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  • Author or Editor: E. T. Sims Jr. x
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Abstract

Succinic acid -2,2-dimethylhydrazide (Alar) was applied at various postbloom spray intervals and concentrations to ‘Ranger’ peaches from 1965 to 1969 and to ‘Cardinal’ and ‘Blake’ peaces in 1969. Fruit of each cultivar was harvested at a uniform firmness to determine the influence of Alar on quality attributes not directly associated with changes in fruit maturity. Color attributes, particularly flesh color, were enhanced by Alar over a wide range of spray dates to a much greater degree than other quality attributes at a given maturity. The results indicated a stimulation of anthocyanin biosynthesis by Alar without a corresponding effect on other attributes normally considered to be indicators of physiological maturity.

Open Access

Abstract

Ethephon ((2-chloroethyl)phosphonic acid) at 50 to 200 ppm hastened the maturation of peach fruit of the cvs. ‘Cardinal’, ‘Ranger’, ‘Redhaven’, ‘Blake’, and ‘Richhaven’ over a range of application times. Stimulation of maturation was not attributed solely to reduced fruit load, since an influence on maturation was found even when ethephon-treated trees bore no fewer fruits than hand-thinned controls. When treated and nontreated ‘Richhaven’ fruit were harvested at a comparable maturity based on firmness, ground and flesh color a and a/b values were increased by ethephon, as were soluble solids. No differences were found in b values for ground or flesh color or in total titratable acidity. Fruit treated with ethephon exhibited more uniformity in firmness and color than untreated fruit at shipping maturity, a characteristic which has potential value in facilitating once-over mechanical harvesting operations.

Open Access

Abstract

With more emphasis upon increasing the proportion of high quality diseasefree peaches available to consumers, new chemicals and chemical combinations are constantly being sought which will retain the high quality of the peach throughout its maximum storage life.

Open Access

Abstract

Peach samples were taken by removing all fruit from preselected limbs at 1 date for each treatment just prior to the 1st commercial harvest, Maturity was evaluated by the indices of firmness, size, undercolor, and overcolor. The estimates of variance among fruit for the maturity attributes were used to objectively measure fruit uniformity. These estimates of variance were then subjected to the analysis of variance to test for differences of fruit uniformity among growth regulator treatments.

Open Access

Abstract

Cuts were generally more prevalent on mechanically harvested peaches than on those hand harvested, although they were usually within acceptable limits. Bruise development during storage was variable and often not significantly higher on machine harvested fruit than on those hand harvested. Fruit position within bulk bins appeared to influence subsequent bruise development. A prototype portable dumper-sorter did not significantly increase fruit injuries. Providing fruit were of comparable maturity, injuries to postbloom regulator-treated fruit were comparable to those untreated. The development of rots during storage was the greatest source of unmarketable fruit and is regarded as the most serious problem related to the mechanical harvesting of peaches for fresh market.

Open Access

Abstract

SADH, applied as postbloom sprays to 9 peach cultivars in a series of experiments from 1964 to 1969, accelerated maturation and reduced the number of pickings required for most cultivars. Although SADH did not affect the number of fruits per tree, yield, or fruit size, it advanced the maturity date of ‘Ranger’ as much as a week; that of ‘Blake’ 4 days. ‘Cardinal’, an early cultivar, was not noticeably affected by SADH applied at different stages of development. SADH caused fruit to abscise more readily from the stem and left less fruit remaining on the trees when harvested mechanically. SADH had no detrimental influence on ‘Redglobe’ peaches stored at 50°F for 3 weeks. These effects support the feasibility of using SADH as an aid in mechanically harvesting freestone peaches intended for fresh market.

Open Access

Abstract

The ethylene-releasing agent CGA-15281 (2-chlorethyl-methylbis (phenylmethoxy) silane) effectively thinned fruit of several cultivars of peach [Prunus persica (L.) Batsch.]. Thinning varied with cultivar, stage of development, concentration, and application technique. Negligible (<1%) leaf injury and drop occurred even at the higher (720 ppm) concentration over the 8-year period.

Open Access

Abstract

CGA-15281 applied in the fall delayed bloom in peach (Prunus persica L. Batsch) by 4–9 days without damage to the trees. The length of the delay was cultivar and concentration dependent. Fall ethephon applications (500 ppm) damaged trees severely, but delayed bloom 10–18 days, whereas 125 or 250 ppm ethephon caused little tree damage and delayed bloom 3–5 days. Bloom delay from application of ethylene-generating compounds resulted from both prolonging rest and slow bud development once rest was complete. Daminozide applied in January caused bloom delay in 1983 but not in 1984. Silver nitrate had little effect on bloom delay or blossom density at any time of application. Dimethipin and merphos applications in late summer caused defoliation and reduced blossom density, but did not affect date of bloom. Thidiazuron did not induce defoliation or delay in bloom, but greatly reduced blossom density. Chemical names used: (2-chloroethyl)methylbis(phenylmethoxy)silane (CGA-15281); (2-chloroethyl) phosphonic acid (ethephon); butanedioic acid mono (2,2-dimethylhydrazide (daminozide); 2,3-dihydro-5,6-dimethyl-1,4-dithiin 1,1,4,4-tetraoxide (dimethipin); N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (thidiazuron); Tributyl phosphorotrithioite (merphos).

Open Access