scholarly journals Influence of Mechanical String Thinning Treatments on Vegetative and Reproductive Tissues, Fruit Set, Yield, and Fruit Quality of ‘Gala’ Apple

HortScience ◽  
2013 ◽  
Vol 48 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Thomas M. Kon ◽  
James R. Schupp ◽  
H. Edwin Winzeler ◽  
Richard P. Marini
Keyword(s):  
Leaf Area ◽  
Fruit Set ◽  
Fruit Size ◽  
Fruit Weight ◽  
Spindle Speed ◽  
State University ◽  
Cross Sectional ◽  
Spindle Rotation ◽  
Return Bloom ◽  
Extension Center

The objectives of this experiment were to test the efficacy of a mechanical string thinner (Darwin PT-250; Fruit-Tec, Deggenhauserertal, Germany) on apple and to identify an optimal range of thinning severity as influenced by spindle rotation speed. Trials were conducted in 2010 and 2011 at the Pennsylvania State University Fruit Research and Extension Center in Biglerville, PA, on five-year-old ‘Buckeye Gala’/M.9 apple trees that were trained to tall spindle. A preliminary trail on five-year-old ‘Cripps Pink’/M.9 was conducted to determine the relationship between string number and thinning severity. As the number of strings increased, the level of thinning severity increased. A range of spindle speeds (0 to 300 rpm) was applied to the same trees for two consecutive years. As spindle speed increased, blossom density (blossom clusters per limb cross-sectional area) was reduced as was the number of blossoms per spur. In 2010, leaf area per spur was reduced 9% to 45%. In 2011, the fastest spindle speed reduced leaf area per spur 20%. Although increased spindle speed reduced cropload, injury to spur leaves may have inhibited increases in fruit size. The largest gain in fruit weight was 28 g (300 rpm) compared with the control. In both years, the most severe thinning treatments reduced yield by more than 50%. There was no relationship between spindle speed and return bloom. Severe thinning treatments (240 to 300 rpm) caused significant reductions in spur leaf area, yield, and fruit calcium and did not improve fruit size or return bloom. Spindle speeds of 180 and 210 rpm provided the best overall thinning response and minimized injury to spur leaves, but cropload reduction was insufficient in years of heavy fruit set. Therefore, mechanical blossom thinning treatments should be supplemented with other thinning methods. Mechanical string thinning may be a viable treatment in organic apple production, where use of chemical thinners is limited.

scholarly journals The Effect of Repeat Annual Applications of Prohexadione–calcium on Fruit Set, Return Bloom, and Fruit Size of Apples

HortScience ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 376-379 ◽  
Author(s):  
Duane W. Greene
Keyword(s):  
Vegetative Growth ◽  
Fire Blight ◽  
Fruit Set ◽  
Fruit Size ◽  
Application Rate ◽  
Fruit Weight ◽  
Initial Application ◽  
Shoot Blight ◽  
Return Bloom ◽  
Prohexadione Calcium

Prohexadione–calcium (ProCa) is used routinely in orchards to control vegetative growth and to reduce the shoot blight phase of fire blight. This communication reports on multiple-year applications of ProCa with special emphasis on treatment effects on fruit set, fruit size, and return bloom. Increased fruit set was confirmed from high rates of ProCa above 125 mg·L−1. The increase in fruit set was attributed primarily to a reduction of abscission during June drop rather than an increase in initial set. ProCa decreased fruit weight in some instances. Part of this reduction could be attributed to increased fruit set. However, the large reduction in fruit weight at harvest could only be explained by a direct effect of ProCa when used at high rates. When ProCa was applied as a concentrate spray at 250 mg·L−1, terminal growth was reduced comparable to the application made as a tree row volume dilute spray (1×). However, fruit set was increased when the spray volume in which ProCa was delivered was reduced to 4×. A range of ProCa rates was used on ‘Mutsu’. An initial application rate of 42 mg·L−1 followed by similar subsequent rates controlled growth comparably to higher initial and total rates, yet low rates had no effect on fruit weight or return bloom. Low rates of ProCa appear to be effective at controlling vegetative growth yet appear to have minimal side effects. High rates, especially those intended to reduce fire blight, come with the risk of increased fruit set and reduced fruit size and return bloom.

scholarly journals 509 Defoliation Affects Return Bloom, Fruit Set, and Fruit Quality of Three Apple Cultivars

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 482D-482 ◽  
Author(s):  
David E. Davis ◽  
John A. Barden ◽  
Ross E. Byers
Keyword(s):  
Fruit Set ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Cross Sectional ◽  
Yield Efficiency ◽  
Tree Defoliation ◽  
Crop Density ◽  
Golden Delicious ◽  
Apple Cultivars ◽  
Return Bloom

In 1997 and 1998, we determined the effects of defoliation on return bloom and fruit set following a light cropping year. In one study, `Braeburn' trees were hand-thinned to a crop density (CD) of 3 fruit/cm 2 trunk cross sectional area (TCSA) in late May 1997, and then either completely defoliated or half of the tree defoliated by hand on one of five dates between June and Sept. 1997. Compared to a nondefoliated control, both whole and half-tree defoliation on all dates reduced fruit count and yield efficiency (kilograms per square centimeter of TCSA) and affected fruit weight, starch, firmness, and soluble solids in 1997. In 1998, return bloom and fruit set were reduced by most 1997 defoliation treatments. Compared to other dates, defoliation on 3 July caused the greatest reduction in return bloom in both whole and half-defoliated trees. In another study, `Braeburn' trees were hand-thinned to a CD of 5 in late May 1998; complete defoliation by hand on 1, 15, or 29 July reduced return bloom and fruit set in 1999; the 1 July treatment resulted in zero return bloom. `Golden Delicious' and `York' trees were thinned to a CD of 3 in late May 1998 and were hand-defoliated on 21 July or 12 August by removing every other leaf or removing three of every four leaves over the entire tree. In 1999, return bloom and spur and lateral fruit set were reduced by all defoliation treatments. Fruit set was most reduced by the 12 Aug. treatment. Fruit set for `York' was lower than for `Golden Delicious' in all cases.

scholarly journals Ethephon as a Blossom and Fruitlet Thinner Affects Crop Load, Fruit Weight, Fruit Quality, and Return Bloom of ‘Summerred’ Apple (Malus ×domestica) Borkh.

HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 432-438 ◽  
Author(s):  
Mekjell Meland ◽  
Clive Kaiser
Keyword(s):  
Fruit Quality ◽  
Malus Domestica ◽  
Fruit Set ◽  
Quality Parameters ◽  
Fruit Weight ◽  
Cross Sectional ◽  
Biennial Bearing ◽  
Green Background ◽  
Soluble Solid ◽  
Return Bloom

‘Summerred’ apples (Malus domestica Borkh.) are highly susceptible to biennial bearing if not properly thinned. This results in erratic yields and also affects fruit quality adversely. Between 2003 and 2005, ‘Summered’/‘M9’ trees were treated with ethephon at concentrations of 250, 375, and 500 mg·L−1 when most king flowers opened (≈20% bloom) or at concentrations of 500, 625, and 750 mg·L−1 when the average fruitlet size was 10 mm in diameter. The experiment was conducted with 2.5-m height slender spindle trees sprayed to the point of runoff with a hand applicator only when temperatures exceeded 15 °C. Within 2 weeks after the second application, fruit set was reduced linearly with increasing concentrations of ethephon to less than one fruitlet per cluster at the highest concentrations used. Most thinning treatments reduced fruit set significantly compared with unthinned trees. Fruit numbers per tree decreased significantly with increasing ethephon concentrations, and the highest concentrations of ethephon applied during bloom or when the average fruitlet size was 10 mm in diameter resulted in overthinning. Yield results confirmed the fruit set response in which yield reductions were significant at the highest concentrations of ethephon (2.1 kg/tree) compared with hand-thinned trees (7.3 kg/tree) in 2005. All thinning treatments resulted in higher percentage of fruits larger than 60 mm diameter compared with unthinned control fruit. Thinning resulted in significantly higher soluble solid contents, and this was especially so for hand-thinned trees. Other fruit quality parameters like yellow–green background color did not show a clear response to thinning. Return bloom was, however, improved on all thinned trees. It is recommended that ethephon be applied at a rate of 375 mg·L−1 when king flowers open or at a rate of 625 mg·L−1 when the average fruitlet size is 10 mm in diameter. This thins ‘Summerred’ apples to a target of approximately five fruits/cm2 per trunk cross-sectional area or 50 to 70 fruits per 100 flower clusters without impacting on fruit quality, yield, or return bloom the next year.

scholarly journals CPPU Influences Fruit Quality, Fruit Set, Return Bloom, and Preharvest Drop of Apples

HortScience ◽  
1993 ◽  
Vol 28 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Eric A. Curry ◽  
Duane W. Greene
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Fruit Weight ◽  
Linear Increase ◽  
Soluble Solids ◽  
Naphthalene Acetic Acid ◽  
Flesh Firmness ◽  
Application Rates ◽  
Solids Concentration ◽  
Return Bloom

CPPU was applied to whole spur `Delicious' apple (Malus domestica Borkh.) trees in central Washington at 0,6.25,12.5,25, or 50 mg·liter-1 at full bloom (FB) or FB plus 2 weeks. At both application times, the flesh firmness of treated fruit linearly increased with increasing concentration. CPPU applied at 0,5,10,15, or 20 mg·liter-1 to spur `Delicious' trees in Massachusetts at king bloom resulted in a linear increase in flesh firmness at harvest and following 28 weeks in air storage at 0C. CPPU did not affect the incidence of senescent breakdown, decay, or cork spot. Fruit length: diameter (L/D) ratios generally increased at all doses. Fruit weight was not influenced at either location. All CPPU concentrations reduced return bloom on `Delicious' apples in Massachusetts in 1989. Of the 10, 20, or 40 mg·liter-1 treatments for `Empire' apples, only CPPU at 40 mg·liter-1 reduced return bloom. CPPU applied to `Empire' apples in Massachusetts did not effect fruit set, soluble solids concentration, L/D, or firmness; however, fruit weight increased linearly with concentration. CPPU applied at 100 mg·liter-1 retarded preharvest fruit drop of `Early McIntosh' in Massachusetts for ≈7 days but was not as effective as NAA at 20 mg·liter-1. In a larger semicommercial trial, `Delicious' fruit treated with CPPU at 5,10, or 15 mg·liter-1 at FB, petal fall (PF), or PF plus 1 week, respectively, were harvested and graded over a commercial packing line. Malformities caused by CPPU at the highest doses reduced packout, although all CPPU application rates reduced the percent fruit culled due to poor color. CPPU increased packed fruit size, since the size of fruit (64 mm in diameter) in the >150-fruit/box size decreased, while the size of fruit (72 mm in diameter) in the 100- and 130-fruit/box sizes increased. Treated fruit stored for 7 months at 1C were firmer than nontreated controls. Chemical names used: N-(2-chloro-4-pyridyl)- N' -phenylurea (CPPU); 1 naphthalene-acetic acid (NAA).

scholarly journals Crop Load Reduction and Fruit Size Following Multi-step Thinning of 'Empire' Apple

HortScience ◽  
2002 ◽  
Vol 37 (1) ◽  
pp. 130-133 ◽  
Author(s):  
Ed Stover ◽  
Mike Fargione ◽  
Richard Risio ◽  
Xiaoe Yang
Keyword(s):  
New York ◽  
Field Experiments ◽  
Total Yield ◽  
Fruit Size ◽  
Fruit Weight ◽  
Naphthalene Acetic Acid ◽  
Cross Sectional ◽  
Crop Load ◽  
Contrast Analysis ◽  
Return Bloom

Two years of field experiments were conducted in eastern New York to evaluate the efficacy of a multi-step thinning approach on reducing crop load (no. fruit per cm2 trunk cross-sectional area) and increasing fruit size of 'Empire' apple (Malus ×domestica Borkh.). Applications of Endothall (ET) at 80% bloom, NAA + carbaryl (CB) at petal fall (PF), and Accel™ + CB at 10 mm king fruitlet diameter (KFD), alone and in all combinations, were compared to a nonthinned control and to the application of NAA + CB at 10 mm KFD (commercial standard). In both 1996 and 1997, orthogonal contrasts indicated the multi-step treatment significantly increased fruit size, reduced cropload, and reduced yield compared to single applications. Effects on cropload of consecutive treatments were largely predicted by multiplying effects of individual treatments. Although all thinning treatments except for NAA + CB at PF in 1997 significantly reduced cropload, no single treatment thinned sufficiently to ensure good return bloom. Compared to NAA + CB at 10 mm KFD, multi-step thinning with NAA + CB at PF followed by Accel™ + CB at 10 mm KFD produced bigger fruits in both years, and resulted in a higher percentage of spurs carrying a single fruit in 1996. When fruit size was evaluated after removing the effect of cropload (cropload adjusted fruit weight), NAA + CB at PF, Accel™ + CB at 10 mm, and the two applied sequentially, resulted in greater cropload adjusted fruit weight than the nonthinned control in both years, whereas NAA + CB at 10 mm did not. Contrast analysis of treatments with and without ET showed no significant effect of including ET on fruit size, though total cropload was reduced at P = 0.10 and total yield was reduced (P = 0.03 in 1996 and P = 0.12 in 1997). No deleterious effects from multi-step treatments have been observed. All thinning treatments significantly increased return bloom in 1996 and 1997 compared to the control with little difference observed between treatments. Chemical names used: naphthalene acetic acid (NAA); 1-naphthyl-N-methylcarbamate [carbaryl (CB)]; 6-benzyladenine [BA (Accel™)]; 7-oxabicyclo (2,2,1) heptane-2,3 dicarboxylic acid [ET (Endothall™)]

scholarly journals Sowing Dates and Fertilizer Application on Growth and Yield of Muskmelon (Cucumis melo L.) at Ado-Ekiti

2020 ◽  
pp. 11-21
Author(s):  
Matthew Aluko
Keyword(s):  
Leaf Area ◽  
Block Design ◽  
Fruit Size ◽  
Fertilizer Application ◽  
Fruit Weight ◽  
Fruit Yield ◽  
Growth And Yield ◽  
State University ◽  
Sowing Dates ◽  
Number Of Leaves

Information on some agronomic practices are required for muskmelon production as there is no record of its production in Ado-Ekiti. A field study of 3 x 2 factorial experiment of sowing dates (January, May and September) and NPK 15:15:15 fertilizer application (0 and 333 kg ha-1) was laid out in a Randomized Complete Block Design in three replicates at the Teaching and Research Farm of Ekiti State University, Ado-Ekiti, Nigeria. Data collected on the number of leaves and branches, leaf area, vine length, day to flowering, 50% flowering, number of fruit, fruit size and yield were subjected to analysis of variance and treatment means separated by Duncan's Multiple Range Test at 5% probability. Dates of sowing did not significantly influence growth but muskmelon planted in May gave a higher number of leaves plant-1, leaf area and vine length. Fertilized plants produced better growth and earlier flowering than unfertilized plants. The number of fruits ha-1, average fruit weight and fruit yield ha-1 of 11606, 0.78 kg and 9.09 t ha-1 respectively were produced by fertilized plants which were significantly higher than 10036.70, 0.28 kg and 2.44 t ha-1 from unfertilized plants. Muskmelon planted in September produced a higher number of fruits and fruit yield of 12418 and 11.29 t ha-1 while muskmelon planted in May produced higher fruit weight (0.94 kg) but these did not differ significantly from other sowing dates. Planting muskmelon under the rain-fed condition with adequate fertilizer application gave better performance and is thereby recommended for muskmelon production in Ado-Ekiti. 

scholarly journals EARLY SPRING APPLICATION OF AMINOETHOXYVINILGLYCINE (AVG) INCREASES FRUIT SET AND YIELD OF ‘ROCHA’ PEARS

2017 ◽  
Vol 39 (4) ◽  
Author(s):  
MATEUS DA SILVEIRA PASA ◽  
BRUNO CARRA ◽  
CARINA PEREIRA DA SILVA ◽  
MARLISE NARA CIOTTA ◽  
ALBERTO FONTANELLA BRIGHENTI ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Fruit Set ◽  
Block Design ◽  
Quality Attributes ◽  
Fruit Weight ◽  
Early Spring ◽  
Full Bloom ◽  
Growing Seasons ◽  
Randomized Block Design ◽  
Return Bloom

ABSTRACT The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. Ethylene is associated with abscission of flowers and fruitlets. Then, the application of ethylene synthesis inhibitors, such as AVG, is a potential tool to increase fruit set of pears. The objective of this study was to evaluate the effect of AVG, sprayed at different rates and timings, on fruit set, yield and fruit quality of ‘Rocha’ pear. The study was performed in a commercial orchard located in the municipality of São Joaquim, SC, during the growing seasons of 2014/2015 and 2015/2016. Plant material consisted of ‘Rocha’ pear trees grafted on quince rootstock ‘BA29’. AVG was tested at different rates (60 mg L-1 and 80 mg L-1) and timings [full bloom, one week after full bloom (WAFB), and two WAFB), either alone or in combination. The experiment was arranged in a randomized block design, with at least five single-tree replications. The fruit set, number of fruit per tree, yield, estimated yield, fruit weight, return bloom, and fruit quality attributes were assessed. Fruit set and yield were consistently increased by single applications of AVG at 60 and 80 mg L-1 at both one and two weeks after full bloom, without negatively affecting fruit quality attributes and return bloom.

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

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.

scholarly journals EFFECTS OF HYDROGEN CYANAMIDE ON APPLE AND PLUM FRUIT THINNING

HortScience ◽  
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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