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Donald N. Maynard and Gary W. Elmstrom

Evaluations of 30 triploid (seedless) watermelon hybrids were conducted in the Spring 1989 season at Bradenton and Leesburg, Florida. There was considerable variation in relative cultivar yields at the two locations. However, consistency in some cultivars did occur. 'HMX 7924' produced the highest total yield and 'CFREC 88-2' had high total yields at both locations. On the other hand, 'ACX 882322', 'Fengshan No. 1', 'FMX 28', 'Fummy', 'Honeyheart', 'Nova', and 'NVH 4295' produced low total yields at both locations. Average fruit weight was high for 'Ssuper Sweet Brand 5244', 'CFREC 88-4', and 'HMX 7924' whereas 'ACX 882322', 'FMX 28', 'Fengshan No. 1', 'Nova', and 'PSR 49087' produced low average fruit weight. Soluble solids exceeded 11% in all entries at Bradenton whereas two entries were lower than 10% at Leesburg. Several experimental lines out performed the named cultivars suggesting that future introductions will be superior to those already available.

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Gary W. Elmstrom and Donald N. Maynard

Muskmelon (Cucumis melo L. reticulatus group), commonly called cantaloupe by growers, shippers, and consumers is a relatively minor crop in the southeastern U.S. The principal restraint on increased muskmelon production in this area is the lack of varieties that consistently produce high quality fruit. Resistance to both fruit rots, especially those induced by Fusarium, and foliar diseases such as downy mildew, powdery mildew, and gummy stem blight are also important because of the high humidity and frequent rainfall common to this area. The ideal shipping variety should have the capacity to produce high yields of round to oval, sutureless, heavily netted fruit that average 1.4 kg each, and that have a deep salmon-colored flesh, a small tight seed cavity, high soluble solids, and a pleasant taste and aroma. Evaluations at Leesburg and Bradenton, Florida over a three-year period have identified several western-type muskmelons well-adapted to this area. `Explorer', `Goldmark', `Mission', and `Tasty Sweet' ranked high in most of the categories mentioned above and should be evaluated in more extensive trials, which should include a study of postharvest quality.

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Jonathan R. Schultheis and Donald N. Maynard

Market demand for diploid fruit has been declining over the past ten years, especially the past three years. Thus, the watermelon industry is looking for ways to produce triploid fruit more efficiently. Several companies have developed pollinizers for planting in-row so as not to take up space like a commercial diploid cultivar. The objective of our experiment was to determine the effects of `Companion' and `SP-1' pollinizers on triploid yield compared with a traditional diploid pollinizer which until recently were routinely sold to grocery chain stores. The experimental locations were Bradenton, Florida and Kinston, NC. Treatments included two triploid cultivars; Tri-X-313 (Syngenta, Rogers Brand Seeds) and Olympia (Seminis Seed Co.), and three pollinizers; `Companion' (Seminis Seed Co.), `SP-1' (Syngenta, Rogers Brand Seeds), and `Summer Flavor 800' (Abbott & Cobb Seed Co.). A seventh treatment included `Tri × 313' in which no pollinizer was planted next to the triploid cultivar. `Companion' was interplanted every two triploid plants. `SP-1' was interplanted every three triploid plants, and `Summer Flavor 800' planted every third hill. All fruit were harvested when ripe and each watermelon was weighed. Results in the Florida location were compromised due to the close proximity of pollen from adjacent watermelon cultivar trials. In North Carolina, some pollen movement did occur between treatment plots as evidenced by fruit set in the `Tri-X-313' plots which did not contain a pollinizer. Yields; however, were 25% to 33% of those treatments which contained a pollinizer. `Tri × 313' yielded greater fruit numbers but individual fruit weights were less than those harvested from `Olympia'. Early fruit yield was similar regardless of pollinizer, while late yields were greater using `SP-1' rather than `Companion' or `Summer Flavor 800'. Cumulative yields (three total harvests) were highest with `SP-1' than the other pollinizers. The use of `SP-1' provided the greatest potential for improved yields over traditional diploid pollinizers.

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William J. Lamont Jr

Knott's Handbook for Vegetable Growers, Fifth Edition. D.N. Maynard and G.J. Hochmuth. 2006. John Wiley and Sons, Inc., 111 River Street, Hoboken, NJ 07030. 640 pages. $75, paperback. ISBN: 978-0-471-73828-2.

The first Handbook for Vegetable Growers was published in 1956 by the late Dr. James Edward Knott, professor of vegetable crops, University of California, as an effort to “bring together in as concise a form as possible much of the widely scattered information that relates to vegetable production.” I have a copy of this

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George J. Hochmuth and Donald N. Maynard

Delivery of modern extension programs involves considerable expenses that are becoming scarce from traditional sources. Successful extension educational programs will need to find additional revenue sources to fund educational materials, speaker costs, conferences, and other needs. It is important to become as financially efficient as possible and sometimes this means consolidating some programs and eliminating others. Charging fees to attendees is one means of covering costs of delivering programs. The University of Florida is partnering with the agriculture industry and trade journal publishers to provide resources and publishing for educational programs and materials.

Open access

Robert J. Precheur and Donald N. Maynard

Abstract

Transplants of asparagus (Asparagus officinalis L.) were grown in sand culture under varying ratios of NO3 and NH4. Maximum growth occurred in a nutrient solution with a N ratio of 75% NO3 – N and 25% NH4 – N. Growth was significantly reduced when the N composition was either 100 or 75% NH4 – N. CaCO3 reduced ammonium toxicity but also reduced seedling growth.

Open access

Donald N. Maynard and Allen V. Barker

Abstract

Spinach, Spinacia oleracea, L., cv. America, Heavy Pack, and Hybrid 424 were grown in sand culture with variable NO3 concentrations from 0.187 to 48 meq/l. The cultivars were representative of savoyed, semisavoyed, and smooth-leaf types, respectively. The plants were harvested when those cultured at 12 and 18 meq NO3/l had obtained approximate market maturity. At this time an array of deficiency, sufficiency, and toxicity symptoms were evident. Great differences in NO3 accumulation and critical NO3 concentrations occurred among cultivars. Critical NO3-N concentrations for the whole leaves of spinach plants were: ‘America’, 0.17%, ‘Heavy Pack’, 0.15%, and ‘Hybrid 424’, 0.045% of their dry weights. Calculations relating spinach consumption and impaired human health suggest that adult health should not be affected even with massive ingestion of spinach.

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Allen V. Barker and Donald N. Maynard

Abstract

The accumulation of cations and NO3-N was higher in cucumber shoots than in pea shoots grown on nitrate nutrition. Total N concn in shoots did not differ between the species. Ammonium nutrition suppressed cation accumulation in cucumbers but not in peas. Differences in cation accumulation in the shoots are attributed to the form in which N is translocated from root to shoot.

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Steven A. Sargent, Peter J. Stoffella, and Donald N. Maynard

Short-day onions (Allium cepa L.) grown under humid, subtropical conditions at two locations were evaluated for bulb size and yield at five harvest dates (H1 to H5) ranging from 94 to 132 days after transplanting (DAT) for `Granex 33' and from 115 to 153 DAT for `Texas Grano 1015Y'. Maximum yields were attained by H4 for both cultivars and were attributed to increased bulb size rather than differences in plant (bulb) population. Nondried, large bulbs (>7.6 cm diameter) from each harvest were trimmed and stored at 1 or 10 °C and 80% relative humidity (RH) for 2 weeks plus 2 weeks at 20 °C and 80% RH to simulate commercial storage and handling. Initial respiration rates of bulbs of both cultivars decreased >60% between H1 and H4. Bulbs also retained higher fresh weight during storage as harvest was delayed. Storage for 2 weeks at 1 °C suppressed sprouting of immature (H1) `Texas Grano 1015Y' bulbs, but not of `Granex 33' bulbs from one location. Storage at 10 °C did not suppress sprouting of either cultivar. Decay became more prevalent with delayed harvest, but `Granex 33' was more resistant to decay than was `Texas Grano 1015Y', which developed up to 40% decay after 2 weeks at 20 °C. Harvest at 115 and 132 DAT resulted in acceptable yields for `Granex 33' and `Texas Grano 1015', respectively, and satisfactory postharvest quality of nondried bulbs following 2 weeks of storage at 1 °C and 80% RH plus 2 weeks at 20 °C.

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Donald N. Maynard, Gary W. Elmstrom, and Linda Wessel-Beaver

Hybrids from crosses between bush/short-vined breeding lines and traditional, vining cultigens were evaluated in the fall 1993 season. Yields of individual hybrids were 0.51 to 1.73 times those of their vining parents and 0.83 to 4.41 times those of the bush/short-vined parents. The average yield response of 58 hybrids was 1.05 times that of vining parents and 2.15 that of bush/short-vined parents. Average fruit weight, flesh thickness, and flesh color of the hybrids tended to be intermediate between that of the bush/short-vined and vining parents. Plant habit of all hybrids was similar to that of the bush/short-vined parent early in the growth cycle, but some became viney later in the growth cycle. Fruit matured earlier on bush/short-vined parent and hybrid plants than on viney parent plants.