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Rachel Leisso, Ines Hanrahan, and Jim Mattheis

‘Honeycrisp’ apple is susceptible to the postharvest chilling disorder soft scald that renders fruit unmarketable. Reducing or preventing this disorder is an important component of ‘Honeycrisp’ postharvest management. In commercial settings, advanced fruit maturity and orchard history contribute to an estimation of soft scald susceptibility, but additional at-harvest information indicative of soft scald risk would enable better management decisions. In this study, we obtained fruit from commercial orchards for 3 successive years, and assessed field growing degree days (GDD), field chilling hours (CH), and fruit quality metrics at harvest, followed by soft scald incidence assessment at 12 weeks of cold storage. The analyses indicated starch index, soluble solids content (SSC), internal ethylene concentration, titratable acidity (TA), peel background color, firmness, GDD, or CH do not reliably indicate fruit susceptibility to soft scald. However, SSC and TA were elevated in fruit that later developed soft scald, and a higher number of GDD also sometimes preceded soft scald, which is consistent with advanced fruit maturity that can enhance soft scald risk. Overall, results suggest that other tools may be required to accurately predict postharvest soft scald on a quality control laboratory scale. The statistical analyses applied to the present study would have utility for assessing other soft scald prediction tools or markers.

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Paul E. Cappiello and Gary J. Kling

Cornus sericea L. rooted cuttings were held in cold storage for 60 days and then transferred to a growth chamber in hydroponic culture. Roots and shoot tips were sampled during storage and through resumption of vegetative growth. Samples were analyzed for abscisic acid (ABA), indole-3-acetic acid (IAA), zeatin, zeatin riboside, glucose, fructose, sucrose, and starch. Budbreak was associated with increasing levels of the cytokinins and IAA, and decreasing levels of sucrose and starch in the shoot tips. Regeneration of new roots was preceded by an increase in the cytokinins and IAA, and a decrease in ABA in roots. Root sucrose increased nearly two times 1 week after budbreak and starch content generally decreased throughout the experiment. The results agree, in general, with previous reports indicating decreasing levels of ABA and increasing levels of cytokinins to be associated with root regeneration and budbreak. They also indicate that, of the four carbohydrates studied, sucrose levels changed most dramatically during the root regeneration and budbreak processes.

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John R. Clark and James N. Moore

Seeds of 25 blackberry (Rubus spp.), five red raspberry (R. idaeus L.), and two black raspberry (R. occidentalis L.) populations that had been stored for 22 to 26 years were planted in the greenhouse to evaluate their germination. Germination ranged from 0% to 84% among all populations. Thorny and thorny × thornless blackberry populations had the highest average germination; most populations had >40% germination. Thornless blackberry populations ranged from 1% to 16% germination. The seeds of two of the five red raspberry populations did not germinate and none of the black raspberry seeds germinated.

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Abdul Hakim, Errki Kaukovirta, Eija Pehu, and Irma Voipio

Mature green tomatoes (cv. Vibelco) were stored at 2°C for 2, 3, and 4 weeks. Intermittent warming treatments for 12, 24, and 36 hours at 24°C were applied at the end of every week. Control Fruit were held continuously at 2°C. All fruit were subjected to poststorage ripening at 24°C for 7 days. Fruit decay, chlorophyll and lycopene content, fruit firmness, pH, TSS and TA were detected after storage or 7 days after transfer to 24°C. Results were compared between control and intermittently warmed fruit when stored at 2°C for 2, 3, and 4 weeks. Compared to fruit kept continuously at 2°C, intermittent warming at 24°C for 12, 24, and 36 hours reduced decay, increased chlorophyll disappearance, lycopene synthesis, and fruit firmness, enhanced pH and TSS, and declined TA. Fruit intermittently warmed for 36 hours/week showed the least decay, higher chlorophyll disappearance, and lycopene synthesis; retention of fruit firmness, pH, and TSS; and lower TA than fruit intermittently warmed for 12 and 24 hours/week. Decay percentage, lycopene content, pH, and TSS were increased from 2 to 4 weeks, but chlorophyll content, fruit firmness, and TA were declined.

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James D. Hansen, Dennis J. Albano, and Millie L. Heidt

The two-component quarantine treatment was shown to be effective against at least 7,000 codling moth (Cydia pomonella) fifth instar larvae infesting `Fuji' apples (Malus × domestica) in each required confirmation test involving two sizes of cartons. After cold storage for 55 days at 36 °F (2.2 °C), infested fruit were placed in vented cartons, either 20-lb [7 × 12 × 12.5 inches (17.8 × 30.5 × 31.8 cm)], or 40-lb [12 × 12.5 × 20.5 inches (30.5 × 31.8 × 52.1 cm)], then fumigated with 0.056 oz/ft3 (56 g·m-3) of methyl bromide for 2 hours at 50 °F (10.0 °C). After each treatment, either no survivors were present or no moribund larvae survived beyond the first week of post evaluation of the larvae.

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James D. Hansen, Harold R. Moffitt, Dennis J. Albano, Millie L. Heidt, Stephen R. Drake, and Jacqueline L. Robertson

Confirmatory tests were performed on a two-component quarantine treatment against the codling moth (Cydia pomonella L.) (Lepidoptera: Tortricidae) for seven apple [Malus sylvestris (L.) var. domestica (Borkh.) Mansf.] cultivars ('Delicious,' `Golden Delicious,' `Braeburn,' `Fuji,' `Gala,' `Jonagold,' and `Granny Smith') intended for export to Japan and Korea. Treatment consists of a 55-day cold storage at 40 °F (2.2 °C) or below, followed by a 2-hour methyl bromide fumigation (0.056 oz/ft3 or 56 g·m-3) at 50 °F (10 °C). No eggs or larvae survived this treatment. Comparison tests were conducted on all cultivars to demonstrate no difference in insect responses between a previously accepted cultivar and proposed cultivars. Concentration-mortality responses were determined for each of the components and no statistical differences were found in the regression slopes of pest mortality with controlling variable (either cold exposure or fumigation) among all cultivars. Descriptive mathematical models, developed for the effects of cold storage on egg mortality and for methyl bromide fumigation on larvae mortality, were sigmoid curve equations.

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Rod Jones and John Faragher

Five members of the Proteaceae and 13 Australian native cut flower cultivars were stored for 35 days under standard conditions at 1C to assess their ability to withstand long-term storage and transport. Protea cynaroides L., Leucadendron `Silvan Red', Leucospermum `Firewheel', Thryptomene calycina (Lindl.) Stapf., Telopea speciosissima R. Br., and Verticordia grandtiflora Endl. retained a vase life of at least 7 days after 21 days of storage. Leucospermum cordifolium Salisb. ex Knight, Protea neriifoli R. Br., Chamelaucium uncinatum `Alba', C. uncinatum `Purple Pride', Verticordia monadelpha Turcz., Verticordia plumosa (Desf.) Druce, and Verticordia nitens (Lindl.) Schau. suffered a decline in vase life ranging from 31% to 100% after 14 to 21 days of storage. Species of Verticordia and Chamelaucium were particularly susceptible to fungal infection. Anigozanthos pulcherrimus Hook. and the Anigozanthos cultivars Ruby Delight, Bush Harmony, Bush Haze, and Gold Fever all showed a significant reduction in vase life after 14 days of storage compared with unstored controls.

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Kathryn L. McDavid, David L. Sanford, and Robert D. Berghage

Green roof construction is constrained by cost of labor to install the plant material. Optimizing seed germination and establishment could significantly reduce installation costs but would require specific growing conditions that are difficult to provide during installation. Plants of the stonecrop (Sedum) genus are commonly used for the roof top because they will tolerate the high temperatures. This study compared the germination rates of four stonecrop species {goldmoss sedum (Sedum acre), ‘Oracle’ sedum (Sedum forsterianum), blue spruce sedum (Sedum reflexum), and amur sedum [Sedum selskianum (synonm Phedimus selskianum)]} at two temperatures, 70 and 90 °F, following storage of seed in dry, cool (40 °F) conditions of different durations (54, 98, 157, 197, 255, or 343 days). At 70 °F seed of goldmoss sedum, ‘Oracle’ sedum, and blue spruce sedum produced minimum germination rates of 60% at 21 days in seed stored for 54, 98, 157, 197, 255, or 343 days. Goldmoss sedum, ‘Oracle’ sedum, and blue spruce sedum showed reduced germination in 90 °F, probably due to temperature-induced dormancy. Amur sedum had germination of at least 83% at 21 days in both temperatures tested. As amur sedum germination rates appear to be unaffected in the temperatures tested, it could provide an excellent seed for use on green roofs where ideal temperatures are rarely available.

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Francisco Artés, Angel J. Escriche, and Jose G. Marin

Several intermittent 13C warming treatments were applied to `Primofiori' lemons (Citrus limon Burn) stored at 2 or SC. Fruit stored at 13C were treated with 10%, 2090, or 30% CO2 for 24 hours at weekly intervals. Reduction in decay and physiological disorders was best with two cycles of 2 weeks at 2C and 2 weeks at 13C and relative humidity >95 %. Under this storage condition, soluble solids concentration, pH, titratable acidity, and reducing sugars did not change relative to values at harvest, but the concentration of ascorbic acid increased and that of nonreducing sugars decreased in relation to harvest values. Carbon dioxide treatments did not prevent the development of alternaria (Alternaria citri Ell. & Pierce) rot and red blotch disorder, but effectively prevented the development of membranosis, rind pitting, and oleocellosis.

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Paul M. Chen, Diane M. Varga, and Eugene A. Mielke

`Columbia' and `Gebhard' strains of red `d'Anjou' pears (Pyrus Communis L.) harvested at similar maturity exhibited different ripening behavior after monthly removal from 1C storage in air. `Columbia' fruit produced ethylene at higher rates than `Gebhard' fruit during 15 days of ripening at 20C after each corresponding storage interval, `Gebhard' fruit required a longer period of chilling than `Columbia' fruit to generate noticeable rates of ethylene during ripening. The unripened fruit of both strains contained similar amounts of ACC at each corresponding storage interval. At each corresponding ripened state, ACC content in `Columbia' fruit increased 2 to 3-fold, while that in `Gebhard' fruit changed very little. After sufficient chilling, `Columbia' fruit were capable of softening to proper ripeness, and they developed buttery and juicy texture as indicated by the apparent reduction of extractable juice (EJ) content. `Gebhard' fruit also softened but to a lesser extent than `Columbia' fruit. Ripened `Gebhard' fruit had only slightly lower levels of EJ than unripened fruit and did not develop a buttery and juicy texture after any storage intervals. Titratable acidity (TA) in fruit of both strains varied between for the 1988 and 1989 seasons but decreased significantly during storage in both years. Soluble solids concentrations (SSC) in both strains also varied seasonally but did not change during storage or ripening. Chemical name used: 1-aminocyclopropane-1-carboxylic acid (ACC).