Igor Chybicki

Kazimierz Wielki University in Bydgoszcz · Department of Genetics

The mating system is a central parameter of plant biology because it shapes their ecological and evolutionary properties. Therefore, determining ecological variables that influence the mating system is important for a deeper understanding of the functioning of plant populations. Here, using old concepts and recent statistical developments, we propo...

--- Background and Aims --- Dispersal is crucial due to its direct impact on dynamics of a species’ distribution as well as having a role in shaping adaptive potential through gene flow. In plants forming scarce and small populations, knowledge about the dispersal process is required to assess the potential for colonizing new habitats and connectiv...

In plant populations, parentage analysis helps understand factors shaping individual reproductive success. However, estimating reproductive success determinants based on parentage counts requires decoupling the effects of individual fecundity and propagule dispersal. The neighborhood model implemented in the NMπ software provides a standard solutio...

The efficient conversion of tissues into reproductive success is a crucial aspect affecting the evolution of life histories. Masting, the interannually variable and synchronous seed production in perennial plants, is a strategy that can enhance reproductive efficiency by mitigating seed predation and pollen limitation. However, evaluating benefits...

Seed production is known to reveal high individual variation in tree populations, shaping regeneration and competition patterns. In isolated populations, individual variation in seed production drives genetic drift and inbreeding, increasing the risk of local extinction. In this study, we investigated the variation in seed production within a natur...

Background Knowledge of genetic structure and the factors that shape it has an impact on forest management practices. European ash (Fraxinus excelsior L.) has declined dramatically throughout its range as a result of a disease caused by the fungus Hymenoscyphus fraxineus. Despite the need for conservation and restoration of the species, genetic dat...

Masting (synchronous and interannually variable seed production) is frequently called a reproductive strategy; yet it is unclear whether the reproductive behaviour of individuals has a heritable component. To address this, we used 22 years of annual fruit production data from 110 Sorbus aucuparia L. trees to examine the contributions of genetic fac...

Scots pine is one of the most widely occurring pines, but future projections suggest a large reduction in its range, mostly at the southern European limits. A significant part of its range is located in the Caucasus, a global hot-spot of diversity. Pine forests are an important reservoir of biodiversity and endemism in this region. We explored demo...

Key message: Taxus baccata remnants established recently tend to contribute less to the species' overall genetic variation than historical populations because they are subjected to a greater impact of the founder effect and genetic isolation. As tree trunk perimeter is a rough indicator of genetic variation in a population, this measure should be c...

• Context: Hymenoscyphus fraxineus is causing high mortality in European ash (Fraxinus excelsior L.). Due to inheritable resistance to the pathogen, natural selection is likely to act in favour of improved resistance in ash forests following natural regeneration. Still, the frequency of healthy trees is low, and the effect of natural selection will...

Individual differences in male reproductive success drive genetic drift and natural selection, altering genetic variation and phenotypic trait distributions in future generations. Therefore, identifying the determinants of reproductive success is important for understanding the ecology and evolution of plants. Here, based on the spatially‐explicit...

During the Last Glacial Maximum in the northern Hemisphere, expanding ice sheets forced a large number of plants, including trees, to retreat from their primary distribution areas. Many host-associated herbivores migrated along with their host plants. Long-lasting geographic isolation between glacial refugia could have been led to the allopatric sp...

The process of adaptation in forest trees might be facilitated if seeds resulting from crossings among different provenances are used for plantation establishment. This can be accomplished if seeds from existing common-garden trials become available. This paper aims to characterize genetic diversity of a provenance/family common-garden trial of Que...

This paper introduces the NMπ computer program designed for estimation of plant mating system and seed and pollen dispersal kernels. NMπ is a re-implementation of the NM+ program and provides new features such as support for multi-core processors, explicit treatment of dioecy, the possibility of incorporating uniparentally cytoplasmic markers, the...

In plants, the spatial genetic structure (SGS) is shaped mainly by gene dispersal and effective population density. Among additional factors, the mode of DNA inheritance and dioecy influence SGS. However, their joint impact on SGS remains unclear, especially in the case of paternally inherited DNA. Using theoretical approximations and computer simu...

The genetic structure of Dactylorhiza incarnata var. incarnata populations is shaped not only by historical events such as recolonization after ice sheet retreat or limited seed and pollen dispersal, but also the bottleneck effect. During the last decade, D. incarnata var. incarnata has also experienced a strong decline in population numbers and si...

Assessing the distribution of chloroplast DNA (cpDNA) haplotype variation is useful for studying the phylogeography of angiosperms. In the last two decades the cpDNA phylogeography of white oaks in Europe has been extensively studied , mostly based on the PCR-RFLP technique. However, PCR-RFLPs have low mutation rates and are primarily useful for re...

Random genetic drift, natural selection and restricted gene dispersal are basic factors of the spatial genetic structure (SGS) in plant populations. Clonal reproduction has a profound effect on population dynamics and genetic structure and thus emerges as a potential factor in contributing to and modelling SGS. In order to assess the impact of clon...

Understanding factors that limit gene flow through the landscape is crucial for conservation of organisms living in fragmented habitats. We analysed patterns of gene flow in Elater ferrugineus, an endangered click beetle living in old-growth, hollow trees in a network of rural avenues surrounded by inhospitable arable land. Using amplified fragment...

In Europe, most of the alpine timberline ecotone has been altered by human activities and climate change. Hence, mountain forests are of the highest conservation interest. Here, we screened 25 populations of Swiss stone pine (Pinus cembra L.) from the Carpathians and the Alps, using a set of ten microsatellite primers to assess the relative conserv...

Ecological conditions shape natural distribution of plants. Populations are denser in optimal habitats but become more fragmented in the areas of suboptimal environmental conditions. Usually, fragmentation increases towards the limits of species distribution. Fragmented populations are often characterised by decreased genetic variation, and this ef...

Raw SSR genotypes of individuals from 13 populations of Acer campestre in Poland. Data related with the content of the paper by Chybicki et al. in Tree Genetics & Genomes (DOI: 10.1007/s11295-014-0793-2). The text file is tab-delimited. Missing genotypes are decoded with "-1". For more information please contact the author.

Mating systems have long been recognized as key factors determining genetic structure within and between populations. Outcrossing promotes genetic diversity and gene flow between populations, while inbreeding, on the other hand, decreases recombination rates, facilitating fixation of co-adapted genes. In small populations, selfing moderates pollen...

Genotype data of P. cembra. For downloading use "Save target as ..." command after right click. For more information contact the first author.

Northern Poland is inhabited by native Apis mellifera mellifera (AMM) and the non-native A. m. carnica (AMC) which was introduced by beekeepers. However, hybrids between the two subspecies of honey bee are relatively rare. The lower than expected proportion of hybrids is hypothesised to be related to reproductive isolation between AMM and AMC. To v...

Background and AimsSexual reproduction is one of the most important moments in a life cycle, determining the genetic composition of individual offspring. Controlled pollination experiments often show high variation in the mating system at the individual level, suggesting a persistence of individual variation in natural populations. Individual varia...

Measuring genetic structure of pollen gametes has become the standard approach in studies on plant mating system and pollen flow. However, the popular statistical procedure, TwoGener, provides the point estimate of the pollen pool heterogeneity based on AMOVA, implying any statistical tests regarding pollen pool structure to be based on permutation...

Species confined to temporally stable habitats are usually susceptible to habitat fragmentation, as living in long-lasting habitats is predicted to constrain evolution of dispersal ability. In Europe, saproxylic invertebrates associated with tree hollows are currently threatened due to the severe fragmentation of their habitat, but data on the popu...

Protecting populations in their natural habitat allows for the maintenance of naturally evolved adaptations and ecological relationships. However, the conservation of genetic resources often requires complementary practices like gene banks, translocations or reintroductions. In order to minimize inbreeding depression and maximize the adaptive poten...

Gene fl ow is a process of transferring and exchanging genetic material among groups of organisms and is an important evolutionary factor that greatly affects genetic variation and differentiation in trees. Gene fl ow within and among populations of forest trees plays an important role in forest tree improvement, conservation genetics, and containm...

Peripheral populations may be crucial for understanding processes underlying adaptive genetic variation. Their evolution and ecology are driven by various genetic and demographic processes, such as selection, gene flow and bottleneck. Peripheral populations often experience a reduction in density resulting in the Allee effect. The presence of inter...

In this study, we characterize and compare the genetic structure of aboveground and belowground populations of the ectomycorrhizal fungus Laccaria amethystina in an unmanaged mixed beech forest. Fruiting bodies and mycorrhizas of L. amethystina were mapped and collected in four plots in the Świętokrzyskie Mountains (Poland). A total of 563 fruiting...

In this article, we examined the effects of the two modes of regeneration (natural vs. artificial) on the genetic diversity of Quercus robur (L.) and Quercus petrea (Matt.) Liebl. populations. Using nuclear microsatellite markers, we investigated the genetic diversity of two-species oak seed stands (Jamy and Legnica, Poland) and their progeny – nat...

Habitat fragmentation can have severe genetic consequences for trees, such as increased inbreeding and decreased effective population size. In effect, local populations suffer from reduction of genetic variation, and thus loss of adaptive capacity, which consequently increases their risk of extinction. In Europe, Taxus baccata is among a number of...

The genetic diversity of the north and western European subspecies of honey bee, Apis mellifera mellifera (the "dark bee") is severely endangered due to hybridization with introduced bees of evolutionary branch C. Genetic variability of native honey bees in the north-eastern part of Poland, including a special isolated breeding zone in the Augustow...

NM+ is computer software designed for making inferences on plant gene dispersal and mating patterns by modelling parentage probabilities of offspring based on the spatially explicit neighbourhood model. NM+ requires a sample of mapped and genotyped candidate parents and offspring; however, offspring may optionally be assigned to single maternal par...

The estimates of contemporary gene flow assessed based on naturally established seedlings provide information much needed for understanding the abilities of forest tree populations to persist under global changes through migration and/or adaptation facilitated by gene exchange among populations. Here, we investigated pollen- and seed-mediated gene...

In plants, the magnitude of seed and pollen dispersal plays a pivotal role in shaping genetic structure of populations. Restricted dispersal of genes can stimulate the increase of inbreeding as well as spatial clustering of relatives. These phenomena are explained by the theory of isolation-by-distance. Because of its biology, European beech (Fagus...

When considering neutral nuclear markers, genetic differentiation of Scots pine (Pinus sylvestrisL.) populations is known to be low. The homogeneity arises particularly as an effect of common ancestry in a recent evolutionary history as well as an extensive gene flow, especially through pollen. However, within populations several other forces may s...

Polyploids, organisms that have multiple sets of chromosomes, are common in certain plant and animal taxa. However, there are only a few reports of intraspecific ploidy variation within the genus Quercus. The aim of the study was to investigate the suspected ploidy level of two oaks that have unusual microsatellite banding patterns. Polyploidy was...

Estimating seed and pollen gene flow in plants on the basis of samples of naturally regenerated seedlings can provide much needed information about "realized gene flow," but seems to be one of the greatest challenges in plant population biology. Traditional parentage methods, because of their inability to discriminate between male and female parent...

Simple sequence repeats have become the tool of choice in a wide range of studies of forest trees. Despite frequent use of multicolor fluorescent labeling DNA fragment analyzers, there are few procedures that reduce time and cost of the analyses by PCR multiplexing. Here we present an example of 2 multiplexes of 7 unlinked nuclear microsatellite lo...

Through simulations we have investigated the statistical properties of two of the main approaches for directly estimating pollen gene flow (m) in plant populations: genotypic exclusion and mating models. When the assumptions about accurately known background pollen pool allelic frequencies are met, both methods provide unbiased results with compara...

Through simulations we have investigated the statistical properties of two of the main approaches for directly estimating pollen gene flow (m) in plant populations: genotypic exclusion and mating models. When the assumptions about accurately known background pollen pool allelic frequencies are met, both methods provide unbiased results with compara...