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1

Use of molecular markers in cereal breeding

100%

Korzun V.

Cellular and Molecular Biology Letters

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2002

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tom 07

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nr 2B

EN

Great advances have been made in recent years in marker detection systems and in the techniques used to identify markers linked to useful traits. While RFLP markers have been the basis for most work in crop plants, useful markers have been generated using RAPD and AFLP methods. More recently, microsatellite or simple sequence repeat (SSR) markers have been developed for major crop plants and this marker system is predicted to lead to even more rapid advances in both marker development and implementation in breeding programs. Identification of markers linked to useful traits has been based on complete linkage maps and bulked segregant analysis. However, alternative methods, such as the construction of partial maps and combination of pedigree and marker information, have also proved useful in identifying marker/trait associations. The value of markers in analysing the inheritance of traits in crop plants and understanding genome structure and organization is now well established. The different properties of markers systems and their applications in genome analysis and molecular breeding of cereals species are discussed.

2

Genetic integrity of ex situ genebank collections

51%

Chebotar S. , Roder M. S. , Korzun V. , Borner A.

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nr 2A

EN

The genetic integrity of four accessions of the cross-pollinating species rye (Secale cereale L.) was investigated. Seeds available from the first and most recent regeneration cycles, multiplied 8, 12 (twice) or 14 times were fingerprinted using microsatellite markers. In all four accessions the allele numbers and frequencies changed after regeneration. Alleles present in the original seed sample were not detectable in the regenerated populations, whereas on the other hand, alleles were found in the recent seed sample, which were not observed in the investigated plants of the original one.

3

Verification of STS markers for leaf rust resistance genes of wheat by seven European laboratories

32%

Blaszczyk L. , Chelkowski J. , Korzun V. , Kraic J. , Ordon F. , Ovesna J. , Purnhauser L. , Tar M. , Vida G.

Cellular and Molecular Biology Letters

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2004

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tom 09

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nr 4B

805-817

EN

A set of Thatcher near-isogenic lines and two breeding lines were used to examine sequence tagged site (STS) markers linked to leaf rust resistance genes Lr9, Lr10, Lr19, Lr24, Lr28, Lr29, Lr35, and a simple sequenced repeat (SSR) marker for Lr39. The selected STS markers for resistance genes Lr9, Lr10, Lr19, Lr24 and Lr28 were identified in seven accessions by seven European laboratories. Near-isogenic lines of the spring wheat Thatcher were used as positive controls. Markers for resistance genes Lr9, Lr10, Lr19, Lr24 were identified in all seven laboratories as amplification products of 1100 bp, 310 bp, 130 bp and 310 bp, respectively. The STS markers linked to resistance genes Lr9, Lr10, Lr19, Lr24, Lr29, Lr35 and the SSR marker for Lr39 were robust and highly specific for these genes and will be useful in marker-assisted selection in wheat. However, the amplification product of 378 bp that corresponded with resistance gene Lr28 was detected in all accessions including genotypes lacking this gene in all seven laboratories. This marker needs to be improved.

4

Extension of the Messapia x dicoccoides linkage map of Triticum turgidum [L.] Thell.

26%

Blanco A. , Simeone R. , Cenci A. , Gadaleta A. , Tanzarella O. A. , Porceddu E. , Salvi S. , Tuberosa R. , Figliuolo G. , Spagnoletti P. , Roder M. S. , Korzun V.

Cellular and Molecular Biology Letters

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2004

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tom 09

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nr 3

EN

A set of recombinant inbred lines (RIL) derived from a cross between the cultivar Messapia of durum wheat (Triticum turgidum var. durum) and the accession MG4343 of T. turgidum var. dicoccoides was analysed to increase the number of assigned markers and the resolution of the previously constructed genetic linkage map. An updated map of the durum wheat genome consisting of 458 loci was constructed. These loci include 261 Restriction Fragment Length Polymorphisms (RFLPs), 91 microsatellites (Simple Sequence Repeats, SSRs), 87 Amplified Fragment Length Polymorphisms (AFLPs), two ribosomal genes, and nine biochemical (seven seed storage proteins and two isozymes) and eight morphological markers. The loci were mapped on all 14 chromosomes of the A and B genomes, and covered a total distance of 3038.4 cM with an average distance of 6.7 cM between adjacent markers. The molecular markers were evenly distributed between the A and the B genomes (240 and 218 markers, respectively). An additional forty loci (8.8%) could not be assigned to a specific linkage group. A fraction (16.4%) of the markers significantly deviated from the expected Mendelian ratios; clusters of loci showing distorted segregation were found on the 1B, 2A, 2B, 3A, 4A, 7A and 7B chromosomes. The genetic lengths of the chromosomes range from 148.8 cM (chromosome 6B) to 318.0 cM (chromosome 2B) and approximately concur with their physical lengths. Chromosome 2B has the largest number of markers (47), while the chromosomes with the fewest markers are 3A and 6B (23). There are two gaps larger than 40 cM on chromosomes 2A and 3B. The durum wheat map was compared with the published maps of bread and durum wheats; the order of most common RFLP and SSR markers on the 14 chromosomes of the A and B genomes were nearly identical. A core-map can be extracted from the highdensity Messapia x dicoccoides map and a subset of uniformly distributed markers can be used to detect and map quantitative trait loci.