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Warren F. Lamboy and Christopher G. Alpha

Curators of plant genetic resources collections must preserve germplasm possessing known useful characteristics as well as material displaying general genetic diversity. In order to ensure that both types of germplasm are included in a collection, germplasm curators require three fundamental types of information about each accession: taxonomic identity, genetic identity, and genetic relationship. Because simple sequence repeat DNA fragments (SSRs) have been successfully used to determine the genetic identity of grape clones, we conducted a study to determine if SSRs would supply all three types of information for the accessions in the cold-hardy Vitis (grape) germplasm collection. SSR fragments were amplified at six different loci for 23 accessions of cold-hardy grape spanning the range of species diversity in the collection. The minimum number of different alleles found at a locus was 9; the maximum was 26. Heterozygosity values ranged between 0.565 and 0.783, while gene diversity values were in the range 0.785 to 0.944. Two hundred fifty-two pairs of plants out of a possible 253 could be distinguished by their SSR profiles. Nei's genetic identities were computed between all pairs of plants and used in a UPGMA cluster analysis. The relationships obtained did not correspond well to expected relationships based on geography and taxonomy. Four species of grapes were represented by two or more accessions in this study. No DNA fragments found at these six loci served to unambiguously distinguish one species from another. Thus, SSR fragments from the six loci studied were useful in determining genetic identity of accessions, but were not helpful in determining genetic relationships or taxonomic identities. We are searching for additional loci that are informative for these types of information. Meanwhile we highly recommend SSRs for determining genetic identity in germplasm resources collections.

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Margaret R. Pooler and Ruth L. Dix

The historic Japanese flowering cherry trees planted around the Tidal Basin in Washington, D.C., were given to the United States in 1912 as a gift from Japan, and have become a popular tourist attraction. Unfortunately, only a small portion of the original trees remain, and these trees are in various states of decline due to old age and stress. In cooperation with the National Park Service, we have propagated from cuttings nine trees that are known to be original and 10 trees that are thought to be original. DNA from these and other P. × yedoensis were compared using RAPD markers. Twenty-one 10-nucleotide primers yielded 80 repeatable bands that were used to assess genetic distance among the accessions. Twenty of these bands were monomorphic across all 28 accessions tested, so were not informative. The frequency of the remaining 60 bands varied from 0.04 to 0.96, with an average frequency of 0.58. Thirteen of the accessions, including six of the nine that are known to be original germplasm, were identical at all loci tested. Other accessions that are thought to be original trees were similar, with similarity values of 0.93 to 0.99. The most genetically dissimilar trees were P. × yedoensis accessions from our collection that were collected as seed in Japan. Accessions obtained from commercial nurseries including `Afterglow', `Akebono” and Yoshino were also dissimilar to the Tidal Basin trees. This study indicates that most of the older trees planted around the Tidal Basin are genetically very similar, but that variability in P. × yedoensis exists, especially in accessions collected as seed from Japan.

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Claudio Cantini, Antonio Cimato, Antonella Autino, Alessandro Redi, and Mauro Cresti

cultivars, their dominant character (RAPDs and AFLPs) or poor reproducibility among different laboratories and experiments (RAPDs) are still considered major drawbacks in cultivar fingerprinting. Among the others, microsatellite markers have proved

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Kirk W. Pomper, Jeremiah D. Lowe, Li Lu, Sheri B. Crabtree, Shandeep Dutta, Kyle Schneider, and James Tidwell

fingerprinting ( Wünsch and Hormaza, 2002 ). SSRs are short (1–6 bp) tandem repeat DNA sequences flanked by unique, conserved DNA sequences. The relative random distribution of microsatellites in the genome, codominant inheritance, high level of reproducibility

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Kanin J. Routson, Ann A. Reilley, Adam D. Henk, and Gayle M. Volk

conventional identification methods difficult, if not impossible, for these century-old trees. Genetic fingerprinting, including microsatellites, have become powerful and accurate tools for analyzing genetic diversity ( Hammer et al., 2003 ). Microsatellite

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Li Li, Ling Liu, Deshuang Zhang, Ping Wu, Fenglan Zhang, and Xiulan Xu

with close genetic relationships are difficult to screen. By contrast, SSR fingerprints have some obvious advantages, such as simplicity, clarity, and accuracy ( Li and Zheng, 2009 ; Li et al., 2009 ; Shi et al., 2007 ; Suwabe et al., 2002 ). Indeed

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Li Li, Xiulan Xu, Ping Wu, Guo Zhang, and Xiaobing Zhang

difficulties associated with SNP genotyping ( Ding and Jin, 2009 ). This is particularly true for monitoring laboratories supported by local governments and small breeding laboratories in developing countries. Simple sequence repeat fingerprints offer obvious

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Noémi Makovics-Zsohár, Magdolna Tóth, Dezső Surányi, Szilvia Kovács, Attila Hegedűs, and Júlia Halász

mapping, population genetics, marker-assisted selection, or fingerprinting ( Wünsch, 2009 ). Conservation of Prunus SSR loci ranged between 57% and 100%, which means that the same primer set could be used in case of different species within the genus

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Phillip A. Wadl, Xinwang Wang, Andrew N. Trigiano, John A. Skinner, Mark T. Windham, Robert N. Trigiano, Timothy A. Rinehart, Sandra M. Reed, and Vincent R. Pantalone

. kousa cultivars used for simple sequence repeat z . Simple sequence repeat primer screening, polymerase chain reaction amplification, and DNA amplification fingerprinting of cultivars not resolved using simple sequence repeats. Primer

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Summaira Riaz, Alan C. Tenscher, Brady P. Smith, Daniel A. Ng, and M. Andrew Walker

aid in authenticating accession identification does not exist. DNA-based molecular markers, particularly simple sequence repeat (SSR) markers, are excellent fingerprinting tools and have been used to identify grape cultivars and to assist in the