Search Results

You are looking at 1 - 10 of 18 items for :

  • Author or Editor: M. N. Westwood x
  • HortScience x
Clear All Modify Search
Author:

Abstract

Pyrus calleryana Dene, is ar. exceptional species because of its resistance to a wide variety of insects, diseases and other pests. The selection of the striking ornamental clone shown on the cover resulted from a chance observation in the long-term pear rootstock research program, which began nearly 70 years ago in Oregon.

Open Access
Author:

Abstract

Viruses and virus-like disorders have been observed in plants for many years. The economic importance of some are obvious, e.g. cull fruit or dead plants, but until recently the effects of some of the less serious viruses had not been determined in detail. Prior to World War II a good deal of the virus research was done in England and the U.S., but since then such work has expanded rapidly throughout the world.

Open Access
Author:

Abstract

Since the release of Pyrus calleryana Done. cv. Bradford by the U.S. Department of Agriculture (4) this species has become popular as a street tree and in landscapes in areas where it is hardy. Because of problems in maturing ‘Bradford’ trees in the nursery, with subsequent problems of dieback in storage and poor transplanting success, some nurseries have sought selections of P. calleryana with all of the good characteristics of ‘Bradford’ but with better growing and handling traits. Also in some climates ‘Bradford’ does not exhibit red leaf coloration in the fall, and a number of selections have been made that are more colorful.

Open Access
Author:

Abstract

Of the 90 plant collections listed by Wyman (The arboretums and botanical gardens of North America, Chronica Botanica X: 395-497, 1947) 54 indicated their chief function as either education, research, or both. These terms have different meanings to different people but either function could best be carried out if the collected species were authentic and correctly labelled.

Open Access
Author:

Abstract

One of the key limiting factors in fruit production is bud or tree damage from fall or winter freezes. This is due to the selection of cultivars by criteria other than hardiness and to man’s attempt to extend otherwise good cultivars beyond their hardiness range.

Open Access

Abstract

In a test designed to study the effect of cross pollination on pear fruit set Stephen (4) found that seeded fruits result almost entirely from cross pollination rather than selfing. He found also that seedless set was mainly from selfing, although a small proportion was parthenocarpic. When he first caged entire trees against insect pollination during the period of open bloom, an average set of seedless fruits resulted. However, after caging during bloom each year for four years, seedless set was gradually reduced to only a few fruits. Stephen extended this study and found (5) that renewed exposure of the caged trees to cross pollination resulted in a good set of seeded fruit. If only one leader of a previously caged tree was exposed to cross pollination, it alone produced fruit. The following year, however, when the entire tree was again caged to prevent cross pollination, a substantial set of seedless fruit occurred on all leaders.

Open Access

Abstract

Considerable work has been done on the effects of gibberellins on parthenocarpic set and growth of apple fruits. Bukovac (1) has reviewed the literature in this field and has presented further evidence that seedless fruits induced to set by gibberellins A3 and A4 (GA3 and GA4) are distinctly more elongate than normal seeded fruits. More recently Dennis and Edgerton (2) found that GA made seeded fruits of one variety of apple more elongate than controls, although shape was not altered on several other varieties. Westwood and Blaney (6) reported several factors other than applied GA that also affected apple shape. Among these were crop density (i.e. leaf: fruit ratio), varietal strain, cluster position, and rootstock. To further study the effect of GA on fruit shape without confounding it with seedlessness, a test was set up using seeded fruits in which crop density and rootstock were held constant.

Open Access

Abstract

Disbudded ‘Old Home’ × ‘Farmingdale’ (OH × F) pear (Pyrus communis L.) cuttings rooted 96% before sufficient chilling to break rest and 84% after chilling. Rooting mass (as rated on a scale of 0 to 3) for disbudded cuttings was also less for chilled (1.22) than for nonchilled (1.94) cuttings. Disbudding of chilled cuttings reduced rooting significantly. Intemodal wounding failed to alter % rooting but reduced rooting masses for both nonchilled and chilled cuttings, relative to non-wounded controls. The rooting mass of nodally wounded chilled cuttings was suppressed even further.

Open Access

Abstract

A method for estimating sweet cherry yields was devised based on the calculation of a yield index value which incorporates estimates of the bearing surface of the tree and density of fruits on limb units. The relationship between yield index and actual yield was determined by regression analysis. The linear regression of yield index (Y) on actual yield (X) accounted for 84.6% of the variation.

Open Access

Abstract

The occurrence of solution pockets in brined sweet cherries has increased during the past 15 years. Affected fruits exhibit translucent pockets beneath the epidermis, filled with ruptured cell contents and brine solution. Pockets may occur anywhere in the fruit but are commonly at the suture. Affected fruits sometimes are not firm enough to pass through a pitting machine without being torn, increasing cullage and lowering grade. Sweet cherries are brined in a solution of sulfur dioxide and lime rather than the usual salt-brine method used on other crops (4).

Open Access