Effect of Sterol-demethylation Inhibiting Fungicides on Apple Fruit Set, Fruit Size, Total Yield, and Gross Returns

Effects of three sterol-demethylation inhibiting (DMI) fungicides and a contact fungicide were compared over two years at each of two locations to determine if fungicide treatments had differential effects on productivity, fruit size and shape, or gross returns for `Empire' apples (Malus ×domestica Borkh.). Treatments were applied four to five times per year during the primary apple scab season. Effects of treatments were assessed by comparing fruit set efficiencies, number of fruit per tree, total harvested fruit weight, and fruit length: diameter ratios at harvest. No significant differences were noted among individual treatments in any of the four trials. However, when treatments were contrasted by grouping individual treatments, significantly larger fruit size was noted for triflumizole treatments vs. combined fenarimol and myclobutanil treatments in one of the four trials and for captan or mancozeb compared to fenarimol and myclobutanil treatments in two trials. None of the DMI fungicides compared in these trials had any consistent adverse affect on fruit size, total yield, or estimated gross return per hectare. We conclude that the plant growth regulator effects of DMI fungicides are inconsistent and are unlikely to have significant economic impact on commercial apple production.

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EFFECTS OF HYDROGEN CYANAMIDE ON APPLE AND PLUM FRUIT THINNING

HortScience ◽

10.21273/hortsci.27.6.690a ◽

1992 ◽

Vol 27 (6) ◽

pp. 690a-690

Author(s):

Esmaeil Fallahi ◽

Brenda R. Simons ◽

John K. Fellman ◽

W. Michael Colt

Keyword(s):

Malus Domestica ◽

Fruit Set ◽

Fruit Size ◽

Apple Fruit ◽

Fruit Weight ◽

Full Bloom ◽

Hydrogen Cyanamide ◽

Fruit Thinning ◽

Prunus Salicina

Influence of various concentrations of hydrogen cyanamide (HC) on fruit thinning of `Rome Beauty' apple (Malus domestica Borkh.), `Friar,' and `Simka' plums (Prunus salicina Lindley) were studied. A full bloom application of HC at all tested concentrations decreased `Rome Beauty' apple fruit set and yield, and increased fruit weight. Hydrogen cyanamide at 0.25% (V/V) resulted in adequate apple thinning, indicated by the production of an ideal fruit weight. Prebloom and full bloom applications of HC at greater than 0.75% reduced plum fruit set and yield in `Friar.' Full bloom application of HC at 0.25% to 0.50% showed a satisfactory fruit set, yield, and fruit size in `Friar' plum. Full bloom application decreased fruit set and yield in `Simka' plum. Hand thinning, as well as chemical thinning, is recommended for plums.

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Thinning response of ‘Redhaven’ peaches to 1-aminocyclopropane carboxylic acid (ACC)

Canadian Journal of Plant Science ◽

10.1139/cjps-2020-0018 ◽

2020 ◽

pp. 1-13

Author(s):

John A. Cline ◽

Catherine J. Bakker ◽

Amanda Beneff

Keyword(s):

Carboxylic Acid ◽

Fruit Set ◽

Total Yield ◽

Fruit Size ◽

Fruit Weight ◽

Full Bloom ◽

Fruit Thinning ◽

Leaf Yellowing ◽

Peach Trees ◽

Fruit Load

Peach trees bear an abundance of flowers which produce a surplus of fruit that the tree is unable to support. A self-regulatory mechanism enhances the abscission of immature fruitlets leading to a reduced fruit load, but this is often insufficient to achieve fruit of marketable size. Supplementary manual fruit thinning is typically required to optimize economic fruit load. This 2-yr study investigated the response of ‘Redhaven’ peach trees to sprays of 300 and 600 mg L−1 1-aminocyclopropane carboxylic acid (ACC) during the phenological stages of full bloom, shuck split, and ∼20 mm fruitlet diameter. The objective was to determine the efficacy of ACC on fruit set, fruit size, and yield at harvest and the amount of hand-thinning required at “June drop”. Although the response to ACC varied between the 2 yr, 600 mg L−1 ACC spray at full bloom (2018) and at ∼20 mm fruit size (2019) reduced fruit set, the need for hand-thinning by 59%–66%, and crop load. Treatments also had varying but significant effects on leaf yellowing and leaf drop when measured shortly after application. ACC reduced total yield and number of fruit per tree in both study years and increased fruit weight in 2019. Overall, peaches were responsive to ACC at a range of timings from bloom to ∼20 mm fruit size. This study enhances our understanding of ACC on fruitlet abscission of peaches and is one of few studies to demonstrate the effectiveness of a chemical fruitlet thinner for peaches.

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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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Flowering period and fruit quality of peach trees selections and cultivars in the metropolitan region of Curitiba

Revista Brasileira de Fruticultura ◽

10.1590/0100-29452018991 ◽

2018 ◽

Vol 40 (3) ◽

Author(s):

Giselda Alves ◽

Jhulia Gelain ◽

Gloria Soriano Vidal ◽

Cristiano Nunes Nesi ◽

Louise Larissa May De Mio ◽

...

Keyword(s):

Skin Color ◽

Fruit Set ◽

Fruit Size ◽

Titratable Acidity ◽

Physicochemical Characteristics ◽

Fruit Weight ◽

Soluble Solids ◽

Metropolitan Region ◽

Flowering Period ◽

Peach Trees

Abstract This study aimed to evaluate the flowering period and the physicochemical characteristics of peaches, aiming to find those most promising for the diversification of the peach crop in the Metropolitan Region of Curitiba, Paraná State. We evaluated 8 selections and three cultivars in Porto Amazonas and 10 cultivars in Araucaria for flowering period, fruit set, diameter and height of fruit, average fruit weight, the skin color, soluble solids (SS), titratable acidity (TA), ratio SS/ TA, hydrogen potential (pH). The flowering period occurred between late June and late September ranging from 16 to 25 days. The fruit set rate was greater than 50% for ‘Cascata 1513’, ‘Cascata 1429’, ‘Cascata 1577’, ‘Cascata 1743’ and for all cultivars in Araucaria. There were significant differences for the other variables assessed. It was concluded that in Araucária, ‘Charme’ and ‘Chimarrita’ are good planting options, have the same duration of the cycle (111 days), being ‘Charme’ a little later. Besides these, ‘Douradão’ and ‘Rubimel’ have good fruit size, moderate acidity and best SS/TA ratio, being earlier than the previous ones. ‘PS 25399’ is the earliest and showed reddish epidermis and great consumer interest. In Porto Amazonas, selections and cultivars tested produced little fruit of small size, being required more studies to be recommended in these area.

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Regulating Budbreak, Flowering, and Fruit Maturity in Sweet Cherry (Prunus avium L.) cv. `Bing' by Surfactant and Nitrate Applications

HortScience ◽

10.21273/hortsci.31.4.603e ◽

1996 ◽

Vol 31 (4) ◽

pp. 603e-603

Author(s):

K.G. Weis ◽

S.M. Southwick ◽

J.T. Yeager ◽

W.W. Coates ◽

Michael E. Rupert

Keyword(s):

Sweet Cherry ◽

Prunus Avium ◽

Fruit Set ◽

Fruit Size ◽

Calcium Nitrate ◽

Potassium Nitrate ◽

Fruit Weight ◽

Full Bloom ◽

Fruit Maturity ◽

Flower And Fruit Development

The years 1995 and 1996 were low chill years in California with respect to stone fruit dormancy. Advancing reproductive budbreak and flowering was accomplished in `Bing' cherry (Prunus avium) by single-spray treatments of a surfactant {a polymeric alkoxylated fatty amine [N,N-bis 2-(omega-hydroxypolyoxyethylene/polyoxypropylene) ethyl alkylamine]} and potassium nitrate in combination when applied at “tightbud,” ≈ 42 days (1 Feb. 1995) before full bloom and with surfactant and potassium nitrate in combination when 10% green calyx was apparent, 33 days before full bloom. Applying 2% surfactant (v/v) + 6% potassium nitrate (w/v) was most effective in advancing bloom, speeding progression through bloom, and advancing fruit maturity when applied at tightbud stage. Surfactant (2% or 4%) applied with 25% or 35% calcium nitrate (w/v) on 2 Feb. 1996 significantly advanced full bloom compared to nontreated controls. Fruit maturity (1995) was somewhat advanced by surfactant–nitrate treatments, but fruit set and final fruit weight were equivalent among treatments. No phytotoxicity was noted in foliage or fruit. In California, marginal and insufficient winter chilling often causes irregular, extended, or delayed bloom periods, resulting in poor bloom-overlap with pollenizers. As a result, flower and fruit development may be so variable as to have small, green and ripe fruit on the same tree, making harvest more time consuming and costly. Data indicate that this surfactant, in combination with a nitrogenous compound, has potential to advance reproductive budbreak and advance maturity in sweet cherry without reducing fruit set or fruit size. Advancing the ripening time of sweet cherry even 2 to 3 days can increase the price received per 8.2-kg box by $10 to $20.

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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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Estimating Apple Fruit Size Distribution from Early-season Fruit Diameter Measurements

HortScience ◽

10.21273/hortsci14281-19 ◽

2019 ◽

Vol 54 (11) ◽

pp. 1947-1954

Author(s):

Richard P. Marini ◽

James R. Schupp ◽

Tara Auxt Baugher ◽

Robert Crassweller

Keyword(s):

Size Distribution ◽

Fruit Size ◽

Apple Fruit ◽

Fruit Weight ◽

Regression Equations ◽

Full Bloom ◽

Actual Distribution ◽

Early Season ◽

Large Size ◽

Fruit Diameter

In three experiments, diameters of apples representing 7% to 30% of the fruit on a tree were measured at ≈60 days after full bloom. Using previously published regression equations, the early-season fruit diameter values were used to estimate apple fruit weight at harvest (FWH). At harvest, all fruit on sample trees were weighed and the distributions of estimated FWH for fruit measured early in the season were compared with distributions of the actual FWH for whole trees. Actual FWH was normally distributed for only one of the three experiments. Although the estimated mean FWH averaged for the 10 trees was within 9% of the actual mean FWH for all three experiments, the distribution of estimated FWH differed significantly from the actual distribution for all three experiments. All fruit were then assigned to appropriate commercial fruit sizes or box counts (number of fruit/19.05 kg). Fruit size tended to peak on the same four box counts for the estimated and actual populations, but the estimated populations had too few fruits in the small- and large-size box counts. Using early-season estimates of FWH, commercial apple growers and packers can predict fairly accurately the percentage of the crop that will fall into the peak box counts, but a more accurate early-season estimate of the fruit size distribution will likely require measuring 50% of the fruit on a tree.

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Black Polyethylene Mulch Doubled Yield of Fresh-market Field Tomatoes

HortScience ◽

10.21273/hortsci.27.7.787 ◽

1992 ◽

Vol 27 (7) ◽

pp. 787-789 ◽

Cited By ~ 16

Author(s):

Aref Abdul-Baki ◽

C. Spence ◽

R. Hoover

Keyword(s):

Field Experiments ◽

Total Yield ◽

Fruit Size ◽

Fruit Weight ◽

Planting Date ◽

Trickle Irrigation ◽

Fresh Market ◽

Planting Dates ◽

Early Production ◽

Polyethylene Mulch

Field experiments were conducted to a) maximize total yield of fresh-market field tomato (Lycopersicon esculentum Mill.) cultivars using black polyethylene mulch (BPM), and b) increase fruit size and yield during the last 5 weeks of the production period by reducing the number of synthate sinks per plant through eliminating all flowers that appeared during this period. Unmulched treatments under trickle irrigation and multiple applications of soluble fertilizer yielded an average of 43 t·ha-1 for `Sunny' and `Pik-Rite' over the two planting dates. With BPM, total yield increased by 95% to 84 t·ha-1. Although total yield increases due to BPM over the control were highly significant in both cultivars and over the two planting dates, yield increases were higher for the early than for the optimum planting date. BPM also significantly increased early production of `Pik-Rite' but not `Sunny', and the increase in early production was more pronounced for the optimum than the early planting date. Sink reduction during the last 5 weeks of the growing season had no effect on yield or fruit weight during that period.

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Weather Affects Seedless Watermelon Yield, But Not Fruit Size or Quality

HortScience ◽

10.21273/hortsci.39.4.748e ◽

2004 ◽

Vol 39 (4) ◽

pp. 748E-748 ◽

Cited By ~ 1

Author(s):

Timothy E. Elkner* ◽

David H. Johnson

Keyword(s):

Fruit Quality ◽

Total Yield ◽

Fruit Size ◽

Fruit Weight ◽

Soluble Solids ◽

Fruit Number ◽

Seedless Watermelon

Medium-sized triploid watermelons were evaluated in southeast Pennsylvania in 2002 and 2003 to determine the best adapted cultivars for this region. The 2002 season was unusually hot and dry, while 2003 was unusually cool and wet. Yields and fruit quality were compared for the eight cultivars that were grown both seasons to determine the effect of weather on seedless watermelon. Cooler temperatures reduced total fruit number and total yield but not average fruit weight or soluble solids. Researchers evaluating triploid watermelons over several seasons can compare size and °Brix among cultivars, but will need to be cautious when predicting total yields.

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Detection of QTL Controlling Fruit Size and Shape in Cucumis melo L.

HortScience ◽

10.21273/hortsci.39.4.774e ◽

2004 ◽

Vol 39 (4) ◽

pp. 774E-775

Author(s):

Soon O. Park* ◽

Kevin M. Crosby

Keyword(s):

Rapd Markers ◽

Bulked Segregant Analysis ◽

Fruit Size ◽

Fruit Weight ◽

Soluble Solids ◽

Fruit Traits ◽

Size And Shape ◽

Large Bulk ◽

Dna Fragment ◽

Fruit Size And Shape

Mature fruit size and shape are important traits of most melon types. Our objective was to identify RAPD markers associated with major QTL affecting fruit weight, length, diameter and shape by means of bulked segregant analysis in an F2 population from the ananas melon cross of Deltex (larger fruit size) × TGR1551 (smaller fruit size). Clear separations for fruit weight, length, diameter, and shape between Deltex and TGR1551 were observed. Continuous distributions for fruit weight, length, diameter and shape were found in the F2 population indicating quantitative inheritance for the fruit traits. Significant positive correlations were detected between fruit weight and shape traits (r = 0.73 to 0.80). A significant positive correlation was observed between fruit weight and glucose (r = 0.35) or fructose (r = 0.25), whereas no correlation was noted between fruit weight and sucrose or total soluble solids. Two small and large bulks for fruit weight and shape were developed from F2 plants. A total of 240 primers were used to simultaneously screen between the small and large bulks, and between Deltex and TGR1551. Twenty-six RAPD markers were polymorphic for the small and large bulks. Ten markers were found to be significantly and consistently associated with fruit size and shape traits on the basis of simple linear regression. Of the 10 markers associated, four displayed an amplified DNA fragment in the small bulk, while six showed an amplified DNA fragment in the large bulk. The associated marker OJ07.350 explained 15% to 27% of the phenotypic variation for the fruit traits. These markers associated with QTL for melon fruit size and shape are expected to be useful in melon breeding programs for modifying fruit size.

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