The transition to more diversified protein sources presents legumes, such as peas, as excellent alternatives to animal protein. In light of this shift, understanding the sensory variation of pea genetic resources becomes crucial in broadening their appeal and promoting greater consumption. This study aimed to identify key factors influencing the sensory attributes of landrace peas, including variety (accession), location (geographical area of cultivation), and harvest year. Through a quantitative descriptive sensory analysis of six Swedish landrace pea accessions, cultivated over 1–2 years in three different Nordic countries, we analyzed the sensory attributes in detail and evaluated potential interactions between the pea accessions, their respective growing locations, and the varying harvest years. The results show that the sensory variation in the studied landrace pea accessions is primarily attributed to the chosen accession, despite the differences in location and harvest year. Notably, the results also reveal the potential impact of the location on the perceived sourness and umami taste of peas. These findings underscore the critical role of careful variety selection and breeding to enhance the sensory experience of peas, enabling the development of diverse pea-based products that cater to consumer preferences.

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. 

Landraces are described as genetically diverse, dynamic populations of unimproved crops. However, studying the development of a landrace population over longer periods of time has rarely been done due to a lack of suitable archaeological materials. The indigenous grain silos of Gran Canaria provide a unique opportunity for genetically analysing multiple specimens from the same time period as well as sampling the same population at multiple time points. Here we report a genetic study of a landrace barley (Hordeum vulgare L.) sampled repeatedly over a period of 1400 years. We successfully enriched extracted aDNA for the barley exome using capture techniques and present sequencing data from ten archaeological and six extant samples. The results show that the landrace barley population of Gran Canaria has not undergone any dramatic genetic turnover or influx of new genetic material since the 7th century CE, but that the scale of cultivation seems to have varied. We detect smaller temporal changes of the genetic composition during the studied period and suggest that these changes reflect natural selection for adaptation to a changing climate and a dynamic agricultural society.

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. 

European gooseberry (Ribes uva-crispa L.) is a popular berry crop in many European countries, including Sweden, Denmark and Ukraine. There is no active gooseberry breeding programme in either Sweden or Denmark, but a successful programme is operating in Ukraine. In Sweden and Denmark, research on gooseberries is primarily focused on collection and phenotypic evaluation of genetic resources. As part of these activities, a large number of inventory finds have been collected but have not yet been characterised morphologically or molecularly. The goal of this study was thus to characterise gooseberry germplasm with 15 simple sequence repeat (SSR) markers. From 242 accessions analysed, 153 unique genotypes were identified. Cultivars that have been in widespread cultivation in Sweden, such as the Finnish cultivars ‘Hinnonmäen Keltainen’ and ‘Hinnonmäen Punainen’, had relatively large numbers of synonymous samples. While many inventory finds were identifiable as synonyms of known cultivars, several were found to constitute unique genotypes within the germplasm studied. The studied genotypes clustered relatively well in three posterior groups, consisting of cultivars originating before and after the American gooseberry mildew (Sphaerotheca mors-uvae) outbreak around 1900 and cultivars originating from the territory of the former Soviet Union. A fourth genetic cluster consisting mainly of inventory finds from central and northern Sweden was also identified. In addition, it was possible to verify recorded and stipulated parentages for some of the cultivars studied and to identify three likely parent-parent-child trios. Thus, inventories of local gooseberry germplasm and a subsequent genotyping proved successful in finding unique local genotypes, with potential local adaptation. The data obtained provide a foundation for future studies of gooseberry genetic resources, while also illustrating the importance of a well-curated and phenotypically characterised set of reference cultivars for future studies.

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.

Potato onions (Allium cepa var aggregatum G. Don) are multiplying or aggregating onions, very similar to shallots and have been historically cultivated throughout Europe. Currently in Northern Europe they are maintained in home gardens and ex situ field collections. Potato onions are primarily vegetatively propagated, however in Estonia, near Lake Peipsi, this species has been propagated by seed since the seventeenth century. There is increasing interest in Northern Europe in utilizing this germplasm in organic and/or sustainable farming systems. The genetic diversity and relationship between and within European potato onion collections is unclear. From historical records it is known that cultivation, exchange and trade of potato onion has occurred throughout Europe for hundreds of years. This study utilised molecular markers to assess genetic diversity, duplication of genotypes and relationships among and between Nordic, Baltic, Czech and Croatian potato onion collections. Of 264 accessions, 80 catalogued as unique had identical genotypes with one or more other accessions, and are putative duplicates. The genetic diversity within two Estonian sexually propagated accessions was comparable to that found in all of the vegetatively propagated accessions. Accessions from the Nordic countries grouped together genetically, as did Latvian and Lithuanian accessions. Croatian accessions were genetically separated. These genetic relationships suggest historical movement of potato onion germplasm in North-Eastern Europe. The results, in conjunction with other passport and characterization data, can assist in the development of potato onion core collections, facilitating the conservation and utilization of valuable potato onion genetic resources.

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.

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.

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.