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

HortScience ◽  
2007 ◽  
Vol 42 (6) ◽  
pp. 1361-1365 ◽  
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.

scholarly journals Effects of Prohexadione-Calcium on Fruit Size and Return Bloom in Pear

HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1305-1308 ◽  
Author(s):  
David Sugar ◽  
Don C. Elfving ◽  
Eugene A. Mielke
Keyword(s):  
Shoot Growth ◽  
Fruit Size ◽  
Fruit Weight ◽  
Single Application ◽  
Pear Fruit ◽  
Crop Load ◽  
Return Bloom ◽  
Old Trees ◽  
Prohexadione Calcium

The effects of prohexadione-calcium (P-Ca) on fruit size and return bloom in three pear cultivars were evaluated in Medford and Hood River, Ore., and in Cashmere, Wash. A variety of treatment dosages and timings was applied to 4- and 5-year-old trees in 2 years of study. Fruit weight of `Bosc' and `Red Anjou' pears was not affected by P-Ca treatments at any location in either year. However, decreased weight of `Bartlett' pear fruit was associated with all P-Ca treatments in 1999 in Medford except for 83 ppm applied at 2.5 to 6.0 cm shoot growth (first treatment) plus 2, 4, 6, and 8 weeks after first treatment (WAFT) and 125 ppm applied at 2.5 to 6.0 cm growth plus 4 WAFT. `Bartlett' fruit weight was reduced in Medford in 2000 by all treatments except 125 ppm applied at 2.5 to 6.0 cm growth plus 4, 8, and 12 WAFT. In Cashmere in 2000, mean weight of `Bartlett' and `d'Anjou' fruit was reduced by treatments with 83 or 125 ppm applied at 2.5 to 6.0 cm growth plus 2, 4, and 6 WAFT and of `Bosc' pear by all treatments that included more than a single application of P-Ca. Crop load was not significantly different among treatments at any location. Return bloom in the year following P-Ca treatment was reduced in `Bosc' pears by some to most treatments at all locations in both years. In contrast, return bloom was reduced in `Bartlett' and `Anjou' pears only in Hood River in 1999.

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 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 Prohexadione calcium on shoot growth of 'Starkrimson' pear trees

2017 ◽  
Vol 52 (2) ◽  
pp. 75-83 ◽  
Author(s):  
Mateus da Silveira Pasa ◽  
Todd Einhorn
Keyword(s):  
Vegetative Growth ◽  
Shoot Growth ◽  
Block Design ◽  
Fruit Size ◽  
Internode Length ◽  
Soluble Solids ◽  
Cross Sectional ◽  
Growing Seasons ◽  
Return Bloom ◽  
Prohexadione Calcium

Abstract: The objective of this work was to evaluate the fruiting and vegetative growth of 'Starkrimson' pear in response to the application of prohexadione calcium (P-Ca). P-Ca (250 mg L-1) was sprayed to scaffold limbs and to whole trees in commercial orchards. A randomized complete block design was used to minimize declivity effects. Vegetative growth (length and number of shoots, increment in limb and trunk cross-sectional area, number of nodes, and internode length), production (fruit number, yield, yield efficiency, and fruit size), and return bloom were evaluated from 2010 to 2013. P-Ca efficiently controlled shoot growth in all growing seasons, when applied early in the season, due to the reduction in internode length. Production was not negatively affected by the application of P-Ca in all years and at both sites, and fruit size and return bloom were not reduced. Fruit quality attributes were also little affected by P-Ca, except for total soluble solids content, which was lower than that of the control. This shows that P-Ca is efficient to manage tree vigor in high-density 'Starkrimson' pear orchards.

scholarly journals 115 Performance of Various Apple Scion Cultivar/Rootstock Combinations and Postharvest Fruit Quality

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 408E-408
Author(s):  
Maria J. Sindoni V. ◽  
Frank B. Matta
Keyword(s):  
Fruit Quality ◽  
Fire Blight ◽  
Fruit Set ◽  
Fruit Size ◽  
Titratable Acidity ◽  
Fruit Weight ◽  
Fresh Fruit ◽  
Soluble Solids ◽  
Soluble Solids Content ◽  
Solids Content

Several cultivar/rootstock combinations were evaluated for overall performance in Mississippi. This study included postharvest fruit quality during storage as influenced by the various rootstocks. Parameters measured were fruit set, scion and stock trunk cross-sectional area, fire blight tolerance, fruit drop, and maturity indices such as fruit size, firmness, fresh fruit weight, soluble solids content, and juice pH. Cultivar/rootstock combinations were `Earligold'/EMLA 7, `Jonagold'/EMLA 111, `Improved Golden'/EMLA 7, `Improved Golden'/EMLA 111, `Scarlet Gala' /EMLA 7, `Jonafree'/Mark, `Macspur'/M 7A, `Royal Gala'/MM 111, and `Williams Pride'/M 7A. Cultivar and rootstock influenced fruit set. `Royal Gala', `Scarlet Gala', `Improved Golden', and `Earligold' showed maximum fruit set among the various cultivars. MM 111 and EMLA 7 rootstocks increased fruit set. Scion cultivars had the greatest trunk diameter on EMLA 111 and MM 111 and the smallest diameter on Mark. Scion cultivars on Mark and M 7A rootstocks showed less susceptibility to fire blight compared to MM 111 and EMLA 111. Cultivars on EMLA 7 showed moderate susceptibility to fire blight. Cultivars `Jonafree', `Williams Pride', `Macspur', and `Scarlet Gala' were least susceptible to fire blight compared to `Royal Gala'. The remaining cultivars were intermediate in susceptibility to fire blight. Fruit size, firmness, fresh fruit weight, soluble solids content, and juice pH were influenced by cultivar. `Jonagold' and `Williams Pride' produced the largest fruit, while `Jonafree' and `Macspur' yielded the smallest fruit. Total soluble solids were not influenced by cultivar and rootstock combinations. Sugar content of the juice increased as the apples matured and ranged from 12% to 14% among the cultivar/rootstock combinations. Firmness was influenced by cultivar but not rootstock. `Jonafree', `Macspur' had firm fruit, while fruit of `Scarlet Gala', `Williams Pride', and `Earligold' was not as firm. After harvest, the cultivars were stored at 2 °C for ≈4 months under controlled conditions and evaluated for soluble solids content, titratable acidity, pH, and firmness at monthly intervals. Overall, firmness, soluble solids content, and titratable acidity in all cultivars decreased with time in storage. `Improved Golden'/EMLA 7, `Royal Gala'/MM 111, and `Jonagold'/EMLA 111 maintained quality during storage, compared with the remaining cultivars/rootstock combinations, and had a longer storage life.

scholarly journals ‘D’Anjou’ Pear Shoot Growth and Return Bloom, but Not Fruit Size, Are Reduced by Prohexadione-Calcium

HortScience ◽  
2014 ◽  
Vol 49 (2) ◽  
pp. 180-187 ◽  
Author(s):  
Todd C. Einhorn ◽  
Mateus S. Pasa ◽  
Janet Turner
Keyword(s):  
Vegetative Growth ◽  
Shoot Growth ◽  
Fruit Size ◽  
Growth Control ◽  
Shoot Elongation ◽  
Early Spring ◽  
Internodal Length ◽  
Fruit Number ◽  
Return Bloom ◽  
Prohexadione Calcium

Prohexadione-calcium (P-Ca) was applied to ‘Anjou’ pear (Pyrus communis L.) trees in the lower and upper Hood River Valley (HRV), Oregon, to determine its effectiveness for managing the excessive vigor of ‘Anjou’ under different growing climates. Vegetative growth and development (weekly shoot growth rate, total annual extension growth, number of initiated shoots, internodal length, and number of nodes), yield (fruit number and fruit size), and return bloom dynamics were evaluated between 2010 and 2013. P-Ca consistently reduced shoot elongation by ≈40% in all years and at both sites when doses of 250 ppm were applied in early spring (i.e., ≈5 cm of annual shoot extension) compared with untreated trees. Shorter shoots were the result of both reduced internodal growth and fewer nodes. In the cooler, upper HRV, a single P-Ca application controlled shoot elongation for the entire season, but in the warmer, lower HRV, a second flush of growth was generally observed ≈60 days after the first application. A subsequent P-Ca application (250 ppm) provided added growth control in some instances. Yield was unaffected by P-Ca the season of application; however, in one year, an increase in fruit number indirectly led to reduced fruit size; otherwise, fruit size was unaffected by P-Ca. Postharvest fruit quality was not influenced substantially by P-Ca. Return bloom, however, was consistently reduced by P-Ca. Return yield, the year after P-Ca application (recorded in 2013 only), was reduced in proportion to the decrease in return bloom relative to untreated trees. In 2012, ethephon was also evaluated, alone or in combination with P-Ca. When applied on its own either once (150 ppm, 5-cm growth), or twice [150 ppm, 5-cm growth; 300 ppm, 57 days after full bloom (DAFB)], ethephon did not affect vegetative growth or yield components but did improve return bloom and return yield relative to other treatments; however, when combined with P-Ca, ethephon did not reverse reductions in return bloom or return yield induced by P-Ca. The most effective ethephon treatment for promoting flowering and return yield (300 ppm, 57 DAFB) was not tested in combination with P-Ca. We conclude that P-Ca is an effective tool for controlling vigor of ‘Anjou’ trees, but the decrease in return bloom requires additional investigation. Further work testing combinations of ethephon and P-Ca are warranted to optimize growth and productivity of ‘Anjou’ trees.

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.

Performance of prohexadione-calcium on shoot growth and fruit quality of apple — Effect of spray surfactants

2008 ◽  
Vol 88 (1) ◽  
pp. 165-174 ◽  
Author(s):  
J. A. Cline ◽  
C. G. Embree ◽  
J. Hebb ◽  
D. S. Nichols
Keyword(s):  
Vegetative Growth ◽  
Shoot Growth ◽  
Management Practice ◽  
Fruit Size ◽  
Growth Control ◽  
Growth And Yield ◽  
Control Treatment ◽  
Royal Court ◽  
The Us ◽  
Prohexadione Calcium

Vegetative growth control of apples (Malus × domestica Borkh.) is necessary to maintain a balance between growth and cropping. Pruning is a labour-intensive management practice to achieve this and intrinsically stimulates new growth. Prohexadione-calcium (PC) is a plant bio-regulator that effectively regulat es the shoot extension growth of apples and other tree fruits. Previous research has demonstrated that its efficacy can vary based on the use of spray surfactants and adjuvants. This study investigated the efficacy of two rates of Apogee™, the commercial form of PC, used in combination with the spray surfactants Sylgard 309 and LI 700, on extension shoot growth and yield parameters. Experiments were conducted in Ontario on Empire and Nova Scotia on Royal Court™ Cortland apples. Treatments of 0, 75 or 125 mg L-1 PC, with and without either 0.5% (vol/vol.) LI 700 surfactant or 0.05% (vol/vol) Sylgard 309 surfactant were applied to Empire trees, and 75 or 125 mg L-1 PC, with or without 0.5% (vol/vol) LI 700, were applied to Royal Court™ trees. An untreated control treatment was also included for comparison purposes. A total of two sprays were applied to the Empire trees and a total of three sprays were applied to the Royal Court™ trees. PC significantly decreased the vegetative growth of Empire and Royal Court™ trees by approximately 18 to 44%, respectively, and the efficacy of PC was enhanced when combined with either Sylgard 309 or LI 700 surfactant. No additional benefit in vegetative growth control was gained when using Apogee™ at rates of 125 mg L-1 PC, relative to 75 mg L-1 PC. The rate of Apogee™ did not influence the number of fruit or yield per tree or mean fruit size of either cultivar. For Empire, LI 700 and Sylgard 309 significantly reduced the number of fruit per tree, resulting in lower yields and crop densities. In addition, higher mean fruit weights, and a greater distribution of fruit in the larger size categories were observed for LI 700. Fruit from Royal Court trees treated with the highest rate of Apogee™ had higher crop densities, poorer coloured fruit, and a higher percentage of fruit less than 60 mm in diameter. These data provide support for the use of alternative surfactants with Apogee™ other than those listed on the US and Canadian product labels. Key words: Apogee™, Empire, Cortland, Regalis, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate, surfactant

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.

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