Apple fruit set is influenced by altered floral bud density but not by reduced carbohydrate reserves

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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Gibberellic acid combined with hand pollination increases ‘Red’ and ‘Lessard Thai’ sugar apple fruit quality and produced parthenocarpic ‘Gefner’ atemoya fruits

Ciência Rural ◽

10.1590/0103-8478cr20180353 ◽

2019 ◽

Vol 49 (9) ◽

Author(s):

Marlon Cristian Toledo Pereira ◽

Silvia Nietsche ◽

Jonathan Henry Crane ◽

Wanda Montas ◽

Célia Lúcia Siqueira ◽

...

Keyword(s):

Gibberellic Acid ◽

Fruit Quality ◽

Fruit Set ◽

Apple Fruit ◽

Fruit Weight ◽

High Quality ◽

Hand Pollination ◽

Fruit Setting ◽

Natural Pollination

ABSTRACT: The present research aimed to evaluate the effect of applying gibberellic acid (GA3) with hand (HP) or natural pollination (NP) on fruit set and the fruit quality of ‘Red’ and ‘Lessard Thai’ sugar apple and ‘Gefner’ atemoya fruits.This study was performed in an experimental orchard located in Homestead, Florida, USA. The experimental design included randomized blocks, with eight treatments, four replicates and four plants per plot. Treatments included: (1) HP; (2) HP + 10 mg L-1 GA3; (3) HP + 100 mg L-1 GA3; (4) HP + 1,000 mg L-1 GA3; (5) NP; (6) NP + 10 mg L-1 GA3; (7) NP + 100 mg L-1 GA3 and (8) NP + 1,000 mg L-1 GA3. The HP plus 1,000 mg L-1 GA3 promoted fruit setting above 90% over the 14 weeks for all genotypes evaluated. Significant increments for length and total fruit weight were observed. ‘Red’ sugar apple and atemoya had a reduced number of seeds per fruit. The NP plus GA3 (1,000 mg L-1) was effective in producing high quality seedless ‘Gefner’ atemoya fruits. This investigationdemonstratedthat GA3 plus hand pollination produced high quality sugar apple and atemoya seeded fruits and in association with natural pollination promoted seedless ‘Gefner’atemoya fruits.

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APPLE FRUIT CHEMICAL THINNING IN CHIHUAHUA, MÉXICO

Revista Fitotecnia Mexicana ◽

10.35196/rfm.2008.3.243 ◽

2008 ◽

Vol 31 (3) ◽

pp. 243

Author(s):

David I. Berlanga-Reyes ◽

Alejandro Romo-Chacón ◽

Ángel R. Martínez-Campos ◽

Víctor M. Guerrero-Prieto

Keyword(s):

Fish Oil ◽

Fruit Set ◽

Fruit Size ◽

Apple Fruit ◽

Naphthalene Acetic Acid ◽

Alternate Bearing ◽

Fruit Thinning ◽

Equatorial Diameter ◽

Large Trees ◽

Golden Delicious

Chemical fruit thinning is a common practice in apple (Malus x domestica Borkh.) orchards for achieving high quality fruits, reduced costs of hand-thinning and promote return of flowering. Hand thinning is a common and high cost practice, not only due to the labor involved, but also because seedling and vigorous clonal rootstocks result in large trees. The chemical thinning agents: Ethephon (ETH), Carbaryl (CB), Naphthalene acetic acid (NAA), 6- Benzyladenine (6-BA), and fish oil were evaluated on ‘Golden Delicious’ and ‘RedChief Delicious’ apple trees in 2004 and 2005. Chemical thinning effect was compared with early and late handthinnings. Treatments were sprayed when the biggest fruit in the clusters was 10 mm in equatorial diameter. NAA showed the best effect in reducing final fruit set in both cultivars and years evaluated, with results comparable to those of early hand-thinning (thinned when king-fruit size was 10 mm) in ‘Golden Delicious’ trees. In ‘RedChief Delicious’, fruit set reduction by NAA, fish oil and CB treatments was similar to early hand-thinned trees only in 2005. In 2005, time spent during supplementary hand-thinning in ‘Golden Delicious’ trees was reduced by chemical thinning treatments, except by fish oil; whereas in ‘RedChief Delicious’ only NAA K-salt reduced it in 2004. An increase in fruit equatorial diameter was observed only in 2004 with NAA and fish oil. Alternate bearing, typical of ‘Golden Delicious’, was not diminished by these chemical thinning treatments.

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301 Bioregulators Affect Apple Yield and Quality Attributes

HortScience ◽

10.21273/hortsci.34.3.494d ◽

1999 ◽

Vol 34 (3) ◽

pp. 494D-494

Author(s):

George Ouma ◽

Frank Matta

Keyword(s):

Fruit Set ◽

Sugar Content ◽

Quality Attributes ◽

Apple Fruit ◽

Diameter Ratio ◽

Cross Sectional ◽

Fruit Length ◽

Yield And Quality ◽

Apple Cultivars ◽

High Yields

Experiments were conducted in 1995 and 1996 to investigate the effect of Accel and Carbaryl sprayed 2 weeks postbloom on apple fruit yield and quality and to relate the degree of fruit set reduction to the yield of three apple cultivars (Empire, Jon-A-Red, and Braeburn). The treatments consisted of Accel 25 ppm, Accel 50 ppm, Accel 75 ppm, Carbaryl 0.05%, Carbaryl 0.1%, Carbaryl 0.2%, and an unsprayed control. Trials conducted over the 2 years indicated that Accel and Carbaryl reduced the fruit set of three apple cultivars as shown by the lower number of fruit per limb cross-sectional area on the sprayed trees compared to the unsprayed trees. Most effective concentrations in reducing the fruit set on apples were Accel 50 ppm, Accel 75 ppm, Carbary 0.01%, and Carbaryl 0.2%, with high yields and high fruit rates. Therefore, it was concluded that these are the best concentrations for thinning of apples. Other quality attributes, such as pH, sugar content, and percent fruit red were also increased by the treatments. The treatments did not influence the number of seeds in the fruit, fruit length, fruit diameter, and fruit length: diameter ratio.

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