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Joseph Postman, Kim Hummer, Ed Stover, Robert Krueger, Phillip Forsline, L.J. Grauke, Francis Zee, Tomas Ayala-Silva and Brian Irish

The year 2005 marked the 25th anniversary of the establishment of the U.S. Department of Agriculture (USDA) National Plant Germplasm System (NPGS), repositories devoted to clonally propagated, horticultural fruit and nut crops. During this quarter century, facilities in Hilo, Hawaii; Mayaguez, PR.; Miami, Fla.; and Riverside, Calif. were developed to preserve collections of tropical and subtropical fruit and nut crops; facilities in Brownwood, Texas; Corvallis, Ore.; Davis, Calif. and Geneva, N.Y. preserve the temperate crops. Each of these facilities now has internationally recognized, globally diverse collections of genetic resources for their assigned genera. Germplasm of unique genotypes are maintained as growing plants, evaluated for phenotypic and genotypic traits, documented in a national public germplasm database, and freely distributed as clonal propaggules to researchers and other germplasm users around the world. Seed collections represent wild populations for some crop relatives. These 8 genebanks maintain 30,000 accessions representing 1600 species of fruit and nut crops and their wild relatives. The genebanks distribute more than 15,000 accessions annually to international researchers. Although originally conceived as working collections for crop improvement, NPGS genebanks have also become invaluable in providing the raw materials for basic plant genetic research, reservoirs for rare or endangered species or vulnerable landraces, archives of historic cultivars, and field classrooms for educating the public. These collections preserve botanical treasures as well as the American horticultural heritage for now and for future generations.

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John M. Nelson, David A. Palzkill and Paul G. Bartels

Flower bud injury resulting from freezing temperatures has been a major problem in jojoba [Simmondsia chinensis (Link) C. Schneid.] production. A 3-year field study, which began with 4-year-old plants, evaluated the effect of three irrigation treatments on growth, flower bud survival, seed yield, seed weight, and seed wax concentration of six clones. After 3 years, irrigation cut-off dates of late May (dry treatment) and early September (medium treatment) resulted in reduced plant height and width compared to irrigating through November (wet treatment). Flower bud survival and seed yields were very low in the first year for all treatments. In the second and third years, bud survival for most clones, even at -8C, was greatly improved by withholding water in the fall. In December of the second and third years, plants in the medium and dry plots had lower leaf water potential than those in the wet plot. In the second year, plants in the medium and dry plots had seed yields that were 3.5 times higher and wax yields that were were 2.3 times higher than plants in the wet plot. In the third year, the medium treatment had the highest seed and wax yields. Average seed weight and seed wax concentration were generally highest for plants in the wet plot where seed yields were low. Withholding irrigation from jojoba in the fall appears to improve flower bud survival and seed and wax yields following cold winters.

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Maria M. Jenderek* and Richard Hannan

In California, rust (Puccinia allii) on garlic (Allium sativum) was not considered an economic problem until 1998, when a severe infection of the disease caused an average 51% reduction in yield throughout the state. The weight of harvested bulbs was 25% to 60% smaller than the average weight in the previous year, and soluble solids were reduced by an average of 15%. Until recently, garlic varieties that are resistant or highly tolerant to rust have not been grown in garlic production fields in California. Open pollinated progenies derived from 3 Plant Introduction accessions of the U.S. Dept. of Agriculture-Agricultural Research Service germplasm collection (PI 493099, PI 540315 and W6 12820) were inoculated with a suspension of urediniospores (1, 2 × 105/mL) isolated from rust infected garlic leaves obtained from production fields in Kings, Fresno and Yolo counties. Inoculations were carried out in a replicated experiment in the field under plastic covers, where 12 hours of misting was applied. The disease symptoms were scored on all leaves of the inoculated plants. The size of observed lesions varied from <1 to 280 mm2. Of the 118 plants evaluated, 9.3% had an average leaf area with rust symptoms of less than 1%. The majority of the plants (83.1%) had 1 to 5% of leaf area infected, and over 6% of plants had symptoms on 5 to 25% of their leaf surface. The highest number of plants with a low percent of rust symptoms on leaves was observed on progenies produced from PI 493099. While all maternal plants used to produce the seeds showed rust symptoms, the presence of progenies with ≤0.5% of leaf area infected indicated that a tolerance source to P. allii may exist in the A. sativum NPGS, germplasm collection.

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Rebecca H. Wehry*, Kathleen M. Kelley, Robert D. Berghage and James C. Sellmer

Gardeners can provide the best insight to their gardening experiences and interests. In order to identify potential buyers of the state plant promotional program, Pennsylvania Gardener Selects (PGS), an intercept survey with 243 participants was conducted at the Philadelphia Flower Show on 6-7 Mar. 2003. Objectives were to better understand Pennsylvania consumer's: current gardening related shopping habits; where they obtain gardening information; and their motives and limitations for pursing gardening. Responses were analyzed to identify potential consumer segments who might purchase PGS plants. Participants with an income >$50,000 (55%) are more likely to gather their gardening information from a university website than those with an income <$50,000 (39%). Respondents with a college education (59%) reported that time was the limiting factor when gardening as compared to those with only a high school diploma (44%). Survey responses were also analyzed using Cluster Analysis, which generated three distinct consumer segments: “Novice Gardener” (consumers with limited experience in gardening), “Non-Gardener” (consumers who prefer not to garden), and “Avid Gardener” (consumers who spend the majority of their leisure time gardening). “Avid Gardeners” are likely to purchase plants evaluated for Pennsylvania (average response of 6.5; scale 1 to 7) and 73% have purchased Pennsylvania products. They also are more likely to purchase their landscape plant material at local nurseries/garden centers (82%) than the other segments (68%). Based on the results it can be assumed that “Avid Gardener” could be a potential market for PGS plants. A marketing strategy for reaching this audience may consist of promotions at local nurseries/garden centers along side other Pennsylvania-grown products.

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Hannah Mathers

Weed growth in container-grown nursery stock is a particularly serious problem. Inexpensive and easily accessible carriers for safe application of concentrated preemergent herbicides have been investigated. Monaco and Hodges (1974) evaluated standard pine bark used in potting media. Coating broadcast fertilizers with preemergents has also been recently examined in agronomic crops (Koscelny and Peeper, 1996; Rabaey and Harvey, 1994). The four objectives of this experiment were: 1) determine the efficacy and duration of weed control of a range of preemergent herbicide-impregnated carriers, applied as a top-dressing. The preemergents to be tested are: Goal, Surflan, Rout, Gallery, Gallery/Surflan, Ronstar and Regal 0; 2) determine the efficacy and duration of weed control of a range of preemergent herbicide-impregnated slow and controlled release fertilizers, applied preplant incorporated in the potting mix; 3) assess the phytotoxicity of the chemical-treated carriers on the ornamental plants evaluated; and 4) determine which weeds were controlled. Of the carriers investigated, bark was the best treatment regardless of pre-emergent used. However, Surflan and Gallery were slightly better than Goal. The effectiveness of the bark in controlling weeds is worth investigating in further studies. A significant species effect with the efficacy data was observed. Euonymus `Emerald Gaiety' was significantly better at competing with the weeds present than the other species evaluated. Top dressing gave significantly fewer weeds, with rated data, vs. incorporation. The effect was most pronounced for Kansel or Fert. plus Ronstar. Osmocote micro-fert. gave less weeds, top-dressed, when weed weights were analyzed. However, using the weed weight data, there were no significant differences whether the carriers were applied top dress or incorporated. Phytotoxicity was not significantly different with incorporation vs. top dressing.

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D. Scott NeSmith

, GA, in 2003. Average fruit and plant evaluations for this test site from 2005, 2006, and 2008 are presented in Table 3 . At this location, ‘Suziblue’ and ‘Star’ generally flowered and ripened at the same time on average and had many similar

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Donna C. Fare

far north as Zone 5 and as far south as Zone 8. Plant evaluations made in transition zones are ideal because results can be used over a wide geographic and climatic area. The primary objective of this research project was to compare yellow

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Mary Lewnes Albrecht

and conservation, taxonomic studies, plant evaluation, sustainable landscape practices, people-plant interaction, science and natural resources education, and technology transfer work. Providing oversight to outreach activities affecting stakeholders

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Samuel G. Obae, Mark H. Brand and Richard C. Kaitany

cultivar verification. Based on our authentication criteria, 263 of the 274 plants evaluated (96%) were confirmed to be true-to-name and correctly labeled, and 11 plants (4%) were determined to be not true-to-name ( Table 3 ). These plants included: four

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Matthew A. Cutulle, Gregory R. Armel, James T. Brosnan, Dean A. Kopsell, William E. Klingeman, Phillip C. Flanagan, Gregory K. Breeden, Jose J. Vargas, Rebecca Koepke-Hill and Mark A. Halcomb

ornamental plants evaluated in their study, thus the injury observed to rose in this study was not surprising. Table 1. Effects of herbicide treatment on tolerance to six ornamental plant species in a shadehouse study at Knoxville, TN in 2008. With the