Genetic diversity and cultivar variants in the NCGR cranberry (Vaccinium macrocarpon Aiton) collection

Authors: SCHLAUTMAN, BRANDON - THE LAND INSTITUTE; Zalapa, Juan; COVARRUBIAS-PAZARAN, GIOVANNY - UNIVERSITY OF WISCONSIN; RODRIGUEZ-BONILLA, LORRAINE - UNIVERSITY OF WISCONSIN; HUMMER, KIM; Bassil, Nahla; SMITH, TYLER - AGRICULTURE AND AGRI-FOOD CANADA

Submitted to: Journal of Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2018
Publication Date: 11/30/2018
Citation: Schlautman, B., Zalapa, J.E., Covarrubias-Pazaran, G., Rodriguez-Bonilla, L., Hummer, K.E., Bassil, N.V., Smith, T. 2018. Genetic diversity and cultivar variants in the NCGR cranberry (Vaccinium macrocarpon Aiton) collection. Journal of Genetics. 97(5):1339–1351. https://doi.org/10.1007/s12041-018-1036-3.
DOI: https://doi.org/10.1007/s12041-018-1036-3

Interpretive Summary: Cranberry is an important commercial fruit crop that is native and was domesticated in North America. The USDA-ARS National Clonal Germplasm Repository (NCGR) houses a collection of accessions which include historical cultivars and wild selected plants that played significant roles in the domestication and crop evolution of cranberry. In this study, we genetically studied 271 plants from 77 acquisitions representing 66 named cultivars. Using molecular markers, we determined clonal purity and relatedness of cultivars within the NCGR collection. We calculated the genetic distances between individuals, and we identified 64 unique genetic individuals and observed variants the cultivar collection and in the commercial bogs from where some accessions originated. Finally, through a combination of comparisons of the genetic information of cultivars in this study with previous studies, a pedigree analysis, and the study of the geographic distribution of cranberry diversity, we identified the consensus genetic constitutions for many acquisitions and cultivars. The NCGR cranberry collection is an important resource for worldwide cranberry researchers and growers since it preserves and freely distributes cranberry genetic resources. The collection represents an important reservoir of genes for improving agronomic traits such as yield, quality, disease and insect resistances. Thus, this research is useful for breeders and researchers to highlight the diversity in the NCGR collection and the important role it plays for conservation of cranberry genetic resources. Moreover, most of the accessions in the collection are wild selections that are no longer commercially grown or are in danger of being lost, and NCGR continues to search for historically relevant cultivars absent from the collection in an effort to preserve these genotypes.

Technical Abstract: The American cranberry is an important commercial fruit crop that is native and was domesticated in North America. The USDA-ARS National Clonal Germplasm Repository (NCGR) houses a collection of accessions which include historical cultivars and wild selected germplasm that played significant roles in the domestication and crop evolution of cranberry. In this study, the genotypes of 271 plants from 77 accessions representing 66 named cultivars were determined with 12 simple sequence repeats (SSRs) to assess clonal purity and relatedness of cultivars within the NCGR. Using principal components analysis and neighbor-joining based on estimated genetic distances between individuals, we identified 64 unique genotypes and observed that intra-cultivar variants existed in the germplasm collection and in the commercial bogs from where some accessions originated. Finally, through a combination of comparisons of the genotypes of cultivars in this study with previous studies, a pedigree analysis, and the study of the geographic distribution of cranberry diversity, we identified consensus genotypes for many accessions and cultivars. We highlight the important role the NCGR collection plays for ex situ conservation of cranberry germplasm for future breeders and researchers. However, a few historically relevant cultivars were absent from the NCGR collection and efforts should be made to find these genotypes before they are lost and no longer commercially propagated.