Genetic diversity of sessile oak populations in the Czech Republic

The sessile oak is a broadleaved tree species of great ecological and silvicultural importance. Oaks are the second most widespread deciduous tree species in the Czech Republic, and ongoing climate change negatively affects the abundant and often monocultural Norway spruce. Therefore, a proportional increase of more resilient tree species such as sessile oak has emerged. This study aimed to depict population genetic diversity when analysing 272 individuals from 10 subpopulations selected across the Czech Republic. Targeted populations were chosen based on the minimal expected human impact on the stand (presumably autochthonous stands). All individuals were genotyped using 18 polymorphic microsatellite markers (SSRs) assembled into two amplification multiplexes. The high discriminatory power of SSR markers was tested and confirmed by the probability of identity analysis. The genetic differentiation of the subpopulations was low yet significant, quantified by Wright’s F-statistics within the range from 0.012 to 0.029. Based on discriminant analysis of principal components (DAPC), we detected two populations with geographic genetic correlation (the 15^th meridian east being a north-south boundary line) and one with a distinct genetic pattern. We assume that the population might previously be established from seed sources outside the Czech Republic. Moreover, to some extent, our findings advocate the legitimacy of the legislative rules for forest reproductive material (FRM) transfer.

Energetic and reproductive costs of coral recovery in divergent bleaching responses

Mass thermal bleaching events are a primary threat to coral reefs, yet the sublethal impacts, particularly on energetics and reproduction, are poorly characterized. Given that the persistence of coral populations is contingent upon the reproduction of individuals that survive disturbances, there is an urgent need to understand the sublethal effects of bleaching on reproductive output to accurately predict coral recovery rates. In 2019, the French Polynesian island of Mo’orea experienced a severe mass bleaching event accompanied by widespread coral mortality. At the most heavily impacted sites, we observed Acropora hyacinthus individuals that were resistant to bleaching, alongside colonies that bleached but showed signs of symbiont recovery shortly after the bleaching event. We collected fragments from A. hyacinthus colonies five months post-bleaching and, using energetic assays and histological measurements, examined the physiological and reproductive consequences of these two distinct heat stress responses. Despite healthy appearances in both resistant and recovered corals, we found that recovered colonies had significantly reduced energy reserves compared to resistant colonies. In addition, we detected compound effects of stress on reproduction: recovered colonies displayed both a lower probability of containing gametes and lower fecundity per polyp. Our results indicate that bleaching inflicts an energetic constraint on the concurrent re-accumulation of energy reserves and development of reproductive material, with decreased reproductive potential of survivors possibly hampering overall reef resilience. These findings highlight the presence of intraspecific responses to bleaching and the importance of considering multiple trajectories for individual species when predicting population recovery following disturbance.

Genetic diversity of Norway spruce ecotypes assessed by GBS-derived SNPs

We investigated the genetic structure of three phenotypically distinct ecotypic groups of Norway spruce (Picea abies) belonging to three elevational classes; namely, low- (acuminata), medium- (europaea), and high-elevation (obovata) form, each represented by 150 trees. After rigorous filtering, we used 1916 Genotyping-by-Sequencing generated SNPs for analysis. Outputs from three multivariate analysis methods (Bayesian clustering algorithm implemented in STRUCTURE, Principal Component Analysis, and the Discriminant Analysis of Principal Components) indicated the presence of a distinct genetic cluster representing the high-elevation ecotypic group. Our findings bring a vital message to forestry practice affirming that artificial transfer of forest reproductive material, especially for stands under harsh climate conditions, should be considered with caution.

The effect of low-intensive coherent seed irradiation on germinant growth of Scots pine and sugar beet

The success of forest and agricultural plant establishment program mainly depends on the quality of reproductive material. The study intends to offer engineers and farm owners a solution for small-size seed improvement before sowing. The effect of low-intensity coherent light on the seeds of various crops is theoretically and empirically hypothesized. The seedlots of Scots pine (Pinus sylvestris L.) and sugar beet (Beta vulgaris L.) of Russian diploid hybrid RMS-127 were germinated in a controlled environment. The germinants were produced from six seed fractions, previously irradiated with 1.274 W·m^–2 at the 632.8 nm wavelength with 1, 2, 3, 5, 10, 15 min exposure to a standard laser system, plus untreated control. Pine germinants were measured on day 15, beetroot on day 10 after germination. An increase in exposure time reduced Scots pine germination energy and capacity, while for sugar beet the results were not conclusive. On the contrary, increasing the exposure time had a positive effect on both the height and biomass growth of both Scots pine and sugar beet germinants. The 10-min exposure time resulted in maximum values for sugar beet height and biomass and Scots pine height, while the 15-min exposure time produced maximum Scots pine biomass.

Low Outcrossing from an Apple Field Trial Protected with Nets

Regulatory compliance of experimental releases into the environment of not yet approved genetically modified plants often requires implementation of measures to reduce the dispersal of reproductive material. To study the impact of nets on pollen flow in an experimental field site in Switzerland, non-GM apple varieties ‘Ladina’ and ’Nicogreen’ were planted inside and outside a netted plot, respectively. Seeds harvested from mature fruits were germinated and the paternal variety of the seedlings was determined using simple sequence repeat (SSR) molecular markers. We demonstrate that pollination frequency from trees inside the netted plot to trees outside over a two-year (2018 and 2019) study of 4500 seedlings is 0.6% (26 seedlings). Moreover, these outcrossing events decreased with increasing distance from the pollen donor. Over the study period, we found on average 0.9%, 0.5%, 0.4% and 0.09% of the seedlings derived from apples of ‘Nicogreen’ trees at 8 m, 15 m, 72 m and 117 m being generated by fertilisations of ‘Ladina’ pollen, respectively. In comparison, 48.3% (2018 season) and 75.1% (2019 season) of examined ‘Ladina’ seedlings in the netted plot originated from ‘Nicogreen’ tree pollen outside the netted plot. The results suggest that insect netting is effective in minimizing egress of apple pollen from an experimental site and that the likelihood of outcrossing is reduced further (<0.1%) when there are no compatible apple trees within a radius of 100 m of the pollen donor. These data are important for biosafety research/regulation to aid understanding of pollen flow in experimental field sites.

Analysis of Latvian and Belarusian Oak (Quercus robur L.) Population Provenance and Genetic Structure Using Chloroplast Markers

In this study, oak specific chloroplast simple sequence repeat (SSR) markers were used to analyse Latvian and Belarusian oak (Quercus robur L.) population provenance and genetic structure. Chloroplast haplotypes were compared between Latvian and Belarusian pedunculate oak, and several common haplotypes were identified. The SSR haplotypes were compared to previously reported PCR-RFLP haplotypes, and haplotypes from the A (eastern European) and C (central European) lineages were identified. C lineage haplotypes were only found in the western region of Latvia. Haplotypes shared between Latvia and Belarus were all from the A lineage. Despite the much smaller population size of oak in Latvia in comparison to Belarus, the level of genetic diversity identified using the chloroplast SSR markers is similar. Provenance trials will need to be established in order to determine the suitability of Belarusian oak reproductive material for deployment in Latvia. Based on the results from this comparison of chloroplast haplotypes, as well as climatic similarities, it is probable that Belarusian oak material will be better suited to the eastern regions of Latvia compared to the western regions of Latvia.

P–433 Pregnancy and livebirth after fertility preservation in cancer patients

Study question What do we know about pregnancy and livebirth after IVF- fertility preservation treatment in women with cancer? Summary answer Most women conceived spontaneously (60%) and more than 50% of those who returned to use their cryopreserved reproductive material have delivered at least one child. What is known already Diminishing ovarian reserve and declining future reproductive potential are important issues in cancer survivors after anti-cancer treatment exposure. Publications on pregnancy and livebirth after fertility preservation in women with cancer are sparse. Studies report most cancer patient who underwent fertility preservation do not come back and use their frozen reproductive material. The purpose of this study was to investigate the fertility preservation outcome among cancer survivors. Study design, size, duration A retrospective cohort study was conducted at a single academic fertility center from including 336 cancer patients who underwent IVF-fertility preservation from January 2009 to June 2020. Participants/materials, setting, methods We included all women with cancer aged ≤40 years old who were referred for fertility preservation treatment prior to chemotherapy. Primary outcome: Number of pregnancies and livebirths after spontaneous conception and/or using their stored frozen material. Secondary outcomes: We also evaluated the utilization rate of the stored reproductive material and mortality rate among those with follow up data. Main results and the role of chance Of 336 patients who underwent IVF-fertility preservation, 214 (63.69%) elected oocyte cryopreservation, 86 (25.5%) underwent both embryo and oocyte cryopreservation and 36 (10.7`%) underwent embryo cryopreservation. Follow up data were available in 198 (58.9%) patients with a mean follow up of 3.2 years. Of 198, 16 (8%) patients died, 40 (20%) became pregnant. Of those pregnant patients, 24 (60%) became spontaneously pregnant and 16 (40%) became pregnant after frozen oocyte or frozen embryo treatment cycles. Almost a quarter (72.5%) of the pregnancies resulted in livebirths. In total, only 23 (7%) patients had returned for frozen oocyte or frozen embryo treatment cycle, of which 16 (70%) achieved a pregnancy and 10 (63%) achieved at least one live birth. Of 142 patients who were still alive at follow up but did not get pregnant, 51 (39%) were in remission from their cancer but had not chosen to use their stored reproductive material; 44 (31%) were still on anti-cancer treatment and had not started trying yet; 13 (9%) were suffering from the end-stage cancer disease; and 7 (5%) had used their stored reproductive material but failed and stopped trying to get pregnant. Limitations, reasons for caution The main limitation was the retrospective cohort study design which could introduce unidentified selection biases. Wider implications of the findings: Of women who underwent IVF-fertility preservation for cancer, most did not come back for treatment for a variety of reasons. Of those who became pregnant, 60% conceived spontaneously. Of those who used their cryopreserved reproductive material, 63% delivered at least one child. Trial registration number 2021/6935

Hybridisation of Malus sylvestris (L.) Mill. with Malus × domestica Borkh. and Implications for the Production of Forest Reproductive Material

This study focuses on the morphological and genetic characteristics of European crab apple (Malus sylvestris (L.) Mill.) and the occurrence of hybrids in its populations. We analyzed a total of 107 putative European crab apple trees in Slovenia: 92 from nine natural populations, five from a seed stand and 10 from a stand of unnatural origin. We also included 18 domesticated apple trees (Malus × domestica Borkh.) and two Japanese flowering crab apple trees (Malusfloribunda van Houtte) as outliers. The trees were classified into groups of European crab apples, hybrids and domesticated apples according to their morphological and genetic characteristics. Classification based on morphological traits produced different results (58.75% European crab apple, 37.11% hybrids and 4.14% domesticated apple) compared to those based on genetic analysis (70.10% European crab apple, 21.64% hybrids and 8.26% domesticated apple). When genetic and morphological characteristics were combined, only 40.20% of the trees were classified as European crab apple, and an additional group of feral cultivars of domesticated apples (6.18%) was identified. The analysis revealed that hybridization with domesticated apple is taking place in all studied natural European crab apple populations; however, hybrids and feral cultivars only occur to a limited extent. When introducing European crab apple into forests in the future, only genetically verified forest reproductive material obtained exclusively from suitable seed stands should be used.