Effect of timing of hand thinning on the cropping potential of Red Fuji apple trees

In a hand-thinning trial of 6-year-old Red Fuji apple trees on seedling rootstocks at the Grove Research Station in southern Tasmania, unthinned controls were compared with trees that were hand-thinned between full bloom and 56 days after full bloom. Trees were thinned to about 200 flowers or fruit per tree. The response of fruit size and weight to later thinning was negative and linear (R2=0.72). This regression was not significantly affected if adjusted for the varying fruit crop per tree. It is concluded that in Australia, Red Fuji is capable of producing larger fruit at higher crop loads than either Red Delicious or Golden Delicious and that thinning at blossom produces much larger fruit than later thinning. Because of the strong correlation between Red Fuji fruit size or weight and time of thinning, we conclude that it is preferable to thin at blossom time.

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Rootstock Effects on Growth, Cell Number, and Cell Size of `Gala' Apples

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.129.1.0037 ◽

2004 ◽

Vol 129 (1) ◽

pp. 37-41 ◽

Cited By ~ 6

Author(s):

Yahya K. Al-Hinai ◽

Teryl R. Roper

Keyword(s):

Cell Division ◽

Cell Size ◽

Agricultural Research ◽

Fruit Size ◽

Cell Number ◽

Fruit Growth ◽

Research Station ◽

Full Bloom ◽

Final Size ◽

Load Effects

The effects of rootstock on growth of fruit cell number and size of `Gala' apple trees (Malus domestica Borkh) were investigated over three consecutive seasons (2000-02) growing on Malling 26 (M.26), Ottawa-3, Pajam-1, and Vineland (V)-605 rootstocks at the Peninsular Agricultural Research Station near Sturgeon Bay, WI. Fruit growth as a function of cell division and expansion was monitored from full bloom until harvest using scanning electron microscopy (SEM). Cell count and cell size measurements showed that rootstock had no affect on fruit growth and final size even when crop load effects were removed. Cell division ceased about 5 to 6 weeks after full bloom (WAFB) followed by cell expansion. Fruit size was positively correlated (r2 = 0.85) with cell size, suggesting that differences in fruit size were primarily a result of changes in cell size rather than cell number or intercellular space (IS).

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Thinning Golden Delicious apples with pre-bloom naphthalene acetic acid and later carbaryl sprays

Australian Journal of Experimental Agriculture ◽

10.1071/ea9840453 ◽

1984 ◽

Vol 24 (126) ◽

pp. 453 ◽

Cited By ~ 2

Author(s):

KM Jones ◽

TB Koen ◽

RJ Meredith

Keyword(s):

Acetic Acid ◽

Fruit Size ◽

Fruit Weight ◽

Naphthalene Acetic Acid ◽

Full Bloom ◽

Golden Delicious

A trial in southern Tasmania examined the thinning effects of naphthalene acetic acid (NAA) on Golden Delicious apples. The NAA was applied at pink bud or balloon blossom at 12, 18 and 24 ppm, with or without carbaryl at 1800 ppm applied 10 d after full bloom. Carbaryl was also applied alone 10 and 20 d after full bloom, and a hand thinned treatment was included. The higher concentrations of NAA did the most thinning but only the hand-thinned and 24 ppm NAA at balloon blossom with carbaryl treatment thinned enough to produce the required fruit size. The NAA sprays at balloon blossom thinned considerably more than those at pink bud. Neither NAA nor carbaryl alone was as effective as the combination. Reduction of fruit numbers increased mean fruit weight from 101 g in the control to 149 g in the 24 ppm NAA at balloon blossom with carbaryl. There was no evidence that increasing the concentration of NAA reduced mean fruit weight. This trial demonstrates that the effect of balloon stage sprays of NAA combined with later carbaryl sprays on Golden Delicious is similar to that achieved by the normal practice of spraying with NAA 7-14 d after full blossom, followed by carbaryl at 20 d. Reduction from 128 fruit/ 100 blossom clusters in the control to 76 after spraying at balloon blossom is still outside present aims of 30-50 fruit and is not considered to be severe enough thinning to assure adequate fruit size.

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Control of pudding spot in Crofton apple

Australian Journal of Experimental Agriculture ◽

10.1071/ea9920503 ◽

1992 ◽

Vol 32 (4) ◽

pp. 503

Author(s):

KM Jones ◽

SA Bound ◽

MJ Oakford ◽

TB Koen

Keyword(s):

Acetic Acid ◽

Fruit Size ◽

Fruit Weight ◽

The Other ◽

Naphthalene Acetic Acid ◽

Full Bloom ◽

Apple Trees ◽

Low Incidence ◽

Thinning Effect

Regularly cropped Crofton apple trees in southern Tasmania were thinned using sprays of naphthalene acetic acid (NAA) at 10 mg/L or ethephon at 200 mg/L at balloon blossom (BB), full bloom (FB), 10 days after full bloom (DAFB) or 20 DAFB. These treatments were compared with hand thinning and an unthinned control. Ethephon had a uniformly mild thinning effect (about 30% compared to control), except at 10 DAFB, where no thinning occurred. NAA was inconsistent, thinning well at BB (50%), overthinning at both FB (85%) and 10 DAFB (88%), and underthinning at 20 DAFB (similar to the control). Ethephon applied at BB and FB increased both mean fruit weight (12 and 22%) and fruit size (28 and 79%), but later applications did not. NAA applications generally resulted in increased mean fruit weight and size, except for the 20 DAFB treatment, which was similar to the control. All ethephon treatments had a low incidence (43%) of pudding spot similar to the controls and hand-thinned treatments. Most NAA treatments showed significantly higher levels of pudding spot than the other treatments. It is concluded that ethephon is a more predictable thinner for Crofton than NAA, and its use to control pudding spot is recommended.

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

HortScience ◽

10.21273/hortsci.25.9.1153b ◽

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.

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Cropping Efficiency of Young `Fuji' Apple Trees

HortScience ◽

10.21273/hortsci.30.4.886a ◽

1995 ◽

Vol 30 (4) ◽

pp. 886A-886

Author(s):

Preston K. Andrews ◽

Margaret L. Collier

Keyword(s):

Vegetative Growth ◽

Fruit Size ◽

Cross Sectional Area ◽

Sectional Area ◽

Apple Trees ◽

Cross Sectional ◽

Crop Load ◽

Previous Season ◽

Crop Density ◽

Fuji Apple

Effects of crop load and time of thinning on productivity of young `Fuji'/M.9 apple trees were tested by hand blossom (B) or fruit (F) thinning to two crop densities (fruit number/trunk cross-sectional area). Heavy (H) crop densities resulted in higher yields in both 2nd and 3rd leaf than light (L) crop densities. Time of thinning had no effect on yields in either year. In the 2nd leaf, fruit size was largest from trees B thinned to L crop densities, and smallest from trees F thinned to either crop density from mid-June through harvest. Both 1° and 2° vegetative growth were greatest in noncropped trees, intermediate in trees with L crops, and least in trees with H crops. Noncropped 2nd-1eaf trees had the highest flowering indices (flower clusters/100 total buds) the following spring and H cropped trees had the lowest. The flowering index was higher when trees were B thinned in the 2nd leaf than when F thinned. In the 3rd leaf, fruit size was largest when borne on weak upright shoots, intermediate on spurs, and smallest on 1-year-old terminal wood. Fruit on spurs had the highest incidence of sunscald (17%) and fruit on weak upright shoots the lowest (8%). Previous-season crop densities affected current-season's vegetative and fruit growth.

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