Location: Vegetable Crops ResearchTitle: Discrimination of American cranberry cultivars and assessment of clonal heterogeneity using microsatellite markers Author
Submitted to: Plant Molecular Biology Reporter
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2012
Publication Date: 8/3/2012
Publication URL: http://handle.nal.usda.gov/10113/55930
Citation: Fajardo, D., Morales, J., Zhu, H., Steffan, S.A., Harbut, R., Bassil, N.V., Hummer, K.E., Polashock, J.J., Vorsa, N., Zalapa, J.E. 2012. Discrimination of American cranberry cultivars and assessment of clonal heterogeneity using microsatellite markers. Plant Molecular Biology Reporter. 31(2):264-271. Interpretive Summary: Cranberries are grown from clonally preserved and vegetatively propagated cultivars. Growers usually select cultivars for their operation based on expected attributes, such as horticultural performance (e.g., yield, fruit color, disease resistance, etc.). Since each cranberry cultivar is theoretically propagated from “the original” cultivar clone, growers expect that each of their beds represent a single genotype with stable and uniform trait performance. However, in practice cranberry beds are established by cuttings from pruning or raking established production fields. Production fields are not managed to maintain genetic purity and are believed to become more genetically diverse over time, presumably due to seedling establishment from self-pollinated and outcrossed flowers. Thus, newly established cranberry beds will not necessarily be genetically uniform or clonal depending on the purity of the starting material. Growers request that their new materials be true-to-type, but no reliable and/or affordable methods exist to provide this assurance. In this study, we developed a reliable and efficient molecular method for cranberry cultivar discrimination. The molecular markers developed herein can also be used for other purposes such as the identification of parental materials used in breeding programs, assessment of genetic diversity, and the maintenance of germplasm collections.
Technical Abstract: Cranberries (Vaccinium macrocarpon Ait.) are an economically important fruit crop derived from a North American native species. We report the application of 12 simple sequence repeats (SSR) or microsatellite markers to assess the genetic diversity of cranberry cultivars. We studied 164 samples of 21 different cranberry cultivars, 11 experimental hybrids, and 6 representative accessions of wild species. Genetic cluster analysis, based on 117 SSR alleles, differentiated the major cranberry cultivars. However, some cranberry cultivar sub-clone variants and mislabeled samples were observed. Consensus genetic profiles identified the most likely clonal representatives of several important cranberry cultivars (e.g., ‘Ben Lear’, ‘Howes’, and ‘Stevens’). The markers were further used to confirm putative parents of several hybrid progenies. The long-term goal of our studies is to identify, preserve, and utilize unique genetic materials to breed improved cranberries. Attaining this goal will help growers maintain sustainability under changing economic and environmental conditions.