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- Author or Editor: Christopher S. Walsh x
Abstract
Bud weight, and spur number, length, and fruitfulness were measured in shoots of ‘Delicious’ apple (Malus domestica Borkh.). In 2-, 3-, and 4-year-old wood, spur number, length, and fruitfulness were greater at the subapical nodes than at the basal nodes of the shoot. In dormant 1-year-old shoots, bud weight was affected by strain, node, position, and vigor. Axillary buds were largest in the apical portion of standard ‘Delicious’ shoots and in the basal portion of spur-types. In extremely vigorous shoots of ‘Gardner Delicious’ basal buds did not grow at the beginning of the second growing season unless treated with 6-benzylamino purine (BA), which induced normal spurs.
Abstract
Delays at 20°C prior to controlled atmosphere (CA) storage decreased ‘McIntosh’ apple (Malus domestica Borkh.) breakdown. Delayed storage did not affect the firmness of fruit unaffected by breakdown after CA storage. Polyethylene box liners decreased firmness and increased the incidence of breakdown.
Abstract
The changes in ethylene concentration of attached, horticulturally mature ‘Lodi’, ‘McIntosh’ and ‘Golden Delicious’ apples (Malus domestica Borkh.) were estimated by measuring the ethylene present in a tube sealed over the fruit calyx. Measurements of this gas sample [the equilibrium ethylene concentration (EEC)] were directly proportional to the internal ethylene concentration (IEC) of the fruit. In ‘Lodi’ and ‘McIntosh’, an increase in the EEC preceded abscisision by at least 3 days. The length of time to abscission after increases in EEC were noted was negatively correlated with daily mean temperature in ‘McIntosh’. ‘Golden Delicious’ fruits did not show a relationship between the EEC and abscission. The commercial harvest period of ‘Lodi’ preceded the rise in EEC. In ‘McIntosh’, ethylene accumulation occurred both during and after the commercial harvest.
In 1998 the U.S. Food and Drug Administration (US-FDA) published formal guidelines for the microbial safety of fresh produce. The guidelines identify and suggest the use of good agricultural practices (GAP) and good manufacturing practices (GMP) for producers and handlers. To extend this important information to international producers and suppliers, an agreement was made to create a GAP and GMP training program through the Joint Institute for Food Safety and Applied Nutrition (JIFSAN). JIFSAN combined resources of US-FDA, the University of Maryland, and other universities to reach audiences outside the U.S. with food safety information. The program is based on the train-the-trainer concept. Its success depends on the ability of the newly trained program participants to reach key audiences in the target country. We present an overview of the development of a training manual and its content, the selection of a teaching team and target countries, and the methods for implementation of the training. Examples of activities in various countries are summarized. Results of a program review conducted in 2004, following nine program deliveries, are also discussed. Future needs are identified and current programming plans are provided.
Abstract
Bloom application of aminoethoxyvinylglycine (AVG) increased the fruit yields of ‘Ultra Red Delicious’ apple (Malus domestica Borkh.) trees. In one season, sprays of 50 ppm AVG were more effective in increasing yield than those of 500 ppm. In the second season, treatment with 150 and 225 ppm AVG was most effective. High levels of AVG (> 225 ppm) caused excessive fruit set and decreased fruit size. Ethylene evolution from developing fruits and fruiting spurs was decreased by AVG treatment.
`Gala' apples are increasing in worldwide popularity. Despite this, little information on the cultivars vigor, precocity, or interaction with size-controlling rootstock is available. In 1985, a factorial planting was set to study these variables. `Gala' and `Golden Delicious' trees were found similar in precocity. Cumulative yields were about 20 kg per tree after the fifth leaf. `McIntosh' and `Delicious' trees were less precocious. `Gala' trees were also quite vigorous. Tree size and yield efficiency data will be presented, comparing `Gala' with other cultivars budded onto M 7a, MM 111, or propagated in tissue culture as scion-rooted plants. Tree management techniques have been identified that decrease fruit size. Trees budded onto precocious rootstock, and fruited heavily on one-year wood produce small-sized fruit. This tendency is pronounced on trees fruiting in the second leaf, or on older trees damaged by late-spring freezes that reduce the proportion of crop borne on spurs.
Abstract
‘Miller Sturdeespur Delicious’ apple (Malus domestica Borkh.) trees made less extension growth than ‘Imperial Red Delicious’ (non-spur) under controlled conditions. No differences in extension growth were measured between ‘MacSpur’ and ‘Imperial McIntosh’ (non-spur) trees. Development of the spur-type morphology was determined by the number of lateral buds which grew into spurs during the second growing season. Application of (2-chloroethyl)phosphonic acid (ethephon) alone, or in combination with butanedioic acid mono-(2, 2-dimethylhydrazide) (daminozide) decreased extension growth and increased shoot ethylene evolution in growth chamber studies, and promoted flowering in the field. Application of daminozide plus ethephon was more effective than ethephon alone. Daminozide alone did not affect shoot ethylene. No change in ethylene evolution or shoot development was detected following applications of gibberellin 4/7 (GA) or 2, 3, 5-triiodo benzoic acid (TIBA) to spur or non-spur type trees. Bark scoring had no effect on shoot ethylene. However, this treatment also promoted flowering of young trees in the field. It is suggested that while some manipulations can increase shoot ethylene evolution and also promote flowering, the ethylene evolved following treatment operates indirectly by retarding growth, rather than by directly stimulating flower bud initiation.
Abstract
During the 1984 growing season, trees of ‘Loring’ peach (Prunus persica L. Batsch) on ‘Halford’ rootstocks were divided into the following components; fruit, leaves, shoots, 1-year wood, 2-year wood, frame, and roots. The sampling dates were coincident with key fruit and tree developmental stages: dormant, 15 days after full bloom, the end of Stages I and II of fruit developement, harvest, and 45 days after harvest (leaf fall). At the beginning of Stage II, four additional trees per remaining sampling date were hand-thinned to 15 cm between fruit. Initially, the mean dry weight of trees was 27.1 kg. Unthinned and thinned trees increased 43% and 39%, respectively, in dry weight by 45 days after harvest. Dormant hand-pruning removed about 4 kg of growth. This amount represented nearly the entire season's dry weight of shoot, 1-year-old, and 2-year-old wood growth. The proportion of total tree weight in fruit was increased at harvest in unthinned trees, whereas leaf and 2-year wood dry weight was reduced. A modified harvest index, the proportion of total annual increase distributed to fruit, was 0.50 for unthinned trees and 0.37 for thinned trees. The ratio of annual dry weight increase per unit leaf area was 0.33 and 0.27 kg·m−2 leaf area for unthinned and thinned trees, respectively. The maximum mean leaf area was estimated to be 62.9 × 103 m2·ha−1. The greatest leaf area density, measured at the end of Stage II, was 7.7. Absolute growth rates of vegetative components were highest during Stage II of peach fruit growth, and intermediate during Stage I.
Abstract
An effective and simple system for studying ethylene evolution from apple (Malus domestica Borkh.) shoots was devised and used to follow seasonal patterns of ethylene evolution, as well as changes in ethylene evolution following ethephon and shoot bending treatments. Field studies using intact two year wood of spur and non-spur strains of ‘Delicious’ and ‘McIntosh’ showed similarly high levels of ethylene early in the season which subsequently declined. The large differences in ethylene evolution between sampling dates may have been caused by climatic differences at the time of sampling. No differences in ethylene evolution were detected among strains or cultivars although differences in flowering were observed in the following season.
Abstract
Ethylene evolution rate and percentage of soluble solids of thornless blackberry (Rubus sp.) increased with maturity and ripening, while titratable acidity decreased. Following harvest of “purple” fruits, their respiration and ethylene evolution rates increased during 7 days at 25°C. Ethylene evolution rates and differences in shelf-life among cultivars were inversely related. We conclude that thornless blackberry is a climacteric fruit.