The genetic variation of wild blueberries species has been the focus of considerable interest around the world, especially in relation to their commercial potential.  Vaccinium myrtillus is a native European berry commonly found throughout central and north Europe.  Little is currently known about the genetic variation of European wild blueberries and how this is related to the geographic distribution.  BioSS staff analysed the genetic diversity of Scottish wild blueberries and found significant diversity and evidence of gene flow not directly related to geographic distance.  Our results are consistent with local adaptation of wild berries to different altitudes, with higher degree of diversity found in grassland rather than woodlands.  These results indicate value in future studies involving more extended sampling along an altitude cline, and sampling in diverse environments, in order better to understand which genetic markers drive local adaptation and how the yield of the wild blueberries is influenced by these factors.

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In more detail

The native European blueberry (Vaccinium myrtillus), found growing wild in natural populations across Europe, is a small perennial plant that produces fruit with an intense blue colour throughout the berry.  There is an un-met demand for UK grown soft fruit in general and specifically for fruit in sufficient quantity and of appropriate character and colour available for processing.  Although related wild ‘lowbush’ material (Vaccinium angustifolium) is grown commercially in the US, Canada and some Scandinavian countries, no commercial plantings of European blueberry exist in the UK.  However, European wild blueberry occurs throughout Scotland, being most abundant in the Highlands, particularly in the north and west especially around spruce and pine dominated heath forests.  Demand for blueberries (Vaccinium spp.) is at record levels.  In the UK, this rapid expansion has been fuelled, in part, by consumer interest in their health benefits.  Blueberries remain one of the richest sources of antioxidants among the fresh fruits and are rich in compounds that have been linked to the prevention of macular degeneration, anti-cancer activity, improved night vision and reduced risk of heart disease, with some results indicating preventive and therapeutic effects on neurological, cardiovascular, metabolic and haematological disorders.

European blueberry is predominantly pollinated by bumblebees (although wasps can also act as pollinators) so larger areas of planting would enhance habitats for bumblebees, many of which are declining in the UK.  More insects feed on European blueberry than on any other plant in pinewoods, and these in turn provide a food source for wild birds.  European blueberry is therefore considered to be a good indicator species for pinewood biodiversity.

In this study, BioSS staff analysed the genetic diversity of 6 wild Scottish blueberry populations, using a total of 17 Simple Sequence Repeat loci.  We estimated basic summary statistics of genetic diversity, genetic distances among samples, inferred population genetic structure and estimated rates of gene flow, using multivariate statistics and Bayesian methods.  We found that groups of individuals sampled in grasslands show a higher genetic diversity than groups of individuals sampled in woodlands.  In our sample, the two different environmental classes were overwhelmingly made at two different altitudes, with grassland samples collected from higher altitudes, and woodland samples from lower.  In future, both factors (i.e., environment and altitude) need to be further investigated at a wider geographic scale and with more in-depth genetic data.  Our study highlights that there may be local adaptation to different climates, pollinator abundance, and soil richness in Scotland, which in turn offers much potential to select commercial variants.

This work was done in collaboration with Susan McCallum, Julie Graham, Dr. Katrin MacKenzie, Linzi Jorgensen and Sandie Williamson and was funded under the Scottish Government's Strategic Research Programme for environment, agriculture and food.