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Ira Silvergleit and Lin Schmale

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Jack E. Staub and Isabelle Y. Delannay

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Richard M. Hannan

The Phaseolus collection is the largest collection maintained at WRPIS. It numbers 11,501 accessions with 1585 accessions pending PI assignment. Over 20% of the Phaseolus accessions must be handled in special ways because of unique pollination or day length requirements. In accordance with the stated mission of the project, evolution of the bean germplasm maintenance program has included the following innovations: 1. Expanded interaction with the international germplasm centers (i.e. CIAT) and national programs. 2. As a result of interactions with the Phaseolus CAC, the increase of this genus was moved to greenhouse production exclusively. 3. A program to clean up seedborne viruses in the Phaseolus collection was established. 4. For some of the wild species, it was necessary to establish suitable and reliable alternate regeneration sites. 5. In collaboration with the Bean Improvement Cooperative (BIC) Bean Genetics Committee, WRPIS assumed responsibility for the Genetic Stocks Collection. 6. Develop a core subset of the P. vulgaris collection based on passport data, plant characters and molecular markers.

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Jinhe Bai, Elizabeth Baldwin, Jack Hearn, Randy Driggers, and Ed Stover

Six ‘Ambersweet’-derived hybrids, similar to sweet orange fruit size, color, and taste and potential as new sweet orange cultivars, were selected to determine their fruit categorization by comparison of their volatile profiles with the parent and ‘Hamlin’, a typical sweet orange. All hybrids are at least ½ sweet orange and varying amounts of mandarin, grapefruit, Poncirus trifoliata, and sour orange in each pedigree. In total, 135 volatiles were detected in the eight hybrid lines/commercial cultivars over two harvests, and 20 compounds were detected in all samples, including terpenes (limonene, β-myrcene, α-pinene, α-terpinene, α-terpineol, and linalool), esters (ethyl butanote, ethyl pentanoate, and ethyl acetate), aldehydes (acetaldehyde, hexanal, and nonanal), and alcohols (ethanol and hexanol). Total abundance of volatiles in January-harvested fruits averaged 30% higher than for fruits of the same trees harvested in November. ‘Ambersweet’ contained the highest total amount of volatiles (mainly as a result of very high levels of monoterpenes), and of them, nootkatone and six other compounds were not detected in any of the hybrids, and some of them were also not detected in ‘Hamlin’. On the other hand, 12 compounds, including pentanal, ethyl 2-butenoate, and ethyl nonanoate, were not detected in ‘Ambersweet’ but were found in ‘Hamlin’ and some of the hybrids. Cluster analysis separated the cultivar/hybrid and harvest time combinations into three clusters. FF-1-76-50, FF-1-76-52 and January FF-1-75-55, all with the same parents (‘Ambersweet’ × FF-1-30-52), were close to FF-1-65-55, but they were separated from ‘Hamlin’ and further separated from ‘Ambersweet’. The cluster containing ‘Hamlin’ has three subclusters: January ‘Hamlin’ and November FF-1-74-14, a hybrid with one-eighth P. trifoliata, which includes a slight off-flavor frequently found in P. trifoliata hybrids, independent of each other, and both were separated from a group of November ‘Hamlin’, FF-1-64-97, and FF-1-75-55. The cluster containing ‘Ambersweet’ included January FF-1-64-97. A principle component analysis (PCA) separated ‘Ambersweet’ from all hybrids and ‘Hamlin’ along the PC1 axis and separated November harvests from January harvests along PC2. This volatile analysis supports the classification of the hybrids as sweet orange.

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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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Patrick J. Conner

USDA breeding program at various locations across the pecan belt ( Thompson and Conner, 2012 ). Selections that perform well in NPACTS testing may then be released as new cultivars by the USDA. Two cultivars, Stuart and Desirable, make up over half of

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John R. Stommel and Bruce D. Whitaker

1 Vegetable Laboratory. To whom reprint requests should be addressed; e-mail stommelj@ba.ars.usda.gov . 2 Produce Quality and Safety Laboratory. We thank Clifford Rice, USDA, ARS, Environmental Quality Laboratory for acquisition of the ES-—MS mass

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Lidia M. Carrera, Aref A. Abdul-Baki, and John R. Teasdale

This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or a recommendation by the USDA.

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John R. Stommel

1 E-mail: stommelj@ba.ars.usda.gov . The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.

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Barbara C. Hellier

The USDA-ARS National Plant Germplasm System (NPGS) is a collection of public and private organizations dedicated to preserving genetic diversity of economically important plant species. Accessions in the NPGS are distributed free of charge and