Characterization of three wheat cultivars possessing new 1BL.1RS wheat-rye translocations

The wheat-rye 1BL.1RS translocation chromosomes have been used widely around the world in commercial wheat ( Triticum aestivum L.) production because of the presence of several disease resistance genes and a yield enhancement factor on the rye ( Secale cereale L.) chromosome. However, the recent reports of the loss of complete effectiveness of the disease resistance genes on the most commonly used 1BL.1RS chromosome have highlighted the need to seek and deploy additional sources of disease resistance genes. Three new sibling wheat cultivars, 'CN12', 'CN17' and 'CN18', were developed carrying 1RS arms derived from the rye inbred line L155. Genomic in situ hybridization and C-banding analysis revealed that all the three cultivars contained the rye chromosome 1RS arm fused to the wheat 1BL wheat chromosome arm. The three cultivars displayed high yields and high resistance to local powdery mildew and stripe rust pathotypes. Fluorescence in situ hybridization analysis indicated the different structure of 1BL.1RS chromosome between 'CN18' and the other two cultivars. The present study provides a new 1RS resource for wheat improvement.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Further manipulation by centric misdivision of the 1RS.1BL translocation in wheat

Complete chromosomes 1R and 1B were reconstructed in wheat from the centric wheat-rye translocation 1RS.1BL. Three substitutions: 1R(1A), 1R(1B), 1R(1D), and three new centric translocations: 1RS.1AL, 1RS.1BL, 1RS.1DL were produced from the reconstructed chromosome 1R. Each one of these has the same rye chromosome arm 1RS which was present in the original translocation 1RS.1BL of ‘Kavkaz’ wheat. Reconstructed chromosome 1B and a normal chromosome 1R were used to produce a new 1RS.1BL translocation. This translocation has the long arm from the original 1RS.1BL translocation of ‘Kavkaz’, but a different 1RS arm. The third generation centric translocations were mitotically stable and were normally transmitted to progeny. Misdivision frequency of the reconstructed chromosomes 1R did not change relative to normal 1R, whereas the misdivision frequency of the two reconstructed chromosomes 1B tested was significantly higher relative to normal 1B. These experiments demonstrate that repeated cycles of centric breakage and fusion do not impair the function of centromeres in wheat and rye but may change chromosome's susceptibility to misdivision. This revised version was published online in July 2006 with corrections to the Cover Date.     

SDS-PAGE of the high-molecular-weight subunits of wheat glutenin and the characterization of 1R (1B) substitution and 1BL/1RS translocation lines

Summary The high-molecular-weight subunits of glutenin from wheat 1R(1B) substitution and 1BL/1RS translocation lines were fractionated by SDS-PAGE. Two new subunits denoted R₁ and R₂ were characterized in 1R(1B) substitution, but not in 1BL/1RS translocation lines. R₁ and R₂ were proved to be rye proteins by 2d electrophoresis (NEPHGE x SDS-PAGE).In contrast to literature citations it was demonstrated that the cultivar Winnetou is a 1R(1B) substitution line and the cultivars Clement and Mildress both are 1BL/1RS translocation lines.     

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.     

1BL/1RS易位对小麦贮藏蛋白组分含量和面团流变学特性的影响

利用1BL/1RS易位系后代研究1BL/1RS易位对贮藏蛋白组分含量和面团流变学特性的影响有助于指导小麦品质改良工作。选用师栾02-1/周麦16组合14份F6品系,于2012—2013年度分别种植在河南安阳和焦作,采用反相超高效液相色谱(RP-UPLC)和凝胶排阻超高效液相色谱(SE-UPLC)方法分析贮藏蛋白组分含量,并研究它们与面团流变学特性的关系。结果表明,拉伸仪延展性和最大抗延阻力、不溶性谷蛋白聚合体含量和谷蛋白、醇溶蛋白等贮藏蛋白组分含量及其比例均受1BL/1RS易位有无类别和类内品系效应的显著影响,以类内品系效应较大;拉伸仪拉伸面积、谷蛋白含量及醇溶蛋白与谷蛋白含量比值的类内品系效应显著且较大。易位系和非易位系的贮藏蛋白组分含量和面团流变学特性的相关系数达显著水平,在易位系中,不溶性谷蛋白聚合体含量和拉伸面积(r=0.92,P0.001)、延展性(r=0.92,P0.001)、最大抗延阻力(r=0.80,P0.01)呈显著正相关,面团流变学特性较好的品系不溶性谷蛋白聚合体含量均较高;在非易位系中,醇溶蛋白与谷蛋白含量比值和拉伸面积(r=?0.91,P0.001)、最大抗延阻力(r=?0.88,P0.001)呈显著负相关,面团流变学特性较好的品系醇溶蛋白与谷蛋白含量比值均较低。上述信息对以不溶性谷蛋白聚合体含量和醇溶蛋白与谷蛋白含量比值为指标改良1BL/1RS易位系的面筋品质有重要意义。     

小麦育种亲本材料Dx5、Bx14亚基及1BL/1RS易位的分子检测

为给小麦优质育种的亲本选配等研究提供参考,利用优质谷蛋白Dx5、Bx14亚基及1BL/1RS易位的特异性分子标记,对本课题组近年常用的38份杂交亲本材料进行了分子检测.结果表明,在引进品种和自育品种(系)中,含Dx5亚基的材料分别占16.0％和7.7％,含Bx14亚基的材料分别占16.0％和23.1％,1BL/1RS易位材料分别占24.0％和38.5％.与引进品种相比,自育品种(系)含Dx5亚基的材料很少,而含Bx14亚基和1BL/1RS易位的材料较多.总体来看,育种亲本含Dx5、Bx14亚基的材料较少,而含1BL/1RS易位的材料相对较多.因此,今后小麦优质育种中应重视含Dx5、Bx14亚基材料的引进和利用,合理使用1BL/1RS易位材料,并加强杂种后代的分子鉴定与选择.     

A comparison of methods for identifying and surveying the presence of 1BL.1RS translocations in bread wheat

Summary Four methods for detecting 1BL. 1RS translocations in bread wheat have been compared winter wheat cultivars: N-banding of mitotic metaphase chromosomes, sodium lactate electrophoresis at pH 3.1, sodium dodecyl sulphate-polyacrylamide gel electrophorests under conditions, and a recently characterised protein, subtilisin inhibitor, separated by isoelectric N-banding was much the most labour intensive method, and, of the three electrophoretic recommend the use of subtilisin inhibitor, which is at least as easy to interpret as the other is often faster for screening purposes. The sources of the 1BL. 1RS translocation in this matenal Avrora. Kavkaz and Skorospelka 35, which have been extensively used as parents in breeding programmes. Out of 59 cultivars that include a line carrying the 1BL. 1RS pedigree. 23 of them did not carry the translocation; thus the effect on plant phenotype of insufficient to guarantee its selection during breeding.     

The effect of chromosome 1AL/1RS translocation on agronomic performance of 85 F2-derived F6 lines from three Triticum aestivum L. crosses

Summary The effect of the 1AL/1RS chromosome translocation on grain yield and other agronomic characteristics of 85 random F₂-derived F₆ bulks from three 1AL 1RS × 1A bread wheat crosses was determined under optimum and reduced irrigation conditions at CIANO, Yaqui Valley, Sonora, Mexico, during the 1991–1992 and 1992–1993 crop production cycles. Harvest plots of 5.0 m² were arranged in an alpha lattice design with three replications. The 1AL/1RS translocation increased grain yield, above-ground biomass, spikes/m², and test weight under both irrigated and dryland conditions. Homozygous chromosome 1A lines, on the other hand, possessed longer spikes with more grains. The 1AL/1RS cultivars had an advantage in 1000-grain weight, which was detected only under optimum irrigation. The translocation lines showed later maturity and longer grainfilling period than the 1A genotypes under one irrigation treatment. A significant relationship between grain yield and test weight was detected only among the 1AL/1RS genotypes, indicating that they possess heavier and plumper grains than the 1A genotypes. These results encourage the continued use of the 1AL/1RS translocation in wheat improvement.