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Acta Veterinaria Hungarica
Authors: S. Bodó, B. Baranyai, Elen Gócza, J. Dohy, and Merja Markkula

Preimplantation Genetic Diagnosis (PGD) is reviewed and novel fields where it may be applied are investigated. Technical advances of PGD in cattle embryos have already enabled its integration as a part of the MOET (Multiple Ovulation Embryo Transfer) breeding system. PGD for well-defined selection targets can enhance cattle breeding and embryo trade. It allows embryo selection according to their sex, and it may be used to breed special cow lines, or top bulls, by selecting embryos for valuable production traits using Marker Assisted Selection (MAS). A good allelic profile and/or the insertion of a transgene can be detected by PGD. This review article presents the technical requirements for PGD, and shows that this biotechnological method has great economic potential.

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Acta Agronomica Hungarica
Authors: M. Hudcovicová, V. Šudyová, S. Šliková, E. Gregová, J. Kraic, F. Ordon, D. Mihálik, V. Horevaj, and Z. Šramková

Marker-assisted selection (MAS) is an efficient modern method for transferring alleles or specific chromosome segments including important agronomic traits into elite cultivars. This approach makes genotypic selection possible, whereby the selection process is more effective. The Research Institute of Plant Production Piešťany uses genetic markers linked to important traits in the following pre-breeding programmes: 1. development of winter barley lines resistant to BaYMV/BaMMV, 2. development of spring barley lines resistant to BYDV, 3. development of winter wheat lines resistant to leaf rust (gene pyramiding), 4. improvement of wheat quality by new combination(s) of known HMW-GS and/or by introduction of novel HMW-GS alleles. Several hundreds of genotypes are usually analysed for the presence or absence of linked molecular markers and selected for use in breeding programmes.

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Barley ( Hordeum vulgare L.) is one of the most economically important crops around the world. Diseases caused by fungi and viruses significantly reduce yield. The most important fungal diseases are leaf rust caused by Puccinia hordei , and powdery mildew caused by Blumeria graminis f. sp. hordei . The most economical and ecologically friendly way to avoid losses caused by these diseases is growing resistant varieties. Concerning practical breeding for powdery mildew and leaf rust resistance, simple, cheap and robust selection methods are required. Marker assisted selection (MAS) is of great potential to fulfil this demand. In this paper, we present development of a robust duplex marker for simultaneous selection of Rph7 , and presence of one of the following Mla alleles: Mla16, Mla19, Mla20, Mla21, Mla27 or Mla28 .

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Rice ( Oryza sativa L.) is one of the most important crops in the world, especially Asian countries. Genetics of important traits in rice for yield improvement have always been a major breeding objective. Agronomic traits are inherited quantitatively, so quantitative trait loci (QTL) mapping for the potential use of molecular markers would be very helpful to plant breeders in developing improved rice varieties. In this investigation, a SSR linkage map of 1440.7cM of rice was constructed using 105 polymorphic simple sequence repeat (SSR) markers. The mapping population of 236 F 2:3 families derived from the cross of two rice varieties (Gharib × Sepidroud) was used for QTL mapping of agronomic traits. As many as 38 QTLs were detected to be associated with agronomic characteristics; some of them are being reported for the first time. The identified QTLs on specific chromosome regions explaining high phenotypic variance could be considered to use in marker-assisted selection (MAS) programs.

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The location of major QTLs or even genes controlling abiotic stress tolerance is now possible by the application of marker-mediated techniques. This is achieved by exploiting precise genetic stocks, such as doubled haploids (DHs), recombinant substitution lines (RSLs) and recombinant inbred lines (RILs), along with the comprehensive genetic maps now available through the application of molecular marker techniques. These strategies are illustrated here showing how QTLs/genes affecting vernalization response, cold tolerance, osmotic adjustment, osmolite accumulation (free amino acids, polyamines and carbohydrates), salt tolerance and cold-regulated protein accumulation have been identified and located. Also, an example of marker-assisted selection (MAS) for frost tolerance is presented. Major loci and QTLs affecting stress tolerance in Triticeae have been mapped on the group 5 chromosomes, where the highest concentration of abiotic stress-related QTLs (vernalization response, frost tolerance, salt tolerance and osmolite accumulation) was located. A conserved region with a major role in osmotic adjustment has been located on the group 7 chromosomes.

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A panel of 94 diverse hexaploid wheat accessions was used to map quantitative trait loci (QTL) underlying the yield related traits on chromosome 3A. Population structure and kinships were estimated using unlinked SSR markers from all 21 chromosomes. Analysis of variance revealed significant difference among accessions; however, genotype × year interaction was non-significant for majority of yield related traits. A mixed linear model (MLM) approach identified six QTLs for four traits that individually accounted for 10.7 to 17.3% phenotypic variability. All QTLs were consistently observed for both study years. New putative QTLs for the maximum fertile florets per spike and spike length were identified. This report on QTLs for yield related traits on chromosome 3A will extend the existing knowledge and may prove useful in marker-assisted selection (MAS) for development of high yielding cultivars.

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Implementation of marker assisted selection (MAS) in conventional breeding programs could allow assessment of the genetic potential of specific genotypes prior to their phenotypic evaluation. Furthermore, it could identify important trait alleles or marker-trait associations for further determination of a precise position for the loci of interest. Potential uses of microsatellite markers in molecular evaluation of bread-making quality was tested in a sample of 69 wheat genotypes that were genotyped with 3 microsatellites linked to previously mapped QTLs for loaf volume and Hagberg falling number on chromosome 3A. A total of 19 alleles were found, with an average of 6.33 alleles per loci, and average PIC value of 0.40. Specific SSR alleles were tested for association with bread-making related parameters. The association study approach, which uses statistical analysis of marker and phenotypic data, showed significant association of a specific allele at the GWM674 locus with Hagberg falling number in wheat.

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Based on published results in 52 peer reviewed articles QTL for FHB resistance are summarized and compared. Suggestions for resistance breeding are given.

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Acta Agronomica Hungarica
Authors: A. A. Belousov, V. M. Sokolo, Y. M. Sivolap, V. P. Domenjuk, and N. J. Storcheus

The performance of maize hybrids developed on the basis of recombined inbred lines (RIL) selected from an F2 hybrid population using marker-assisted selection (MAS) was studied. The task was to estimate the efficiency of DNA marker technology for intrapopulation selection and to study the performance of hybrids produced from marker-derived inbreds of the F2 population (GK 26 × Mo 17). Two hundred RILs of marker origin were crossed with 3 unrelated testcross lines from the Lacaune, Mindszentpuszta and Reid heterotic groups. An effective marker test system and informative marker criteria were elaborated for increasing MAS effectiveness. A two-locus system on the basis of linked SSR markers proved to be the most effective. The genetic improvement effect (ΔG) of the C1 population for plant productivity, plant height and grain length ranged from 9.1 to 16.1%, depending on the phenotypic trait and h2 level. The best hybrids developed on the basis of RILs of marker origin outyielded the national check for grain yield by 6.8-7.6%.

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In PI466495, a powdery mildew resistance source of wild barley ( Hordeum vulgare ssp. spontaneum ), one gene conferring powdery mildew resistance was identified in the Mla locus. In this paper, the RGH1a gene sequence was used as source for the development of a cleaved amplified polymorphic sequence (CAPS) marker. Co-segregation between this marker and powdery mildew resistance was analysed by specific DNA fragments associated with each allele of the gene using 286 F 2 plants derived from a cross between winter barley ( H. vulgare L.) variety ‘Tiffany’ and PI466495. For the co-dominant marker RGH1aI1a , three fragments, 370 bp, 82 bp and 59 bp in size, were amplified from F 2 plants exhibiting resistance reaction types 0 and 0–1 to powdery mildew; whereas two fragments, 429 bp and 82 bp in size, were amplified in susceptible plants. Simple procedures based on polymerase chain reaction and restriction enzyme digestion allowed for identifying the plants susceptible to powdery mildew ( Blumeria graminis f. sp. hordei ) and plants homozygous or heterozygous for the resistance allele. The RGH1aI1a marker was positioned 0.85 cM to the resistance gene and the efficiency of marker-assisted selection (MAS), evaluated as the probability of crossing-over between the marker and the targeted gene, was 99%. The CAPS marker RGH1aI1a is a valuable candidate for MAS and gene transfer into barley varieties susceptible to powdery mildew.

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