Domestication and Breeding History of Strawberry

Fan and Whitaker explore the genetic footprint of the breeding history of cultivated strawberry.

Zhen Fan and Vance M. Whitaker

Horticultural Sciences Department, University of Florida, IFAS Gulf Coast Research and Education Center, Wimauma, FL, 33597, USA

Background: Cultivated strawberry arose as a hybrid between the species F. virginiana from North America and F. chiloensis from South America. The initial hybridization occurred in the 18th century in Europe, making strawberry one of the world’s most recently domesticated crops. Over the past fifty years, varieties from University of California, Davis and University of Florida gained worldwide popularity due to their improved yield and fruit quality and adaptation to their respective Mediterranean and subtropical climates.

Questions: How did the initial hybridization and subsequent adaptations to different climates shape the genetic composition of modern breeding populations? What are the wild species/subspecies that have been used in breeding? Can we identify regions of the genome associated with important agronomic traits, and are they under selection?

Findings: By examining whole-genome sequences of 289 strawberry varieties, we determined that the proportion of F. virginiana ancestry increased by 20% in modern varieties over initial hybrids, and the proportion of F. chiloensis subspecies pacifica rose from 0 to 3.4%. Divergent selection for Mediterranean (California) and subtropical (Florida) climates resulted in differential selection for genes from F. virginiana or F. chiloensis in 21 out of 28 chromosomes. We also found 16 genomic regions that may be important for climatic adaptation. More than 20 cycles of crossing and selection have happened in breeding since initial hybridization, but more than half of the genetic loci underlying yield and fruit size are still not under artificial selection.

Next steps: Candidate genes associated with fruit size and yield warrant future biological validation.

Fan, Z. and Whitaker, V.M. (2024). Genomic signatures of strawberry domestication and diversification.