Collaborative Research: An investigation of the evolution and taxonomy of the true blueberries (Vaccinium section Cyanococcus)

Duke University, Durham NC

Investigators

Abstract

North American blueberries, a rare example of domesticated woody species with origins in the US, have been intensively studied by agronomists because of their economic importance as a food crop. However, the evolutionary history of the group is still uncertain. In particular, a clear view of how many species exist in nature remains elusive: current estimates range between nine and 24. One reason for this is extensive morphological variation within species. Additionally, the ability of blueberry species to hybridize (cross-breed) further confounds species identification. These hybridization events also occasionally result in the formation of completely new species via duplication of the parent genomes, a phenomenon known as polyploidy. These polyploids, however, are often difficult to distinguish from the parents, resulting in unrecognized diversity. This study will attempt to remedy this by providing a thorough assessment of blueberry species boundaries and diversity while accounting for evolutionary history. The project will result in biodiversity discovery, a revision of the naming convention in blueberries, and a detailed understanding of polyploidy and its role in shaping the evolutionary history and species composition of this ecologically and economically important group. The project will also include many training opportunities, and an illustrated storybook will educate children about basic botany and the natural history of blueberries. Extensive field- and herbarium-based research will be integrated with a variety of molecular techniques and analytical approaches to provide a comprehensive systematic and evolutionary study of Vaccinium sect. Cyanococcus. A phylogenomic dataset will be assembled from target enrichment data to infer evolutionary relationships and biogeographic history of the group. A custom pipeline will be designed that allows for the identification of alleles from polyploids, filling an important gap in the study of naturally occurring, non-model polyploid complexes. Alleles will be used to test hypotheses regarding the origins and mode of polyploidization and identification of diploid progenitors. The study will conclude with a thorough taxonomic revision of Cyanococcus based on extensive morphological study of herbarium and field-collected material and common garden studies. This will comprise dichotomous and interactive keys, species descriptions, and geographic distribution maps. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.