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Guy J. Hallman

Canistel [Pouteria campechiana (HBK.) Baehni] fruit were subjected to cold storage and hot-water immersion treatments known to kill immature Caribbean fruit flies [Anastrepha suspensa (Loew)] in other fruit. Cold storage at 1 or 3C for 17 days did not cause appreciable loss in canistel quality compared with fruit stored at the normal 10C. Unripe canistels immersed in water at 46C for 90 min or at 48C for 65 min, however, developed dark blotches on the peel and a 2- to 3-mm-thick layer under the peel that did not soften. Canistels were infested with Caribbean fruit flies and subjected to 1 or 3C storage for up to 14 days. The resulting lethality data were fitted to three probability density functions (PDF) to estimate the number of days required to achieve quarantine security (99.9968% dead). The normal and Gompertz PDFs gave some reasonable estimates, while the logistic PDF gave low estimates. At 1C, 14 days would be needed to achieve quarantine security, while at 3C a minimum of 15 days would be required. These estimates must be tested to determine if they are valid after a large amount of Caribbean fruit fly immatures is subjected to the treatments.

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W. Todd Watson, David N. Appel, Charles M. Kenerley, and Michael A. Arnold

Effects of washing and storing soil core samples of apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. (syn. M. domestica Borkh. non Poir.)] roots were studied to determine root losses from processing samples. Root losses were assessed by measuring root lengths before and after elutriation and storage at 4 °C (39.2 °F). The accuracy of the automated root length scanner to measure individual fine roots [<1 mm (0.04 inch) diameter] of varying lengths was evaluated by first measuring roots, then cutting the roots into 2 to 3 cm (0.79 to 1.18 inch) lengths and rescanning. There was a significant relationship between the measurement of cut and noncut roots (r 2 = 0.93). Losses from elutriating samples with cut and noncut roots indicated a mean loss of50% for samples with cut roots and 34% for samples with noncut roots (P ≤ 0.01). Total mean root loss (elutriation loss of noncut roots and degradation loss in cold storage) for the 12-month period ranged from 34% at month 0% to 53% at month 12 (P ≤ 0.01). Mean root degradation losses from long-term cold storage ranged from 6% at month 1 to 19% at month 12 (P ≤ 0.01). No losses were identified for roots with diameters of 1 to 5 mm (0.04 to 0.20 inch) and 5 to 10 mm (0.20 to 0.39 inch). A data correction curve was developed to correct root length data (<1 mm) for root losses associated with processing of soil cores.

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Stephen L. Love, Asunta Thompson-Johns, and Timothy P. Baker

Eight hundred and fifty-three clones of Russet Burbank and 1012 clones of Lemhi Russet were obtained from Native Plants, Inc. in 1988. The clones were produced via a tissue culture system designed to produce somoclonal variants. Four cycles of selection were completed from 1988-1991. Selection was based on resistance to blackspot bruise, a tuber flesh discoloration caused by condensation of free tyrosine; or the ability to produce light french fry color following cold storage. At the end of the four selection cycles all but six Russet Burbank clones and seven Lemhi Russet clones were eliminated. ANOVA across years was completed for the eleven somaclonal variants and Russet Burbank and Lemhi Russet checks.

Of the Russet Burbank clones, three were significantly (p = .05) more resistant to blackspot bruise and one had significantly better fry color after cold storage. All four clones had significantly reduced yield in comparison to the check clones. Of the Lemhi Russet clones, three were significantly more resistant to blackspot bruise, and four had significantly better fry color than the check clone. Only one of the seven clones (one with superior fry color designated L1908) did not show a significantly lower yield potential.

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Jinwook Lee, James P. Mattheis, and David R. Rudell

rootstock ( Fallahi et al., 2013 ), irrigation ( Opara et al., 2000 ), nutrient management ( Opara et al., 1997b ; Perring, 1984 ), and fruit maturity ( Byers, 1998 ; Opara et al., 1997b ). During and after cold storage, fruit size positively contributes

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Rick M. Bates and Alexander X. Niemiera

Shoot and root water potentials were determined for bare-root Norway maple (Acer platanoides L.) and washington hawthorn (Crataegus phaenopyrum Med.) seedlings subjected to shoot and root exposure treatments for six cold storage durations. Shoot and root water potentials for all exposure treatments and both species decreased with increased time in storage, and the greatest degree of water stress occurred during the first six weeks of storage. Maple shoot and root water potentials for the exposed shoot treatment were the same as the whole plant covered treatment. In contrast, hawthorn shoot and root water potentials for the exposed shoot treatment were the same as values for the roots exposed treatment. Based on these data, we conclude that desiccation sensitive species such as washington hawthorn require root and shoot protection to minimize water loss.

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Karen L.B. Gast

Fresh-cut peonies are one of few cut flowers that can be stored for weeks and still provide a marketable flower. Peonies are usually marketed by color: reds, pinks, whites, and corals. Several different cultivars may be included in each color depending on their country of origin and time during the harvest season. Previous work with peonies has shown that different cultivars of the same color may behave differently during postharvest handling, whether it is storage life, vase life, opening time, storage temperature, etc. One problem of long-term cold storage is diseases that may render flowers unmarketable. This study evaluated the effect of four storage disease prevention treatments on seven peony cultivars, two reds, two pinks, and three whites, stored at 1 °C. The four disease prevention treatments included a control, methyl jasmonate during storage, a pre-storage calcium chloride pulsing for 2 h at room temperature, and a pre-storage fungicide spray. Flowers were evaluated for disease incidence on leaves and flowers, and for flower bud openness after 4, 8, and 12 weeks of cold storage. Overall results support previous work that shows peony cultivars react differently to postharvest treatments. Two cultivars were greatly affected by the disease prevention treatments and three were moderately affected, while there were few treatment effects seen with the other two. The calcium chloride pulse produced the greatest disease incidence and resulted in the flowers being more opening, which is not desirable. There was often no difference in the control, methyl jasmonate, and fungicide treatments. It appears that pre-storage treatments may not be beneficial for some fresh-cut peony cultivars.

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Mario Schirra and Maurizio Mulas

Freshly harvested `Fortune' mandarins (Citrus reticulata Blanco) were dipped for 3 minutes in 25 or 52C water and then stored for 5 weeks at 2C. Then, the fruit were or were not intermittently warmed at 10C for 3 days after each 4-day storage period. All fruit then were held at 20C for 1 week to simulate retail marketing. Chilling injury was more severe in fruit dipped in 25C water and stored at 2C than in fruit dipped in 25C water and stored under intermittent warming. The hot dip treatment significantly reduced the extent of damage during storage and the subsequent 1 week of holding at 20C. The hot dip treatment reduced the incidence of fungal decay, especially during holding at 20C. Dip temperature and storage conditions slightly affected fruit physiological and quality characteristics. We conclude that prestorage hot dip treatments can be used to improve `Fortune' mandarin storing qualities. Also, this practice may be combined with intermittent warming during cold storage, and it could help limit fungicide use in postharvest treatments.

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David M. Obenland and Tanya R. Carroll

`Elegant Lady', `O'Henry' and `September Sun' peaches [(Prunus persica (L.) Batsch (Peach Group)] and `Summer Bright' and `Summer Grand' nectarines [(Prunus persica (L.) Batsch f. nucipersica (Nectarine Group)] heated to a seed surface temperature of 47.2 °C over a period of 4 hours developed mealy flesh sooner and to a much greater extent than nonheated fruit following cold storage at 5 °C for 1 to 3 weeks. Exo- and endopolygalacturonase activities were reduced following 3 to 4 hours of heating and may have been responsible for the increased mealiness. Mealiness often developed in defined regions rather than throughout the entire fruit. Comparison of juicy and mealy regions within individual fruit revealed that mealy regions contained 65% and 86% less exo- and endopolygalacturonase activity, respectively, than juicy regions, whereas pectinmethylesterase activity was unchanged. Extractable protein was reduced by >50% in the mealy regions of the fruit. Intermittent warming periods of 24 hours at 20 °C at weekly intervals during storage at 5 °C were less effective in reducing mealiness in heat-treated than in control fruit. It is important that future work with heat treatments and stone fruit closely monitor potential effects on this disorder to avoid loss of market quality following treatment.

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Mary Lewnes Albrecht and Jerald T. Lehmann

Greenhouse- and field-produced plants of Asclepias tuberosa L., butterfly flower, were forced in the greenhouse under various daylengths to produce flowering plants for the florist industry. Examined were post-production cold storage temperature (4.5 and 10C) and period (12, 14, and 16 weeks), forcing daylength (9, 13, 15, or 17 hours), plant-production scheme (greenhouse- vs. field-produced), and planting depth (exposed crowns or crowns planted 1.3 cm below the medium surface). When forced under a 9-hour daylength, blind shoots and aborted flower buds were prevalent. When daylengths exceeded 13 hours, using night interruption, the time to produce a marketable plant was reduced from 71 days to 61 days for 18-month-old greenhouse-produced plants. Daylength of 17 hours delayed flowering of field-produced liners by 15 days in comparison to those forced under 13-hour daylength. Greenhouse-produced plants stored at 10C did not sprout when brought into the forcing greenhouse held at 17/25C (night/day). Field-produced plants, when greenhouse-forced, had fewer flowers per inflorescence (88 to 94 flowers) than greenhouse-produced plants (79 to 87 flowers).

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Armida Rodriguez-Felix, Evelia Araiza-Lizarde, Monica A. Villegas-Ochoa, and Elsa Brineas-Taddei

Physico-chemical and physiological changes of `Flordaprince peach fruits harvested at different maturity stages were evaluated during low temperature storage. Harvested fruits were immediately classified into four different maturity stages based on red-skin color (I, 20%; II, 40%; III, 60%; and IV, 80%). Fruits were stored at 2 C (90% R.H.) for 0, 15, and 30 days. Following cold storage conditions, fruits were transferred to a 20 C room. Physico-chemical and physiological characteristics evaluated during storage included weight loss, firmness, pH, titratable acidity, skin color (hue), total soluble solids, respiration rate, and ethylene production. Weight loss increased (up to 40%) after 27 days storage at 2C. The fruits harvested at maturity stage I showed the lowest weight loss. Flesh firmness decreased significantly during storage at 2 C. Fruits from stages I and II had higher firmness than fruits harvested at stages III and IV. A significant change from green-yellow to red color was observed in fruits of the distinct maturity stages during storage at 20 C.