You are looking at 1 - 10 of 12 items for
- Author or Editor: R. M. Crassweller x
Application of (2-chloroethyl)methylbis (phenylmethoxy) silane (CGA-15281) in combination with butanedioic acid mono-2-2-dimethylhydrazide (daminozide) and naphthaleneacetic acid (NAA) increased fruit color of ‘Delicious’ apple (Malus domestica Bork.) in 1980 within 5 days after treatment at concentrations of 250 and 500 ppm, but was not significantly better than untreated controls at harvest. Fruit firmness was reduced within 10 days by the application of 500 ppm CGA in the absence of daminozide. In 1981, application of CGA at various rates from 250 to 1000 ppm did not significantly alter percent soluble solids, starch index, surface color or fruit firmness in comparison to a 500-ppm ethephon treatment. Fruit ethylene levels of all CGA treated fruit were higher 2 hours after treatment in comparison to ethephon at 500 ppm. Ethylene levels of 1000 ppm CGA treatment remained higher than ethephon treatment until 24 hours after treatment.
Apple scab is the primary disease that drives commercial pesticide recommendations; therefore, the use of cultivars that are resistant to this disease would help in reducing chemical inputs in apple production. To date, there has been only limited information on the performance of the scab-resistant apple cultivars. In 1990 and 1991, apple cultivars that are resistant to apple scab were planted at two sites in Pennsylvania, one site was the Fruit Research and Extension Center (FREC) in south-central Pennsylvania, and the other was the Horticulture Research Farm (HRF) in central Pennsylvania. Horticultural characteristics measured were trunk cross-sectional area (TCSA), flowering characteristics, yields, and fruit maturity. Trees at the FREC produced fruit 1 year earlier than those at HRF. `Enterprise'/M.26 has been the most-productive cultivar at FREC, as measured by average total weight of fruit per tree. At HRF, `CO-OP 26'/M.26 had been the most-productive cultivar. At the end of the 1994 growing season, `CO-OP 26' and `Williams Pride', both on M.26, are the largest trees as measured by TCSA at HRF. At the FREC, `Enterprise' was the largest cultivar.
A peach and nectarine cultivar and training trial was planted in 1989. Training methods were open center (OC) and central leader (CL). The orchard was divided into three sections for early, mid-, and late season peaches with 10 individual-tree replications. The following characteristics were measured from 1989 to 1994: trunk cross sectional area, fruit yield, number of fruit, and fruit color. Early season peaches, those ripening with and before `Salem' in the OC system had significantly greater TCSA at the end of the fifth growing season. At the end of the sixth growing season, however, there was a significant training cultivar interaction. There were no differences between the mid- or late season cultivars. Measurable yields were obtained in 1991 through 1993. In all years, greater yields per tree were observed from trees in the CL system, although not significantly different for the late season cultivars. `Redhaven' and `Newhaven' had the highest yields for the early season cultivars, `Glohaven' for the mid-season cultivars, and `Cresthaven' and Biscoe for the late season cultivars. Trees in the CL system tended to have higher tree efficiency than trees in the OC system. Fruit color at harvest varied by year and training system.
Water-sorbing polymers have been used in greenhouses and in arid and semiarid regions to improve soil water properties. Laboratory and field studies were conducted to investigate the effects of a cross-linked polyacrylamide polymer when incorporated into a silt loam. The soil treatments consisted of 0%, 0.06%, 0.12%, and 0.25% polymer by weight. The laboratory study consisted of four soil columns each containing a treatment. Water was added at a rate of 6.1 mm to the columns every 2 days. Soil moisture and volume was measured daily. The field experiment contained apple trees planted into soil amended with the different rates of polymer and covered with a polypropylene weed barrier. Tree growth and fruit yield were recorded from 1996-1998. The volume and bulk density of the soil-polymer matrix were dependent on the moisture content due to the swelling properties of the polymer. Bulk density was highest when no polymer was added and lowest for soil containing 0.25% polymer. Soil moisture measured by time delay reflectometry showed multiple wetting fronts in the soil columns after water was added. During the 1996 growing season, soil moisture was higher for field plots containing the weed barrier and amended with polymer; however, this trend was reversed in 1997. Tree growth was not effected in any of the years data was taken. Fruit yields did not differ between treatments in 1997. Fruit set and yield in 1998 was greater for trees planted without the weed barrier and polymer. The addition of polymer was not found to benefit apple tree growth or yields.
Fifty-nine flowering crab apple cultivars (Malus spp.) were evaluated in 1977 and 1978 to determine time and pattern of bloom period relative to that of 5 commercial cultivars. The crab apple cultivars ‘David’, ‘Simpson 10-35’, and ‘Ellen Gerhart’ had similar bloom patterns with the commercial cultivars, ‘Delicious’, ‘Jonathan’, ‘Golden Delicious’ and ‘Gallia Beauty’. Bloom patterns of ‘Donald Wyman’ and ‘Indian Magic’ were similar to the bloom patterns of ‘Jonathan’, ‘Golden Delicious’, and ‘Delicious’. ‘E.H. Wilson’, M. robusta ‘Erecta’, ‘Ormiston Roy’, ‘Sentinel’, and ‘Turesi’ had bloom patterns that were similar with ‘McIntosh’. Hand pollination with pollen from 10 crab apple cultivars resulted in fruit set on ‘Delicious’ equal to open pollination or hand pollination with ‘Jonathan’ pollen.
Apple orchards are highly diversified and complex ecological and economic systems. Production is affected by a wide range of insects, diseases, weeds, and mammalian pests. The incidence of these pests is often dependant upon climatological effects; and the microclimate within orchards. An expert system, a form of artificial intelligence, has been developed and commercially released to apple growers that utilizes weather data to make recommendations regarding production decisions. Users of the system are instructed on how to establish a weather station, and to collect, and input weather data from the farm. The information is utilized to calculate disease infection periods and pesticide residues to arrive at a control recommendation. Other weather dependant modules include the scheduling of trickle irrigation as well as water application rates during a frost. An interactive demonstration of the system will be presented to the group.
Decreasing resources and increasing complexity of horticultural crop production necessitate that new technologies be developed to transfer information to commercial producers. Expert systems (ES) have been cited as potential tools that can facilitate knowledge transfer. The definitions of an expert system, however, technically only indicates a computer program that simulates the thought processes of a human expert and, as such, does not supply all the facets necessary to assist commercial producers. The combination of databases, graphic capabilities, and textual information into a comprehensive program would provide a more complete package. To differentiate the two, we use the term decision support systems (DSS). The development, testing, and release of DSS, however, require greater commitment and interdisciplinary cooperation. Developing DSS fosters interstate, interregional, and international cooperation among researchers and extension personnel. Using systems developed in fruit production as examples, we outline the value of DSS to promote cooperation, the resources necessary to develop these systems; and the attitudinal change necessary to build the systems.
Overtree misting for bloom delay reduced fruit set of ‘Golden Delicious’ apple (Malus domestica Borkh.) flowers hand-pollinated with ‘Jonathan’ or ‘Golden Delicious’ pollen in 1978, or open-pollinated or hand cross-pollinated with ‘Jonathan’ pollen in 1979. Misting did not affect fruit set of flowers that were open-pollinated in 1978 or self-pollinated in 1979. The number of seeds per fruit was not reduced. Soil Ca, Mg, pH and base saturation of Ca and Mg were increased, and flower and spur leaves contained lower concentrations of N, P, K, B, Mn, Fe, Zn, and Cu at either full bloom or petal fall as a result of misting. Foliar sprays of B increased B concentrations but did not influence fruit set on either misted or nonmisted trees.