the Cover Date.     

Development and application of a new codominant PCR marker for detecting 1BL·1RS wheat–rye chromosome translocations

The 1BL·1RS translocation has been widely used in wheat breeding programmes throughout the world. Unfortunately, this translocation has frequently resulted in unsatisfactory grain processing quality. Two primer combinations derived from the published sequence of a ω‐secalin gene on 1RS gave polymerase chain reaction (PCR) fragments 0.4 and 1.1 kb in size. Both fragments can be used to quickly detect 1BL·1RS translocations. By combining the PCR assay resulting in the 1.1‐kb fragment from 1RS and a PCR assay resulting in a 0.6‐kb fragment from the Glu‐B3 gene on 1BS, plants homozygous for the 1BL 1RS could clearly be distinguished from the heterozygous ones. This codominant marker was successfully applied to genotype a segregating F₂ population and a local cultivar collection.     

Cumulative and interaction effects of prolamin allelic variation and of 1BL/1RS translocation on flour quality in bread wheat

The allelic variation of prolamin loci was studied in three F₂ progenies from three crosses between the 1BL/1RS cultivar Triana and Yécora Rojo, Pavón and Florence Aurora, cultivars without the translocation. According to the 1:2:1 theoretical proportions observed in the allelic variants of the Glu-B3/Gli-B1 loci of the parent without the translocation, the inheritance as a block of the rye chromosome arm was confirmed. A group of F₃-F₄ recombinant lines, developed from these crosses was evaluated using the SDS-sedimentation test and the mixograph and alveograph tests. The presence of the 1BL/1RS translocation was not associated with significantly lower grain protein content values or with the optimum mixing time in the mixograph of the genotypes. The effect of the 1BL/1RS translocation on most of the quality parameters was highly dependent on the genetic pool. Significant increases in gluten strength and better mixing properties associated with the presence of some alleles of the Glu-A1, Glu-A3/ Gli-A1 and Gli-D2 loci were detected. The additivity and the interaction of prolamin gene effects with the rye translocation in the 1BL/1RS lines and its possible use in plant breeding are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Using a gel-free PCR-ELISA for the molecular identification of wheat genotypes carrying wheat–rye translocations

Current techniques to identify wheat lines possessing the 1RS chromosome are generally unsuitable in relation to the speed and cost needs in modern wheat breeding programmes. A gel-free, direct amplicon capture PCR-ELISA assay was developed and evaluated, aiming at speeding the identification of wheat genotypes possessing the 1RS chromosome arm in breeding programmes. The chosen target sequence was the repetitive, interspersed rye-specific element RIS-1. Primers were end-labelled with digoxigenin and biotin, and amplicons captured on to straptavidine-coated microplates. Subsequent immunodetection of the digoxigenin moiety readily distinguished 1RS from non-1RS control genotypes tested. When a nursery consisting of 120 winter and spring wheat lines was screened by PCR-gel electrophoresis and the PCR-ELISA, a perfect agreement between both techniques was observed. Test robustness, as measured by the tolerance to variations in DNA input, was better for PCR-ELISA than PCR-gel electrophoresis. In conclusion, a simple, robust, fast and scalable technique for the detection of 1RS chromosome carriers in wheat breeding programmes is now available.     

1BL/1RS易位染色体在小麦育种中的应用效果分析

以来自周麦18/郑麦9023//周麦18回交组合的156个BC1F5品系(其中89个为1BL/1RS易位系,67个为非1BL/1RS易位系)为材料,研究1BL/1RS易位染色体在小麦育种中的应用效果。结果表明,在周麦18和郑麦9023遗传背景下,1BL/1RS对产量及其相关性状无显著正向作用,与SDS沉淀值呈显著负相关,与白粉病抗性无显著相关。说明来自"洛类"系统的1BL/1RS易位染色体在特定的遗传背景和生态条件下没有明显值得继续利用的价值。     

Mapping of powdery mildew and leaf rust resistance genes on the wheat-rye translocated chromosome T1BL·1RS using molecular and biochemical markers

Powdery mildew and leaf rust resistance genes on the 1RS arm of the T1BL·1RS translocated chromosome were mapped in relation to the Sec‐1 locus and AFLP and restriction fragment length polymorphism markers, respectively, employing segregating F₃ populations. Integration of molecular markers indicated that Pm17 lies between the Lr26 and Sec‐1 loci, with both resistance genes allocated distally to the Sec‐1 locus in the satellite of the 1RS arm.     

The Effect of Chromosome 1B/1R Translocation on the Yield Potential of Certain Spring Wheats (Triticum aestivum L.)

Nearly 50 percent of the 1988 advanced breeding lines of the CIMMYT bread wheat breeding program possess the 1B/1R homozygous translocation. Hence, a trial was conducted to estimate the effect of 1B/1R chromosome translocation on the yield potential of some of our high-yielding spring wheats, where non-limiting levels of fertility, moisture, preventive pest and disease programs were used. In conclusing the 1B/1R lines seemed to have increased their above-ground biomass yield, number of spikes per meter², 1000-grain weight and test weight. They also exhibited a slight advantage over the 1B homozygous lines on grain yield. The observed difference, however, was non-significant, as was the plant height difference observed among the two groups. Varietal comparisons indicated that the 1B/1R group headed later than the 1B group.     

1BL/1RS易位对小麦加工品质的影响

分析了138份国内小麦品种和14份国外优质品种的1BL/1RS易位状况和高低分子量麦谷蛋白亚基组成，并将其中的78个品种连续两年在两地种植，研究了1BL/1RS易位对小麦籽粒品质和面条品质的影响。结果表明，1BL/1RS易位品种的优质高、低分子量麦谷蛋白亚基出现频率显著低于非1BL/1RS易位品种；1BL/1RS 易位主要影响面团稳定时间、