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  • Author or Editor: P.M. Chen x
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Abstract

‘Bartlett’ and ‘d’Anjou’ pears (Pyrus communis L.) were passed through several brushrollers during washing, rinsing, waxing, and drying sequences of a simulated packing process. In-line application of Fresh-Cote, a wax coating formula with porosity, to the pear surface at waxing location of the packing line reduced peel discoloration of ‘Bartlett’, but not ‘d’Anjou’, due to brush friction. Fruits also were subjected to a return flow belt for 5 minutes to simulate the sorting sequence during packing. Fresh-Cote substantially reduced the susceptibility of both ‘Bartlett’ and ‘d’Anjou’ pears to peel discoloration due to belt friction.

Open Access

Abstract

The lowest survival temperatures were determined quantitatively for dormant terminal buds of ‘Newtown’, ‘Golden Delicious’ and ‘Rome Beauty’ apples (Malus domestica Borkh.) that were either healthy or infected with powdery mildew (Podosphaera leucotricha (Ell. & Ev) Salm.). Irrespective of cultivar, all mildew-infected buds were more susceptible to freezing injury than healthy buds. Survival of mildew-infected buds at about −22°C was similar to survival of healthy buds at −26°. Field data on ‘Jonathan’ showed that terminal mildew infection following winters warmer than −22° was 26.5%, but was only 4.0% following winters −24° or colder.

Open Access

Synthesis of non-ethylene volatiles (NEV) undergoes significant alterations during the transition from vegetative growth to senescence in apple fruit. This change results in a substantial increase in the production of esters characteristic of ripe apples. The relationship between changes in NEV synthesis and other indicators of physiological and horticultural maturity were investigated using `Bisbee Delicious' apples. Analysis of NEV was conducted using headspace sampling and GC-MS. Aldehydes and alcohols were the largest NEV components from pre-climacteric fruit although several esters were detected. The concentration of all NEV components declined to a minimum prior to the onset of the climacteric rise in ethylene synthesis. Initial detection of 2-methyl butylacetate, the major ester in ripening `Bisbee Delicious' fruit, occurred several weeks prior to the onset of the climacteric. The increase in ester synthesis accelerated during the post-climacteric period and the amount of total aldehydes also increased.

Free access

Abstract

‘Bose’ pear fruits (Pyrus communis L.) grown in northern Oregon (NO, Hood River) and southern Oregon (SO, Medford) were harvested during the commercial harvest period and stored in either 1 % O2 with trace CO2 or in 5 other controlled atmosphere (CA) regimes, O2/CO2 at 0.5%/0%, 1.0%/0.5%, 1.5%/0.5%, 2.0/0.5%, and 2.5%/1.0%, for 6 months at −1°C in 1982, 1983, and 1984. Fruits from the NO were more susceptible to brown core (BC) disorder than those from SO. Late-harvested fruits, especially from NO, were more susceptible than early harvested ones. A low O2 concentration of <1% in CA storage without CO2 increased the potential for fruit to develop BC, and an elevated CO2 level enhanced the effect of low O2. Based on this study, it is recommended that ‘Bose’ pear fruits from NO can be safely stored in O2 not less than 1.5% with trace CO2 and those from SO in O2 as low as 1% with CO2 between 0 and 0.5% for 6 months at −1° with little probability of BC.

Open Access

Abstract

Ethylene production of ‘Bartlett’ pears (Pyrus communis L.) was suppressed by 1 % O2 during storage at − 1°C. Elevated CO2 concentrations further suppressed ethylene production. Organic acids were retained at higher levels in fruits stored in 1% O2 than in those stored in air, and elevated CO2 concentrations in 1% O2-enhanced acid retention. Both malic and citric acids decreased linearly during 8 days of ripening at 20° regardless of previous storage conditions. The suppression of ethylene production and the retention of organic acids implied a beneficial effect of elevated CO2 in storage of ‘Bartlett’ pears at 1% O2. Fruit stored in 1% O2 at −1° for 4 months developed brown-core regardless of CO2 levels in the storage, but the incidence of the disorder was enhanced when CO2 level in the storage was ≥2%. This preliminary study indicated that ‘Bartlett’ pears grown in the Hood River district of Oregon could be stored at −1° for 4 months in 1% O2 with CO2 at <1.5% with a minimum risk of brown-core development.

Open Access

Seed germination patterns were studied in Echinacea purpurea (L.) Moench grouped by seed source, one group of seven lots from commercially cultivated populations and a second group of nine lots regenerated from ex situ conserved wild populations. Germination tests were conducted in a growth chamber in light (40 μmol·m–2·s–1) or darkness at 25 °C for 20 days after soaking the seeds in water for 10 minutes. Except for two seed lots from wild populations, better germination was observed for commercially cultivated populations in light (90% mean among seed lots, ranging from 82% to 95%) and in darkness (88% mean among seed lots, ranging from 82% to 97%) than for wild populations in light (56% mean among seed lots, ranging from 9% to 92%) or in darkness (37% mean among seed lots, ranging from 4% to 78%). No germination difference was measured between treatments in light and darkness in the commercially cultivated populations, but significant differences were noted for treatments among wild populations. These results suggest that repeated cycles of sowing seeds during cultivation without treatments for dormancy release resulted in reduced seed dormancy in E. purpurea.

Free access