Commercially grown honeydew fruit (Cucumis melo Inodorus group) and netted cantaloupe fruit (C. melo Reticulatus group) in low-humidity regions of the U.S. are typically field packed, eliminating the possibility for postharvest chelated-calcium dip treatments to extend fruit shelf life. In this study, calcium treatments were applied to orange-flesh honeydew fruit commercially grown in 2001 and 2002 in Sacramento Valley, Calif. and orange-fleshed netted cantaloupe fruit commercially grown in 2002 in Imperial Valley, Calif., and Rio Grande Valley, Texas. Aminoacid-chelated calcium and mannitol-complexed calcium compounds were applied to field-grown plants at the rate of 2.3 L·ha-1 (1 qt/acre) at 0, 1, 2, or 4 total applications during growth of honeydew and cantaloupe fruit. Applications were A) at female flowering, B) within 15 days (cantaloupe) or 20 days (honeydew) after flowering, C) within 30 days (cantaloupe) or 40 days (honeydew) after female flowering, and/or D) within 3 to 5 days before abscission. One application equaled (A) or (D), two applications equaled (A + B) or (C + D) and four applications equaled (A + B + C + D). Evaluations of fully abscised fruit were exterior and interior firmness, marketability, calcium concentrations, interior soluble solids concentration (sugars), and consumer preference (taste) following harvest and up to 3 weeks commercial/retail storage. Cantaloupe fruit at both locations did not appear to benefit from preharvest plant applications of calcium when compared to fruit from plants treated with water. Honeydew fruit, however, did and the benefit was observed both years. Honeydew fruit that received four preharvest plant applications of calcium, regardless of source, were generally superior in firmness, marketability, and had a higher calcium concentration than fruit from plants receiving water or one or two applications of calcium. Fruit sugars and taste were not affected by preharvest plant applications of calcium.
Abstract
A method is presented to calculate net heat gain per unit time (G) for normal (N) and for whitewashed (W) cantaloupe fruits (Cucumis melo, L., var. reticulatus Naud.) exposed to direct solar radiation. Calculations of G were based on pulp temp. G of the W fruits averaged 80% of that for the N fruits during warming. Values of G can aid in evaluating the effectiveness of radiation-reflective materials that protect cantaloupe fruits from sunburn, a major cause of culls and market quality losses. Maximum pulp temp about 1 mm below the surface reached 49°C for the N and 42° for the W fruit. Maximum ambient air temp was 43°C.
Cucumber (Cucumls sativus L.) and cantaloupe (Cucumis melo var. Cantaloupensis L.) seedlings have been subjected to a wide range of rhyzosphere pH. Each plant was grown in one pot in water culture. The results obtained showed a great influence of pH on plant root length, root diameter and number of roots, in addition to the subsequent effect on the vegetative growth. The experiment suggests the importance of rhyzospher pH to produce healthy cucumber and cantaloupe seedlings with the maximum root performance. Obtained date were discussed according to the prevailed microlimatic conditions.
The author thanks Dean Liere and Alex May, Syngenta Seeds, Inc., Rogers Brand Vegetable Seeds, for supplying cantaloupe; Gene Lester for supplying honeydew; Ken Gross for supplying apples; and Jeanne M. Lea and Debbie Harrell for volatile
Abstract
Applications of 2-chloroethylphosphonic acid to field grown cantaloupes resulted in yellowing of leaves, early abscission, apparent ripening of immature melons and increased total and marketable yields of full-slip melons. The percentage of soluble solids was slightly lower in treated melons.
Several postharvest quality parameters of cantaloupe fruit were grown under different organic and mineral fertilization schemes We evaluated a Laguna hybrid (Asgrow) cantaloupe grown under a design of blocks completely randomized, with three fertilizer treatments corresponding to: T1, goat manure; T2, simple fertilization; T3 mixed fertilization, with six replications each. The fruits were mature-harvested and stored in a room with an average temperature of 18°C for posterior laboratory analysis. The results showed different effects of the treatments on the following parameters: total soluble solids, diameter of the fruits, and thickness of the pulp, and showed no effects on consistency of fruits, cavity, dry matter, and fresh weight. All these parameters decreased during the period of storage. The organic manure treatments showed the best values of most of the evaluated parameters.
A whitefly trap recently developed by Chu and Henneberry was tested in a cantaloupe field at the University of Arizona Maricopa Agricultural Center in 1995. The trap was compared with a 3 × 5-inch yellow sticky card trap, a commercial dome trap, and the leaf-turn sampling method. Results showed that the new whitefly trap effectively caught adults in cantaloupes. Numbers of adults increased as whitefly adult population densities increased during the season. Numbers of adults caught by the new whitefly trap were comparable to numbers of adults caught with the commercial dome trap and to a lesser extent the counts of adults determined by leaf-turn sampling method. Results with the new trap were not comparable to adults caught with yellow sticky card traps.
Abstract
Near ultraviolet radiation appears to be largely responsible for solar injury (SI) and vein tract browning (VTB) of cantaloupes (Cumis melo L., Reticulatus group, cv. PMR 45) grown under field conditions in the San Joaquin Valley of California. Incidence and severity of SI were substantially reduced when near UV flux impinging on the fruits at solar noon was reduced to 21 Wm-2 or less and especially when wavelengths below 320 nm were excluded by the use of plastic UV filters. VTB was reduced when UV flux was 12 Wm-2 or less or when wavelengths below 320 nm were excluded. In cantaloupes, near UV appears to directly induce SI but to indirectly induce VTB, a postharvest disorder, by accelerating aging of surface tissues.
Winter cover crops were evaluated to determine their influence on yield, nematodes, and soil-borne pathogens in sustainable cantaloupe production during a two year period. Six cover-cropping regimes, including a weedy fallow control, were tested in a replicated trial. Pesticide and commercial fertilizer inputs were significantly reduced in the cover crop treatments. No insecticides were needed throughout the study due to high populations of beneficial insects. Fertilizer inputs were only one-fourth the recommended rate used for conventional cantaloupe production. Populations of southern root-knot nematode (Meloidogyne incognita) and soil-borne pathogens Rhizoctonia solani and Pythium spp. were significantly higher in crimson clover and subterranean clover cover crops, yet yields were greater following crimson clover. Lowest yields and highest number of worm-damaged fruit occurred in the weedy control.
Fresh-cut melons in many consumer-ready packages are notorious for “wetting” and accumulation of standing juices. These conditions likely create undesirable flavor and aroma changes. We initiated a study to investigate flavor changes in stored fresh-cut cantaloupe. One objective was to optimize solid phase microextraction (SPME) to evaluate organoleptic compounds. Static head-space SPME analyses were performed on fresh-cut cantaloupe cubes (≈2.5 mm, 5 mm, or 2.5 cm), expressed juice, and homogenized slurries. SPME fiber (100 μm PDMS vs. 75 μm Carboxen/PDMS) exposure time (5, 7.5, 10, 12.5, 15, 17.5, 20 min) was evaluated at 40 °C with various head-space: product ratios, plus or minus NaCl to produce typical chromatograms. Fibers were desorbed in an HP5890 GC with a DB-624 or DB-5 column for 45-min runs and an HP6890 GC (DB-5) equipped with a 5973 MS detector for 35-min runs. Albeit qualitative, the best chromatograms were obtained with 7-ml slurries, stirred with NaCl, exposed to a 10 0μm PDMS SPME fiber for 12.5 min. The 100 μm PDMS fiber produced better chromatograms considering the fact that many important flavor volatiles are low-molecular-weight polar esters and alcohols. These conditions were subsequently used to analyze numerous fresh-cut cantaloupe samples stored various times (0 to 9 days). Over 100 peaks were identified, many of which changed through storage and some are suspected as probable agents responsible for undesirable flavor changes. Our analyses are progressing in an attempt to authenticate compounds associated with flavor-related changes in numerous fresh-cut cantaloupe varieties from various growing regions.