Search Results
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
Abstract
Paclobutrazol (ICI PP333), an inhibitor of gibberellin biosynthesis, suppressed early season number of berries but did not affect seasonal yield of field grown strawberry plants. Plant growth was greatly suppressed at all application rates. Petioles, peduncles, and pedicels were shortened with leaves and fruit tightly appressed to the crown. Green leaf color was intensified in all paclobutrazol treatments, but fruit color was not appreciably influenced. Runner suppression was obtained in mid-July field applications, but runners were not inhibited by August application. In the greenhouse, PP333 applied directly to the soil of potted plants was more effective than foliar applications in suppressing crown, leaf, and root growth. The degree of suppression generally was related to increasing the concentration of the chemical.
Abstract
Application of 50 ppm gibberellin (GA3) at full bloom + 2 weeks in 197981 on ‘Montmorency’ cherry trees planted in 1978 reduced flowering the year after application. Treated trees grew larger, presumably due to reduced early fruiting. Projected cumulative grower return during the period 5 years after planting was increased because of GA3 application the first 3 years.
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.
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.
Abstract
The yield-plant density relationships of 5 bush snap bean cultivars and the effect of rate of N application on the yield-density relationship of a single cultivar were studied in 2 separate experiments. Responses were described by the equation W-θ = α + βρ where W is the pod weight per plant, ρ is the plant population density, and θ, α and β are constants. The θ, α and β values were tested for significant differences among the cultivars and levels of N. In experiment 1, θ = 0.836 was acceptable for all 5 cultivars and in experiment 2, θ = 0.897 was acceptable for the 3 rates of N. Values of θ were similar to those found for bush snap beans by other researchers. Significant differences existed among both α and β values of the cultivars. In the N experiment, α was constant but values of β differed significantly and were inversely related to the level of N. Optimum plant density was dependent on the cultivar and increased with the level of N.
Abstract
Rooted cuttings of blueberries (Vaccinium corymbosum L.) were grown in nutrient solutions containing different levels and combinations of NH4-N and NO3-N. Disappearance rate of the two forms from the nutrient solutions as determined by periodic analysis indicated that the plants absorbed the NH4-N more rapidly than NO3-N. Although both forms produced healthy plants, the plants receiving NH4-N were twice the size and dry matter yield of the NO3 plants after 15 weeks. Shoot N concentrations ranged from 0.99% to 1.29% for the N forms except where the blueberry plants had depleted the solutions of NH4-N before termination of the experiment. The N forms had a significant affect on the concentration of other plant nutrients, notably very low concentrations of Ca and Mg in roots with NH4-N and very high concentrations of Mn and Fe in roots with NO3-N plants. Expected levels of Mn and Fe and light brown roots were found with NH4-N plants.
Abstract
Overtree misting for bloom delay reduced fruit set of ‘Golden Delicious’ apple (Malus domestica Borkh.) flowers hand-pollinated with ‘Jonathan’ or ‘Golden Delicious’ pollen in 1978, or open-pollinated or hand cross-pollinated with ‘Jonathan’ pollen in 1979. Misting did not affect fruit set of flowers that were open-pollinated in 1978 or self-pollinated in 1979. The number of seeds per fruit was not reduced. Soil Ca, Mg, pH and base saturation of Ca and Mg were increased, and flower and spur leaves contained lower concentrations of N, P, K, B, Mn, Fe, Zn, and Cu at either full bloom or petal fall as a result of misting. Foliar sprays of B increased B concentrations but did not influence fruit set on either misted or nonmisted trees.