The marmot plum is a wild fruit tree from the southern Alps that scientists have long struggled to place among plums or apricots. A broad phylogenomic study published in 2026 now assigns it to the plum section. This botanical clarification has a practical dimension: the rare tree is adapted to dry slopes and poor soils, and its genes may one day help researchers prepare more robust orchards.

INRAE brought the species back into the spotlight on 2 September 2026. The news does not announce a miracle fruit or a variety ready for growers. It shows how knowledge, conservation and plant breeding fit together. Before the useful traits of a wild relative can be studied, researchers need to know what it is, measure the diversity that remains in nature and preserve representative trees.

What is the marmot plum?

The marmot plum’s scientific name is Prunus brigantina, also written Prunus brigantiaca. Its common names include Briançon plum and Briançon apricot. It grows naturally in the southern French Alps and the Italian Piedmont. INRAE describes it as endemic to this region and reports that it can grow above 1,900 metres.

Its small yellow fruit is smooth-skinned, acidic and not very sweet, looking more like a plum than a commercial apricot. The tree is often shrubby and thorny. It grows in dry, sunny habitats, including open scrub and rocky mountain slopes. In the past, it was also used in hedges that marked plots and helped contain livestock.

The many names are more than folklore. They reflect a genuine classification problem. The genus Prunus contains many stone-fruit trees, including plums, apricots, peaches, cherries and almonds. Visible similarities do not always reveal the full evolutionary story. Researchers now compare much larger sets of genetic sequences to reconstruct those relationships.

Why did scientists hesitate between plum and apricot?

Traditional classifications often placed the marmot plum with apricots. A 2021 study of 71 wild trees using 24 microsatellite markers supported that view. It put P. brigantina closer to the Armeniaca section than to the diploid plums included in the comparison.

Results also depend on which species are sampled and which parts of the genome are examined. Other whole-genome studies had suggested that the marmot plum was distinct from true apricots. This disagreement did not simply mean that one team had looked at the tree incorrectly. It showed how a family tree can gain resolution when the sampling becomes wider and more regions of the genome are compared.

The 2026 study in Molecular Phylogenetics and Evolution reconstructed deep relationships across Prunus using extensive nuclear data. In that broader analysis, the marmot plum falls within the Prunus section. The best available evidence therefore places it on the plum side today. This is still a scientific conclusion based on a dataset and a method, and it can be refined as more genomes become available.

What does its genetic diversity tell us?

Its position on the family tree is not the only important issue. The 2021 study found three differentiated genetic groups in the Alps, associated with populations separated across different areas. The authors also described severe fragmentation and a strong impact of human activity on population size.

INRAE mentions the Queyras, Mercantour and Écrins among the places where the species remains. Overgrazing, development and ski runs can fragment its habitat. When groups become small and isolated, part of their diversity can be lost even while a few trees are still visible. Two members of the same species do not carry exactly the same set of genetic variants.

Researchers selected 36 trees for a collection outside the natural habitat, designed to represent all the allelic diversity detected in the study. A conservation orchard does not replace wild populations. It safeguards living material, while on-site conservation also protects interactions with soil, climate, pollinators and the rest of the ecosystem.

What is a reference genome for?

A reference genome is an ordered map of an organism’s DNA. It does not represent every marmot plum, but it gives researchers a common basis for comparing individuals, identifying variants and linking parts of the genome to observed traits. The drPruBrig project, produced by Genoscope with INRAE through the European Reference Genome Atlas, provides a chromosome-level assembly in the public NCBI and European Nucleotide Archive collections.

This resource supports sharper questions. Which regions does the marmot plum share with cultivated plums? Which variants might be connected to growth on poor soils or in dry environments? How do Alpine populations differ? A sequence does not answer these questions automatically, but it enables finer comparisons than a small set of isolated markers.

ERGA is pursuing the same goal at continental scale by building high-quality reference genomes to understand and protect European biodiversity. Genomic data cannot replace field surveys or repeated observations through the seasons. It adds another layer of information, helping conservationists decide what should be protected and avoid losing differences that are invisible to the eye.

Could the marmot plum really help climate-ready orchards?

Its potential is credible, but it remains a research question. The marmot plum survives in dry, sunny and nutrient-poor environments where many cultivated fruit trees would struggle. Wild crop relatives can retain variants lost during domestication, when people selected heavily for fruit size, taste, appearance, regular production or ease of harvest.

Finding an interesting variant is not the same as producing a new plum variety. Researchers must confirm that the trait is inherited, understand how it works, make compatible crosses and evaluate offspring. Drought response, fruit quality, flowering time, yield, disease sensitivity and performance in different soils all need to be considered together. A useful mountain trait may come with an unwanted characteristic in a commercial orchard.

Drought tolerance should not be confused with needing no water. A tree that survives a dry slope is not guaranteed to produce a large crop without irrigation. Research may learn from that robustness, but the effect still has to be demonstrated under real growing conditions. The genome is therefore a library of leads, not a catalogue of ready-made solutions.

Why protect the wild tree before trying to use it?

A genetic resource has lasting value only while it continues to exist. Careless collection of seeds, cuttings or saplings from small populations could weaken the very resource that scientists are trying to conserve. The sound approach is to document populations, protect habitats and work through scientific collections or authorised nurseries rather than move wild material opportunistically.

In-situ conservation allows the species to continue evolving under local conditions. An ex-situ collection provides a safety net and controlled material for research. The two approaches complement each other. This matters especially when distinct genetic groups live in separate mountain ranges: saving only one group would not preserve the species’ full history.

What can gardeners and small orchards learn?

The first lesson is the value of diversity. In a home orchard, varying species, cultivars and flowering or ripening dates does not provide perfect insurance, but it reduces dependence on a single response to frost, heat or disease. Local and heritage varieties also deserve accurate identification and conservation through responsible networks.

The second lesson is patience. A newly mapped genetic resource does not replace basic orchard care: choosing rootstock suited to the soil, planting at the right time, protecting young trees, keeping soil covered and monitoring plant health. Genomics creates future options; everyday agronomy remains essential.

Better knowledge of local harvests can also make existing diversity more useful. Seeed enables individuals and producers to give, sell or swap harvests and local products with people nearby. When gardens and orchards grow different fruits, their seasons and surpluses can complement each other. Such local exchange should never be used to collect or distribute material from fragile wild populations.

Key points

  • The marmot plum is a wild fruit tree endemic to the southern French Alps and Italian Piedmont.
  • A 2026 phylogenomic study now places it in the plum section.
  • Three differentiated genetic groups have been identified in its Alpine populations.
  • A core collection of 36 trees was designed to preserve the diversity detected outside the natural habitat.
  • Its reference genome can support research on robustness, but it has not produced a miracle variety.
  • Protecting habitats and wild populations remains the first priority.

Sources

Image: “Prunus brigantina” by Axel Kristinsson, Wikimedia Commons, licensed under CC BY 2.0. Source page. Used without modification.