A selection from Stockholm University publication database

• The introduction history of Hordeum vulgare var. nudum (naked barley) into Fennoscandia

  2023. Jenny Hagenblad (et al.). Vegetation History and Archaeobotany

  Article

  Hordeum vulgare var. nudum (naked barley) is one of the oldest and most common cereals found from Neolithic Fennoscandia. After the Bronze Age, naked barley largely disappeared and was replaced by Hordeum vulgare var. vulgare (hulled barley) and other cereals. During the early 19th century, naked barley of Asian origins was reintroduced to Fennoscandia. In this study, we have genetically characterized samples of Fennoscandian landraces of naked barley which were preserved in gene banks and museum collections. The analyses show that the Fennoscandian naked barley can be split into three groups: First, naked two-row barley, with a likely origin in Asia; second, naked six-row barley, with a likely origin in the eastern Himalayas and introduced during the 19th century; third, naked six-row barley genetically related to the original Fennoscandian hulled barley. The results suggest that this last group represents the ancient form of naked barley, which was possibly introduced in the Neolithic. At that time both naked and hulled barleys were grown and enough gene flow probably occurred between these two subspecies to create a Fennoscandian barley that is genetically distinct, irrespective of whether it is hulled or naked. This hypothesis was further supported by genotyping of the Nud gene, which is responsible for the naked phenotype. All naked barleys which we studied contained the same mutation allele, nud1.a, thus showing that naked Fennoscandian barley arose by crossings between naked and hulled barley and not by new mutations of hulled barley.

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• Chevalier barley: The influence of a world-leading malting variety

  2022. Jenny Hagenblad, Matti W. Leino. Crop science 62 (1), 235-246

  Article

  During the 19th century, ‘Chevalier’, said to have been developed from a single plant found in 1820, was the world-leading malting barley (Hordeum vulgare). The superior malting quality of Chevalier lead to its world-wide spread at the time of the development of the malting industry. In this study, we investigate how this cultivar was spread and adopted to Nordic seed systems of the time. Single nucleotide polymorphism genotyping of up to 155-yr-old museum specimens of historical grains labelled “Chevalier” and of Chevalier accessions preserved in genebanks, in total 282 individuals representing 47 accessions, allowed us to divide the accessions into four categories: True Chevalier, seed mixtures, crosses, and non-Chevaliers. Comparisons with previously genotyped Nordic landraces showed how, in the 19th century, Chevalier seed was mixed with locally produced landrace seed and cultivated together. We suggest that spontaneous outbreeding events gave rise to hybrids which were subsequently selected and propagated when resulting in superior genetic combinations. Such farmer-driven breeding activities would have preceded modern plant breeding but resembled the breeding principles that were later used, even though the scientific understanding of inheritance was not yet known. 

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• Protein content and HvNAM alleles in Nordic barley (Hordeum vulgare) during a century of breeding

  2022. Jenny Hagenblad (et al.). Hereditas 159 (1)

  Article

  Background: Barley has been bred for more than a century in the Nordic countries, with dramatic improvements of yield traits. In this study we investigate if this has come at the cost of lower grain protein and micronutrient (iron, zinc) content, by analysing 80 accessions representing four different improvement stages. We further re-sequenced the two grain protein content associated genes HvNAM-1 and HvNAM-2 in full and performed expression analyses of the same genes to search for genetic associations with nutrient content.

  Results: We found higher thousand grain weight in barley landraces and in accessions from the late improvement group compared to accessions from the mid of the twentieth century. Straw length was much reduced in late stage accessions. No significant temporal decrease in grain protein, iron or zinc content during twentieth century Nordic crop improvement could be detected. Out of the 80 accessions only two deviant HvNAM-1 sequences were found, represented by one accession each. These do not appear to be correlated to grain protein content. The sequence of HvNAM-2 was invariable in all accessions and no correlations between expression levels of HvNAM-1 and HvNAM-2 and with grain protein content was found.

  Conclusions: In contrast to studies in wheat, where a strong negative correlation between straw length and grain protein and micronutrient content has been found, we do not see this relationship in Nordic barley. The last 60 years of breeding has reduced straw length but, contrary to expectations, not protein and micronutrient content. Variation in grain protein and micronutrient content was found among the Nordic barley accessions, but it is not explained by variation of HvNAM genes. This means that HvNAM is an unexploited source of genetic variation for nutrient content in Nordic barley.

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• Genetic Diversity in 19th Century Barley (Hordeum vulgare) Reflects Differing Agricultural Practices and Seed Trade in Jämtland, Sweden

  2021. Martin N. A. Larsson, Matti W. Leino, Jenny Hagenblad. Diversity 13 (7)

  Article

  Landrace crops are important genetic resources, both for plant breeding efforts and for studying agrarian history. The distribution of genetic diversity among landraces can reflect effects of climate, economic structure, and trade also over a limited spatial and temporal scale. In this study, we have SNP genotyped historical barley seed samples from the late 19th century, together with extant barley landrace accessions from Jamtland, Sweden, a county centrally located, situated between Sweden and Norway. We found two main genetic clusters, one associated with the main agricultural district around lake Storsjon and one in the peripheral areas. Data was also compared with genotypes from landraces from across the Scandinavian peninsula. Accessions from the peripheral part of Jamtland show genetic similarity to accessions from a large part of central Scandinavia, while the accessions from the Storsjon district are more differentiated. We suggest that these dissimilarities in genetic diversity distribution are explained by differences in the relative importance of agriculture and trading. We further compared the historical material with ex situ preserved extant landraces from the same region and found that their genetic diversity was not always representative of the given provenience. The historical material, in contrast, proved particularly valuable for assessing how crop genetic diversity has historically been influenced by economic focus.

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• Trait Expression and Environmental Responses of Pea (Pisum sativum L.) Genetic Resources Targeting Cultivation in the Arctic

  2021. Ulrika Carlson-Nilsson (et al.). Frontiers in Plant Science 12

  Article

  In the Arctic part of the Nordic region, cultivated crops need to specifically adapt to adverse and extreme climate conditions, such as low temperatures, long days, and a short growing season. Under the projected climate change scenarios, higher temperatures and an earlier spring thaw will gradually allow the cultivation of plants that could not be previously cultivated there. For millennia, Pea (Pisum sativum L.) has been a major cultivated protein plant in Nordic countries but is currently limited to the southern parts of the region. However, response and adaptation to the Arctic day length/light spectrum and temperatures are essential for the productivity of the pea germplasm and need to be better understood. This study investigated these factors and identified suitable pea genetic resources for future cultivation and breeding in the Arctic region. Fifty gene bank accessions of peas with a Nordic landrace or cultivar origin were evaluated in 2-year field trials at four Nordic locations in Denmark, Finland, Sweden, and Norway (55 degrees to 69 degrees N). The contrasting environmental conditions of the trial sites revealed differences in expression of phenological, morphological, crop productivity, and quality traits in the accessions. The data showed that light conditions related to a very long photoperiod partly compensated for the lack of accumulated temperature in the far north. A critical factor for cultivation in the Arctic is the use of cultivars with rapid flowering and maturation times combined with early sowing. At the most extreme site (69 degrees N), no accession reached full maturation. Nonetheless several accessions, predominantly landraces of a northern origin, reached a green harvest state. All the cultivars reached full maturation at the sub-Arctic latitude in northern Sweden (63 degrees N) when plants were established early in the season. Seed yield correlated positively with seed number and aboveground biomass, but negatively with flowering time. A high yield potential and protein concentration of dry seed were found in many garden types of pea, confirming their breeding potential for yield. Overall, the results indicated that pea genetic resources are available for breeding or immediate cultivation, thus aiding in the northward expansion of pea cultivation. Predicted climate changes would support this expansion.

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• Population genetic structure in Fennoscandian landrace rye (Secale cereale L.) spanning 350years

  2019. P. Larsson (et al.). Genetic Resources and Crop Evolution 66 (5), 1059-1071

  Article

  Rye (Secale cereale L.) was for centuries the economically most important crop in Fennoscandia (Denmark, Finland, Norway and Sweden). Historical records tell of a range of different types adapted to climate and varying cultivation practices. Genetic analyses of genebank maintained landrace rye have yet failed, with a few exceptions, to detect differentiation between rye types. Concerns have been raised that genebank material does not truly reflect the historical variation in landrace rye. In this study, we have therefore genotyped old and historical samples of rye as well as extant material. Two historical seventeenth century samples were obtained from a grave and a museum archive respectively, and 35 old samples were taken from 100 to 140-year-old seed collections and museum artefacts made of straw. We could confirm the results of previous studies suggesting Fennoscandian landrace rye to be one major meta-population, genetically different from other European rye landraces, but with no support for slash-and-burn types of rye being genetically different from other rye landraces. Only small differences in genetic diversity and allele distribution was found between old landrace rye from museum collections and extant genebank accessions, arguing against a substantial change in the genetic diversity during twentieth century cultivation and several regenerations during genebank maintenance. The genotypes of the old and historical samples suggest that the genetic structure of Fennoscandian landrace rye has been relatively stable for 350years. In contrast, we find that the younger samples and early improved cultivars belong to a different genetic group, more related to landraces from Central Europe.

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• Morphological and genetic characterization of barley (Hordeum vulgare L.) landraces in the Canary Islands

  2019. Jenny Hagenblad (et al.). Genetic Resources and Crop Evolution 66 (2), 465-480

  Article

  Barley has been continuously cultivated in the Canary archipelago for millennia, and to this day landrace barley is the preferred choice for cultivation. We have morphologically and genetically characterized 57 landraces collected during the twenty-first century and conserved in genebanks. The majority of accessions were of the six-row type. Although landraces from the same island tended to be similar, the results showed morphological and genetic diversity both within and in the case of genetic data among islands. Accessions from the easternmost islands were genetically distinct from those from the central and western islands. Accessions from the western islands often had a mixed genetical composition, suggesting more recent exchange of plant material with the central islands. The geographic distribution of diversity suggests that conservation of barley genetic resources needs to consider all islands in the archipelago. Landrace barley from the Canary archipelago was found to be morphologically distinct from continental landrace barley. We suggest the uniqueness of Canarian barley, in terms of morphology and genetic diversity, can be used for marketing purposes providing added market value to the crop.

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• Population structure in landrace barley (Hordeum vulgare L.) during the late 19th century crop failures in Fennoscandia

  2019. Nils E. G. Forsberg, Matti W. Leino, Jenny Hagenblad. Heredity 123 (6), 733-745

  Article

  Agricultural disasters and the subsequent need for supply of relief seed can be expected to influence the genetic composition of crop plant populations. The consequences of disasters and seed relief have, however, rarely been studied since specimens sampled before the events are seldomly available. A series of crop failures struck northern Fennoscandia (Norway, Sweden and Finland) during the second half of the 19th century. In order to assess population genetic dynamics of landrace barley (Hordeum vulgare), and consequences of crop failure and possible seed relief during this time period, we genotyped seeds from 16 historical accessions originating from two time periods spanning the period of repeated crop failure. Reliable identification of genetic structuring is highly dependent on sampling regimes and detecting fine-scale geographic or temporal differentiation requires large sample sizes. The robustness of the results under different sampling regimes was evaluated by analyzing subsets of the data and an artificially pooled dataset. The results led to the conclusion that six individuals per accession were insufficient for reliable detection of the observed genetic structure. We found that population structure among the data was best explained by collection year of accessions, rather than geographic origin. The correlation with collection year indicated a change in genetic composition of landrace barley in the area after repeated crop failures, likely a consequence of introgression of relief seed in local populations. Identical genotypes were found to be shared among some accessions, suggesting founder effects and local seed exchange along known routes for trade and cultural exchange.

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• Patterns of Exchange of Multiplying Onion (Allium cepa L. Aggregatum-Group) in Fennoscandian Home Gardens

  2018. Matti W. Leino (et al.). Economic Botany

  Article

  Multiplying onion (Allium cepa L. Aggregatum-Group), commonly known as shallot or potato onion, has a long tradition of cultivation in Fennoscandian home gardens. During the last decades, more than 80 accessions, maintained as vegetatively propagated clones, have been gathered from home gardens in all Fennoscandian countries. A genetic analysis showed regional patterns of accessions belonging to the same genetic group. However, accessions belonging to the same genetic group could originate in any of the countries. These results suggested both short- and long-distance exchange of set onions, which was confirmed by several survey responses. Some of the most common genetic groups also resembled different modern varieties. The morphological characterization illustrated that most characters were strongly influenced by environment and set onion properties. The only reliably scorable trait was bulb skin color. Neither our morphological nor genetic results support a division between potato onions and shallots. Instead, naming seems to follow linguistic traditions. An ethnobotanical survey tells of the Fennoscandian multiplying onions as being a crop with reliable harvest, excellent storage ability, and good taste. An increased cultivation of this material on both household and commercial scale should be possible.

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• Archaeological and Historical Materials as a Means to Explore Finnish Crop History

  2018. Mia Lempiäinen-Avci (et al.). Environmental Archaeology

  Article

  In Northern Europe, barley (Hordeum vulgare L.) has been cultivated for almost 6000 years. Thus far, 150-year-old grains from historical collections have been used to investigate the distribution of barley diversity and how the species has spread across the region. Genetic studies of archaeobotanical material from agrarian sites could potentially clarify earlier migration patterns and cast further light on the origin of barley landraces. In this study, we aimed to evaluate different archaeological and historical materials with respect to DNA content, and to explore connections between Late Iron Age and medieval barley populations and historical samples of barley landraces in north-west Europe. The material analysed consisted of archaeological samples of charred barley grains from four sites in southern Finland, and historical material, with 33 samples obtained from two herbaria and the seed collections of the Swedish museum of cultural history.

  The DNA concentrations obtained from charred archaeological barley remains were too low for successful KASP genotyping confirming previously reported difficulties in obtaining aDNA from charred remains. Historical samples from herbaria and seed collection confirmed previously shown strong genetic differentiation between two-row and six-row barley. Six-row barley accessions from northern and southern Finland tended to cluster apart, while no geographical structuring was observed among two-row barley. Genotyping of functional markers revealed that the majority of barley cultivated in Finland in the late nineteenth and early twentieth century was late-flowering under increasing day-length, supporting previous findings from northern European barley.

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• Genetic analyses of Scandinavian desiccated, charred and waterlogged remains of barley (Hordeum vulgare L.)

  2018. Maria Lundström (et al.). Journal of Archaeological Science 22, 11-20

  Article

  Barley, Hordeum vulgare L., has been cultivated in Fennoscandia (Denmark, Norway, Sweden, Finland) since the start of the Neolithic around 4000 years BCE. Genetic studies of extant and 19th century barley landraces from the area have previously shown that distinct genetic groups exist with geographic structure according to latitude, suggesting strong local adaptation of cultivated crops. It is, however, not known what time depth these patterns reflect. Here we evaluate different archaeobotanical specimens of barley, extending several centuries in time, for their potential to answer this question by analysis of aDNA. Forty-six charred grains, nineteen waterlogged specimens and nine desiccated grains were evaluated by PCR and KASP genotyping. The charred samples did not contain any detectable endogenous DNA. Some waterlogged samples permitted amplification of endogenous DNA, however not sufficient for subsequent analysis. Desiccated plant materials provided the highest genotyping success rates of the materials analysed here in agreement with previous studies. Five desiccated grains from a grave from 1679 in southern Sweden were genotyped with 100 SNP markers and data compared to genotypes of 19th century landraces from Fennoscandia. The results showed that the genetic composition of barley grown in southern Sweden changed very little from late 17th to late 19th century and farmers stayed true to locally adapted crops in spite of societal and agricultural development.

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• Farmer fidelity in the Canary Islands revealed by ancient DNA from prehistoric seeds

  2017. Jenny Hagenblad (et al.). Journal of Archaeological Science 78, 78-87

  Article

  The Canary Islands were settled in the first millennium AD by colonizers likely originating from North Africa. The settlers developed a farming economy with barley as the main crop. Archaeological evidence suggests the islands then remained isolated until European sea-travellers discovered and colonized them during the 14th and 15th centuries. Here we report a population study of ancient DNA from twenty-one archaeobotanical barley grains from Gran Canaria dating from 1050 to 1440 cal AD. The material showed exceptional DNA preservation and genotyping was carried out for 99 single nucleotide markers. In addition 101 extant landrace accessions from the Canary Islands and the western Mediterranean were genotyped. The archaeological material showed high genetic similarity to extant landraces from the Canary Islands. In contrast, accessions from the Canary Islands were highly differentiated from both Iberian and North African mainland barley. Within the Canary Islands, landraces from the easternmost islands were genetically differentiated from landraces from the western islands, corroborating the presence of pre-Hispanic barley cultivation on Lanzarote. The results demonstrate the potential of population genetic analyses of ancient DNA. They support the hypothesis of an original colonization, possibly from present day Morocco, and subsequent isolation of the islands and reveal a farmer fidelity to the local barley that has lasted for centuries.

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