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

The antitranspirant di-l-p-menthene (Wilt-Pruf) increased red color development in ‘McIntosh’ apples when used alone or in combination with diuron or CaCO3.

Open Access
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Abstract

A microcomputer program is used to calculate the production and profitability of student-created apple orchard designs. The program accumulates productivity for each year following planting and uses economic parameters to determine the net present value of total orchard profits for each design. Students can alter not only design inputs and economic predictors but are encouraged to change production cost parameters to demonstrate their effects on orchard profitability over the life of the orchard.

Open Access
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Abstract

The severity of russet on ‘Golden Delicious’ apple (Malus domestica Borkh.) grown at Ithaca, New York was well correlated with weather parameters. The best correlations were found with humidity parameters although net precipitation was also well correlated. The fruits were especially sensitive to weather conditions during a short (5 day) interval which occurred between 16 and 20 days after full bloom.

Open Access
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Abstract

The capacity to synthesize the stilbene resveratrol in response to UV irradiation is used as a measure of the phytoalexin production potential of grape berry skin. Greenhouse-grown berries after set, but before maturation, had high phytoalexin potential, whereas buds, flowers, and mature fruits had low potential. Stilbenes were not synthesized in the fleshly part of fruit and were found erratically in small amounts in noninduced berry skin. In field samples, ‘Concord’, ‘Cabernet Sauvigon’, and ‘Catawba’ had high resveratrol production potential whereas ‘White Riesling’, ‘Chancellor’, and ‘Cayuga White’ had low potential. The phytoalexin production potential decreased in all cultivars after late August, independent of their maturity.

Open Access
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Abstract

Russet on ‘Golden Delicious’ apple (Malus domestica Borkh.) was induced by sprays of butanedioic acid mono-(2,2-dimethylhydrazide) (daminozide), Diazinon, superior oil, and by environmental factors. Russet severity was reduced by application of a silicon dioxide formulation and by protecting fruit from environmental conditions by bagging, plastic covers, or by filtering ambient air.

Open Access

Abstract

The concentrations of chlorophylls, carotenoids, and flavonoids were measured in ‘Golden Delicious’ apple (Malus domestica Borkh.) skin during maturation, ripening, and storage. Chlorophyll was found to be the most important color determinant. Yellow coloration was not visible unless chlorophyll concentration was less than 0.15-0.20 µg/cm2 of skin. The minimum amount of carotenoids necessary for yellow color was found to be 0.3-0.4 µg/cm2 of skin. Flavonoids play a secondary role in yellow coloration. A decrease in total carotenoids occurred in September, followed by an increase to the original level. The flavonoid concentration was relatively constant during ripening.

Open Access
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Abstract

To determine whether grape (Vitis sp.) replant problem might be an example of autotoxicity, soil samples from fields that had or had not been replanted with grape cuttings were extracted with a neutral solution of ethylenediaminetetraacetic acid (EDTA) and by leaching with half-strength Hoagland's solution. Rooted grape cuttings growing in sand also were leached. Fractions of the leachates and extracts were assayed for toxicity using lettuce seedlings. Grape roots and replant soil yielded a toxic substance not present, or possibly present only at low levels, in non-replant soil. The replant soil extract inhibited phenylalanine ammonia-lyase activity in grape roots more than did the non-replant soil extract. The toxic substance in the replant soil extract was partially purified and a 1H nuclear magnetic resonance (NMR) spectrum taken, but the substance has not been identified. Thus, grape roots appear to be the source of at least one compound that is toxic to plants and accumulates in the soil in which grapes are grown.

Open Access

Abstract

Attached green apples of the cultivar ‘McIntosh’ exposed to the natural prevailing light within the tree canopy supplemented by continuous irradiation for 48 hours demonstrated that “Daylight” or “Grolux” fluorescent lamps were more efficient than incandescent or mercury-vapor lamps in promotion of anthocyanin synthesis. No anthocyanin was formed at energy levels less than 0.5 mW/cm2 for 48 hours. This suggested a minimum energy requirement of about 100 joules/cm2 for the initiation of anthocyanin synthesis, or a minimum intensity for response. The potential of these apples to synthesize anthocyanin when exposed to supplementary light was greatest about August 20. The anthocyanin induced in green apples within the tree by suplementary irradiation was gradually lost after the energy source was removed. Length of the induction stage for anthocyanin formation in continuous irradiation was the same, about 12-15 hours, for both attached and detached apples. If attached green apples were exposed to alternating light and dark periods, instead of continuous irradiation, 9 hours of supplementary irradiation (about 58 joules/cm2) at an intensity of 0.5 mW/cm2 was adequate to initiate pigment synthesis.

Open Access