Cultivated apple (Malus × domestica Borkh.) is a major crop of economic importance, both globally and regionally. It is currently, and was also in the past, the main commercial fruit in the northern European countries. In Finland, apple trees are grown on the frontier of their northern growing limits. Because of these limits, growing an apple tree from a seed was discovered in practice to be the most appropriate method to get trees that bear fruit for people in the north. This created a unique culturally and genetically rich native germplasm to meet the various needs of apple growers and consumers from the late 1800s to the mid-1900s. The preservation, study and use of this genetic heritage falls within the mandate of the Finnish National Genetic Resources Program. The first national apple clonal collection for germplasm preservation was reorganized from the collections of apple breeders. The need to evaluate the accessions, both in this collection and possible missing ones, to meet the program strategy lead us to evaluate the Finnish apple heritage that is still available in situ in gardens. In this article we use multiple-approach methodologies and datasets to gain well-described, proof-rich samples for the trueness-to-type analysis of old heirloom apple varieties. The approach includes a combination of socio-historic, pomological and genotyping methods and datasets that are all valued as equally important. The main finding was that in addition to the pomological, molecular and genetic evaluation of ex situ apple collections, an extensive historical data and socio-economic conditions research are essential to perform good characterization of accessions. After implementing the results in re-creating the Finnish national apple germplasm collection, the number of Finnish local varieties was more than doubled from 38 accessions to 97.

European wild apple (Malus sylvestris L.) is the only Malus wild species native to Europe which is a relative of cultivated apples (Malus × domestica Borkh.). It grows on forests’ edges, farmland hedges, and marginal sites; by living in those scattered meta-populations, it is exposed to genetic erosion in relation to hybridization and habitat degradation. In Finland, it grows at the northern edge of its distribution in Europe and is considered as a near-threatened taxon requiring urgent conservation. In order to evaluate the molecular genetic diversity of M. sylvestris, five populations including 43 trees were analyzed using 15 microsatellite markers. Additionally, a similar number of samples from cultivated apples, which are common to the same region, was included in order to estimate gene diversity gaps and give an insight into putative hybridization. European wild apple in Finland proved to be populationally structured, and seems not to be threatened by introgression events from its cultivated relative. They were all separated into different clusters, except for one individual. However, urgent conservation is indeed needed, especially due to the very low total number of trees (four) in some of the analyzed populations. These populations should be restored in order to enable permanent access to the wild relatives’ diversity, as they might be a critical source of gene variants for future needs.

European hazelnut (Corylus avellana L.) is a strictly cross-pollinated diploid tree species, which has its northernmost populations in Fennoscandia, and it was one of the first species to recolonize northern Europe after the last ice age. Hazelnut produces edible nuts in Finland but nowadays they are underutilized as food, and currently no breeding programmes exist. In the present study, 300 hazelnut specimens were collected from 20 different locations (= populations) in Finland, and they were genetically analyzed using nine simple sequence repeat (SSR) markers. Most of the genetic diversity existed within populations (83%). According to different genetic analyses (STRUCTURE, principal coordinates analysis, and clustering), a general lack of structure was observed, suggesting extensive gene flow among hazelnuts between 17 investigated populations. However, genetic structuring was clearly observed in three populations: Hakavuori, Mustiala, and Pähkinämäki, which might have become isolated due to geographical barriers that kept them separate, diminishing gene flow from other populations. Studying the diversity of European hazelnut is of great interest for understanding population genetics of a species distributed in its marginal areas in the north, and the results are also valuable for further uses in plant conservation, selection, and possible future breeding actions in Finland.

A set of 32 citrus genotypes were selected from Montenegro collection and analyzed by the use of 11 microsatellite markers. Analyses harvested 72 different alleles having 6.5 alleles per locus and discovered presence of 23 unique genotypes. Distance analysis and model-based clustering revealed both the presence of 4 groups: satsuma (Citrus unshiuMarc.) mandarins, clementine (Citrus reticulata) mandarins, sweet oranges (Citrus × sinensis) and lemons (Citrus limon). Distance based clustering enabled the differentiation between red and yellow flashed fruits due to the presence of allele 158 on the locus AC01 in blood oranges. Specific goal of the study was to clarify the identity of 3 local citrus genotypes through observing their relationships within well-established clustering with the rest of genotypes being known citruses. Local orange ‘Domaca Pomorandza’ grouped with other sweet oranges but could not be differentiated from ‘Navelina’ and ‘Skagss Bonanza Navel’. ‘Gorka Pomorandza’ had unique fingerprint and showed to be sour orange. Local lemon ‘Mjesecar’ showed to may be belonging to the Femminello group of lemons. Genetic characterization of local genotypes will serve for cultivar recognition and their future improvement.

Oat grain is a traditional human food rich in dietary fiber that contributes to improved human health. Interest in the crop has surged in recent years owing to its use as the basis for plant-based milk analogs. Oat is an allohexaploid with a large, repeat-rich genome that was shaped by subgenome exchanges over evolutionary timescales. In contrast to many other cereal species, genomic research in oat is still at an early stage, and surveys of structural genome diversity and gene expression variability are scarce. Here, we present annotated chromosome-scale sequence assemblies of 33 wild and domesticated oats along with an atlas of gene expression across six tissues of different developmental stages in 23 accessions. We describe the interplay of gene expression diversity across subgenomes, accessions and tissues. Gene loss in the hexaploid is accompanied by compensatory up-regulation of the remaining homeologs, but this process is constrained by subgenome divergence. Chromosomal rearrangements have significantly impacted recent oat breeding. A large pericentric inversion associated with early flowering explains distorted segregation on chromosome 7D and a homeologous sequence exchange between chromosomes 2A and 2C in a semidwarf mutant has risen to prominence in Australian elite varieties. The oat pangeome will promote the adoption of genomic approaches to understanding the evolution and adaptation of domesticated oats and will accelerate their improvement.

We sampled 351 hop herbarium specimens for genetic analyses of their identities through definition of unique set of samples by extraction of duplicates and comparative analyses with modern hop samples from Finland and worldwide. We also analyzed genetic diversity and assessed genetic clustering and structure within and between herbarium hops specimens and modern hop germplasm. A set of 26 previously published hop microsatellites (SSRs) proven in diversity analyses have been used for genetic evaluations of herbarium hop DNA extracted from pressed and dried specimens of which the oldest was dated back to the year of 1841. A genetic fingerprint was generated for all samples and unique ones has been generated in pairwise comparisons of pairs of samples and eliminations of duplicates. For unique set of samples, a genetic distance matrix was created for clustering analyses as well allele frequencies matrix for model-based clustering analyses. Herbarium hop samples representing historical DNA showed no clear differentiation (clustering or sub-clustering) when analyzed with presently grown modern hops. Weak tendency of hops to cluster according to the geographical origin has been noticed. We detected 39 groups of hop herbarium duplicates representing 94 specimens, where redundancy showed to be low when compared to modern Finnish hops (redundancy >70%). Analyzing herbarium hops through DNA extraction will add another link in investigating the origin and spread of Finnish hops from ancient times. Finnish hops has been described as a millennia old and native to Finland.