| 1. |
- Hagenblad, Jenny, et al.
(författare)
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Exploring the population genetics of genebank and historical landrace varierties
- 2012
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Ingår i: Genetic Resources and Crop Evolution. - : Springer. - 0925-9864 .- 1573-5109. ; 59:6, s. 1185-1199
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Tidskriftsartikel (refereegranskat)abstract
- Landrace accessions have long been recognized as an important source of genetic diversity for crop species, and landraces are stored in genebanks across the world as genetic resources for future crop development. Landraces are also an important part of the human cultural heritage and as such they have been used for genetic studies to make inferences about historical agriculture. However, surprisingly little is known about the within-accession diversity of landrace crops of different species. In order to evaluate the diversity of Swedish landraces we used microsatellite markers to genotype accessions of four species (barley, pea, oats and rye), both extant genebank material and 114-year-old seed samples of similar geographic origin and type. We found consistently high levels of within-population genetic diversity in the historical material, but varying and often lower diversity levels in the genebank accessions. We also make tentative conclusions about how representative the genebank material is to what was originally cultivated in its reported area of origin and suggest that the true identity of the genebank accessions is unclear and that historical seed collections should be a more appropriate material for the study of historical agriculture.
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| 2. |
- Asplund, Linnea, et al.
(författare)
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Allelic Variation at the Rht8 Locus in a 19th Century Wheat Collection
- 2012
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Ingår i: Scientific World Journal. - : Hindawi Limited. - 1537-744X .- 2356-6140. ; , s. 385610-
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Tidskriftsartikel (refereegranskat)abstract
- Wheat breeding during the 20th century has put large efforts into reducing straw length and increasing harvest index. In the 1920s an allele of Rht8 with dwarfing effects, found in the Japanese cultivar “Akakomugi,” was bred into European cultivars and subsequently spread over the world. Rht8 has not been cloned, but the microsatellite marker WMS261 has been shown to be closely linked to it and is commonly used for genotyping Rht8. The “Akakomugi” allele is strongly associated with WMS261-192bp. Numerous screens of wheat cultivars with different geographical origin have been performed to study the spread and influence of the WMS261-192bp during 20th century plant breeding. However, the allelic diversity of WMS261 in wheat cultivars before modern plant breeding and introduction of the Japanese dwarfing genes is largely unknown. Here, we report a study of WMS261 allelic diversity in a historical wheat collection from 1865 representing worldwide major wheats at the time. The majority carried the previously reported 164 bp or 174 bp allele, but with little geographical correlation. In a few lines, a rare 182 bp fragment was found. Although straw length was recognized as an important character already in the 19th century, Rht8 probably played a minor role for height variation. The use of WMS261 and other functional markers for analyses of historical specimens and characterization of historic crop traits is discussed.
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| 3. |
- Asplund, Linnea, et al.
(författare)
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Re-evaluating the history of the wheat domestication gene NAM-B1 using historical plant material
- 2010
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Ingår i: JOURNAL OF ARCHAEOLOGICAL SCIENCE. - : Elsevier Science B.V., Amsterdam. - 0305-4403 .- 1095-9238. ; 37:9, s. 2303-2307
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Tidskriftsartikel (refereegranskat)abstract
- The development of agriculture is closely associated with the domestication of wheat, one of the earliest crop species. During domestication key genes underlying traits important to Neolithic agriculture were targeted by selection. One gene believed to be such a domestication gene is NAM-B1, affecting both nutritional quality and yield but with opposite effects. A null mutation, first arisen in emmer wheat, decreases the nutritional quality but delays maturity and increases grain size; previously the ancestral allele was believed lost during the domestication of durum and bread wheat by indirect selection for larger grain. By genotyping 63 historical seed samples originating from the 1862 International Exhibition in London, we found that the ancestral allele was present in two spelt wheat and two bread wheat cultivars widely cultivated at the time. This suggests that fixation of the mutated allele of NAM-B1 in bread wheat, if at all, occurred during modern crop improvement rather than during domestication. We also discuss the value of using archaeological and historical plant material to further the understanding of the development of agriculture.
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| 4. |
- Edstam, Monika, 1981-
(författare)
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Plant lipid transfer proteins : Evolution, expression and function
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The plant non-specific lipid transfer proteins (nsLTPs) are known for the ability to transfer different lipids in vitro, but their in vivo functions have not yet been elucidated. They seem to play a role in the defense against biotic and abiotic stresses; the gene expression of nsLTPs is often upregulated when exposed to stresses. Further, two different nsLTPs have been shown to affect the lipid composition of the plant cuticle, a structure acting as a protective barrier. However, more evidence is needed to prove this hypothesis and to pinpoint their exact role in this process.In this thesis I have shown that the nsLTPs are found in all land plants, but not in any of the studied algae. This supports a role in defense response, since protection against dehydration, radiation, pathogens and other stresses played a crucial role when plants adapted to a life on land. Characterization of the nsLTPs in early diverging land plant revealed that even though the amino acid similarity towards nsLTPs in flowering plants is not very high, the main properties of the proteins are still the same (Paper I). This includes the protein structure, which consists of α-helices surrounding a lipid binding cavity, a conserved pattern of cysteine residues involved in disulphide bonds and a signal sequence directing the protein to the extracellular space. Further, the expression of nsLTPs in the moss Physcomitrella patens was shown to respond to stresses, and construction of an YFP-LTP fusion protein confirmed the localization to the periphery of the cell in planta (Paper II). Heterologous expressed Physcomitrella nsLTPs were also shown to have the ability to bind lipids and to be very heat stable, features previously only studied in nsLTPs from flowering plants. By examining the presence of a cuticle in Physcomitrella, a correlation between the nsLTPs´ lipid binding ability and the lipid composition of the cuticle could be found, which further strengthens the involvement of nsLTPs in transfer of lipids for cuticle construction.In the flowering plant Arabidopsis thaliana, I showed that several of the nsLTPs followed the same expression pattern when examining data from different tissues, stress treatments, hormones, chemical treatments and developmental stages, but also that four of the genes were undergoing alternative splicing resulting in different isoforms of the proteins (Paper III). Based on their expression patterns, the genes could be divided into three different coexpression networks. By examining other genes similarly expressed, each network could be designated to a putative function: Transfer of lipids for synthesis of the cuticle, suberin layer and sporopollenin, respectively. In Paper IV, these hypotheses were tested in vivo by examining knockout mutants of several nsLTPs in Arabidopsis. The involvement in sporopollenin deposition could be confirmed; two of the knockout lines showed collapsed pollen grains. Further, two other lines showed an increased seed coat permeability due to an altered lipid composition of the suberin layer. Together, the results support a role for nsLTPs in construction of the protecting barriers in all land plants.
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| 5. |
- Hagenblad, Jenny, Associate Professor, 1974-, et al.
(författare)
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Data from: Farmers without borders - genetic structuring in century old barley (Hordeum vulgare)
- 2014
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Annan publikationabstract
- The geographic distribution of genetic diversity can reveal the evolutionary history of a species. For crop plants, phylogeographic patterns also indicate how seed has been exchanged and spread in agrarian communities. Such patterns are, however, easily blurred by the intense seed trade, plant improvement and even genebank conservation during the twentieth century, and discerning fine-scale phylogeographic patterns is thus particularly challenging. Using historical crop specimens, these problems are circumvented and we show here how high-throughput genotyping of historical nineteenth century crop specimens can reveal detailed geographic population structure. Thirty-one historical and nine extant accessions of North European landrace barley (Hordeum vulgare L.), in total 231 individuals, were genotyped on a 384 single nucleotide polymorphism assay. The historical material shows constant high levels of within-accession diversity, whereas the extant accessions show more varying levels of diversity and a higher degree of total genotype sharing. Structure, discriminant analysis of principal components and principal component analysis cluster the accessions in latitudinal groups across country borders in Finland, Norway and Sweden. FST statistics indicate strong differentiation between accessions from southern Fennoscandia and accessions from central or northern Fennoscandia, and less differentiation between central and northern accessions. These findings are discussed in the context of contrasting historical records on intense within-country south to north seed movement. Our results suggest that although seeds were traded long distances, long-term cultivation has instead been of locally available, possibly better adapted, genotypes.
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| 6. |
- Hagenblad, Jenny, Associate Professor, 1974-, et al.
(författare)
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Data from: Twentieth-century changes in the genetic composition of Swedish field pea metapopulations
- 2012
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Annan publikationabstract
- Landrace crops are formed by local adaptation, genetic drift and gene flow through seed exchange. In reverse, the study of genetic structure between landrace populations can reveal the effects of these forces over time. We present here the analysis of genetic diversity in 40 Swedish field pea (Pisum sativum L.) populations, either available as historical seed samples from the late nineteenth century or as extant gene bank accessions assembled in the late twentieth century. The historical material shows constant high levels of within-population diversity, whereas the extant accessions show varying, and overall lower, levels of within-population diversity. Structure and principal component analysis cluster most accessions, both extant and historical, in groups after geographical origin. County-wise analyses of the accessions show that the genetic diversity of the historical accessions is largely overlapping. In contrast, most extant accessions show signs of genetic drift. They harbor a subset of the alleles found in the historical accessions and are more differentiated from each other. These results reflect how, historically present metapopulations have been preserved during the twentieth century, although as genetically isolated populations.
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| 7. |
- Hagenblad, Jenny, et al.
(författare)
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Genetic diversity in local cultivars of garden pea (Pisum sativum L.) conserved on farm and in historical collections
- 2014
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Ingår i: Genetic Resources and Crop Evolution. - : Springer Verlag (Germany). - 0925-9864 .- 1573-5109. ; 61:2, s. 413-422
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Tidskriftsartikel (refereegranskat)abstract
- During a national Swedish collection mission of vegetable varieties conserved on farm more than 70 pea accessions were obtained, many of which had been grown locally for more than 100 years. In spite of a likely origin in the multitude of obsolete commercial pea varieties available on the Swedish seed market in the nineteenth century, the rediscovered local cultivars have lost their original names and cultivar identity while being maintained on farm. To analyze genetic diversity in the repatriated material, 20 accessions were genotyped with twelve SSR markers and compared with 15 obsolete cultivars kept in genebanks and 13 cultivars preserved as non-viable seeds collected in 1877-1918. Most of the local cultivars were genetically distinct from each other, and in only a few cases could a possible origin in a tested obsolete cultivar be suggested. These results reflect the wide diversity of pea cultivars present in Sweden during the nineteenth century. Both between and within accession genetic diversity was larger among the historical samples of obsolete cultivars compared to local cultivars and cultivars preserved in genebanks, indicating genetic erosion over time both in genebanks and during conservation on farm. The constraints on identifying and verifying historical cultivars using genetic markers are discussed.
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| 8. |
- Hagenblad, Jenny, et al.
(författare)
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Strong presence of the high grain protein content allele of NAM-B1 in Fennoscandian wheat
- 2012
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Ingår i: Theoretical and Applied Genetics. - : Springer Verlag (Germany). - 0040-5752 .- 1432-2242. ; 125:8, s. 1677-1686
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Tidskriftsartikel (refereegranskat)abstract
- Grain protein content in wheat has been shown to be affected by the NAM-B1 gene where the wildtype allele confers high levels of protein and micronutrients but can reduce yield. Two known non-functional alleles instead increase yield but lead to lower levels of protein and micronutrients. The wildtype allele in hexaploid bread wheat is so far mainly known from historical specimens and a few lines with an emmer wheat introgression. Here we report a screening for the wildtype allele in wheats of different origin. First, a worldwide core collection of 367 bread wheats with worldwide origin was screened and five accessions carrying the wildtype NAM-B1 allele were found. Several of these could be traced to a Fennoscandian origin and the wildtype allele was more frequent in spring wheat. These findings, together with the late maturation of spring wheat, suggested that the faster maturation caused by the wildtype allele might have preserved it in areas with a short growing season. Thus a second set consisting of 138 spring wheats of a northern origin was screened and as many as 33 % of the accessions had the wildtype allele, all of a Fennoscandian origin. The presence of the wildtype allele in landraces and cultivars is in agreement with the use of landraces in Fennoscandian wheat breeding. Last, 22 spelt wheats, a wheat type previously suggested to carry the wildtype allele, were screened and five wildtype accessions found. The wildtype NAM-B1 accessions found could be a suitable material for plant breeding efforts directed towards increasing the nutrient content of bread wheat.
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| 9. |
- Karlsson Strese, Else-Marie, et al.
(författare)
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Den svenska humlens ursprung
- 2012
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Ingår i: Svensk Botanisk Tidskrift. - Uppsala : Svenska Botaniska föreningen. - 0039-646X. ; 106:3-4, s. 165-176
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Karlsson Strese, Else-Marie, et al.
(författare)
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Genetic Diversity in Remnant Swedish Hop (Humulus lupulus L.) Yards from the 15th to 18th Century
- 2014
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Ingår i: Economic Botany. - : Springer. - 0013-0001 .- 1874-9364. ; 68:3, s. 231-245
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Tidskriftsartikel (refereegranskat)abstract
- Hop (Humulus lupulus L.) is a perennial plant cultivated for its use in beer production. The plant is dioecious, and the female plants produce cones containing substances that enhance the taste and durability of beer. Beer was long an essential part of food supply in Northern Europe, and hop has thus been a very important crop during the last 1,000 years. In Sweden, hop cultivation was, by law, mandatory for farmers from 1414 till 1860. Today, Swedish hop cultivation is negligible, but historical remnant hop plants can still be found as feral populations. Using historical maps and documents, we have located ten historical hop yards from the 15th to 18th century where hop plants still persist as now feral populations. Some fifteen plants of each population were sampled and genotyped with ten SSR markers and one marker diagnostic for sex type. In addition, 25 genebank preserved clones of older landraces and cultivars from Europe were genotyped. Genotyping results show abundant clonality and low rates of sexual reproduction within the feral populations. Two of the populations had markedly higher genetic diversity and a higher number of haplotypes, and in these populations a mix of female and male plants was also found. The populations were all clearly differentiated, with no haplotypes shared between populations and little evidence of exchange of genetic material. These results indicate that natural spread and genetic recombination is uncommon or slow in Sweden, and that the feral plants could be remnants of the original historical cultivations. In the assembly of European genebank clones, several clones showed identical genotypes and overall limited genetic diversity. The Swedish populations were in most cases genetically clearly different from the genebank clones. This contrasts with historical records of massive introductions of hop clones from continental Europe during the 19th century and shows that these imports did not replace the original hops being cultivated. A possible better adaption of the Swedish hops and primitive historical breeding are discussed.
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