Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2026
Abstract
The soil-borne oomycete Phytophthora cactorum causes crown rot, a major disease of the allo-octoploid strawberry (Fragaria × ananassa Duch., 2n = 8× = 56) that limits cultivation worldwide. Resistance to P. cactorum is a highly desirable trait but is typically quantitative and moderately heritable. A better understanding of the genetic basis of resistance to crown rot is essential for developing durable crown rot-resistant cultivars. We conducted a genome-wide association study (GWAS) using multi-locus models on 100 wild strawberry accessions from South and North America. The accessions were genotyped using the Axiom™ 50 K strawberry SNP array and mapped to the F. × ananassa cv. Royal Royce v. 1.0 reference genome. Testing for resistance to P. cactorum revealed a wide range of phenotypes. A single genetic marker, AX-184528282, located on chromosome 7B, was strongly associated with resistance to P. cactorum and explained 53% of the observed phenotypic variation. This marker was present in several highly resistant exotic Fragaria accessions that represent potential donors for introgression of favorable alleles into modern strawberry cultivars. In addition, several strong candidate resistance genes were identified within the 2 Mb genomic region surrounding the significant marker. This study advances understanding of resistance to P. cactorum in strawberry and identifies genetic resources that can accelerate the development of crown rot-resistant cultivars through marker-assisted breeding.
2025
Authors
Jorunn BørveAbstract
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Authors
Volkmar Timmermann Nenad Potočić Anne-Katrin Prescher Alexa Michel Katrin Haggenmüller Till KirchnerAbstract
In 2024, our sample remained stable with 27 participating countries and the largest number of assessed plots since 2019. We witnessed a very slight increase of 0.2 percentage points (%p) in mean defoliation as compared to 2023, mainly due to an increase of 0.5%p for broadleaves, while defoliation of conifers remained almost unchanged (0.1%p decrease). The strongest increase in defoliation occurred in deciduous (sub-) Mediterranean oaks (+2.1%p), while the strongest decrease was recorded in Norway spruce (-0.8%p). Deciduous temperate oaks had the highest (29.7%) and Norway spruce the lowest (22.4%) mean defoliation. Trend analyses show a considerable increase in defoliation of evergreen oaks (7.1%p), common beech (6%p), Norway spruce (5.5%p), and deciduous temperate oaks (5%p) over the past 20 years. The increase in defoliation for Scots pine and Mediterranean lowland pines (3.7 and 3.3%p, respectively) was more moderate. The results of the trend analyses were not significant for deciduous (sub-) Mediterranean oaks and Austrian pine. The percentage of trees with damage symptoms (48.6%) was almost the same as in 2023 (-0.5%p). As in previous years, the number of damage symptoms per assessed tree was substantially higher for broadleaves than for conifers (0.86 vs. 0.55, respectively). Insects, abiotic causes, and fungi were the most common damage agent groups for all species, comprising altogether more than half of all damage records. Tree mortality in 2024 was 1.1% (1 145 trees), i.e. at the same level as in the year before. While mortality rates for the main species and species groups ranged from 0.6 to 1.6%, mortality of Betula spp. and European ash was higher with 2.4% and 7% respectively.
Authors
Volkmar TimmermannAbstract
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Authors
Lena Wohlgemuth Mathieu Jonard Andreas Schmitz Peter Waldner P. Schmidt Walter Heleen Deroo Nathalie Cools Bruno de Vos Anne Thimonier Arne Verstraeten Inken Krüger Volkmar Timmermann Mathias Neumann Pasi Rautio Kai SchwärzelAbstract
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