scholarly journals EFFECTS OF SEVERAL GROWTH CONTROLLING TECHNIQUES ON APPLE TREES

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1162c-1162
Author(s):  
Wesley R. Autio ◽  
Duane W. Greene
Keyword(s):  
Tree Growth ◽  
Fruit Set ◽  
Fruit Size ◽  
Root Pruning ◽  
Apple Trees ◽  
The Third ◽  
Flesh Firmness ◽  
Bitter Pit ◽  
Spray Treatment

In 1991, experiments were conducted to assess the effects of several growth controlling techniques on tree growth and fruit set, abscision, ripening, and other qualities. The first two experiments assessed the effects of root pruning (4-8 days after petal fall, 1 m from the trunk, 30 cm deep) in commercial orchards. Compared to controls, root pruning reduced fruit abscision from mature `Cortland'/M.7A trees by 70% on 17 Sept. In another orchard, root pruning reduced fruit abscision from mature `McIntosh'/MM.106 trees by 47% on 24 Sept. The third experiment utilized vigorous `Gardiner Delicious'/MM.106 trees. Treatments included root pruning (as described above), trunk scoring (single, complete circle, approximately 40 cm from the soil), trunk ringing (single, complete circle, 1 mm wide, approximately 40 cm from the soil), ethrel spray treatment (500 ppm), and dormant-pruned and unpruned controls. Treatments were applied on 15 May, when terminal growth was 12-15 cm. No treatment affected fruit set. Trunk growth was less for ringed and scored trees than other treatments. Ringing and scoring advanced ripening compared to controls, and ethrel resulted in intermediate ripening. Treatments had no effect on fruit size, flesh firmness, or the development of bitter pit and cork spot. Fruit abscision was least from controls and root-pruned trees. Trees that were treated with ethrel in May had the most rapid abscision rate.

Orchard soil management trials. 2. Effect of herbicides and nitrogen on growth and yield of young apple trees in permanent pasture

1971 ◽  
Vol 11 (48) ◽  
pp. 105 ◽  
Author(s):  
P Baxter ◽  
BJ Newman
Keyword(s):  
Tree Growth ◽  
Fruit Set ◽  
Fruit Size ◽  
Soil Management ◽  
Growth And Yield ◽  
Apple Trees ◽  
Narrow Strip ◽  
Permanent Pasture ◽  
Orchard Soil ◽  
Young Apple

On two cultivars of young apple trees growing in a permanent pasture, a narrow strip was kept bare with herbicide sprays used either during spring and summer or during the entire year. This increased tree growth, fruit set, fruit yield, and fruit size. Using more nitrogen fertilizer did not compensate for the grass competition and did not increase growth or yield as much as did the herbicide sprays. Most of the applied nitrogen could be accounted for in the increased growth of grass. The herbicide simazine increased tree growth more than other herbicides.

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 Daminozide, Root Pruning, Trunk Scoring, and Trunk Ringing Effects on Fruit Ripening and Storage Behavior of `McIntosh' Apple

1991 ◽  
Vol 116 (2) ◽  
pp. 195-200 ◽  
Author(s):  
D.C. Elfving ◽  
E.C. Lougheed ◽  
R.A. Cline
Keyword(s):  
Ethylene Production ◽  
Fruit Size ◽  
Soluble Solids ◽  
Starch Hydrolysis ◽  
Root Pruning ◽  
Full Bloom ◽  
Ethylene Evolution ◽  
Flesh Firmness ◽  
Solids Concentration ◽  
Storage Behavior

A midsummer foliar daminozide (DZ) application (750 mg a.i./liter) to `Macspur McIntosh'/M.7 apple trees (Malus domestics Borkh.) reduced preharvest drop and retarded flesh firmness loss and starch hydrolysis when tested at harvest; DZ also reduced fruit ethylene production at harvest and after 19 weeks of storage at 0.5C. Root pruning at full bloom (May) resulted in increased soluble solids concentration (SSC) and firmer flesh and less starch hydrolysis at harvest, but not consistently each year. Full-bloom root pruning reduced the incidence of stem-cavity browning and brown core, but again not each year. Full-bloom root pruning did not influence ethylene evolution at harvest but did reduce post-storage ethylene evolution in two of three seasons. Full-bloom root pruning generally was less effective than DZ in altering fruit behavior, while root pruning later than full bloom had virtually no effect. Trunk scoring or ringing increased SSC and retarded loss of flesh firmness before harvest and following storage, but had little effect on starch hydrolysis. Scoring or ringing decreased incidence of some disorders and reduced post-storage ethylene evolution, although these treatments had little effect on ethylene production at harvest. Trunk scoring influenced some fruit characteristics more strongly than DZ. Fruit size was not affected by any treatment in any year. Chemical name used: butanedioic acid mono (2,2 -dimethylhydrazide) (daminozide).

scholarly journals Growth and Productivity of Vigorous `Northern Spy'/MM.106 Apple Trees in Response to Annually Applied Growth Control Techniques

1990 ◽  
Vol 115 (2) ◽  
pp. 212-218 ◽  
Author(s):  
D.C. Elfving ◽  
R.A. Cline
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Growth Control ◽  
Shoot Length ◽  
Apple Trees ◽  
Bud Formation ◽  
Control Techniques ◽  
Terminal Bud ◽  
Time Required ◽  
Growth Regulator Treatment

Beginning in 1982, daminozide (DZ) was applied annually for 5 years to whole, 5-year-old `Northern Spy'/MM.106 (Malus domestics Borkh.) trees: a) shortly after bloom, b) together with ethephon (ETH) 6 to 7 weeks after bloom, or c) after harvest. Controls were unsprayed. One-half of the trees receiving each growth regulator treatment were summer-pruned after terminal-bud formation each year. Postharvest DZ reduced shoot numbers, mean shoot length, trunk enlargement, and fruit size, but had little or no effect on bloom, fruit set, or yield. Postbloom DZ, summer DZ plus ETH, and summer-pruning reduced vegetative growth and time required for dormant-pruning, but only postbloom DZ and summer DZ plus ETH increased spur density in the tree. Postbloom DZ and summer DZ plus ETH increased both flowering and cropping in 3 of the 5 years, with little effect on fruit set. Fruit size was reduced only in years when cropping was enhanced. Total yields (1982-86) were increased 34% and 36% by postbloom DZ and summer DZ plus ETH, respectively. Summer-pruning had no effect on fruit size in any year, but reduced yields in 1984 and 1986. Year-to-year fluctuation in yield was unaffected by any treatment. Growth-control treatments had no direct effect on foliar or fruit macronutrient concentrations. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); 2-chloroethylphosphonic acid (ethephon).

scholarly journals Net Enclosure of ‘Honeycrisp’ and ‘Gala’ Apple Trees at Different Bloom Stages Affects Fruit Set and Alters Seed Production

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 478 ◽  
Author(s):  
Mokhles Elsysy ◽  
Sara Serra ◽  
Phil Schwallier ◽  
Stefano Musacchi ◽  
Todd Einhorn
Keyword(s):  
Seed Production ◽  
Fruit Set ◽  
Insect Pests ◽  
Fruit Size ◽  
Quality Attributes ◽  
Parthenocarpic Fruit ◽  
Apple Trees ◽  
Apple Production ◽  
Commercial Crop ◽  
Mature Seeds

Thinning is a critical but challenging practice in apple production, especially for organic producers. The objective of this experiment was to determine if exclusion netting, used to manage insect pests and stress, could reduce fruit set and thinning requirements of ‘Gala’ and ‘Honeycrisp’ apple trees in Michigan and Washington, U.S.A., respectively. Nets were closed around whole canopies at different timings based on a predetermined percentage of open flowers. In 2017 and 2018, netted trees set a full commercial crop regardless of percentage of open bloom at the time of netting, including prebloom enclosures. Fruit set and yield of netted ‘Honeycrisp’ trees were significantly lower than non-netted, nonthinned controls but similar to non-netted hand-thinned controls. ‘Gala’ fruit set and yield did not differ among treatments. Exclusion netting markedly reduced the number of mature seeds and increased the number of nonfertilized seeds in both cultivars. Pollinator exclusion to ‘Gala’ in a frost year increased parthenocarpic fruit set two-fold compared to non-netted trees. Fruit size, shape, and quality attributes of ‘Gala’ were were similar among treatments, but ‘Honeycrisp’ fruit were significantly smaller than hand-thinned, non-netted controls. Netting may constitute an alternative, viable strategy to manage fruit set but requires testing on different cultivars.

scholarly journals The Effect of Prohexadione-calcium on Fruit Set and Chemical Thinning of Apple Trees

HortScience ◽  
2007 ◽  
Vol 42 (6) ◽  
pp. 1361-1365 ◽  
Author(s):  
Duane W. Greene
Keyword(s):  
Vegetative Growth ◽  
Fire Blight ◽  
Fruit Set ◽  
Fruit Size ◽  
Load Level ◽  
Apple Trees ◽  
Management Tools ◽  
Crop Load ◽  
Prohexadione Calcium ◽  
Treated Apple

Prohexadione-calcium (ProCa) has emerged as one of the most important management tools that an orchardist has available to control vegetative growth and to reduce the incidence and severity of fire blight. It has also been implicated in increased fruit set on treated apple trees. This investigation was initiated to confirm the effects of ProCa on fruit set and to evaluate different thinning strategies that might be used to appropriately thin treated trees. ProCa increased fruit set when applied at petal fall at initial rates of 125 or 250 mg·L−1 in three of the four experiments described in this article. Thinners were applied before, at the time of, and after application of ProCa. In all experiments, chemical thinners did not reduce fruit set to the same crop load level on ProCa-treated trees as they did on untreated trees. It was concluded that a different and more aggressive chemical thinning strategy must be used on trees that were treated with ProCa. Fruit size was reduced on ProCa-treated trees. This reduction was usually, but not always, related to increased fruit set. ProCa increased the number of pygmy fruit on ‘Delicious’ apple trees.

scholarly journals Effects of the Fall Foliar Urea Application on N Reserves and Fruiting Performance of Gala/M26 Apple Trees in Pot-in-Pot System

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 796A-796
Author(s):  
Pinghai Ding* ◽  
Minggang Cui ◽  
Leslie H. Fuchigami
Keyword(s):  
Fruit Set ◽  
Foliar Application ◽  
Fruit Size ◽  
Growing Season ◽  
Fruit Crops ◽  
Apple Trees ◽  
Fruit Thinning ◽  
Tree Fruit ◽  
Dormant Season ◽  
Foliar Urea

Reserve nitrogen is an important factor for plant growth and fruiting performance in tree fruit crops. The fall foliar urea application appears to be an efficient method for increasing N reserves. The effect of fall foliar urea application on N reserves and fruiting performance were studied with four year old `Gala'/M26 trees grown in 20 gallon containers in a pot-in-pot system from 2001 to 2003 at the Lewis-Brown Horticulture Farm of Oregon State Univ.. The trees were either sprayed with 0 or 2 times 3% urea after harvest in October. Shoot and spur samples were taken at the dormant season for reserve N analysis. Fruit performance was recorded in the following growing season. The fall foliar application significantly increased spur N reserve and had the trend to increase shoot N reserve but not significantly. The fall foliar application significantly increased tree fruit set and cluster fruit set. With normal fruit thinning, fall foliar urea application has the trend to increase both tree yield and average fruit size; without fruit thinning, fall foliar urea application has the trend to increase tree yield. These results indicate that fall foliar urea application an effective method to increase reserve N for maintaining tree yield.

scholarly journals Chemical Thinning of `Gala' Apples in California

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 525E-525
Author(s):  
Warren C. Micke ◽  
Joseph A. Grant ◽  
James T. Yeager
Keyword(s):  
Untreated Control ◽  
Fruit Set ◽  
Fruit Size ◽  
Apple Cultivar ◽  
The Third ◽  
Commercial Use

`Gala', the third most widely planted apple cultivar in California, requires early and precise thinning to produce good fruit size. Thus, chemical thinning would be ideally suited for this cultivar. However, the normally prolonged bloom for apples in California makes timing of chemical thinning applications difficult. In 1995 and 1996 trials, several chemical thinning treatments provided significantly reduced fruit set on `Gala' compared to the untreated control. Three treatments showed promise for commercial use: 1) carbaryl, two applications at petal fall and again at 10-15 mm diameter of the king fruit; 2) carbaryl plus NAD at petal fall; and 3) carbaryl plus 6-benzyladenine and GA4+7 (Accel®), two applications at petal fall and at ≈10 mm diameter of the king fruit. These treatments generally gave reduced fruit set per 100 flower clusters, fruit set per fruiting cluster and/or numbers of fruit removed by follow-up hand-thinning. None of these treatments showed evidence of phytotoxicity, and some increased fruit size over the untreated control.

scholarly journals Influence of Root Pruning and Rootstock on Growth and Performance of `Golden Delicious' Apple

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 645-648 ◽  
Author(s):  
D.C. Ferree ◽  
M. Knee
Keyword(s):  
Cell Division ◽  
Size Effect ◽  
Fruit Size ◽  
Root Pruning ◽  
Sectional Area ◽  
Cumulative Yield ◽  
Apple Trees ◽  
Cross Sectional ◽  
Golden Delicious ◽  
And Performance

`Smoothee Golden Delicious' apple trees on nine rootstocks or interstems were mechanically root pruned annually for 9 years beginning the year after planting. Root pruning reduced trunk cross-sectional area (TCA) by 14% over the first 5 years and 22% in the last 4 years of the trial. Yield and fruit size were reduced by root pruning in most years with the fruit size effect obvious in June at the end of cell division. Interstem trees of MAC.9/MM.106 were larger than trees on M.9 and the following interstems: M.9/MM.106, M.9/MM.111, M.27/MM.111. Trees on seedling (SDL) rootstock were the largest and had the lowest yield per unit TCA and lower cumulative yield/tree than trees on M.7, MM.106, and MM.1ll. There was no interaction for any measure of growth or yield between root pruning and rootstock or interstem.

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.

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