Genetic Diversity in Chestnut Species

Chestnut trees (Castanea spp.) represent a group of economically and ecologically significant forest species distributed across Europe, Asia and North America. Genetic diversity within and among chestnut species underpins adaptation to diverse climates, resistance to pests and pathogens, and the preservation of valuable wood and nut traits. Historical events—from glacial refugia and domestication to recent cultivar exchanges—have shaped contemporary gene pools, yielding complex patterns of local adaptation and gene flow. Threats such as chestnut blight, ink disease and climate change have driven breeding programmes focused on introgression of resistance alleles, while conservation efforts aim to safeguard wild stands from genetic erosion. Advances in molecular and genomic tools, including high-throughput sequencing and durable molecular markers, now enable detailed characterisation of genetic variation, informing both restoration of decimated populations and optimisation of nut production. A comprehensive understanding of diversity patterns is essential for sustainable management and the development of resilient chestnut varieties in the face of global change.

Research from Nature Portfolio

Recent studies have employed drought-associated genomic markers to assess genetic variation among key chestnut cultivars in Mediterranean environments, revealing full polymorphism across SSR and EST-SSR loci and identifying alleles linked to enhanced drought tolerance. Parallel work on cultivated and wild Japanese chestnut populations has mapped genetic clusters along the archipelago, detected substantial gene flow from cultivars into natural stands, and emphasised the need to conserve true wild genotypes. These investigations demonstrate the power of targeted molecular markers to inform breeding strategies and in situ conservation of chestnut genetic resources under changing climatic and anthropogenic pressures.

Genetic Diversity in Chestnut Species publication trend

The graph below shows the total number of articles in genetic diversity in chestnut species across all publications each year (not limited to Nature Index journals).

Technical terms

Simple sequence repeat (SSR) marker: Tandemly repeated short DNA motifs used to assess genetic variation due to differences in repeat number.

Expressed sequence tag (EST-SSR) marker: SSR marker derived from transcribed regions, often linked to functional genes and adaptive traits.

Heterozygosity: Proportion of individuals possessing two different alleles at a given genetic locus, reflecting genetic variability.

Gene flow: Movement of genes between populations through pollen, seed dispersal or interbreeding, influencing genetic structure.

Quantitative trait loci (QTL): Genomic regions associated with variation in complex traits, identified by statistical linkage to phenotypic measurements.

References

1. Tolerance evaluation and genetic relationship analysis among some economically important chestnut cultivars in Türkiye using drought-associated SSR and EST-SSR markers. Scientific Reports (2023).
2. Genetic structure analysis of cultivated and wild chestnut populations reveals gene flow from cultivars to natural stands. Scientific Reports (2021).
3. New insights into the evolution and local adaptation of the genus Castanea in east Asia. Horticulture Research (2024).
4. Genetic Relationships of 118 Castanea Specific Germplasms and Construction of Their Molecular ID Based on Morphological Characteristics and SSR Markers. Plants (2023).
5. Mediterranean and Northern Iberian gene pools of wild Castanea sativa Mill. are two differentiated ecotypes originated under natural divergent selection. PLOS ONE (2019).