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  • Author or Editor: E. L. Denisen x
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Abstract

An experimental model strawberry harvester with a series of counter-rotating coneshaped vinyl tips for fruit pickup and removal showed potential for rapid harvesting with reduced injury. Flexible auger-like tips on steel shafts were fabricated by molding and heat curing liquid vinyl around the shafts. Tips were molded in pairs with oppositely twisted ribs to provide upward and backward lift to the fruit. Fruit detachment was achieved with a pinching and snapping action of the screw-like ribbed tips counter-rotating in an upward pattern. A soft nylon bristle brush mounted above the picker tips was found unsatisfactory for pushing detached fruit backward onto a transport belt

Open Access

Abstract

A mechanized system for harvesting strawberries with minimal damage to fruit is proposed. Cultural requirements involve placing plastic or fiber mesh netting over the beds before growth of leaves and inflorescences begins, permitting leaves and fruit to develop above the netting. The prototype machine developed for the system mows off leaves, raises the netting, cuts off pedicels of fruit supported on the netting and delivers the fruit to a conveyor and bulk box before rolling up the netting for storage. The harvester is supported under and can readily be adapted to most conventional garden tracter designs. Observations on a small sample of fruit harvested by the machine suggest the possibility of a sizable reduction in amount of injury to fruit compared with earlier designs.

Open Access

Abstract

Morphological differences exist in pre- and postdormant inflorescence and fruit development of concentrated ripening selections Iowa 23-6214 and 26-6215 when compared with nonconcentrated ripening strawberry cultivars ‘Midway’ and ‘Cyclone’. Inflorescences sectioned before dormancy, however, revealed no characteristics considered indicative of concentrated ripening. Stylar development in secondary and tertiary flowers of greenhouse grown, concentrated ripening selections was retarded in the early post-dormant period. In single harvests in the field and greenhouse, these selections had higher percentages of ripe and partially ripe secondary and tertiary fruit than ‘Midway’ and ‘Cyclone’. A high abortion rate and/or arrested development in late-blooming flowers was characteristic of concentrated ripening selections. Pedicel length and inflorescence branching habit were not correlated with developmental or ripening rates.

Open Access

Abstract

Experimental techniques are described for concentric circular test patterns with intentional exposure to a 2,4-D source at the center. With the intensity of exposure as a function of distance from the center, various degrees and symptoms of expression of 2,4-D damage were obtained for a wide variety of horticultural plants. Observations were made on overwintering damage, carry-over effects on potted specimens returned to the greenhouse, seed carry-over effects (none), and effects on virus-infected plants.

Open Access

Abstract

Crops were grown in field plots under plastic-covered greenhouses for 3 years under ambient, charcoal-filtered, and charcoal-filtered with 2,4-D added atmospheres. No differences in market quality were found with green beans and raspberries. Deformed fruit in strawberries, uneven berry ripening in grapes, and blotchy ripening and deformed fruit in tomatoes occurred in “2,4-D added” treatment but not in “charcoal-filtered” treatment, while “ambient” was generally intermediate. The amount of 2,4–D in the atmosphere also influenced yields of grapes and strawberries.

Open Access

Abstract

Chromosomal behaviro during diakinesis and metaphase I was studied in 4 octoploid cultivated strawberry progenies and their parental clones (Fragaria × ananassa Duch.). In all genotypes studied, most of the chromosomes were paired as bivalents. Loose bivalents and/or univalents were observed in some pollen mother cells (PMCs) during diakinesis. Two nucleoli were observed in a few PMCs. Twenty-eight bivalents in diakinesis indicated that the progenies and their parents were octoploid, with 2n = 8χ = 56 chromosomes. Some bivalents associated together were observed for all genotypes; however, the configurations of these associations were only end-to-end, end-to-side, or side-to-side, but not ring or chain configurations. The appearance of these configurations, therefore, indicated that they are probably formed by the aggregation of bivalents and are pseudomultivalents, not genuine multivalents.

Open Access