Morus alba - EUFORGEN European forest genetic resources programme

Genetic summary

Genetic diversity and variation

White mulberry has high genetic diversity and phenotypic variation across its range, reflecting its adaptability to diverse environments (Keskin, Akca, and Ercisli, 2022). In Europe and northern Türkiye, white mulberry populations show high levels of genetic diversity, particularly within populations. Studies report that 79% of the genetic variation occurs within populations and 21% between populations, demonstrating substantial intra-population diversity and moderate differentiation between populations (Sümbül, 2025). Similarly, in the Trans-Himalayan region, 80% of the genetic variation is within populations and 20% between populations, showing genetic differentiation driven by restricted gene flow and local adaptation (Bajpai et al., 2014). This pattern is typical of outcrossing, wind-pollinated tree species, where gene flow maintains diversity within stands while geographic barriers create some differentiation.

Genetic distribution and clustering

White mulberry’s genetic structure is influenced by both natural and human factors, including geographic barriers, natural dispersal, and cultivation practices that have facilitated the movement of genetic material across regions (Sümbül, 2025). Despite this, genetic clustering is weak for populations in Türkiye; genotypes do not group clearly according to their geographic origin due to frequent gene exchange through cross-pollination and human-mediated distribution, despite natural barriers in mountainous regions (Sümbül, 2025). However, some research shows mulberry populations in eastern Türkiye to cluster into two major groups with wide variation in morphological and biochemical traits (Keskin, Akca, and Ercisli, 2022).

Gene flow

The species is outcrossing and primarily wind-pollinated, which promotes genetic exchange across nearby populations and maintains high heterozygosity (Sümbül, 2025). However, natural geographic barriers, such as mountains in the Trans-Himalayan region, have been shown to limit gene flow and lead to genetic differentiation between populations (Bajpai et al., 2014).

In addition to pollen dispersal by wind, seed dispersal occurs through both deliberate and spontaneous spread, with self-seeding being common in naturalized and cultivated areas (Blitek et al., 2022). Seeds are typically dispersed by birds and small mammals that feed on the fruits, facilitating short- to medium-distance dispersal.

The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2025.

Further relevant genetic traits

Cultivation and human intervention

White mulberry has a long history of cultivation and human selection which has significantly shaped its genetic diversity and distribution. In Poland, the species has been cultivated since the seventeenth century, primarily for ornamental purposes in urban environments. It demonstrates exceptional adaptability, withstanding temperatures down to −30 °C, tolerating drought and polluted or saline soils, making it suitable for urban greening and reclamation projects (Blitek et al., 2022). Despite its widespread cultivation, hybridization risk is minimal in Europe due to the absence of native mulberry species (Blitek et al., 2022).

In contrast, in Türkiye and Asia, white mulberry is primarily cultivated for fruit production, with selection focusing on larger, sweeter fruits and traits such as juice yield and fruit weight (Keskin, Akca, and Ercisli, 2022). Türkiye is one of the original centres of mulberry domestication and a global leader in production, maintaining extensive morphological diversity among local genotypes (Sümbül, 2025). Centuries of selective breeding and cultivation have enhanced morphological and genetic diversity within regional populations, although it has also caused artificial structuring of genetic variation through human management. Understanding and conserving this cultivated genetic diversity remains crucial for future breeding, adaptation, and resilience efforts (Blitek et al., 2022; Keskin, Akca, and Ercisli, 2022; Sümbül, 2025).

The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2025.

Genetic conservation

Threats

In Europe, white mulberry has few direct threats to its genetic diversity due to its widespread cultivation and adaptability. However, as a non-native species, it has not been the focus of conservation-oriented studies; most research addresses its commercial and horticultural value (Blitek et al., 2022). One exception is studies in Wrocław, Poland, which show that the structure of white mulberry populations depends on anthropogenic pressure and thermal conditions, highlighting potential vulnerability to climate and urban changes (Blitek et al., 2022).

Management

Because white mulberry is primarily cultivated for economic and ornamental purposes, genetic conservation measures are limited in Europe. Management efforts emphasize selection and breeding for fruit quality and resilience, but these activities can inadvertently narrow genetic diversity if a few genotypes dominate cultivation (Keskin, Akca, and Ercisli, 2022; Sümbül, 2025). To maintain the species’ genetic resources, future management should include systematic genetic monitoring, particularly in urban populations, and preservation of diverse genotypes across climatic regions. Expanding research on genetic conservation beyond the species’ commercial use will be essential to ensure long-term adaptability and sustainability of white mulberry populations in Europe (Blitek et al., 2022).

The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2025.

Morus alba
White mulberry

Environmental zones

Genetic summary

Genetic diversity and variation

Genetic distribution and clustering

Gene flow

Further relevant genetic traits

Cultivation and human intervention

Genetic conservation

Threats

Management

Further reading

References

Morus albaWhite mulberry

Environmental zones

Genetic summary

Genetic diversity and variation

Genetic distribution and clustering

Gene flow

Further relevant genetic traits

Cultivation and human intervention

Genetic conservation

Threats

Management

Further reading

References

Morus alba
White mulberry