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Abstract

Aqueous ammonium fluoride (NH4F) sprays on ‘Early Improved Elberta’ peaches (Prunus persica (L.) Batsch) resulted in increased O2 consumption of suture tissue and inconsistent changes in O2 consumption of dorsal tissue as the spray concentration was increased. Flesh firmness on the suture side of treated fruit was less than non-sprayed fruit and decreased as either the NH4F spray concentration or number of sprays increased. The effect of the spray on the dorsal side differed from year to year. Levels of fluoride (F) in the fruit tissue were associated with F concentration and number of F sprays applied only within the same year.

Open Access
Authors: and

Abstract

Factorial combinations of 50 and 100 ppm (2-chloroethyl)phosphonic acid (ethephon) and 1000, 2000 and 4000 ppm succinic acid-2,2-dimethyl hydrazide (daminozide) sprayed on young ‘Napoleon’ sweet cherry trees (Prunus avium L.) for 3 consecutive years showed no antagonistic or synergistic effects on either growth or flowering, Daminozide, at 2000 and 4000 ppm, reduced terminal growth but had no effect on flower initiation or flower density. Ethephon significantly reduced growth only the first year applied and appeared to increase flower initiation on wood previously untreated. Daminozide at 4000 ppm reduced fruit set on all combinations of year-wood and years but when applied at a concentration of 2000 ppm reduced set only 2 out of 5 possible year-wood, year combinations. Ethephon reduced set 3 out of the 5 year-wood combinations but the average response was not significant.

Open Access
Authors: and

Abstract

Pollen tube growth of ‘Tilton’ apricot (Prunus armeniaca L.) was reduced by exposure to SO2. An empirical model, based on modified spline functions, described the decrease in pollen tube growth due to increasing dose (hours exposure × concentration of SO2) expressed on logarithmic scale. The response curve, based on this analysis, was “S-shaped” with a decrease from 98.5% pollen tube growth (PTG) for unexposed pollen tubes, based on percent of the style that the longest pollen tubes had grown to 91.6% at ℓ n dose 4.0. These was then a very sharp decrease in PTG to about 45% at ℓn dose 5.7, then a gradual curvilinear response to <1% PTG at the maximum ℓn dose of 7.7. There data strongly indicate that there is a threshold response to SO2 with respect to PTG. Response of ‘Van’ PTG in ‘Napoleon’ sweet cherry (P.avium L.) styles was similar to apricot, but not as definitive because of greater within year variation and differences between years. In one year (1979), a spline function model of PTG in cherry suggested a threshold value at about ℓn dose of 2.1, while in another year (1978), there was a nearly linear decrease in PTG with increasing ℓn dose.

Open Access
Authors: and

Abstract

Six annual surveys indicated that % soluble solids and fruit weight were the only consistent predictor variables for fruit surface pitting in ‘Lambert’ sweet cherry (Prunus avium L.). Both were inversely related to pitting. Similar associations were found ‘Bing’ when fruit were handled excessively. In spite of tree-to-tree variation, the degree of pitting was relatively uniform in a given orchard in a given year. High and low percentage pitting orchards appeared to be fairly consistent over the 6 years, but intermediate ones were extremely variable. Postharvest factors (time delay prior to storage, hydrocooling temperature, or storage temperature) had little or no effect on surface pitting. Foliar sprays of gibberellic acid (GA3 or GA4+7) applied 3 weeks prior to harvest increased fruit firmness and reduced color. Gibberellic acid sprays reduced pitting when the disorder was present (1974 and 1976) or where the fruit were bruised. Mechanical bruising of cherries increased the incidence of pitting. Surface pitting of sweet cherries may be caused by bruising but fruit characteristics (% soluble solids, size and firmness) can indicate whether or not pitting may occur on bruised fruit.

Open Access

Abstract

There was no reduction of surface pitting of sweet cherry (Prunus avium L.) or bruising in 7 trials over a 4-year period as a result of applications of CaCl2 from 950, 1400, or 3800 mg Ca/liter in single or multiple applications from 1 to 6 weeks before harvest. Cherry fruit firmness was increased and fruit size was decreased by increasing the amount of Ca applied in 3 out of 7 trials. The time of application, from shuck stage to 1 week before harvest, was not critical.

Open Access

Abstract

Multiple applications (1-3) of 10 and 50 ppm GA3 to ‘Bing’ and ‘Lambert’ (Prunus avium L.) sweet cherries increased fruit firmness and weight, and delayed harvest. Firmness was positively related to dose of GA3 (number of applications × concentration), soluble solids (SS), and In leaf/fruit ratio. GA3 interacted with SS so that the effect of GA3 dose on firmness was increased at higher SS levels. Fruit coloring was delayed by GA3. Chemical name used: gibberellic acid (GA3).

Open Access

Abstract

The muskmelon (Cucumis melo L.) breeding population Wisconsin (Wl) 998 was developed jointly by the U.S. Department of Agriculture, the University of Wisconsin, and Michigan State University to provide breeders and seedsmen with a source from which gynoecious inbreds can be developed for use in the production of hybrid cultivars. In addition to a high incidence of gynoecious plants, WI 998 provides other useful plant and fruit characteristics.

Open Access

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.

Open Access

Abstract

Foliar uptake of fluoride (F) resulting from hydrogen fluoride (HF) fumigations was linear with dose (concentration F in μg/m3 × duration of exposure in hours) at F concentrations lower than 17.5 μg/m3. Above this level, duration of exposure was the only important factor and uptake was non-linear with time. Higher leaf N levels resulted in greater F uptake. Production of CO2 was increased more by high F concentration for short periods than by low concentration for longer periods where leaf N was optimal or supraoptimal. Amino nitrogen (AN) levels increased more at low F concentration for longer periods than high concentration for shorter periods. The response patterns were similar at optimal and supraoptimal leaf N. Protein nitrogen (PN) decreased with increasing In HF dose at optimal and very low leaf N levels. Changes in PN and AN were significantly correlated in leaf tissue with optimal, but not in tissues with deficient or supraoptimal N.

Open Access

Abstract

Increased flouride (F) fumigation levels resulted in decrease in percent ‘Royal Ann’ pollen germination and pollen tube growth. As dose (hour x concentration in μgF/m3) increased, ‘Van’ pollen tube growth in vivo decreased. A linear relationship between increased dose and flouride residue in the flowers was shown.

Open Access