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ARS Home » Pacific West Area » Corvallis, Oregon » National Clonal Germplasm Repository » Research » Publications at this Location » Publication #308591
Title: Vaccinium species ploidy assessment

Author
item Hummer, Kim
item Bassil, Nahla
item RODRIGUEZ, ARMENTA - University Of Florida
item OLMSTEAD, J. - University Of Florida

Submitted to: Acta horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2014
Publication Date: 11/1/2016
Citation: Hummer, K.E., Bassil, N.V., Rodriguez, A., Olmstead, J.W. 2016. Vaccinium species ploidy assessment. Acta Horticulturae. 1101:199-204. doi: 10.17660/ActaHortic.2015.1101.30.

Interpretive Summary: The U.S. Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository (NCGR), Corvallis, Oregon, maintains the national collection for blueberry wild relatives. The NCGR genebank includes more than 1700 accessions, with representatives of 81 species from around the world. The primary collection of clonal blueberries and their wild relatives are maintained as plants in containers in greenhouses and screenhouses. The highbush blueberry is the main crop of economic importance. Breeders wish to expand gene accessibility to include representatives of the rich diversity present in other sections. Knowledge of number of chromosomes is critical, and previous research has been limited. The objective of this research was to evaluate number of chromosomes sets for about 50 species within the NCGR collection. Ploidy was evaluated through a laboratory technique called "flow cytometry" using leaf samples. The base chromosome set for blueberries is 12. Many species native to the South Pacific and Southeast Asia were diploid (two sets of chromosomes or 2x). Some diploid, tetraploid (4x), and hexaploid (6x) members. Some unusual clones were triploid. Samples from Meso- and South America, had the same amount of chromosomes as the highbush blueberry. These species could be directly crossed with the highbush blueberry of commerse.

Technical Abstract: 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.