2017 ASHS Annual Conference

Commercial blueberry production in the U.S. relies on cultivars derived from combinations of different blueberry species. Interspecific hybridization is used to improve overall fruit quality as well as abiotic and biotic tolerance to expand the range of blueberry production. Knowing both ploidy and nuclear genome size can help in determining the evolutionary relationships among plant species and also lead to better breeding strategies for the development and selection of new cultivars. Blueberry species have many different genome sizes, presumably due to differing ploidy levels and/or DNA content. In some species, such as V. pallidum Aiton, there are different ploidy series available for breeding, further complicating the observed DNA content in elite selections. In this study we determined DNA content in 79 blueberry taxa including 11 species and 68 hybrid cultivars and selections. Chromosome spread was performed in selected taxa to verify presumptive ploidy levels. Diploid, tetraploid, pentaploid, and hexaploid blueberry species and accessions were included in this study. Holoploid genome size (2C DNA) was significantly correlated with ploidy, or presumed chromosome number (2n), but only weakly correlated with monoploid genome size (Cx).