Abstract
Temperatures for several post-bloom periods were correlated with days from full bloom to ‘Bartlett’ pear maturity. Date of maturity based on pressure test showed a high negative correlation (r = -.88) with mean temp above 40°F for the 36 days following bloom. The peak thermal period occurred 26-30 days after bloom, with the highest correlation on the 28th day. Days to maturity had a higher correlation with accumulated mean temp above 45°F than with degree hr above 45°F for the same periods. Base temp of 38.5°F to 50°F gave r values greater than -.85 in this prediction method. Mean temp between 41.5°F and 68.5°F on the 28th day had a linear correlation r of -.71 with days to maturity. Equal temp increments were more effective at min levels than at max levels for accelerating maturity. The post-bloom thermal period affecting maturation coincides with the stage of cell division and most effective time for application of chemical thinning sprays.
effects of GA on apple fruit present during treatment (i.e., current season fruit). In sweet cherry ( Prunus avium ), GA 3 can delay fruit maturation ( Proebsting, 1972 ). The Pacific northwestern U.S. industry widely uses 10 to 20 mg·L −1 to increase
Abstract
The changes of amino acid compositions of peach proteins from the Alcohol Insoluble Solids of peaches (Prunus persica (L.) Batsch cvs. Redhaven and Redskin at 5 stages of maturation were investigated by gas-liquid chromatography. Most amino acids in the peach proteins showed gradual increases, as percent of total amino acid, throughout the maturation periods except aspartic acid in both peach cultivars and arginine in the ‘Redskin’ peaches. The amino acid profiles of the ripe fruits from both cultivars were nearly identical.
Embryogenic callus cultures of three genetically diverse cultivars of rose (Rosa hybrida L.), the floribunda `Trumpeter', the multiflora `Dr. Huey', and the hybrid tea `Tineké', were used to study the effect of various carbohydrates and osmotically active compounds on somatic embryo maturation and conversion. Cotyledonary-stage embryos were produced by dispersing callus in liquid medium followed by filtration to isolate globular-stage embryos. Quantitative experiments were conducted to determine maturation and conversion of the three rose cultivars in response to medium with sucrose, glucose, fructose, or maltose as the primary carbon source and also in response to various concentrations of either myo-inositol, polyethylene glycol, or mannitol in combination with 3% sucrose. Conversion of 27% was achieved for `Trumpeter' embryos following their maturation on 3% fructose. `Dr. Huey' embryos required maturation on medium containing 3% sucrose supplemented with either 2.5% or 5% mannitol for 36% and 61% conversion, respectively. Maturation of `Tineké' embryos on either 3% sucrose, 3% glucose, or 3% fructose resulted in a maximum 12% conversion.
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.
Abstract
To study the effect of maturity on ethylene induced ripening, ‘Anjou’ pears were picked at 4 stages of development representing 57%, 71%, 86% and 100% of total growth period. Beginning of a distinct maturation stage in ‘Anjou’ pears was not evident from changes in wt, firmness, soluble pectin, soluble solids, protein N or malic acid. Respiration, ethylene production and softening were differentially affected by ethylene treatment, according to concn applied (0.05-2.0 ppm) and time required for stimulation. Threshold concn affecting these reactions decreased progressively during maturation. Ripening as measured by softening was not dependent on development of the respiratory climacteric. Maturation of the ‘Anjou’ pear appears to involve a reorganization of metabolism preparatory for ripening.
Malonic acid, 3(3,4 dichlorophenyl)–1, 1 dimethyurea, Gibberellic acid, and 2,4,5-trichlorophenoxypropionic acid were applied to muscadine grapes (Vitis rotundifolia Michx) during maturation and ripening. Total soluble solids, sugars, anthocyanin contents, and other fruit qualities were affected. 3(3,4 dichlorophenyl)–1, 1 dimethylurea (diuron) seemed to induce better and different effects than the other chemicals.
Morphological and physiological changes during maturation and ripening of eight Asian pear cultivars grown in the southeastern United States were evaluated. Fruit size increased throughout maturation. Flesh firmness decreased as fruit matured and averaged ≈30 to 35 N at harvest maturity. The average TSS in mature fruit ranged from 10% to 13%, with `Shinko' having the lowest and `Shinsui' having the highest. TSS increased during 4 weeks of storage at 1C, but the increase was greater in immature fruit than in mature fruit. Respiration rate declined as fruit matured. Ethylene production was low in `Hosui', `Kosui', `Nijisseiki', `Shinseiki', `Chojuro', and `Shinko' fruit. Mature `Ichiban' and `Shinsui' fruit produced high amounts of ethylene. `Kosui', `Shinsui', `Chojuro', and `Ichiban' fruit showed a climacteric rise in respiration and ethylene production at 20C, while `Hosui', `Nijisseiki', `Shinseiki', and `Shinko' behaved as nonclimacteric fruit. Ethylene production by 1C-stored `Kosui', `Shinsui', `Chojuro', and `Ichiban' fruit was increased on removal to 20C. Glucose and fructose were low during early maturation but sharply increased ≈80 to 85 days after full bloom (DAFB). Sucrose was low in immature fruit but accumulated rapidly late in maturation ≈100 to 107 DAFB. In mature `Hosui', `Kosui', `Nijisseiki', `Shinsui', `Shinko', and `Ichiban' fruit, fructose was the predominant sugar, while in `Shinseiki' and `Chojuro' fruit, sucrose was the predominant sugar.
Abstract
Ethephon applications at 250 to 1500 ppm rates during final swell of ‘Babygold-9’, a clingstone peach, accelerated maturation as measured by firmness and skin and flesh color changes and reduced titratable acidity. High rates were phytotoxic and detrimental to fruit quality. Increased immature fruit abscission appears to limit the practical use of ethephon at this growth stage in peach.
Abstract
Single and split applications of (2-chloroethyl)phosphonic acid (ethephon) at different concentrations to ‘Concord’ grapes(Vitis labrusca L.)did not influence maturation. When ethephon was applied 8 days prior to harvest, abscission was enhanced and postharvest alcohol accumulation was reduced when fruit was shaken from the vine and held at 30°C for up to 24 hours.