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Abstract
Fruits of muskmelon (Cucumis melo L.) dipped in water at 24° and at 57°C did not differ significantly in incidence of Fusarium roseum (LK) emend. Syn. & Hans. ‘Semitectum’ and Diaporthe melonis Beraha & O’Brien and stem scar and rind decay fungi. Immersion time of fruits, regardless of water or chemical treatment, had no significant effect on stem-scar decay, rind fungal growth, fusarium lesions, or general appearance. The value of hot water as a postharvest treatment of muskmelon fruits was to increase efficacy of fungicides.
Abstract
The performance of a prototype refrigerated barge-on-ship system and arrival condition of grapefruit were evaluated. No differences were observed between boxes stacked in register or stacked on pallets except significantly more bruising in palletized fruit. Weight loss of the fruit was minimal. Pulp temperatures in both register and pallet stacks reached the optimum transit temperature of 10°C within 72 hours after the refrigeration system began operating. Humidity levels remained constant at 95% once optimum pulp temperatures were reached. Quality of the grapefruit was considered excellent upon arrival. No significant differences in arrival quality of the fruit, except bruising, could be found between shipping the fruit on pallets or stacking in register.
During the fall of 1993 and 1994, four commonly used growth retardants (B-nine, Cycocel, A-rest, and Bonzi) were compared for their effect on the growth and development of three ornamental flowering cabbage cultivars (white, red, and pink) and two ornamental flowering kale cultivars (frizzy red and red peacock). Two weeks after transplanting, seedlings of each cultivar were sprayed with aqueous solutions of the four growth retardants. Treatments for each cultivar were arranged in a randomized complete block design with 6 replications. Plant height, plant width, and dry weight were the parameters used to measure growth and development. Treatments for each cultivar were rated for head formation and color development. Results showed that all the growth retardants except for Cycocel significantly affected growth and development without any effect on head formation and color development. Bonzi caused the greatest growth suppression.
In the United States, the common daylily is cultivated as an ornamental. However, in other countries, such as China and Japan, it is an important food crop. With this in mind, a study was conducted to determine the mineral nutrient content of edible parts (flower buds, flowers and tubers) of the daylily plant. Edible parts were analyzed for P, K, Ca, Mg, Mn, Fe, B, Cu, Al, and Na. Results of this study showed that flower buds had significantly higher level of P and Mg than tubers and flowers. The K and B concentration in flower buds were similar to flowers, but significantly greater than in the tubers. The respective Zn concentrations in flowers and flower buds were 32% and 23% greater than those in the tubers. There was no difference in the Mn concentration among the edible parts. Tuber contained significantly higher contents of Ca and Cu than the flowers and flower buds. It also had 10.6-, 14.3-, and 2.8-times greater concentration of Mn, Al, and Na, respectively, than the combined average flower buds and flowers. From this study, daylily appears to have potential as a nutritious food source for human consumption.
Field studies were conducted during 1992 and 1993 to determine the effect of six monthly planting dates from April to September on gas exchange, plant height, and leafy fresh and dry yields of vegetable amaranth (Amaranthus tricolor L.). Vegetative growth was satisfactory for May to August planting. Seeds planted in April failed to germinate due to low soil temperatures. Plant growth was significantly reduced in the September planting possibly due to low fall temperatures and shortened day length. Soil and air temperatures 25 °C or higher promoted optimal stand establishment and growth. The vegetative growth of June seeded amaranth took place during the warmest part of the summer and as a result had maximum CO2 exchange rate (CER), plant height, and leafy fresh and dry yields. The relationship between planting date and CER, transpiration rate (E), stomatal conductance (gs), plant height, and leafy fresh and dry yields was quadratic, while a cubic equation provided best fit between the planting date and internal leaf CO2 concentration (Ci). The results suggest that it is possible to stagger the planting of Amaranthus tricolor in the southeastern United States to assure availability of fresh leafy greens throughout the summer. However, the crop produces maximum leaf biomass when grown during the warmest part of the summer.
Abstract
Magnesium sulfate applied as a soil amendment (34 kg Mg/ha annually for 3 years or a single application of 224 kg Mg/ha) increased leaf Mg 5 years after initial application. Dolomite increased soil pH and soil test Mg but not leaf Mg. Sulfate of potash magnesia and MgO increased soil test Mg and slightly, though insignificantly, increased leaf Mg. Single foliar sprays of MgSO4 and Mg(NO3)2 did not affect leaf Mg.
Abstract
Factors determined to have a pronounced effect on shear-press peak-force values of asparagus, Asparagus officinalis L. included sample size, spear diameter, length of green, and preharvest temperature. Shear-press values were greater following periods of cold weather in early spring. Larger diameter spears had lower peak-force values than smaller spears, indicating that larger spears are more tender than smaller spears. The number and diameter of spears produced by a particular cultivar, and not differences between cultivars, were the characteristics observed to influence shear-press values. Shear-press max peak-force values correlated well with subjective and objective determinations of asparagus fiber.
Twenty-eight seedlots of Capsicum annuum from several commercial seed companies were tested for tolerance to low temperatures. Each cultivar was tested three times at 25, 20, and 15°C in laboratory incubators. It was observed that while high germination percentages (r85%) and fast germination rates were found in several seedlots, the relationship was not strongly linked to type of chile, age of seed, or treatment temperature. Of the 28 seedlots, 14 came from companies which are in the top 10% in volume and sales. The other 14 seedlots were from smaller companies. Seventy-one percent of the seedlots with germination at r85% came from the top ten companies. Ninety-two percent of the seedlots with s85% came from small companies. To further test this finding, we randomly choose six seedlots from a small company and 6 seedlots from a small company. There was a clear delineation in germabiltiy between the small company and the large company. Our results indicate a trend that could have a negative impact on some chile seed markets. Electrical conductivity (EC) is commonly used to detect membrane leakage in seeds. Chile seed from 12 seedlots (6 from the large company and 6 from the small company) were soaked 18 hours at 25 and 5°C. There was a negative correlation (r 2 = 0.76) between the 15°C germination at 40 days and the EC. It is important to determine why membrane leakage varies in seedlots from different companies and whether the leakage is due to phenotypic or cultural factors, or due to management practices within the company.
Abstract
Gibberellic acid (GA) applied at 20 ppm 4−6 weeks before harvest increased the ascorbic acid content of fresh and processed ‘Rainier’ cherries (Prunus avium L.) while also increasing fruit size and yellow color. Anthocyanin content was also reduced. GA treated fruit rated higher according to USDA processed fruit grades. Ascorbic acid content did not change with maturity. There was no interaction between GA and maturity on ascorbic acid content (2-Chloroethyl)phosphonic acid (ethephon), applied at 500 ppm 1 to 3 weeks before harvest, reduced fruit size compared with untreated fruit. Fruit treated with succinic acid-2,2-dimethylhydrazide (daminozide) at 2000 ppm 2 weeks after full bloom reduced the weight per fruit after processing but not before processing. This was reflected in a greater loss in drained weight. Daminozide increased anthocyanin content and reduced yellow and green color of fresh fruit.
Polypeptides from pecan [Carya illinoensis (Wangenh.) C. .Koch] leaves were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and visualized by silver staining. Pecan leaf protein profiles were similar irrespective of cultivar (Desirable and Stuart), leaflet position, reproductive status of the allied shoot, or seasonal leaf age relative to fruit development. The large subunit of ribulose l,5-bisphosphate carboxylase and the majority of the other polypeptides were consistently present. However, the most striking change in the polypeptide composition was the seasonal decline of a polypeptide with an approximate molecular mass of 24.5 kDa. This leaf polypeptide was present in leaves collected in June and July, coinciding with the periods of initial fruit elongation and rapid increase in fruit volume. A detectable decrease occurred by mid-August, when kernel development was initiated. Changes in the abundance of this polypeptide relative to other polypeptides were observed over two growing seasons. Cells of young leaves collected early in the growing season contained more ribosomes and starch granules, but fewer vesicles and smaller electron-dense osmophilic granules than old leaves collected late in the growing season.