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  • Author or Editor: L. L. Morris x
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Abstract

Most, if not all, horticultural fruits, vegetables, and ornamentals of tropical origin are subject to physiological injury when subjected to temperatures below about 12.5°C but above their freezing temperature. This damage does not involve freezing and is commonly termed chilling injury. Chilling-sensitive plants, and plant parts, are subject to injury at all stages of their development, except in the dry-seed stage.

Open Access
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Abstract

The past quarter century has been a “Golden Era” for the development of a multitude of vegetable cultivars. We have seen the development of tomatoes that can be mechanically harvested with only slight injury to the fruit; sweet corn that is “super-sweet” with an extremely tender pericarp; green beans that are stringless and peas tha-t are very determinate and adaptable to mechanical harvesting. Countless other breeding achievements have been made in vegetable quality and adaptability, not to mention the broad spectrum of disease and insect resistance that has been bred into nearly every vegetable species. We can be thankful for our highly competitive system for bringing about so many of these advances in such a short time.

Open Access

Abstract

Plants of head lettuce (Lactuca sativa L.) were rapidly regenerated in vitro using apex segments, expanded axial buds, and leaf sections. Shoot development occurred after 14 days on Miller’s medium plus 5.0 mg/liter 3-indoleacetic acid (IAA) and 0.5 mg/liter kinetin at 22.5°C. Root initiation was induced by transferring rootless plantlets to Miller’s medium plus 1 mg/liter indolebutyric acid (IBA) for 2 weeks. Plants were transplanted to pots 4 weeks after initial culturing, and to the field within an additional 3 to 5 weeks. Heads appeared similar to those propagated from seed and viable seed was produced.

Open Access

The Las Vegas Valley receives most of its water from the Colorado River due to a static federal water allocation the remainder from pumping groundwater. The increased water demand due to the population rise in the Las Vegas Valley is expected to overtake its current water allocation in the next few years. Over 60% of the potable water used in the Las Vegas valley is used to irrigate urban landscapes. Poorly designed desert landscapes can ultimately use more water than traditional landscapes and increase residential energy costs. Most of the desert landscaping currently installed by homeowners either ignores principles that conserve water or conserve energy. The program was designed to be used with homeowner associations and commercial landscapers. The residential homeowner proved to be the most responsive to this type of program. The overall goal of this program is to teach residents how to convert a high water use landscape to lower water use and reduce dependence on potable water for irrigation and still maintain high quality landscapes. In 1995, a 7-week, hands-on, landscape design curriculum was developed and used to teach homeowners how to create desert landscape designs that conserve water and energy and compared its water use to traditional, turfgrass landscapes. Participants leave the course with a finished design of their making with information on how to install the landscape themselves or how to hire a professional to do the installation. In 1996-97 a Master Gardener was taught and mentored how to teach the class in Las Vegas using the existing curriculum. Since 1995, over 500 residents have been trained and water use savings documented by the existing water purveyors. This program is self-funded through class fees.

Free access
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Abstract

Fruit of muskmelon (Cucumis melo L.) were treated with 0–104 mg/liter of the fungicides: benomyl (methyl-1-[butylcarbamoyl]-2-benzimidazole carbamate); etaconazole (l-{[2-(2,4-dichlorophenyl)-4-ethyl-1,3-dioxolan-2-yl]-methyl}-1 H-1,2,4-triazole); fenapanil (1-butyl-1-phenyl-1 H-imidazole-1-propanenitrile); imazalil (1-[2-allyloxyl-2-(2,4-dichlorophenyl)ethyl]imidazole); and prochloraz (l-{N-propyl-N-[2-(2,4,6-trich-lorophenoxy) ethyl]}carbamoyliinidazole). Damage from Fusarium rots, Geotrichum and Rhizopus soft rots, and Alternaria surface blemish was assessed. Fenapanil, imazalil, and prochloraz had the most useful range of fungicidal activities. Prochloraz was the most efficacious fungicide tested, expressed as disease control per unit concentration of active ingredient.

Open Access

Abstract

The severity of internal damage to mature-green tomatoes increased with the number of drops. Impact-bruised, mature-green tomatoes, (Lycopersicon esculentum Mill. cvs. Cal Ace and Tropic), exhibited an increase in ethylene production within 1 hour after injury. When mature-green fruits of ‘Manapal’, ‘Tropic’, ‘Cal Ace’ and ‘VFN Bush’ were impact-bruised all cultivars except ‘VFN Bush’ exhibited sustained increases in rate of ethylene and CO2 production. The magnitude of ethylene production increased with number of impacts. Ripening of bruised fruit tended to be accelerated, and titratable acidity was decreased.

Open Access

We investigated foliar damage to five landscape species sprinkler irrigated with either reuse water or one of five synthesized saline waters that contained elevated single salts mixed with Colorado River water, all having similar electrical conductivities. The experiment allowed us to compare the impact of elevated concentrations of Na, Mg, Ca, Cl, and SO4 on an index of visual damage (IVD), tissue ion concentrations, and spectral reflectance. Waters containing elevated concentrations of MgCl2 or NaCl caused greater foliar damage than did MgSO4, Na2SO4, CaSO4, or reuse water, as recorded in higher IVD values (p < 0.05). Privet and elm were damaged to a greater extent (higher IVD values) than were desert willow, guava and laurel (p < 0.05). Higher IVD values were recorded for all species irrigated with the MgCl2 waters, with mortality recorded in privet. Tissue nutrient concentrations were correlated with the IVD values. In the case of guava, 61% of the variability in the IVD could be accounted for based on N, P and K (P < 0.01). On a treatment basis, the single salts added to the municipal water showed little correlation with the IVD values, except in the case of MgCl2, where Mg was included in the regression equation (r 2 = 0.82, P < 0.01, IVD↑ as S04↓, Mg and P↑). Eleven different spectral indices separated based on treatment and/or species (P < 0.05). In elm, 70% of the variability in the IVD could be accounted for by including Red Edge, Normalized Difference Vegetation Index (NDVI) and Water Band Index (WBI)/NDVI. A mixed response was observed to a post 30-day irrigation rinse in an attempt to reduce IVD values. Based on our results, care should be given to monitoring not only the EC (and osmotic potential) but also the ionic composition when saline waters are blended with other water sources, with the aim of minimizing the concentration of Mg, Cl, and Na.

Free access