Testing a Power Duster for Pollination of `McIntosh' Apples

This study was undertaken to test the efficacy of a power duster for supplemental pollination of `McIntosh' apple trees, where lack of nearby pollinizing cultivars was thought to be a limiting factor to productivity. The pollen duster was ineffective in increasing fruit set, fruit size, or seed number in fruits on limbs that were covered with spun-bonded rowcover material prior to bloom. Applying supplemental pollen to open-pollinated `McIntosh' trees had no effect on fruit set, yield, fruit size, or seed number, regardless of pollen dose, timing, or number of applications. Dispersal of supplemental pollen with a power duster appears to be an inefficient method of pollinating apple trees.

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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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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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Effect of blossom thinning on fruit density, fruit size and seed count of Williams' Bon Chretien and Packham's Triumph pears

Australian Journal of Experimental Agriculture ◽

10.1071/ea9710248 ◽

1971 ◽

Vol 11 (49) ◽

pp. 248 ◽

Cited By ~ 1

Author(s):

A Selimi

Keyword(s):

Fruit Set ◽

Fruit Size ◽

Seed Number ◽

Cross Pollination ◽

Hand Pollination ◽

Bud Removal

Effects on fruit density, fruit size, and fruit fertilization (seed count) of several degrees of fruit bud removal three to four weeks before bloom, was studied on Williams Bon Chretien and Packham's Triumph pears. The effects were studied in the presence or absence of cross pollination. Fruit set increased with increasing severity of blossom bud removal, indicating that poor setting was not due to faulty flowers. This was also confirmed by hand pollination of the clusters on unthinned limbs, where fruit set was much higher than on unthinned unpollinated limbs. Fruit density in Packham's was not reduced even by 80 per cent of fruit bud removal, and in Williams' fruit density was significantly reduced at 60 or 40 per cent of fruit bud removal, in a heavy or intermediate flowering years, respectively, whereas in a poor flowering year, fruit density was not significantly reduced even by 80 per cent of bud removal. Heavy thinning resulted in increased fruit size in Williams' but not in Packham's pears. Hand poIlination or bouquets increased seed number and fruit size greatly in \Villiams7 and increased seed number but not fruit size in Packham's.

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

Agronomy ◽

10.3390/agronomy9090478 ◽

2019 ◽

Vol 9 (9) ◽

pp. 478 ◽

Cited By ~ 4

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.

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Prebloom Treatments to Alleviate Cold Injury in Apple

HortScience ◽

10.21273/hortsci.30.4.807e ◽

1995 ◽

Vol 30 (4) ◽

pp. 807E-807

Author(s):

E.W. Stover ◽

T.E. Paine ◽

W.C. Stiles

Keyword(s):

Leaf Area ◽

Untreated Control ◽

Fruit Set ◽

Fruit Size ◽

Cold Injury ◽

Seed Number ◽

Flower Buds ◽

Active Growth ◽

Strong Trend ◽

Winter Temperatures

Damage to xylem subtending apple buds is often observed following very low winter temperatures. Reports suggest that prebloom application of boron, zinc, and urea facilitate recovery. Prebloom nutrient treatments were applied to `McIntosh' and `Empire' at three sites in Spring 1994. The following treatments were applied to drip at half-inch green: boron (22.8 mM, solubor); Zn-EDTA (0.75 mM); boron and Zn-EDTA; boron, Zn-EDTA, and urea (59.4 mM). Another treatment used boron and Zn-EDTA at half-inch green, followed by boron, Zn-EDTA, and urea at pink. Spur leaf area, fruit set, fruit size, and seed number were determined. There were no clear treatment effects at the warmest site (mid-winter low –32C); however, this orchard was more variable than other treatment sites. The intermediate site (mid-winter low –37C) had a strong trend of increasing fruit set in `Empire' and `McIntosh' as more nutrients were applied. The combined half-inch green and pink treatment significantly increased fruit set by 23.8% compared to the untreated control. At the coldest site (mid-winter low –42C), `Empire' again displayed a strong trend of increasing fruit set with additional nutrients. All treatments combining boron and zinc significantly increased fruit set. The combined half-inch green and pink treatment increased fruit set by 43%. At this site `McIntosh' did not respond to treatment. However, `McIntosh' trees had continued active growth into late Fall 1993 and sustained severe cold injury in November. Data suggest that, when they were effective, nutrient treatments resulted in increased retention of flower buds on damaged spurs.

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Effective Pollination Period of Actinidia chinensis ‘AU Golden Sunshine’ and A. deliciosa ‘AU Fitzgerald’ Kiwifruit

HortScience ◽

10.21273/hortsci13617-18 ◽

2019 ◽

Vol 54 (4) ◽

pp. 656-660

Author(s):

Ashley K. Brantley ◽

James D. Spiers ◽

Andrew B. Thompson ◽

James A. Pitts ◽

J. Raymond Kessler ◽

...

Keyword(s):

Fruit Set ◽

Linear Trend ◽

Fruit Size ◽

Fruit Weight ◽

Open Pollination ◽

Seed Number ◽

Alternate Bearing ◽

Size Index ◽

Days After Anthesis ◽

Female Flowers

Commercial kiwifruit production often requires substantial inputs for successful pollination. Determining the length of time that female flowers can be successfully pollinated can aid management decisions concerning pollination enhancement. The purpose of this research was to determine the effective pollination period (EPP) for ‘AU Golden Sunshine’ and ‘AU Fitzgerald’. Either 30 (2013) or 32 (2014, 2015) flowers of ‘AU Golden Sunshine’ were hand pollinated each day for 1 to 5 (2013) days after anthesis (DAA) or 1 to 7 DAA (2014, 2015), and then isolated to prevent open pollination. Anthesis was considered the day the flower opened. Similarly, ‘AU Fitzgerald’ flowers were pollinated and then isolated 1 to 6 DAA in 2013 and 1 to 7 DAA in 2015. For ‘AU Golden Sunshine’ in 2013, fruit set was consistent over the 5-day period, but fruit weight, fruit size index, and seed number decreased between 1 and 3 and 4 and 5 DAA. In 2014, fruit set decreased between 1 and 6 and 7 DAA, whereas fruit weight, fruit size index, and seed number each decreased in a linear trend. In 2015, fruit set also decreased between 1 and 6 and 7 DAA, whereas all other responses decreased linearly. Based on fruit set in 2014 and 2015, the EPP for ‘AU Golden Sunshine’ was 6 DAA. The EPP for ‘AU Fitzgerald’, however, was more variable. In 2013, fruit weight, fruit size index and seed number decreased between 1 and 4 and 5 and 6 DAA, suggesting that the EPP was 4 DAA. In 2015, fruit set remained consistent over the 7-day period with fruit weight, fruit size index, and seed number decreasing linearly. Differences in temperature and the alternate bearing tendency of kiwifruit species likely contributed to the discrepancies between the years for the EPP. For each cultivar, reductions in fruit weight, size, and seed number were observed before an observed decrease in fruit set. Greater fruit weight, size, and seed number were observed when flowers were pollinated within the first few DAA, with results varying thereafter.

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

HortScience ◽

10.21273/hortsci.42.6.1361 ◽

2007 ◽

Vol 42 (6) ◽

pp. 1361-1365 ◽

Cited By ~ 8

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.

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

HortScience ◽

10.21273/hortsci.39.4.796a ◽

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.

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

Australian Journal of Experimental Agriculture ◽

10.1071/ea9710105 ◽

1971 ◽

Vol 11 (48) ◽

pp. 105 ◽

Cited By ~ 5

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.

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