GENETIC DIFFERENTIATION OF DIPLOID BLUEBERRY, VACCINIUM SECT CYANOCOCCUS (ERICACEAE)

The most dissected taxonomic treatment of Vaccinium section Cyanococcus, generated by Camp in 1945, recognized nine diploid (2n = 24) taxa. More recently, Vander Kloet recognized six taxa nesting the two hillside blueberries and the three highbush blueberries, respectively. Whereas previous taxonomic treatments have been based primarily upon morphological data, field studies, chromosome counts, and crossability, the present study employs allozyme data to assess genetic relationships of representative diploid blueberry populations. Starch gel electrophoresis was conducted on population samples obtained from 25 sites identified in an extensive field survey of this endemic North American section. Data were collected at 11 polymorphic loci previously observed to have high taxonomic information content. Data were analyzed to obtain similarity, as well as standard measures of population genetic structure. Five genetic lineages were discriminated; these were supported by highly disparate allelic frequencies. Conspecific populations were undifferentiated, with distribution of genetic variation similar to that described for other predominantly outcrossing species. In conjunction with patterns of morphological variation, this study supports the recognition of seven species: two highbush species, V. corymbosum and V. elliottii, and five lowbush species, V. boreale, V. darrowii, V. myrtilloides, V. pallidum, and V. tenellum.