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  • 1
    ISSN: 0957-4166
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0968-0004
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2242
    Keywords: Key words Barley ; Genome mapping ; Stripe rust ; Leaf rust ; BYDV ; Resistance Gene Analog Polymorphism ; QTL
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Stripe rust, leaf rust, and Barley Yellow Dwarf Virus (BYDV) are important diseases of barley (Hordeum vulgare L). Using 94 doubled-haploid lines (DH) from the cross of Shyri x Galena, multiple disease phenotype datasets, and a 99-marker linkage map, we determined the number, genome location, and effects of genes conferring resistance to these diseases. We also mapped Resistance Gene Analog Polymorphism (RGAP) loci, based on degenerate motifs of cloned disease resistance genes, in the same population. Leaf rust resistance was determined by a single gene on chromosome 1 (7H). QTLs on chromosomes 2 (2H), 3 (3H), 5 (1H), and 6 (6H) were the principal determinants of resistance to stripe rust. Two- locus QTL interactions were significant determinants of resistance to this disease. Resistance to the MAV and PAV serotypes of BYDV was determined by coincident QTLs on chromosomes 1 (7H), 4 (4H), and 5 (1H). QTL interactions were not significant for BYDV resistance. The associations of molecular markers with qualitative and quantitative disease resistance loci will be a useful information for marker-assisted selection.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2242
    Keywords: Key words Hordeum vulgare ; Two-rowed ; Six-rowed ; Quality traits ; Quantitative trait loci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Characterization of the determinants of economically important phenotypes showing complex inheritance should lead to the more effective use of genetic resources. This study was conducted to determine the number, genome location and effects of QTLs determining malting quality in the two North American barley quality standards. Using a doubled-haploid population of 140 lines from the cross of Harrington×Morex, malting quality phenotype data sets from eight environments, and a 107-marker linkage map, QTL analyses were performed using simple interval mapping and simplified composite interval mapping procedures. Seventeen QTLs were associated with seven grain and malting quality traits (percentage of plump kernels, test weight, grain protein percentage, soluble/total protein ratio, α-amylase activity, diastatic power and malt-extract percentage). QTLs for multiple traits were coincident. The loci controlling inflorescence type [vrs1 on chromosome 2(2H) and int-c on chromosome 4(4H)] were coincident with QTLs affecting all traits except malt-extract percentage. The largest effect QTLs, for the percentage of plump kernels, test weight protein percentage, S/T ratio and diastatic power, were coincident with the vrs1 locus. QTL analyses were conducted separately for each sub-population (six-rowed and two-rowed). Eleven new QTLs were detected in the subpopulations. There were significant interactions between the vrs1 and int-c loci for grain-protein percentage and S/T protein ratio. Results suggest that this mating of two different germplasm groups caused a disruption of the balance of traits. Information on the number, position and effects of QTLs determining components of malting quality may be useful for maintaining specific allele configurations that determine target quality profiles.
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  • 5
    ISSN: 1432-2242
    Keywords: (Hordeum vulgare L.) ; Hordeum bulbosum ; Haploid production ; Floret culture ; Detached tiller culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A high efficiency of Hordeum bulbosum-mediated haploid production in barley has been achieved using a floret culture technique in which florets pollinated with Hordeum bulbosum are cultured on modified N6 media containing 0.5 mg/l kinetin and 1.2 mg/l2,4-D. Cultures were maintained at 25 °C with a 16 h photoperiod for 9 days before embryo rescue. In a comparison of haploid production efficiency using five F1 hybrids from winter x winter and winter x spring barley crosses, 41.6 haploid plants/100 florets pollinated were produced using floret culture. Using detached tiller culture, 13.5 haploid plants/100 florets pollinated were produced. Higher efficiencies achieved with floret culture are attributed to the formation of larger, differentiated embryos. Such embryos lead to higher frequencies of plant regeneration. The F1 from a winter x winter cross was inferior in haploid production compared to F1s from winter x spring crosses. No genotype x technique interaction was observed.
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  • 6
    ISSN: 1432-2242
    Keywords: Sequence-tagged-site ; Polymerase chain reaction ; Polyacrylamide-gel electrophoresis ; Four-base cutter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Speed, efficiency, and safety considerations have led many genome mapping projects to evaluate polymerase chain reaction (PCR) sequence amplification as an alternative to Southern blot analysis. However, the availability of informative primer sequences can be a limiting factor in PCR-based mapping. An alternative to random amplified polymorphism detection (RAPD) is the sequence-tagged-site (STS) approach. If informative primer sequences could be derived from known sequences, then current maps, which are based on both known function and anonymous clones, might be easily converted to maps utilizing PCR technology. In this paper, four pairs of primer sequences were obtained from published sequences, and four pairs were obtained by sequencing portions of DNA clones from genomic clones derived from a random genomic library used in the North American Barley Genome Mapping Project (NABGMP). These primers were used to screen for polymorphisms in the progeny of a winter x spring and a spring x spring barley cross. Two types of polymorphisms were distinguished using these primer sets: (1) insertion/deletion events that could be read directly from agarose gels, and (2) point mutation events. The latter were identified using polyacrylamide-gel electrophoresis of PCR products following digestion with restriction endonucleases (four-base cutters). To determine whether the PCR-based polymorphisms were allelic to polymorphisms identified by the clones from which the primer sequences derived, chromosomal assignments and (when possible) co-segregation analysis was performed.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-2242
    Keywords: QTL mapping ; β-Glucan ; β-Glucanase Malt barley ; Hordeum vulgare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic study of β-glucan content and β-glucanase activity has been facilitated by recent developments in quantitative trait loci (QTL) analysis. QTL for barley and malt β-glucan content and for green and finished malt β-glucanase activity were mapped using a 123-point molecular marker linkage map from the cross of Steptoe/Morex. Three QTL for barley β-glucan, 6 QTL for malt β-glucan, 3 QTL for β-glucanase in green malt and 5 QTL for β-glucanase in finished malt were detected by interval mapping procedures. The QTL with the largest effects on barley β-glucan, malt βglucan, green malt β-glucanase and finished malt βglucanase were identified on chromosomes 2,1,4 and 7, respectively. A genome map-based approach allows for dissection of relationships among barley and malt βglucan content, green and finished malt β-glucanase activity, and other malting quality parameters.
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  • 8
    ISSN: 1432-2242
    Keywords: Key wordsHordeum vulgare ; Quantitative trait loci ; Genotype×environment interaction ; Pattern analysis ; Molecular marker-assisted selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The additive main effects and multiplicative interaction (AMMI) model has emerged as a powerful analytical tool for genotype × environment studies. The objective of the present study was to assess its value in quantitative trait locus (QTL) mapping. This was done through the analysis of a large two-way table of genotype-by-environment data of barley (Hordeum vulgare L.) grain yields, where the genotypes constituted a genetic population suitable for mapping studies. Grain yield data of 150 doubled haploid lines derived from the ‘Steptoe’בMorex’ cross, and the two parental lines, were taken by the North American Barley Genome Mapping Project (NABGMP) at 16 environments throughout the barley production areas of the USA and Canada. Four regions of the genome were responsible for most of the differential genotypic expression across environments. They accounted for approximately 50% of the genotypic main effect and 30% of the genotype×environment interaction (GE) sums of squares. The magnitude and sign of AMMI scores for genotypes and sites facilitate inferences about specific interactions. The parallel use of classification (cluster analysis of environments) and ordination (principal component analysis of GE matrix) techniques allowed most of the variation present in the genotype×environment matrix to be summarized in just a few dimensions, specifically four QTLs showing differential adaptation to four clusters of environments. Thus, AMMI genotypic scores, when the genotypes constituted a population suitable for QTL mapping, could provide an adequate way of resolving the magnitude and nature of QTL×environment interactions.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2242
    Keywords: Key words Fine mapping ; Additive effects ; Marker assisted backcrossing ; Isogenic lines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Current techniques for quantitative trait locus (QTLs) analyses provide only approximate locations of QTLs on chromosomes. Further resolution of identified QTL regions is often required for detailed characterization. An important region containing malting-quality QTLs on barley (Hordeum vulgare L.) chromosome 1 was identified by previous QTL analyses in a Steptoe×Morex cross. This region contains two putative adjacent overlapping QTLs, each of which has effects on malt-extract percentage, α-amylase activity, diastatic power, and malt β-glucan content. All favorable alleles for these traits are attributed to Morex. The objective of the present study was fine structure mapping of this complex QTL region to elucidate whether these two putative overlapping QTLs are really one QTL. Another question was whether the apparently overlapping QTLs are due to the pleiotropic effects of a single gene, or the independent effects of several genes. A high-resolution map in the target region was developed which spans approximately 27 cM. Molecular-marker-assisted backcrossing was employed to create isogenic lines with a Steptoe background differing only in the region containing the QTLs of interest. A total of 32 different recombinants were identified, of which eight most-informative isogenic lines plus one reconstructed Steptoe control were selected for field testing. The additive effects on malt-extract percentage, α-amylase activity, diastatic power, and malt β-glucan content from eight isogenic lines were calculated based on malting data from three locations. By comparing the significant additive effects among isogenic lines carrying different Morex fragments, two QTLs each for malt extract and for α-amylase, and two to three for diastatic power were identified in certain environments and resolved into 1–8-cM genome fragments. There was a significant QTL×environment interaction for diastatic power, and there are indications that epistatic interactions for malt β-glucan content occur between the QTLs on chromosome 1 and QTLs on other chromosomes.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-2242
    Keywords: RFLP ; Mapping ; Barley ; Genome ; Centromeres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A map of the barley genome consisting of 295 loci was constructed. These loci include 152 cDNA restriction fragment length polymorphism (RFLP), 114 genomic DNA RFLP, 14 random amplified polymorphic DNA (RAPD), five isozyme, two morphological, one disease resistance and seven specific amplicon polymorphism (SAP) markers. The RFLP-identified loci include 63 that were detected using cloned known function genes as probes. The map covers 1,250 centiMorgans (cM) with a 4.2 cM average distance between markers. The genetic lengths of the chromosomes range from 124 to 223 cM and are in approximate agreement with their physical lengths. The centromeres were localized to within a few markers on all of the barley chromosomes except chromosome 5. Telomeric regions were mapped for the short (plus) arms of chromosomes 1, 2 and 3 and the long (minus) arm of chromosomes 7.
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