scholarly journals Controlling Growth of Bearing Apple Trees with Ethephon

HortScience ◽  
1993 ◽  
Vol 28 (11) ◽  
pp. 1103-1105 ◽  
Author(s):  
Ross E. Byers
Keyword(s):  
Tree Growth ◽  
Phosphonic Acid ◽  
Fruit Set ◽  
Diameter Ratio ◽  
Soluble Solids ◽  
Full Bloom ◽  
Apple Trees ◽  
Fruit Abscission ◽  
Solids Concentration ◽  
Soluble Solids Concentration

Ethephon applied 12 to 26 days after full bloom at 1000 to 1500 mg·liter-1 not only substantially inhibited apple (Malus domestia Borkh., spur `Delicious' strains) tree growth but also caused fruit abscission. Gibberellin plus ethephon did not prevent fruit abscission when ethephon was used at these rates. Several low weekly doses of ethephon controlled tree growth without causing fruit abscission. Ethephon increased fruit soluble solids concentration and substantially reduced fruit starch in the application year. Ethephon greatly increased flowering and fruit set the following season. Fruit length: diameter ratio was not altered by the previous seasons' low weekly doses of ethephon. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).

scholarly journals Apple Thinning by Photosynthetic Inhibition

1990 ◽  
Vol 115 (1) ◽  
pp. 14-19 ◽  
Author(s):  
R.E. Byers ◽  
J.A. Barden ◽  
R.F. Polomski ◽  
R.W. Young ◽  
D.H. Carbaugh
Keyword(s):  
Tree Growth ◽  
Shoot Growth ◽  
Fruit Set ◽  
Full Bloom ◽  
Apple Trees ◽  
Fruit Abscission ◽  
Hand Pump ◽  
Photosynthetic Inhibition ◽  
Fruit Thinning ◽  
Leaf Yellowing

Shading (92%) of `Redchief Delicious' apple (Malus domestics Borkh.) trees for 10-day periods from 10 to 20, 15 to 25, 20 to 30, and 25 to 35 days after full bloom (DAFB) caused greater fruit abscission than shading from 5 to 15, 30 to 40, 35 to 45, or 47 to 57 DAFB. Fruit 8 to 33 mm in diameter (10 to 30 DAFB) were very sensitive to 10 days of shade, even though fruit sizes of 6 to 12 mm are considered the most sensitive to chemical thinners. In a second test, shading for 3 days caused fruit thinning; 5 days of shade in the periods 18 to 23, 23 to 28, and 28 to 33 DAFB caused greater thinning than 11 to 16 or 33 to 38 DAFB. Shading reduced photosynthesis (Pn) to about one-third that of noncovered trees. Terbacil (50 mg·liter-1) + X-77 surfactant (1250 mg·liter-1) applied with a hand-pump sprayer 5, 10, or 15 DAFB greatly reduced fruit set and caused some leaf yellowing, particularly in the earliest treatments. Terbacil reduced Pn by more than 90% at 72 hours after application. Shoot growth of trees defruited by shade or terbacil was equivalent to defruited or deblossomed trees; ethephon (1500 mg·liter-1) inhibited tree growth and defruited trees. No terbacil residues were dectected in fruit at harvest from applications made 5, 15, 20, 25, or 30 DAFB. Eleven of 12 photosynthesis-inhibiting herbicides were also found to thin `Redchief Delicious' apple trees. Shading caused more thinning than terbacil at the later applications, which may reflect poorer absorption and/or lesser photosynthetic inhibition than when terbacil was applied to older leaves.

scholarly journals Ethylene Evolution from Detached Apple Spurs in Response to Chemical Thinners

HortScience ◽  
2002 ◽  
Vol 37 (4) ◽  
pp. 662-665 ◽  
Author(s):  
Steven J. McArtney
Keyword(s):  
Phosphonic Acid ◽  
Fruit Set ◽  
Average Diameter ◽  
Naphthaleneacetic Acid ◽  
Similar Amount ◽  
Full Bloom ◽  
Ethylene Evolution ◽  
Apple Trees ◽  
Fruit Abscission ◽  
Initial Drop

Ethylene evolution from detached fruiting apple spurs was measured after application of various bloom and post-bloom thinning agents. Ethylene evolution from fresh detached spurs of `Splendor' apple trees increased one day after application of a bloom thinning spray of ethephon or NAA, and remained higher than rates of ethylene evolution by detached spurs from unsprayed control trees for 6 (NAA) or 10 (ethephon) days. Both ethylene evolution and fruit abscission during the initial drop period were higher on trees treated with ethephon compared to NAA, however final fruit set was similar for these two treatments. Ethylene evolution was significantly higher following NAA application onto `Fuji' trees compared with NAAm, but final fruit set was reduced by a similar amount (≈20%) for both of these materials. Application of BA to `Pacific Rose™' apple trees when the average diameter of spur fruit was either 4 mm (6 days after full bloom) or 7 mm (12 days after full bloom) resulted in a significant increase in the rate of ethylene evolution and also reduced final fruit set. When application of BA was delayed until the average diameter of spur fruit was 14 mm (24 days after full bloom) neither the rate of ethylene evolution or final fruit set was affected. Although an increase in the rate of ethylene evolution was a prerequisite for thinning in the present experiments, the magnitude of this increase was not related to the final thinning efficacy. Chemical names used: benzyladenine (BA); 2-chloroethyl phosphonic acid (ethephon); naphthaleneacetic acid (NAA); naphthalene acetamide (NAAm).

scholarly journals Thidiazuron Effects on Fruit Set, Fruit Quality, and Return Bloom of Apples

HortScience ◽  
1995 ◽  
Vol 30 (6) ◽  
pp. 1238-1240 ◽  
Author(s):  
Duane W. Greene
Keyword(s):  
Fruit Set ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Refrigerated Storage ◽  
Full Bloom ◽  
Crop Load ◽  
Flesh Firmness ◽  
Solids Concentration ◽  
Return Bloom ◽  
Soluble Solids Concentration

Thidiazuron (THI) applied at full bloom (FB) at 10 or 50 mg·liter–1 thinned `McIntosh' apples (Malus domestica Borkh.) and reduced return bloom. The same concentrations applied at 22 days after FB (DAFB) thinned excessively and inhibited return bloom even more. THI at 1, 5, or 15 mg·liter–1 did not thin `Empire' at FB, but when applied 18 DAFB, these concentrations achieved thinning, with 5 mg·liter–1 reducing crop load to near ideal commercial levels. Return bloom of `Empire' was not influenced by THI at these concentrations. THI increased fruit weight, flesh firmness, soluble solids concentration, and fruit asymmetry on `McIntosh' and `Empire' and reduced red pigmentation and seed count on `McIntosh', especially when applied 22 DAFB. A FB application of CPPU and THI, each at 5 or 10 mg·liter–1, on `Delicious' increased the fruit length: diameter (L: D) ratio and flesh firmness (at harvest and following 26 weeks of refrigerated storage and reduced return bloom). CPPU at either 5 or 10 mg·liter–1 increased the fruit L: D ratio more than 25 mg Promalin/liter. Chemical names used: N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (thidiazuron); N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU); N-(phenylmethyl)-1H-purine-6-amine plus gibberellins A4+7 (Promalin).

scholarly journals AN EVALUATION OF BENZYLADENINE AS A POSSIBLE CHEMICAL THINNER OF “EMPIRE”

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 592a-592
Author(s):  
V.E. Emongor ◽  
D.P. Murr ◽  
J.T.A Proctor ◽  
E.C. Lougheed
Keyword(s):  
Field Trials ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Research Station ◽  
Full Bloom ◽  
Ethylene Concentration ◽  
Solids Concentration ◽  
Cambridge Research ◽  
Thinning Effect ◽  
Soluble Solids Concentration

Field trials at Cambridge Research Station, Ontario, Canada, studied the thinning effect of benzyladenine (BA) on eighteen-year-old “Empire” apple trees. At 16 days after full bloom (fruit diameter 12.87 mm) whole trees were hand sprayed to drip point with BA (0, 100, or 200 mg.1-1). Untreated control trees were compared with treated and hand thinned trees. BA significantly reduced crop load on “Empire”. The thinning response to BA was linear, with recommended thinning occurring at 200 mg.1-1. At harvest, fruit weight, size (diameter and length), flesh firmness and soluble solids concentration, chlorophyll and anthocyanin contents, and seed number were increased by BA treatments. BA had no effect on fruit L:D ratio, internal ethylene concentration, maturity, and the onset of the respiratory climacteric, but significantly reduced respiration at harvest. BA also reduced ethylene production and ACC content at harvest, though the reduction was not significant. Although firmness of BA-treated fruit was significantly higher at harvest, upon storage for 1 month at 0-0.5°C and 90-95% RH the firmness advantage was lost BA shows potential as a thinner of “Empire” apple and has advantage of increasing fruit weight and size, since “Empire” is a relatively small apple compared to other commercial cultivars.

scholarly journals Diploid Watermelon Pollenizer Cultivars Differ with Respect to Triploid Watermelon Yield

2007 ◽  
Vol 17 (4) ◽  
pp. 518-522 ◽  
Author(s):  
Joshua H. Freeman ◽  
G.A. Miller ◽  
S.M. Olson ◽  
W.M. Stall
Keyword(s):  
Experimental Design ◽  
Fruit Set ◽  
Citrullus Lanatus ◽  
Pollen Flow ◽  
Soluble Solids ◽  
Average Weight ◽  
Solids Concentration ◽  
Triploid Watermelon ◽  
Experimental Plots ◽  
Soluble Solids Concentration

As triploid watermelons (Citrullus lanatus) increase in popularity, production has shifted away from seeded watermelons. To achieve successful fruit set in triploid watermelons, a diploid watermelon cultivar must be planted as a pollen source. Three diploid cultivars in 2005 and seven diploid cultivars in 2006 were evaluated at one and three locations, respectively, to determine their effectiveness as pollenizers. Each cultivar was planted within plots of the triploid watermelons ‘Tri-X 313’ (2005) and ‘Supercrisp’ (2006) with buffers on all sides of the plots to contain pollen flow within individual plots. Performance of pollenizers was based on triploid watermelon yield, soluble solids concentration, and incidence of hollowheart. In 2005, there were no significant differences in total weight, fruit per acre, average weight, or soluble solids concentration among pollenizers. In 2006, significant differences in yield were observed, and plots with ‘Sidekick’ as a pollenizer yielded the highest but were not significantly different from ‘Patron’, ‘SP-1’, ‘Jenny’, or ‘Mickylee’. In 2006, there were no significant differences in fruit per acre, soluble solids concentration, or incidence of hollowheart between pollenizers. The experimental design was successful in isolating pollenizers and there was minimal pollen flow outside of experimental plots as indicated by minimal fruit set in control plots.

scholarly journals EcoLyst Application Timing and Juice Corrected Soluble Solids (Brix) of Processing Oranges and Grapefruit in Florida

2004 ◽  
Vol 14 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Frederick S. Davies ◽  
Glenn R. Zalman ◽  
Ed Stover ◽  
Scott Ciliento
Keyword(s):  
Fruit Set ◽  
Sweet Orange ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Application Timing ◽  
Time Of Application ◽  
Solids Concentration ◽  
Best Response ◽  
Florida Citrus ◽  
Soluble Solids Concentration

EcoLyst, a formulation of N-N-diethyl-2-(4-methylbenzyloxy) ethylamine hydrochloride containing 1 g/floz [4.5 oz/gal (33.8 g·L-1)] a.i., is a plant growth regulator that has been reported to increase soluble solids concentration (SSC) in juice oranges by 0.6% to 1.2%. Our objectives were to determine the effectiveness of EcoLyst application for increasing SSC in Florida oranges (Citrus sinensis) and grapefruit (C. paradisi), and to identify the optimum rate and time of application. Experiments were conducted for three seasons using `Hamlin,' `Pineapple,' and `Valencia' sweet oranges; and for two seasons using `Flame,' `Marsh,' and `Ray Ruby' grapefruit, all in commercial groves. EcoLyst was applied at 6 and 12 floz/acre (0.44 and 0.88 L·ha-1) for oranges and 16 and 32 ppm (mg·L-1) [effectively 9 and 18 floz/acre (0.66 and 1.32 L·ha-1) in most sprays] for grapefruit, and included Silwet L-77 adjuvant at 0.05%. Applications were made at several stages of development from prebloom to initial fruit set. In all cases, SSC was determined as juice corrected SSC, by adjusting refractometer readings based on titratable acidity. In 13 trials with sweet orange only five displayed significant increases in SSC (P ≤ 0.05) resulting from EcoLyst application. Two additional trials produced SSC increases significant at P < 0.10. Even where significant increases in SSC occurred they were typically observed in only one harvest and at one time of application and were always relatively low in magnitude (highest increase over controls was 0.38%). No rate or timing of EcoLyst application was consistently associated with best response, although eight of nine SSC increases observed in orange occurred with applications ranging from prebloom to 25% open flowers. Only one significant increase in SSC was observed in five trials with grapefruit. In these studies, increases in SSC resulting from EcoLyst application were neither sufficiently consistent nor large enough to justify a recommendation for commercial use in Florida citrus.

scholarly journals 242 Fruit Quality Parameters of Various Apple Scion/Rootstock Combinations

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 432F-433
Author(s):  
Usman Siswanto ◽  
Frank B. Matta
Keyword(s):  
Fruit Quality ◽  
Fruit Juice ◽  
Quality Parameters ◽  
Fruit Weight ◽  
Diameter Ratio ◽  
Soluble Solids ◽  
Apple Rootstocks ◽  
Fruit Length ◽  
Solids Concentration ◽  
Soluble Solids Concentration

A study of spur-type apple scion cultivars on semi-dwarf and dwarf apple rootstocks was conducted to evaluate and identify suitable scion/stock combination for Mississippi. Fruit weight varied among scion/stock combinations. `Royal Gala' on MM111 and MM106 and `Ultra Gold' on MM106 yielded the heaviest fruit. `Jon-A-Red' on Mark produced the lightest fruit. Fruit length diameter ratio (L/D) was the highest for `Blushing Golden' on M7A and MM111, and `Ultra Gold' on MM111. The L/D ratio of `Royal Gala' was not affected by rootstock. Scion cultivars on M7A and M26 tended to have more red fruit than on the remaining rootstocks. `Ultra Gold' on M26 and `Braeburn' on Mark and MM111 had the firmest fruit. Overall, trees on M7A and Mark rootstock tended to produce firm fruit. Juice pH was significantly affected by scion-stock combination. In general, `Royal Gala', regardless of rootstock, had the highest juice pH, whereas `Ultra Mac' and `Jon-A-Red' produced the lowest pH. `Blushing Golden' on MM111 and `Royal Gala' on M26 had the highest soluble solids concentration (SSC). Soluble solids concentration of scion cultivars on MM106 did not differ.

scholarly journals BLOOM THINNING OF FUJI, ROYAL GALA, AND BRAEBURN APPLE WITH MONOCARBAMIDE DIHYDROGENSULFATE

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 591f-591 ◽  
Author(s):  
Stephen C. Myers ◽  
Steven McArtney ◽  
Stuart Tustin ◽  
Wendy Cashmore ◽  
Richard Mangin
Keyword(s):  
Fruit Set ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Linear Effect ◽  
Fruit Drop ◽  
Solids Concentration ◽  
Root Stock ◽  
Drying Conditions ◽  
Mature Apple ◽  
Soluble Solids Concentration

Foliar applications of monocarbamide dihydrogensulfate (D-88, Unocal Chemicals Division) at rates of 0, 2.5 ml/1, 3.75 ml/1 or 5.0 ml/1 were made to mature apple trees of “Fuji”, “Royal Gala” or “Braeburn” on MM106 root-stock. Treatments were applied dilute when spurs were at 95% full bloom. D-88 was applied at 5.0 ml/1 to “Fuji” at three different times during the day (0730, 1400 or 1810) with and without surfactant in an attempt to evaluate the effect of different atmospheric and drying conditions. Fruit set (number of fruit per 100 flower clusters) was determined after natural fruit drop. D-88 had no effect on fruit set of “Royal Gala” or “Braeburn”. There was a linear effect between D-88 rate and fruit set on “Fuji”, with the 5.0 ml/1 rate reducing set by 30%. D-88 affected the number of fruit at individual fruiting sites, most significantly the percentage of flower clusters setting 3 fruits decreasing with increasing rate. Timing and surfactant had no effect. Fruit finish, mean fruit weight, seed number and soluble solids concentration were measured at harvest.

scholarly journals Reduced Rates and Multiple Sprays of Paclobutrazol Control Growth and Improve Fruit Quality of `Delicious' Apples

1991 ◽  
Vol 116 (5) ◽  
pp. 807-812 ◽  
Author(s):  
Duane W. Greene
Keyword(s):  
Shoot Growth ◽  
Fruit Set ◽  
Fruit Size ◽  
Soluble Solids ◽  
First Year ◽  
Tight Cluster ◽  
Solids Concentration ◽  
Control Growth ◽  
Soluble Solids Concentration

`Gardiner Delicious'/MM.lO6 apple (Malus domestics Borkh.) trees were initially sprayed in 1985 with paclobutrazol (PB) at 250 mg.liter-1 at tight cluster and again on 10 and 25 June and 29 July. From 1986 through 1988, PB sprays of 85 or 100 mg·liter-1 were applied at either petal fall (PF) + 2 or PF + 4 weeks and one to two additional sprays were applied per year when growth resumed. Promalin was applied to one group of trees that received PB starting at PF + 2 weeks. PB reduced terminal, lateral, and total shoot growth the year of application and in subsequent years. Although average shoot length of lateral and terminal shoots was reduced, the greatest reduction in growth occurred because PB prevented spurs from growing into lateral and terminal shoots. Compared to unsprayed trees, PB reduced pruning time in all 4 years by 23% to 70%. PB increased bloom only the first year after application, but increased fruit set for 2 years due to a carryover effect. Application of PB in 1985 caused a reduction in fruit size, sometimes in soluble solids concentration, length: diameter (L : D) ratio, and pedicel length. Promalin either overcame the reduction in the ratio or increased it in 1986. Reduced rates of PB in subsequent years caused few adverse effects on the fruit. PB increased flesh firmness when applied at PF + 2 weeks but not at PF + 4 weeks. Trees treated with PB produced fruit with higher flesh Ca and less bitter pit, cork spot, and senescent breakdown following regular air storage. Chemical names used: ß -(4 -chlorophenyl)methyl α -(1,1-dimethylethyl) -1H-l,2,4-triazole-1-ethanol (paclobutrazol, PB); gibberellins A4+7 plus N-(phenylmethyl) -1H-purine-6-amine (Promalin).

scholarly journals Fruit Characteristics of `York' Apples during Development and after Storage

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 95-98 ◽  
Author(s):  
Morris Ingle ◽  
Mervyn C. D'Souza ◽  
E.C. Townsend
Keyword(s):  
Acid Concentration ◽  
Malic Acid ◽  
Soluble Solids ◽  
Fruit Characteristics ◽  
Full Bloom ◽  
Ethylene Concentration ◽  
Titratable Acid ◽  
Solids Concentration ◽  
And Storage ◽  
Soluble Solids Concentration

Firmness, soluble solids concentration (SSC), starch index (SI), internal ethylene concentration (IE), and titratable acid concentration (TA) of `York Imperial' apple (Malus ×domestica Borkh.) fruit changed linearly with harvest date between 152 and 173 days after full bloom (DAFB). Firmness was positively correlated with TA, SSC was correlated with SI, and SI was negatively correlated with TA. After 150 days of refrigerated-air (RA) storage, there was no relationship between DAFB at harvest and firmness or superficial scald, but the malic acid concentration declined linearly and storage decay increased linearly with DAFB. Firmness had declined to a plateau and was not correlated with any variable at harvest. Malic acid concentration after CA storage was correlated with DAFB, firmness, SSC, and SI; scald was correlated with firmness and SI; and decay was correlated with DAFB, firmness, SSC, and SI. During 150 days of controlled-atmosphere (CA) storage (2.5% O2, 1.0% CO2), firmness and TA decreased as a linear function of DAFB. Percentage of fruit with scald and scald rating changed quadratically with DAFB, and decay increased linearly with DAFB. After 150 days of CA, firmness was correlated with DAFB, SI, and IE at harvest; TA was correlated with DAFB, firmness, SSC, TA, and SI; scald was correlated with firmness and SI; and decay was correlated with DAFB, SSC, and scald index at harvest. During 250 days of CA storage, firmness, TA, scald, and decay changed linearly with DAFB in only 1 or 2 years out of 3. Formulas were created to predict firmness after CA within 10 to 12 N (2.0–2.5 lb-f) and TA to within 25%.

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