Vaccinium species ploidy assessment
The U.S. Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository (NCGR), Corvallis, Oregon, maintains the national collection for Vaccinium L. germplasm. The NCGR genebank includes more than 1700 accessions, with representatives of 81 Vaccinium taxa from around the world. The primary collection of clonal blueberries and their wild relatives are maintained as plants in containers in greenhouses and screenhouses. While the primary genepool for highbush blueberry (V. corymbosum L.), the main crop of economic importance, is within Section Cyanococcus, breeders wish to expand gene accessibility to include representatives of the rich diversity present in other sections. Knowledge of ploidy level is paramount for this task, but has been limited. The objective of this research was to evaluate ploidy levels of approximately 50 species within the NCGR collection. Ploidy was evaluated through flow cytometry using cell preparations from leaf samples. The base haplotype for Vaccinium is x=12. Many species native to the South Pacific and Southeast Asia were diploid (2n=2x=24). Sections Cyanococcus and Myrtillus each included diploid, tetraploid, and hexaploid members. Section Oxycoccus had diploids and hexaploids. The clones of V. dependens (G. Don) Sleumer (sect. Brachyceratium) and V. poasanum (Donn. Sm.) (synonym = Symphysia poasanum (Donn. Sm.) Vander Kloet) were triploid. Pyxothamnus members from Meso- and South America, V. consanguineum Klotzsch and V. corymbodendron Dunal, were tetraploid. These two species are candidates for direct crosses with V. corymbosum. Ploidy levels from other species representatives and standards are reported.
Hummer, K.E., Bassil, N.V., Rodríquez Armenta, H.P. and Olmstead, J.W. (2015). Vaccinium species ploidy assessment. Acta Hortic. 1101, 199-204
blueberry, flow cytometry, genetic resources, plant breeding