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

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.

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184 Timing of Benzyladenine Application as a Chemical Thinner of `Empire' Apple

HortScience ◽

10.21273/hortsci.29.5.455d ◽

1994 ◽

Vol 29 (5) ◽

pp. 455d-455 ◽

Cited By ~ 1

Author(s):

V. E. Emongor ◽

D. P. Murr

Keyword(s):

Fruit Quality ◽

Ethylene Production ◽

Fruit Set ◽

Fruit Size ◽

Fruit Weight ◽

Seed Number ◽

Full Bloom ◽

Apple Trees ◽

Effective Time ◽

Fruit Diameter

Benzyladenine (100 or 200 mg.litre-1) was applied to mature Empire/M.26 apple trees as dilute sprays 2, 4, 9, 11, 13, 15, 17, 20, 25, 27, 29 or 31 days after full bloom (DAFB). The most effective time of thinning was 25-29 DAFB (king fruit diameter 8.94-13.91 mm), and the thinning response to BA concentration was linear. Benzyladenine (BA) did not reduce fruit set when king fruit diameter was less than 5.35 mm, but BA significantly increased fruit weight, diameter (D), length (L) and L:D ratio compared to unsprayed controls and later BA treatments. BA - treated fruitlets had higher ethylene production, 24 hours and 7 days after spraying compared to untreated controls. We suggest that the response of apple fruitlets to BA applied as a thinner is mediated by ethylene. High fruit quality was obtained when BA was applied at 17-31 DAFB. Timing of BA sprays had no effect on seed number, though BA significantly increased seed number, fruit size, weight and L:D ratio. These results suggest that BA has the potential to substitute for the use of carbaryl as a thinner of apples in Ontario orchards.

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Root Pruning and Trunk Scoring Have Limited Effect on Young Bearing Apple Trees

HortScience ◽

10.21273/hortsci.30.5.981 ◽

1995 ◽

Vol 30 (5) ◽

pp. 981-984 ◽

Cited By ~ 9

Author(s):

Stephen S. Miller

Keyword(s):

Fruit Size ◽

Shoot Length ◽

Root Pruning ◽

Trickle Irrigation ◽

Apple Trees ◽

Cross Sectional ◽

Practical Advantage ◽

Deep Well ◽

Golden Delicious ◽

Terminal Shoot

To control excessive growth, vigorous `Smoothee Golden Delicious', `Jonagold', `Empire', and `Gala' apple (Malus domestica Borkh.) cultivars on Malling 7A (M.7A) rootstock planted at close in-row spacing (2.5 or 1.8 m) were mechanically root-pruned (RP), trunk-scored (TS; ringing), or both, annually for 3 to 5 years beginning in the fourth leaf. Trees were grown in a deep, well-drained, fertile soil and supplied with trickle irrigation. RP reduced terminal shoot length in 2 of 5 years on `Smoothee Golden Delicious'; trunk cross-sectional area (TCSA) was not affected by RP. TS reduced terminal length in 3 years and TCSA in each of 5 years of treatment on `Smoothee Golden Delicious'. Bloom density was not affected by RP on `Smoothee Golden Delicious' but was increased by TS in two of the three years measured. RP reduced terminal shoot length in `Gala', `Empire', and `Jonagold' in most years and TCSA in 1993 for all cultivars. TS had no effect on shoot length or TCSA in these three cultivars. Effects of RP and TS on yield and fruit size varied with year and cultivar. In general, the effects of RP and TS were inconsistent and often failed to reduce shoot growth or canopy spread. No practical advantage was recognized from these techniques for young apple trees growing on a fertile site with trickle irrigation.

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

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.115.2.212 ◽

1990 ◽

Vol 115 (2) ◽

pp. 212-218 ◽

Cited By ~ 7

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).

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EFFECTS OF SEVERAL GROWTH CONTROLLING TECHNIQUES ON APPLE TREES

HortScience ◽

10.21273/hortsci.27.11.1162c ◽

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.

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

HortScience ◽

10.21273/hortsci.32.4.645 ◽

1997 ◽

Vol 32 (4) ◽

pp. 645-648 ◽

Cited By ~ 8

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.

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

Australian Journal of Experimental Agriculture ◽

10.1071/ea9940669 ◽

1994 ◽

Vol 34 (5) ◽

pp. 669 ◽

Cited By ~ 2

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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166 Influence of Crop Level on Growth and Quality of `Braeburn' Apple Fruit

HortScience ◽

10.21273/hortsci.35.3.418e ◽

2000 ◽

Vol 35 (3) ◽

pp. 418E-419

Author(s):

P.I. Garriz ◽

G.M. Colavita ◽

H.L. Alvarez

Keyword(s):

Fruit Size ◽

Growing Season ◽

Apple Fruit ◽

Full Bloom ◽

Cross Sectional ◽

Crop Load ◽

Commercial Crop ◽

Source Sink ◽

Fruit Diameter

Crop load and the genetic biological carrying capacity (source–sink relationships) determine the potential for fruit size development on apple; however, the environment within which the fruit grows attenuates this potential. The effects of different crop loads on the growth pattern and the progress of maturity in apples were evaluated at the Comahue National Univ., Argentina (lat. 38 56'S long 67 59'W), during the 1998–99 growing season. Our experiment was conducted on 6-year-old `Braeburn'/Malling Merton 111 apple (Malus domestica Borkh.) trees spaced 4.0 × 2.3 m and trained to palmette leader. Treatments were 1) light crop load (LC), 2.5 fruit/cm2 trunk cross-sectional area (TCSA), 2) moderate crop load (MC), 6.5 fruit/cm2 TCSA (standard commercial crop load) and 3) high crop load (HC), minimum 8 fruit/cm2 TCSA, no fruit removed from tree. Whole trees were hand-thinned 19 days after full bloom (DAFB). Fruit diameter (FD) was taken at two weekly intervals (n = 24 per date and treatment) and maturity indexes were determined at harvest. Analysis of variance was used and mean separations were computed with Student's t test. From 38 DAFB until harvest, fruit size was significantly reduced (P < 0.01) in the HC trees, indicating that they were source-limited during growth. At 166 DAFB, FD was 7.48, 7.14, and 6.89 cm for the LC, MC and HC treatments, respectively. Adequate carbon was apparently available to support a commercial crop load since no differences were found between LC and MC trees. Crop level influenced flesh firmness; at 173 DAFB, it was significantly lower in HC trees than MC and LC trees (84.33, 92.51, and 91.57 N, respectively). These results suggest some goals of thinning for ensuring sizable `Braeburn' fruit.

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Almond Fruit Drop Patterns under Mediterranean Conditions

Agriculture ◽

10.3390/agriculture11060544 ◽

2021 ◽

Vol 11 (6) ◽

pp. 544

Author(s):

Jaume Lordan ◽

Lourdes Zazurca ◽

Mercè Rovira ◽

Laura Torguet ◽

Ignasi Batlle ◽

...

Keyword(s):

Fruit Set ◽

Growing Season ◽

Fruit Weight ◽

Key Factors ◽

Full Bloom ◽

Tree Management ◽

Fruit Drop ◽

Mediterranean Conditions ◽

New Cultivars ◽

Scion Cultivar

Almond is an important tree nut crop worldwide, and planted areas have been increasing year after year. While self-fertility is one of the key factors when it comes to improved almond productivity of new cultivars, yield is also affected by the number of flowers produced, pollination, fruit set, fruit drop, and fruit weight. Almond fruit drop patterns of 20 Mediterranean almond cultivars were studied over three years. In addition, fruit drop patterns of two scion cultivars ‘Marinada’ and ‘Vairo’ budded onto eight to 10 different rootstocks managed with three different pruning strategies were studied for two years. Cumulative flower and fruit drop ranged from 50% to 90% among cultivars and treatments, and there were up to four fruit drop events during the growing season, the main one occurring from 20–60 days from full bloom (DFFB). Subsequent drops were at 100 DFFB, 120–140 DFFB, and the last one at 160–180 DFFB. The later drops were less apparent. In general, about half of the cumulative drop was comprised of buds and flowers, and the remaining percentage was fruit that dropped 20 or more days after full bloom. Furthermore, different fruit drop patterns were observed depending on the cultivar. For late- and extra-late flowering cultivars, cumulative fruit drop began to decrease earlier, with most of the drops occurred already at full bloom, whereas the opposite was observed for the early flowering cultivars. Rootstocks also had an important effect on the fruit drop pattern, with different effects depending on the scion cultivar. Tree management, such as type of pruning, also had an important effect on the rate of fruit drop and cumulative drop. Therefore, each combination of cultivar × rootstock × pruning type will require different strategies in order to reduce the fruit drop and optimize crop loads.

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

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.116.2.195 ◽

1991 ◽

Vol 116 (2) ◽

pp. 195-200 ◽

Cited By ~ 10

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).

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

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.129.2.0175 ◽

2004 ◽

Vol 129 (2) ◽

pp. 175-181 ◽

Cited By ~ 5

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).

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