Abstract
This study was conducted to determine if Brassica germplasm bulks created and maintained by the USDA-ARS North Central Plant Introduction Station (NCRPIS) were made with genetically indistinguishable component accessions and to examine newly identified putative duplicate accessions to determine if they can be bulked. Using ten microsatellite primer pairs, we genotyped two bulks of B. rapa L. ssp. dichotoma (Roxb.) Hanelt comprising four accessions and three bulks of B. rapa L. ssp. trilocularis (Roxb.) Hanelt comprising fourteen accessions, as well as four pairs of putatively duplicate accessions of B.␣napus L. Assignment tests on ten individual plants per accession were conducted using a model-based clustering method to arrive at probabilities of likelihood of accession assignment. The assignment tests indicated that one of the two bulks of B. rapa ssp. dichotoma involves genetically heterogeneous accessions. It was observed in the B. rapa ssp. trilocularis bulks that the component accessions could be differentiated into groups, with misassignments observed most frequent within groups. In B. napus, only one of the four pairs of putative duplicates showed significant genetic differentiation. The other three pairs of putative duplicates lack differences and support the creation of bulks. The results of the assignment tests were in agreement with cluster analyses and tests of population differentiation. Implications of these results in terms of germplasm management include the maintenance and/or re-creation of some Brassica germplasm bulks by excluding those accessions identified as being unique in this study.
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Acknowledgements
This is a journal paper of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 1018, and was supported by Hatch Act and the State of Iowa. The authors wish to thank Ms. Jody Hayes and Ms. Lori Lincoln (USDA-ARS Corn Insect and Crop Genetics Research Unit) for help in the laboratory, and Dr. Mark P. Widrlechner for reviewing the draft manuscript. Mention of commercial brand names in this paper does not constitute an endorsement of any product by the U.S. Department of Agriculture or cooperating agencies.
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Cruz, V.M.V., Nason, J.D., Luhman, R. et al. Analysis of bulked and redundant accessions of Brassica germplasm using assignment tests of microsatellite markers. Euphytica 152, 339–349 (2006). https://doi.org/10.1007/s10681-006-9221-5
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DOI: https://doi.org/10.1007/s10681-006-9221-5