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  • Author or Editor: Porter B. Lombard x
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Abstract

‘Cascade’ is a new red-skinned pear (Pyrus communis L.) that provides a large-fruited red pear for the holiday and late-winter markets. The fruit has excellent dessert quality and sizes well, with heavy cropping.

Open Access

Abstract

Cross-pollination increased fruit set, fruit size and seed content of ‘Cornice’ pear (Pyrus communis L.) in 3 large orchards without pollenizers. Supplemental self-pollination was equivalent to open pollination in its effect on fruit set and size. Low female fertility of ‘Comice’ could not be accounted for by early ovule degeneration or frost injury. Pollen transfer by bees was observed to be low in 2 orchards, with 36 and 41% of seedless fruit the result of open pollination. In comparison, only 6% of open-pollinated fruit were seedless in the orchard of greatest bee activity. Seedlessness was due to seed abortion during early fruit development. Classification of aborted seeds as to size at time of abortion revealed that in most fruits a minimal amount of seed growth occurs, although fruit retention does not require the presence of fully developed seeds. Fruit size was positively correlated with seed content, although this relationship was less pronounced in fruits with high seed count. The importance of seed development before abortion and of fully developed seeds in fruit set as well as fruit size is shown.

Open Access

Abstract

Overhead sprinkler systems are not new to orchard management but have been used almost exclusively for irrigation. However, economic considerations would encourage a modification of this one-purpose system into multi-purpose usage. Potentially, with the correct physical arrangements of pumps, pipes, risers, and nozzles it would be possible not only to irrigate, but to have frost protection and summer environmental and pest control as well. The present paper examines the latter two uses of an overhead sprinkler system and the effects of the system on the pear tree.

Open Access

One- and two-year-old `Pinot noir' grapevines were irrigated with Hoagland's nutrient solution and shaded with 60% shade cloth to investigate the effect of shading on inflorescence necrosis (IN), tissue ammonium, and nitrate status. Shading increased IN, tissue ammonium, and nitrate concentrations of laminas, petioles, and rachis in two-year-old vines. IN was positively correlated with tissue ammonium and nitrate levels. In one-year-old vines, tissue ammonium and nitrate concentrations were increased by shading in most tissues except for nitrate in tendrils and old roots. Tissue ammonium correlated with nitrate concentration in various tissues after anthesis in one-year-old vines and in laminas, petioles, fruit, and rachis of two-year-old vines. Elevated tissue ammonium in rachis has been suggested as a possible cause of IN.

Free access

Abstract

Controlled freezing tests showed no hardiness differences between comparable floral developmental stages on weak and vigorous ‘Bartlett’ (Pyrus communis L.) pear trees. Bloom delay through evaporative cooling resulted in a loss of hardiness beyond that found earlier in the season on non-misted trees for similar stages of development, although a certain degree of frost protection was gained through bloom delay.

Open Access

`Napoleon' grafted onto Colt, F/12-1, and MxM60 rootstock were planted into three types of tree holes: augered; backhoed, and backhoed plus fumigation. The auger treatment resulted in lower yields, smaller trunk cross-sectional area (TSCA), and smaller canopy volume when compared to backhoed holes. Fumigation had no significant effect. Trees on Colt rootstock were more precocious, had a smaller TCSA and canopy volume, greater cumulative yield efficiency, and, in 1987, the smallest fruit weight. The yield efficiency of Colt was the highest until 1988, when it was surpassed by MxM60, but was still similar to F/12-l. Yields were highest on trees of MxM60 in 1987 and 1988.

Free access

Abstract

Freezing studies on ‘Bartlett’ pear (Pyrus communis L.) bouquets of buds, flowers, and small fruit showed injury increased with decreasing temperature, increasing developmental stage, and increasing duration of frost. At the minimum temperature, 30 and 60 minutes of frost exposure in all stages increased injury, however, in the small fruit stage injury at −2°C increased for up to 2 hours exposure. The effect of freezing rate was dependent on minimum temperature and dry florets were injured slightly more than florets misted just prior to freezing.

Open Access

Studies in the use of fall ethephon to delay bloom in peach and prune were carried out during 1985-87. In `Italian' prune, ethephon at 250 and 500 mg·liter-l at 10% leaf-drop stage delayed bloom 13 and 16 days, respectively. Only a 5- and 7-day bloom delay occurred when applied at 50% leaf-drop stage. Fruit set and yield were not reduced in `Italian' prune when ethephon was applied at the 50% leaf-drop stage. Early applications, from vegetative maturity to the 10% leaf-drop stage, did not reduce yield in prone when trees had been previously defoliated with 3.0% urea. Early leaf removal, before vegetative maturity, caused reduction in peach flower and fruit number. In several peach cultivars, all the ethephon treatments were detrimental to flower density, fruit set, and yield, in spite of bloom delay. The ethephon-treated prune trees yielded more than the untreated trees in 1987 as a result of frost avoidance.

Free access