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  • Author or Editor: G.C. Denny x
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Abstract

Various techniques have been used for emasculation of rosaceous fruits; fingernails, scalpels, and tweezers are typical tools (1, 3, 5, 7). Emasculation tools for stone fruits have been made from a hacksaw and from square-jawed forceps with cut out corners (6). Barrett and Arisumi (2) devised an instrument that consisted of a pair of scissors with a triangular notch in the blade whose width could be adjusted by an adjustable arm or set screw.

Open Access

Abstract

Black, purple, and tan discolorations have been found within red-pigmented areas of the peach fruit skin. Scanning electron and light micrographs show damage caused by defuzzing and roller drying, which could facilitate entry of causal agents associated with peach skin discoloration. Comparisons of reflectance and transmittance spectra (380-700 nm) of discolored (purple) and nondiscolored (red) peaches show the mean reflectance value for discolored peaches is 100% darker than nondiscolored peaches. However, transmittance spectra of acidified extracts of discolored and nondiscolored peach skins are similar throughout these wavelengths. Extracted pigment color was altered by pH changes and metallic ion concentration. At low pH, discoloration may be caused by ion complexing with anthocyanin pigment. At high pH, discoloration may result from alkaline hydrolysis of the pigment molecule.

Open Access

Abstract

Semihardwood peach [Prunus persica (L.) Batsch] cuttings were successfully rooted when the bases and tops were misted intermittently with water. Rooting was not affected by cultivar or type of cutting (basal vs. terminal). Closer proximity of the bases of the cuttings to the mist line and overhead misting improved rooting percentage.

Open Access

Concerns over the environmental impact and economics of harvesting sphagnum and reed-sedge peat have increased the desire to identify acceptable peat substitutes for use in container substrates. This preliminary study evaluated the use of composted dairy manure solids as a substitute for sphagnum or reed-sedge peat in container substrates for production of woody ornamental shrubs and assessed potential leaching of nutrients. Walter's viburnum (Viburnum obovatum), sandankwa viburnum (Viburnum suspensum), and japanese privet (Ligustrum japonicum) were grown in 3-gal plastic containers with seven substrates containing (by vol.) 60% pine bark, 10% sand, and 30% sphagnum peat (S), reed-sedge peat (R), and/or composted dairy manure solids (C). Substrate composition had no effect on plant quality ratings for any species, growth index (GI) of walter's viburnum, or shoot and root dry weight of walter's viburnum and japanese privet. However, the GI of japanese privet and sandankwa viburnum was the lowest when grown in substrates containing a high percentage of reed-sedge peat (0S:3R:0C). Substrate effects on average nitrate + nitrite nitrogen leachate losses were minimal over the 88-day leachate collection period. However, the substrate containing the highest proportions of composted dairy manure solids (0S:0R:3C) generally had the highest average ammonium nitrogen and dissolved reactive phosphorus losses compared with other substrates. All substrates tested as part of this study appeared to be commercially acceptable for production of container-grown woody ornamental shrub species based on growth and quality. However, average nutrient losses from containers differed depending on the peat or peat substitute used to formulate the substrates.

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Abstract

In vitro propagation of ‘Nemaguard’ peach rootstock [Prunus persica (L.) Batsch] was obtained on a modified Murashige and Skoog (MS) medium using shoot tips as primary explants. Shoot proliferation was induced on MS medium supplemented with 50 mg/liter L-ascorbic acid, 20 ml/liter Staba vitamin mixture, 2.0 mg/liter 6-benzylamino purine (BA), and 0.1 mg/liter naphthaleneacetic acid (NAA). Rooting was induced by subculturing plantlets on a similar medium without the Staba vitamins and without BA. When the Staba vitamin mixture was present, rooting was reduced; the inhibition resulted from the presence of riboflavin.

Open Access