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- Author or Editor: M. W. Williams x
Abstract
(2-Chloroethyl)phosphonic acid (ethephon) applied to ‘Delicious’ apples before harvest to improve fruit quality can change fruit shape (length/diameter ratio) the next year. The change is magnified when ethephon follows a summer application of succinic acid-2,2-dhnethylhydrazide (SADH) and is most evident on low vigor trees.
Abstract
Limb units and whole trees of ‘Delicious’ and ‘Golden Delicious’ sprayed in the fall with 250 ppm, 500 ppm and 1000 ppm Ethrel significantly decreased fruit set and vegetative growth the following season.
Abstract
A method is described for introducing small quantities of chemicals by gravity flow into terminal shoots of young apple trees. The destruction of acid fuchsin and 14C labelled growth regulators by this method was down the main stem, out to the lateral branches, and into the leaves.
Abstract
In 3 different seasons watercore began to develop in ‘Delicious’ fruit as the minimum temperatures dropped to near 4°C. In 1970 and 1971 watercore started to appear just before a sharp rise in sorbitol level occurred in the limb sap. In 1972 considerable watercore developed in the fruit before a significant increase in sorbitol was observed in the sap.
Abstract
Lanolin bands containing 2, 3, 5-triiodobenzoic acid (TIBA) applied to the pedicel of apple fruits 2 to 3 weeks after bloom caused the fruits to drop. Naphthaleneacetic acid (NAA) applied to the cut end of defruited pedicels prevented pedicel abscission, but a band of lanolin containing TIBA at mid-pedicel caused most of them to abscise. Cytokinins did not prevent pedicel abscission. Indole-3-acetic acid (IAA) and gibberellins A3 and A4,7 more effectively prevented pedicel abscission of ‘Delicious’ than ‘Golden Delicious’.
Abstract
The application of cytokinins and gibberellins alone and in combination to ‘Delicious’ apples just after full bloom affected fruit shape by increasing the length-to-diameter ratio of the fruits. Cytokinins caused fruits to be longer with prominent well-developed calyx lobes. The treated fruit had the appearance of fruits grown where early season temperatures are cool. Gibberellin A4 + A7 caused fruits to be longer but did not appreciably affect the development of the calyx lobes.
Abstract
Fruit color and quality of ‘Golden Delicious’ apples was directly related to the nitrogen content of the tree. When leaf-nitrogen (N) levels were above 2.2% dry weight, the fruit tended to be large and green. Maximum yields of high-quality fruit were obtained when leaf-N levels were from 1.9 to 2.1% dry weight.
Abstract
Succinic acid 2,2-dimethylhy drazide (Alar) applied commercially to 'De licious’ apple trees at a concentration of 1,000 ppm at 8 and 125 days after full bloom in 1968 caused flattened misshapen fruit to be produced in 1969.
Abstract
Translocation patterns of the triazole plant growth retardants paclobutrazol, triapenthenol, and BAS111 were found to be similar when applied as a trunk paint, soil drench, or in hydroponic systems. Chemical degradation studies indicate that the greatest percentage of parent compound is translocated to roots and mature leaves following soil drench and hydroponic treatments. Generally, residue levels of BAS111 were significantly lower than those of paclobutrazol and triapenthenol. Data from trunk paint applications indicate triapenthenol and BAS111, even at concentrations 5 times greater than paclobutrazol, are not as effective in controlling shoot growth. Significant negative correlations were found between shoot growth and foliar residue levels of paclobutrazol and triapenthenol 13 weeks after trunk paint application. Chemical names used: (2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pentan-3-ol (paclobutrazol); (E)-(RS)-1-cyclohexyl-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)-pent-1-en-3-ol (triapenthenol); 1-phenoxy-5,5-dimethyl-3-(1,2,4-triazol-1-yl)-hexan-5-ol] (BAS111); trimethylonylpolyethoxyethanol (WK surfactant).
Nursery stock of plum (Prunus salicina Lindel., `Casselman') was planted 1 Apr. 1988 in an experimental orchard at the Kearney Agricultural Center, Univ. of California, near Fresno. The trees were enclosed in open-top fumigation chambers on 1 May 1989 and exposed to three atmospheric ozone partial pressures (charcoal-filtered air, ambient air, and ambient air + ozone) from 8 May to 15 Nov. 1989 and from 9 Apr. to 9 Nov. 1990. Trees grown outside of chambers were used to assess chamber effects on tree performance. The mean 12-hour (0800-2000 hr Pacific Daylight Time) ozone partial pressures during the 2-year experimental period in the charcoal-filtered, ambient, ambient + ozone, and nonchamber treatments were 0.044, 0.059, 0.111, and 0.064 μPa·Pa-1 in 1989 and 0.038, 0.050, 0.090, and 0.050 pPa·Pa-1 in 1990, respectively. Leaf net CO2 assimilation rate of `Casselman' plum decreased with increasing atmospheric ozone partial pressure from the charcoal-filtered to ambient + ozone treatment. There was no difference in plum leaf net CO2 assimilation rate between the ambient chamber and nonchamber plots. Trees in the ambient + ozone treatment had greater leaf fall earlier in the growing season than those of the other treatments. Cross-sectional area growth of the trunk decreased with increasing atmospheric ozone partial pressures from the charcoal-filtered to ambient + ozone treatment. Yield of plum trees in 1990 was 8.8, 6.3, 5.5, and 5.5 kg/tree in the charcoal-filtered, ambient, ambient + ozone, and nonchamber treatments, respectively. Average fruit weight (grams/fruit) was not affected by atmospheric ozone partial pressure. Fruit count per tree decreased as atmospheric ozone partial pressure increased from the charcoal-filtered to ambient + ozone treatment. Decreases in leaf gas exchange and loss of leaf surface area were probable contributors to decreases in trunk cross-sectional area growth and yield of young `Casselman' plum trees during orchard establishment.