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 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 Benzyladenine and Other Chemicals for Thinning `Empire' Apple Trees

1993 ◽  
Vol 118 (5) ◽  
pp. 593-598 ◽  
Author(s):  
D.C. Elfving ◽  
R.A. Cline
Keyword(s):  
Fruit Set ◽  
Fruit Weight ◽  
Mineral Nutrient ◽  
Nutrient Concentrations ◽  
Naphthaleneacetic Acid ◽  
Full Bloom ◽  
Apple Trees ◽  
Return Bloom ◽  
Set Up ◽  
Better Than

Postbloom applications of benzyladenine (BA) thinned young fruitlets of mature `Empire' apple trees (Malus domestica Borkh.) as well as or better than NAA or carbaryl (CB). BA increased fruit weight more effectively than either NAA or CB. Promalin (PR) was less effective than BA for both thinning and fruit-weight increase. In 1990, both BA and PR reduced fruit set up to 29 days after full bloom, but PR showed less thinning activity. BA and NAA produced independent and additive thinning responses when tank-mixed. Effects of all thinners on foliar mineral-nutrient concentrations were associated with changes in fruit load. BA increased return bloom as much or more than NAA or CB. PR did not affect return bloom. Chemical names used: N -(phenylmethyl)-1 H -purine-6-amine [benzyladenine (BA)]; BA plus gibberellins A, and A, [Promalin (PR)]; 1-naphthaleneacetic acid (NAA); 1-naphthalenyl methylcarbamate [carbaryl (CB)].

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 Combinations of Ethephon and Accel for Thinning `Delicious' Apple Trees

2004 ◽  
Vol 129 (2) ◽  
pp. 175-181 ◽  
Author(s):  
Richard P. Marini
Keyword(s):  
Phosphonic Acid ◽  
Fruit Set ◽  
Fruit Weight ◽  
Analysis Of Covariance ◽  
Apple Trees ◽  
Fruit Diameter

For 4 years, `Redchief Delicious' apple [Malus ×sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] trees were treated with ethephon and/or Accel (6-BA + Gibberellins 4+7) when average fruit diameter was 5.0 to 11.4 mm. Effective thinning was obtained with ethephon at concentrations >500 mg·L-1 and with Accel at concentrations of 100 to 125 mg·L-1. In only 1 year out of 4 did combinations of Accel plus ethephon reduce fruit set more than either material applied alone. Repeat applications of either material alone or in combination reduced fruit set no more than single applications. Fruit weight was negatively related to the number of fruit per tree. After adjusting fruit weight for number of fruit per tree at harvest with analysis of covariance, ethephon did not improve fruit weight at harvest, but Accel improved fruit weight in two of three experiments. The effect of combinations of Accel and ethephon on fruit weight was inconsistent. Chemical names used: 2-chloroethyl phosphonic acid (ethephon); polyothyethylleneploypropanol dihydroxy-propane 2, butoxyethanol (Regulaid); N-(phenylmethyl)-1H-purine-6-amine plus giberrellins A4 + A7 (Accel).

scholarly journals AVG, NAA, boron, and magnesium influence preharvest fruit drop and fruit quality of ‘Honeycrisp’ apples

2018 ◽  
Vol 98 (3) ◽  
pp. 741-752 ◽  
Author(s):  
Michelle H. Arseneault ◽  
John A. Cline
Keyword(s):  
Fruit Quality ◽  
Starch Degradation ◽  
Naphthaleneacetic Acid ◽  
Full Bloom ◽  
Ethylene Evolution ◽  
Malus Domestica Borkh ◽  
Fruit Drop ◽  
Honeycrisp Apples ◽  
Colour Development

Preharvest fruit drop (PFD) of apple (Malus domestica Borkh.) can cause significant losses resulting in up to 50% reduction in yield in some years. In a 2-yr study, ‘Honeycrisp’ trees were treated with six foliar treatments including 20 mg·L−1 1-naphthaleneacetic acid (NAA) 2 wk before anticipated harvest (WBAH), 125 mg·L−1 aminoethoxyvinylglycine hydrochloride (AVG) 4 WBAH, AVG plus NAA 2 WBAH, and repeat sprays of 200 mg·L−1 B, and 2000 mg·L−1 Mg applied 48–93 d after full bloom to evaluate their effect on PFD and fruit quality. Fruit drop associated with broken pedicels and physiological causes was monitored. During a year with ∼43% PFD on untreated control trees, AVG retained up to ∼35% and NAA retained up to ∼27% of the total fruit number, relative to the control trees. The combination of AVG plus NAA had similar PFD compared with AVG alone, while B and Mg were similar to the control. The proportion of PFD associated with broken pedicels was ∼5%. Aminoethoxyvinylglycine delayed starch degradation, ethylene evolution, and blush skin colour development of fruit. This study supports the use of AVG 4 WBAH and NAA 2 WBAH to manage ‘Honeycrisp’ PFD, which may offer economic advantages for growing quality apples. Foliar sprays of Mg or B failed to reduce PFD.

A comparison of air-shear and electrostatic spray technology with a conventional air-blast sprayer to thin apples

1994 ◽  
Vol 34 (5) ◽  
pp. 669 ◽  
Author(s):  
MJ Oakford ◽  
KM Jones ◽  
SA Bound ◽  
L O'Rielly
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
High Volume ◽  
The Other ◽  
Full Bloom ◽  
Apple Trees ◽  
Air Blast ◽  
Fruit Number ◽  
Low Volume ◽  
Electrostatic Spray

Red Delicious apple trees at Spreyton in northwest Tasmania were thinned with ethephon using an air-shear-electrostatic sprayer (low volume: 100 or 200 L/ha with or without electrostatics) or a commercial air-blast sprayer (high volume: 2000 or 4000 L/ha). Treatments were applied at 2 and 10 days after full bloom. Also included were an unsprayed control and a hand-thinned treatment (15-20 days after full bloom). Carbaryl + Thiram was also applied 3 times (20, 32 and 40 days after full bloom) using the same spray treatments. All dosage rates were equilibrated to apply the same amount of active ingredient/ha. The spray treatments thinned fruit more than the controls when compared for fruit number and all size variables measured except percentage of fruit >80 mm. There were significant differences for fruit number between the hand-thinned, 4000 L/ha high volume and 200 L/ha air-shear treatments, and all the remaining treatments. This applied to both total numbers of fruit set or numbers of fruit hand-thinned at 80-90 days after full bloom. This late hand-thinning had the effect of evening up the fruit size but the control still had significantly smaller fruit than all the other treatments due to the larger number of fruit carried through to hand-thinning.

scholarly journals Time of metamitron application and concentration in the chemical thinning of ‘Maciel’ peach

2019 ◽  
Vol 41 (4) ◽  
Author(s):  
Roseli de Mello Farias ◽  
Carlos Roberto Martins ◽  
Caroline Farias Barreto ◽  
Marcos Antônio Giovanaz ◽  
Marcelo Barbosa Malgarim ◽  
...  
Keyword(s):  
Fruit Set ◽  
High Efficiency ◽  
Production Costs ◽  
Full Bloom ◽  
Average Mass ◽  
Fruit Abscission ◽  
Different Seasons ◽  
Peach Trees ◽  
Thinning Effect ◽  
Peach Orchard

Abstract In the peach tree cultivation, the producer has the challenge of obtaining good quality fruits and maintaining production in a balanced way over the years. Thinning favors these parameters and reduces the fruit load on plants. Manual thinning commonly practiced on peach trees requires high labor and increases production costs. Chemical thinning as an alternative to manual thinning, which depending on the species, time and concentration, has demonstrated high efficiency. The aim of this study was to evaluate the effect of metamitron applied at different seasons and concentrations on the chemical thinning of peach trees in southern Brazil. Experiments were conducted in a commercial peach orchard (‘Maciel’ cultivar), in the municipality of Morro Redondo, Rio Grande do Sul, Brazil, during the 2015 and 2016 harvests. In experiment 1, metamitron at concentration of 200 mg L-1 was applied at 20, 30, 40, 50 and 60 days after full bloom and manual thinning performed at 40 days after full bloom. In experiment 2, metamitron was applied at concentrations of 100 mg L-1, 200 mg L-1, 300 mg L-1 and 400 mg L-1 and manual thinning at 40 days after full bloom, in addition to control plants. Fruit abscission, fruit set, total number of fruits per plant, yield per plant, average mass and fruit diameter were evaluated. Metamitron at concentration of 200 mg L-1 has thinning effect when applied before 40 days after full bloom. Metamitron concentration of 100 mg L-1 applied at 40 DAFB promoted fruit abscission superior to manual thinning. Therefore, the application of metamitron to ‘Maciel’ peach trees close to full bloom at concentration of 100 mg L-1 results in thinning practice similar to manual thinning.

scholarly journals Storage Responses of `Empire' Apples to Benzyladenine and Other Chemical Thinners

1994 ◽  
Vol 119 (2) ◽  
pp. 253-257 ◽  
Author(s):  
D.C. Elfving ◽  
E.C. Lougheed
Keyword(s):  
Malus Domestica ◽  
Soluble Solids ◽  
Starch Hydrolysis ◽  
Naphthaleneacetic Acid ◽  
Full Bloom ◽  
Ethylene Evolution ◽  
Flesh Firmness

In three trials over 3 years, foliar BA applications for fruitlet thinning of `Empire' apple (Malus domestica Borkh.) trees produced small and inconsistent effects on flesh firmness at harvest and after air storage. Soluble solids concentrations at harvest and after air storage were consistently increased by BA alone or together with GA4+7 [Promalin (PR)], and were also increased by CB in one trial. Starch hydrolysis was slightly delayed by BA applications in 1990. Ethylene evolution at harvest was increased by NAA in 1988 and slightly increased by PR applied 29 days after full bloom (DAFB) in 1990, while poststorage ethylene evolution was stimulated by BA and PR treatments in 1990 except BA at 29 DAFB. Incidence of poststorage disorders was low and largely uninfluenced by thinning treatments. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine [benzyladenine (BA)]; BA plus gibberellins A4 and A7 (GA 4+7) [Promalin (PR)]; 1-naphthaleneacetic acid (NAA); 1-naphthalenyl methylcarbamate [carbaryl (CB)].

scholarly journals EFFECT OF ROOT PRUNING AND CHEMICAL THINNING ON GROWTH AND FRUITING OF `McINTOSH' APPLE TREES.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1153b-1153
Author(s):  
James R. Schupp ◽  
Highmoor Farm
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Shoot Length ◽  
Root Pruning ◽  
Full Bloom ◽  
Apple Trees ◽  
Cross Sectional ◽  
Fruit Drop ◽  
Napthaleneacetic Acid ◽  
Fruit Diameter

Mature `McIntosh'/MM.111 apple (Malus domestica, Borkh.) trees were treated to evaluate the response of root pruned trees to chemical thinning and to determine if reducing the crop load increased fruit size on root pruned trees. The trees were root pruned at full bloom in 1988 and 1989, by cutting on both sides of the row 1m from the trunk and 30cm deep. Water, 600mg/liter carbaryl, 5mg/liter napthaleneacetic acid (NAA), or NAA plus carbaryl were applied when fruit diameter was approximately 10mm. Trunk cross-sectional area (TCSA) was increased by thinning treatments in 1988, but root pruning had no effect. In 1989, root pruning reduced TCSA increment by 35%. Shoot length was reduced by root pruning both years. All treatments reduced percent fruit set in 1989, however root pruned trees and trees treated with NAA had the highest fruit numbers at harvest. Preharvest fruit drop was reduced by root pruning in both 1988 and 1989. Root pruning had no influence on the response of apple trees to chemical thinning. Removing a portion of the crop with chemical thinners was partially successful in counteracting the reduction in fruit size caused by root pruning.

scholarly journals Effects of 1-Methylcyclopropene and Naphthaleneacetic Acid on Fruit Set and Expression of Genes Related to Ethylene Biosynthesis and Perception and Cell Wall Degradation in Apple

2010 ◽  
Vol 135 (5) ◽  
pp. 402-409 ◽  
Author(s):  
Hong Zhu ◽  
Rongcai Yuan ◽  
Duane W. Greene ◽  
Eric P. Beers
Keyword(s):  
Cell Wall ◽  
Fruit Set ◽  
Ethylene Biosynthesis ◽  
Apple Fruit ◽  
Naphthaleneacetic Acid ◽  
Cell Wall Degradation ◽  
Fruit Abscission ◽  
Expression Of Genes ◽  
Small Influence ◽  
Negative Effect

The effects of 1-methylcyclopropene (1-MCP) and naphthaleneacetic acid (NAA) on fruit set and the expression of genes related to ethylene biosynthesis and perception and cell wall degradation in apple (Malus ×domestica Borkh.) were studied when applied during the normal chemical thinning period. 1-MCP at 209 mg·L−1 had a small negative effect or no effect on the final fruit set, depending on the experiment, but could cause a transient delay of June drop when applied at petal fall or the 10-mm stage in ‘Pioneer McIntosh’ apple. 1-MCP at 160 mg·L−1 had no effect on fruit abscission but induced ethylene production by leaves and fruit of ‘Golden Delicious’ apple. NAA at 6 or 15 mg·L−1 effectively increased fruit abscission in both apple cultivars. NAA enhanced the expression of genes related to ethylene biosynthesis (MdACS5A, MdACS5B, and MdACO1) or perception (MdETR1, MdETR1b, MdETR2, MdERS1, and MdERS2) and cell wall degradation (MdPG2). 1-MCP did not affect the expression of MdACS5A and MdACS5B in the fruit abscission zone (FAZ), although it enhanced the expression of these two genes in the fruit cortex (FC) from 6 hours to 1 day after treatment. The expression of MdACO1 in both tissues was increased by 1-MCP by 3 days post-treatment and thereafter. 1-MCP had only a small influence on the expression of most ethylene receptor genes, with the exception of MdETR1, which was upregulated in the FC to a level similar to that observed for NAA treatment. In response to 1-MCP, in the FAZ, the expression of MdCel1 and MdPG2 was upregulated at the beginning and the end, respectively, of the experiment, but otherwise remained at or below control levels. 1-MCP did not inhibit NAA-induced abscission of young apple fruit, suggesting that abscission does not solely depend on ethylene signal transduction, or that the periods of effectiveness for 1-MCP and ethylene were asynchronous.

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