Search Results
You are looking at 11 - 20 of 20 items for
- Author or Editor: George M. Greene x
This study quantifies the discounts and premiums associated with various quality factors for processing apples (Malus domestica Borkh.). Discounts and premiums were estimated using a hedonic price model and quality data from a total of 137 samples representing three processing apple cultivars (45 `York Imperial', 43 `Rome Beauty', and 49 `Golden Delicious'). Price discounts in the sample were statistically significant for fruit size, bruising, bitter pit, decay, misshapen apples, and internal breakdown. Commonly cited defects, such as insect damage and apple scab, did not cause significant price discounts.
Replicated studies were conducted from 1996 to 1999 to evaluate the effect of a metalized reflective film (RF) on red color development in several apple (Malus ×domestica) cultivars that often develop poor to marginal color in the mid-Atlantic growing region. Film was applied to the orchard floor in the middle between tree rows or under the tree beginning 5 to 7 weeks before the predicted maturity date. Light reflected into the canopy from the RF was measured and compared with a standard orchard sod, a killed sod or various polyethylene films. Fruit color was estimated visually and with a hand-held spectrophotometer. Fruit quality (firmness, soluble solids, starch index) was determined from a representative sample of fruit. RF increased the level of photosynthetic photon flux (PPF) reflected into the canopy resulting in darker, redder colored `Delicious', `Empire', and `Fuji' apples with a greater proportion of surface showing red color. RF increased canopy temperature and fruit surface temperature. A white polyethylene film increased reflected PPF and fruit color, but generally not to the extent of the metalized RF. Large [>13 ft (4.0 m) height] well-pruned `Delicious' trees showed increased fruit color, especially when the RF was placed under the canopy, but `Empire' trees of similar size and a more dense canopy showed no effect. The effect of the RF was most pronounced in the lower portion [up to 8 ft (2.4 m) height] of the canopy. A high-density RF was as effective as a low-density RF and the high-density film was about 60% less expensive. A high-density RF may be a cost effective method to enhance red color on selected apple cultivars in the mid-Atlantic region. Comparisons between ethephon and the RF were variable: ethephon appeared to have more effect on color in `Empire' than the RF, but less effect than the RF on `Hardibrite Delicious'. Ethephon consistently advanced fruit maturity. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).
Water stress in mature `Redhaven' / Lovell peach [Prunus persica (L.) Batsch] trees was imposed, during the 1988 growing season. Trickle irrigation was reduced from 100% to 25% of a calculated weekly evaporation amount on 22 June, 11 July, and 8 and 27 Aug. Trees were isolated from rainfall by tents under the canopy and from horizontal water movement between root systems on 4 sides to a depth of 0.5 m by a water-proof barrier. Canopy to air temperature differentials monitored throughout the growing season were developed into 3 stress indexes: crop water stress index (CWSI); cumulative crop water stress index (CCWSI); and postharvest cumulative crop water stress index (PCCWSI). CWSI values varied from 0 to 0.6, while both CCWSI and PCCWSI increased through late Sept. Mean PCCWSI of the 22 June 25% treatment increased at a greater rate than the other treatments. Significant linear regressions were found with some of the indexes and net photosynthesis or stomatal conductance; however, the r-square values were low. In general, no linear relationships were found between either CCWSI of PCCWSI and the Index of Injury for cold hardiness.
A two year study of `Golden Delicious' and `York Imperial' apple responses to delayed cooling and CA storage imposition after harvest was completed in 1991. Apples from six to eight commercial orchards were harvested at an acceptable maturity level for long-term storage, subjected to a delay in refrigeration (0,3, or 6 days) followed by a delay in CA storage imposition (0,14, or 28 days), and then stored at 0°c, 2.4% oxygen, and 1.6% carbon dioxide for up to eight months. Fruit acidity, soluble solids content, bitter pit incidence, scald, internal breakdown, and the development of low oxygen injury were not influenced by the delays. Delays often resulted in more rot and excessive weight loss during storage. Delays in both cooling and CA storage imposition had an additive effect on fruit softening, such that the longest delays resulted in the softest fruit.
Mature peach trees were grown in six different-sized vegetation-free areas (VFAs) (0.36 to 13 m2) with and without stage 3 drip irrigation for 6 years. As VFA size increased, so did the trunk cross-sectional area, canopy diameter, total yield/tree, large fruit yield/tree, and pruning weight/tree. The yield efficiency of total fruit and large fruit initially increased with the increasing size of VFAs and then remained stable over the range of VFAs. Applying supplemental irrigation increased yield of large fruit and leaf N percentage in all VFAs. Cold hardiness was not affected by VFA size or irrigation treatment. The smaller VFAs resulted in smaller, equally efficient trees. Sod management was an effective, low-cost approach to controlling peach tree size, and, when combined with irrigated, high-density production, potentially increased productivity.
Abstract
‘Delicious’, ‘Golden Delicious’, and ‘Yorking’ apple trees (Malus domestica Borkh.) were assessed in 1979-80 for the influence of foliar damage by the European red mite, Panonychus ulmi (Koch) (Acari: Tetranychidae) on preharvest drop with and without a stopdrop chemical 2-(2,4,5-trichlorophenoxy) propionic acid (2,4,5-TP). The cumulative percentage of fruit drop did not differ between uninjured and mite-injured trees at mite damage levels that included severe bronzing, nor was there any apparent reduction in the efficacy of the stopdrop spray due to mite damage. Commercially acceptable drop control was obtained with 2,4,5-TP regardless of mite damage. These data do not support the widely accepted view that the uptake and/or performance of stopdrop sprays is impaired on mite-injured apple trees.
York Imperial is an important processing apple cultivar in the mid-Atlantic region and is often stored for up to eleven months. This experiment was designed to further examine the optimum CA storage conditions for this cultivar. Six orchards were used as statistical blocks. The factorial experiment was set up with 2 temperatures (0 and 2C), 2 oxygen (1 and 2%) and 3 carbon dioxide concentrations (2,3.5 and 5%). Sample size was 20 fruit at all analysis periods (at harvest, 4, 6, and 8 months). The apples were stored in a recirculating CA research facility and evaluated for firmness, soluble solids and weight loss. In the overall statistical analysis, orchard blocks, harvest dates and storage times significantly influenced all 3 quality parameters. Differences between blocks at harvest were substantial with firmness ranging from 9.5 to 11.3 kg and the soluble solids ranging from 12.8 to 14.8%. At the third storage removal (8 months), low oxygen increased firmness and decreased weight loss during storage while at the lower temperature, apples were firmer, had higher soluble solids and less weight loss than at the higher temperature. Although statistically significant, the differences may not be commercially important Block differences were generally maintained throughout storage.
Abstract
In order to reduce the cost of fumigation and weed control in seedling nurseries of peach (Prunus persica (L.) Batsch.), a number of herbicides, used with and without Nemagon as a nematicide, were evaluated. While necessary for soil fumigation, the presence or absence of Nemagon did not effect weed control or seedling performance. The best and most economical herbicides were the spring application of simazine at 4.5 kg ai/ha or the fall application of diuron at 3.4 kg ai/ha.
A grant from the Pa. Dept. of Agriculture has allowed Penn State University to increase postharvest physiology research of fruit, vegetables, and mushrooms. One part of this program is a CA storage research facility described herein. An insulated pole barn (26m × 18m with 5m ceilings) houses the facility. Three coolers (6m × 7m with 10cm insulation) provide environmental control for the CA systems (-2 to 10C ±0.5C). A laboratory within the building (6m × 7m × 3m) provides space for product evaluation and for CA control equipment. A total of 239 steel drums (208-liter), fitted with 28 cm round plexiglass windows, are the CA chambers. Gas pumps provide flow to: each chamber, the gas analysis system, and the CO2 scrubbing system. A David Bishop Instruments Oxystat 2, analyzes O2 and CO2 and provides control signals. High CO2 can be removed either by lime scrubbing or by flushing with gases containing N2 and the desired O2 level. Several large experiments involving 7.8 MT of apples were started and preliminary results will be presented.
Abstract
‘Nittany’ is a ‘York Imperial’-type apple possessing outstanding processing characteristics. Fruit from the original seedling tree has been essentially free of corking; mild corking has been observed in some large fruits from propagules on size-controlling rootstocks. The fruit can be held in refrigerated storage for at least 6 months without appreciable shrinkage or loss of quality. The flesh oxidizes very slowly when exposed to the air and imparts a highly desirable yellow color to processed products.