Assessing resistance to spotted-wing drosophila across populations of wild and domesticated blueberries

Spotted-wing drosophila (SWD), Drosophila suzukii, is an invasive pest that targets many soft-
skinned fruits, including blueberries. Host-plant resistance to SWD is influenced by various
physical and chemical fruit traits, which are affected by domestication. Crop domestication often
reduces resistance against herbivores due to trade-offs between defense and reproduction.
While some studies have identified traits associated with resistance to SWD, there remains a
gap in understanding how domestication has affected SWD resistance across wild and
domesticated populations. This study aims to explore the impact of domestication on resistance
to SWD in highbush blueberry (Vaccinium corymbosum). Highbush blueberry, a perennial shrub
native to the northeastern United States, was domesticated approximately 100 years ago. In
New Jersey, wild and domesticated populations coexist in a region known as the Pinelands. We
hypothesize that wild blueberries are more resistant to SWD than cultivated blueberries, though
the strength of these differences may vary across populations. To test this hypothesis, we
collected wild and domesticated blueberries from nine sites in New Jersey and analyzed various
physical and chemical traits known to influence SWD resistance. Additionally, we conducted
bioassays to determine SWD performance on different berry types. In support of our hypothesis,
our findings revealed that domesticated blueberries are more susceptible to SWD than wild
blueberries and that fruit traits differ between wild and domesticated blueberries. Moreover, the
level of resistance and differences in traits varied among wild and domesticated populations.
The results of this study could assist plant breeders in developing SWD-resistant highbush
blueberry varieties.