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Abstract
A mathematical analysis of optimum locations for frozen green pea processing was conducted. Inputs to the model included: raw product costs, procurement costs, economies of scale in freezing and freezer storage, labor costs, fuel and electrical costs, state, local and federal taxes, length of the pea processing season, length of the total processing season, weighted regional consumption by state, and transportation costs to market centers (states). Analytical procedures used Stollsteimer’s method for number and sizes of plants combined with a transhipment model to compare regions.
The results suggest that the numbers of processing plants within an area are significantly less important than cost differentials between areas. The models developed were sensitive to changes in many costs – raw product costs, wage rates, length of season, allocation of overhead, freight costs, and in some states, state and local taxes.
The optimum solution called for a few large plants in each of the Eastern, Midwestern and Western regions. The Washington-Oregon-Idaho complex would predominate with approximately 59 percent of total production, followed by Maryland-Delaware with 14 percent and Wisconsin with 10 percent.
Abstract
Greenhouse experiments using seedling pecan trees [Carya illinoensis (Wan-genh.) C. Koch] compared rates and repeated applications of K2SO4, K2SO4 vs. KNO3, and Ν adjuvants in combination with K2SO4 or KNO3. Leaf and stem Κ concentrations increased linearly with rates to 87.1 g/liter K2SO4 applied 5 times at 14-day intervals. Phytotoxicity was negligible to 10.9 g/liter K2SO4. Plants receiving individual applications of KNO3 or K2SO4 at 9.8 g K/liter 2 times at 14-day intervals had 92% and 53% more Κ than the control, respectively. KNO3 at 25.3 g/liter or K2SO4 at 21.8 g/liter, in combinations with urea and/or NH4NO3 at 6.25, 12.50, and 25.00 g/liter, increased leaf Κ concentration significantly and the increase was consistently greater using KNO3 than K2SO4. Both urea and NH4NO3 applied with either KNO3 or K2SO4 increased leaf Κ concentrations. Negligible phytotoxicity occurred when urea or NH4NO3 was applied at 6.25 g/liter with K2SO4 or KNO3.
Curriculum revision for science-oriented degrees can be based on input from research journals and discipline-oriented society meetings, but the professional nature of a landscape horticulture degree requires more detailed industry input. The curriculum revision at the Univ. of Delaware started with discussions amongst faculty who were concerned with the current plant science curriculum. A mail survey of alumni from 1984 to 1993 and employers of Univ. of Delaware Plant and Soil Sciences Dept. graduates was conducted in 1994. Survey results were evaluated and incorporated into the development of two curricula: plant biology and landscape horticulture. Focus groups were used to seek industry input for the landscape horticulture curriculum. Two focus groups—established professionals in the landscape horticulture industry and recent graduates from the Plant and Soil Sciences Dept. with landscape horticulture positions—were convened in December 1995. Focus group members received a packet of information about the department including the proposed curricula prior to the meeting. A group of faculty presented information about departmental facilities, faculty, academic opportunities and practical experiences and accomplishments. The previous survey results and proposed curricula were reviewed. A professional facilitator, using a moderator's guide prepared by faculty members, led each focus group discussion. Tapes from each discussion were transcribed and summarized. Original transcriptions and executive summaries were distributed to focus group participants and faculty. Suggestions from focus group participants were incorporated into the final curriculum. Problems associated with the focus group technique include a reluctance of faculty to accept outside opinions, a reluctance to publicly air departmental concerns, and the cost associated with a professional facilitator and rented facilities. However, the focus group technique provided significant feedback in a short period of time and helped build liaisons with industry constituents by including them in the process. Several focus group participants will be invited to join an advisory council for the department.
Legume ground covers were evaluated in pecan orchards to reduce nitrogen inputs and increase beneficial insects. Treatments were established at two sites in Oklahoma, each with 5 ha of a `Dixie' crimson clover/hairy vetch mixture and 5 ha of grass sod. Nitrogen was applied at 0-200 kg·ha-1 to the sod plots, but legume plots were not fertilized. Aphids and selected arthropods were monitored on ground covers and in the pecan canopies. Data indicated that a mixture of crimson clover/hairy vetch supplied up to 186 kg·ha-1 N to the trees. Beneficial arthropods monitored were Coccinellidae, Chrysopidae, Nabid, Syrphid, and spiders. Lady beetles, primarily Hippodamia and Coleomegilla, were the most important aphid predator in the spring, and green lacewing was the most important fall predator. There were fewer aphids infesting pecans using a crimson clover/hairy vetch ground cover than a grass sod.
Annual legume ground covers were evaluated in pecan (Carya illinoinensis) orchards to supply nitrogen and increase beneficial arthropods. Treatments were established at two sites, each with 5 ha of a `Dixie' crimson clover (Trifolium incarnatum) /hairy, vetch (Vicia villosa) mixture and 5 ha of grass sod. Data indicated that the legume mixture supplied over 100 kg·ha-1 N to the pecan trees. Beneficial arthropods were greater in orchards with legume ground covers than in orchards with a grass groundcover. Lady beetles and green lacewings were the most important spring predators, and green lacewings were the most important fall predator. The Species distribution on the ground covers differed from that in the canopy. Coleomegilla maculata lengi, Hippodamia convergens and Coccinella septempunctata were the most abundant lady beetle species in the legume ground covers, and Olla v-nigrum, Cycloneda munda, and Hippodamia convergens were the most abundant species in the pecan canopies. Beneficial arthropods appeared to suppress injurious pecan aphids.
Abstract
Retention and early growth of ovaries of tomato cultivar Earlipak No. 7 (L. esculentum, Mill.) and a related breeding line were recorded for several weeks at 4 locations. Percent fruit-set, defined as the percentage of flowers of which ovaries were retained and reached a diameter of at least ¼ inch in 2 weeks, was not a reliable index of either ovary retention or early ovary growth. Important information concerning the fruiting of tomato may be lost, when data are collected on the basis of the defined fruit set rather than observed ovary retention and ovary growth specifically.
Seeds of a Kentucky bluegrass cultivar (Poa pratensis 'SD Common') and two native buffalograss (Buchloe dactyloides) strains, Texas (TX) selection and North Dakota (ND) selection, were tested for their germination tolerance to increasing levels of NaCl at 0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2% in solution. Both the TX and ND strains of buffalograss exhibited a high degree of salt tolerance with the upper limit of seed germination at 2.8% NaCl (2% to 7% germination after 6 days). At high NaCl concentrations, however, percent seed germination was much greater in the ND strain than the TX strain of buffalograss. For instance, seed germination at 0.8% NaCl was 90% in ND strain and 53% in TX strain as compared to the control. Kentucky bluegrass was least tolerant to NaCl with the upper limit of seed germination at 0.4% NaCl (14.7% germination in 6 days). Seed germination in Kentucky bluegrass was completely inhibited at 0.6% NaCl.
Abstract
The effect of low temperature on cell ultrastructure was investigated in chilling-sensitive and chilling-resistant tomato fruit (Lycopersicon esculentum Mill.) Damage to the chilling-sensitive cultivar included microvesiculation of the endoplasmic reticulum and loss of ribosomes, chloroplast, and mitochondrial swelling; loss of starch granules; disorganization of the internal lamellae of chloroplasts; grana unstacking, as well as plastoglobuli and tonoplast degradation. Only a slight disorganization of the internal chloroplast lamellae was evident in the resistant species after 7 days at 5C. The primary site of damage appeared to be the chloroplast in both chilling-sensitive and -resistant species. The ultrastructural damage observed could be explained in terms of membrane disruption.
The influence of fruiting stress on shuck decline, nut quality, and premature germinaiton was evaluated on trees of pecan [Carya illinoensis (Wangenh.) C. Koch]. Fruit at the liquid endosperm state were removed from trees with a mechanical shaker to reduce crop load by 0%, 25%, 41%, 56%, or 77%. Shuck decline and premature germination decreased and kernel quality increased with a reduction in crop load. An excessive fruit load or fruit stress elevated the incidence of shuck decline, previously referred to as shuck disease, tulip disease, shuck die-back, or late season shuck disorder; decreased kernel development; and increased premature germinaiton. Shucks were dissected from fruit ranging from healthy to those with premature shuck opening and examined by scanning electron, transmission electron, and light microscopy. Fungal growth was detectable, but only after tissue degeneration had occurred. Thus, results indicate the onset of shuck decline is caused by stress associated with an excessive crop load and not a pathological disorder. Fungal growth is a secondary, not a primary, factor in deterioration of shucks with decline.