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Root regeneration and time to first budbreak of two-year white ash (Fraxinus americana L.) seedlings were strongly correlated with the number of hours of chilling. Physiological dormancy of the buds was removed after approx 2500 hours of storage at 5°C and this coincided with the beginning of increased root regeneration potential. Increased periods of chilling enhanced the rate at which growth was resumed after transfer of seedlings to environmental conditions adequate for growth. The present study indicates that fall-harvested white ash seedlings can be stored at 5° at least until May without any apparent detrimental effects on root regeneration potential or seedling condition.

Open Access

Seeking non-chemical alternatives to use of DPA for scald control on apples, we interrupted storage with a brief warming period. This often reduces chilling injuries of fruit. Warming `Granny Smith apples for 5 days at 20 C after 2 weeks at 0 C reduced scald as effectively as a 1000 ppm DPA treatment at that time. To better characterize this response, we tested other timings of the warming period, and also lower warming temperature. Warming at 10 C, or for shorter times at 20 C, or after longer periods at 0 C all were less effective. Maintaining a warm period before storage was not effective. During warming of `Cortland' and `Delicious' apples softening and loss of green color occurred, the extent of which increased with warming time and usually was greater if the fruit had initiated the ethylene climacteric before warming.

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Ozone treatment has many advantages for control of fungal diseases. There are no residue concerns, no registration is required, and it is non-specific, therefore potentially effective against a broad spectrum of pathogens. However, ozone is known to cause plant damage. There is little information available on either the ozone tolerance of floriculture crops or the levels required to kill plant pathogens under commercial conditions. Nine floriculture crops (begonia, petunia, Impatiens, Kalanchoe, pot roses, pot chrysanthemums, lilies, snapdragons and Alstroemeria) were subjected to increasing levels of ozone. Trials were conducted at 5 and 20 °C (90% to 95% RH) and ozone exposure was for 4 days for either 10 hours per day (simulating night treatment) or for 10 minutes every hour. Damage was assessed immediately after treatment and after an additional 3 days at room temperature in ozone-free air. Trials were terminated for the crop when an unacceptable level of damage was observed. Trials to determine the lethal dose for actively growing pathogens (Alternaria alternata, Alternaria zinniae and Botrytis cinerea) and fungal spores were conducted under identical conditions. Ozone tolerance varied with plant type and ranged between <0.2 and 3ppm. Generally, the crops surveyed were more susceptible to ozone damage at the low temperature. As a group, the bedding plants were the least tolerant. Fungal spores were killed at treatment levels between 0.8 and 2 ppm ozone. The actively growing fungal mycelium was still viable at 3 ppm ozone when the trial had to be terminated due to ozone-induced structural damage in the treatment chambers. Under the trial conditions, only the Kalanchoe would be able to tolerate the high levels of ozone required to kill the fungal spores.

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Strawberry plants (Fragaria ×ananassa Duch. ‘Dover’ and ‘Florida Belle’) produced increased December fruit yields during 2 seasons when stored at 2°C for 1 week prior to transplanting rather than transplanting directly from the nursery. The total fruit yield of ‘Dover’ decreased with storage the 2nd season, whereas the total fruit yield of ‘Florida Belle’ was unaffected by storage. Lowering the soil fertility in the nursery prior to plant harvest increased ‘Dover’ December fruit yield the 2nd season, and increased ‘Florida Belle’ December yield both seasons. Total fruit yields of both cultivars as related to nursery fertility were inconsistent. Total fruit yields of ‘Dover’ in both seasons were greater with a fertilizer application in the fruit production field of 224N-50P-224K kg·ha-1 than with double this application. Total fruit yield of ‘Florida Belle’ was not affected by fertilization in a fruiting field. During the first season, both cultivars produced more misshapen fruit with the 448N-100P-448K kg·ha-1 application than with the 224N-50P-224K kg·ha-1 application.

Open Access

`D'Anjou' pears (Pyrus communis, L.) growing in 3 locations with the elevation at 150 meters, 380 meters, and 610 meters respectively in Hood River valley, Oregon were harvested at the commercial maturity with the flesh firmness of 62.3 Newton (±2.2 N) and stored in air at -1°C. Regardless of different growing elevations, the incidence of superficial scald became noticeable after 2.5 months of storage and became substantial after 3 months. The rate of scald development was higher on the fruit from 150 meters elevation than those from higher elevations. Alpha-farnesene and conjugated trienes in the peel tissue accumulated at faster and higher rates in the fruit from 380 meters and 610 meters elevations than those from 150 meter elevation. The threshold level of conjugated trienes which causes superficial scald disorder was different from the fruit grown at different elevations.

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shelf life ( Clark and Finn, 2008 ). For instance, many growers harvest early in the morning to minimize field heat and reduce the time before fruit is placed in cold storage. Some of the most common and potentially devaluing defects in blackberry fruit

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could be determined shortly after harvest. However, the differences among cultivars regarding the degradation of fruit quality in shelf life conditions were not assumed to be the same as those in cold storage, which is the typical method of storage

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development and severity of CI in japanese plums based on the oxidative stress theory following time course analysis of enzymatic and non-enzymatic antioxidants in a multiple sampling framework. Materials and Methods Fruit material and cold storage. Japanese

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., 2004 ; Leja et al., 2003 ; Nguyen et al., 2003 ). Crude extracts of ripe pawpaw fruit pulp have been reported to display PPO activity ( Fang et al., 2007 ); however, there are no studies examining whether PPO activity changes during cold storage of

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Two mild and two pungent onion (Allium cepa L.) selections (hereafter referred to as cultitypes), W420B, W424B, MSU8155B, and Exhibition, were grown at two locations in two states (Wisconsin and Oregon) during 1994 and 1995. Onion bulbs were harvested, stored at 4 °C and sampled for antiplatelet activity, pungency, and soluble solids 10 days after harvest and every 40 days during a 210-day postharvest storage period. Significant cultitype × state and cultitype × year interactions were detected. However, these were primarily due to the change in rank of cultitypes within the mild or pungent group. Averaged over all environments, antiplatelet activity was significantly greater in 1994 compared to 1995 for all cultitypes. Significantly greater antiplatelet activity was measured for three out of four cultitypes grown in Oregon compared to Wisconsin. During postharvest storage, antiplatelet activity increased 61% and 56% across all cultitypes and across both states during 1994, and across all cultitypes in Wisconsin during 1995, respectively. Although pungency determination can be a good indicator for relative rankings of different cultitypes for antiplatelet activity, changes in pungency were not correlated with changes in antiplatelet activity during postharvest storage. Results demonstrate cultitype, environment, duration of postharvest storage and genotype × environment interactions influence pungency, soluble solids, and antiplatelet activity, which should be considered when assessing onion-induced antiplatelet activity.

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