scholarly journals Gibberellic Acid-induced Fruit Set of Rabbiteye Blueberry following Freeze and Physical Injury

HortScience ◽  
1995 ◽  
Vol 30 (6) ◽  
pp. 1241-1243 ◽  
Author(s):  
D. Scott NeSmith ◽  
Gerard Krewer ◽  
Mark Rieger ◽  
Ben Mullinix
Keyword(s):  
Gibberellic Acid ◽  
Field Experiments ◽  
Fruit Set ◽  
Field Trials ◽  
Fruit Weight ◽  
Physical Injury ◽  
Vaccinium Ashei ◽  
Freeze Injury ◽  
Green House ◽  
Series Of Experiments

In a series of experiments, gibberellic acid (GA3) was applied to rabbiteye blueberries (Vaccinium ashei Reade) under field and greenhouse conditions to determine if fruit set could be improved following physical or freeze injury to flowers. In field experiments, physically damaged flowers (i.e., corollas and styles removed, styles only removed, or ovaries lanced) of `Climax' and `Tifblue' treated with GA3 (4% ProGib at 250 mg·liter–1) set substantially more fruit than nontreated, damaged flowers. Under green-house conditions, GA3 applied postfreeze to `Tifblue' and `Brightwell' resulted in increased fruit set compared to unsprayed control plants of the same cultivars. Freeze-damaged plants had substantially reduced fruit set overall but to a much lesser extent for GA3-treated plants than for those not treated with GA3. Individual fruit weight was reduced by GA3 applications, as was berry seediness. Results from these greenhouse and field trials suggest that GA3 can be used to salvage a blueberry crop following a moderate freeze during bloom.

scholarly journals Effect of GA3 Bloom Sprays on Fruit Set and Yield of Rabbiteye Blueberry

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 853D-853 ◽  
Author(s):  
J.G. Williamson ◽  
R.L. Darnell ◽  
G. Krewer ◽  
S. NeSmith
Keyword(s):  
Fruit Development ◽  
Field Experiments ◽  
Fruit Set ◽  
Fruit Size ◽  
Fruit Weight ◽  
Night Temperature ◽  
Vaccinium Ashei ◽  
Hand Pollination ◽  
Southern Georgia

Field and growth chamber experiments, and grower trials, were conducted to determine the effects of GA3 sprays on yield and fruit quality of rabbiteye blueberry (Vaccinium ashei Reade) in northern Florida and southern Georgia. Multiple GA3 sprays at various stages of flower development increased fruit set and yield in field experiments (Florida) and grower trials (Georgia) when compared to controls. Nonpollinated rabbiteye flowers sprayed with GA3 had greater percent fruit set and delayed fruit development compared to hand pollination. Percent fruit set and average fruit weight were reduced at 21C night temperature when compared to 10C night temperature for both hand-pollinated and GA3-treated fruit. Overall, yields were increased by multiple applications of GA3 during bloom, but average fruit size was reduced and the fruit development period was lengthened.

scholarly journals Flower Bud Stage and Chill Hours Influence the Activity of GA3 Applied to Rabbiteye Blueberry

HortScience ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 316-318 ◽  
Author(s):  
D.S. NeSmith ◽  
Gerard Krewer
Keyword(s):  
Gibberellic Acid ◽  
Growth Regulator ◽  
Flower Development ◽  
Fruit Set ◽  
Developmental Stages ◽  
Single Application ◽  
Flower Buds ◽  
Flower Bud ◽  
Vaccinium Ashei

Individual flower clusters of `Tifblue' rabbiteye blueberry (Vaccinium ashei Reade) were treated with 300 ppm GA at several flower bud stages to determine the activity of the growth regulator in promoting fruit set. Applications were made one time only at a specified stage of flower development, or once followed by a second application. A single application of GA when flower buds had elongated but corollas had not expanded (stage 5) led to the largest increase in fruit set. Two applications of GA, 10 to 18 days apart, increased fruit set compared with a single application at flower developmental stages other than stage 5. Fruit set promoted by a single spray of GA imposed on fully expanded corollas (stage 6) decreased with increasing number of chill hours (350, 520, 760, or 1150). Chemical names used: gibberellic acid (GA).

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

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.

scholarly journals Response of Rabbiteye Blueberry (Vaccinium ashei Reade) to the Growth Regulators CPPU and Gibberellic Acid

HortScience ◽  
2002 ◽  
Vol 37 (4) ◽  
pp. 666-668 ◽  
Author(s):  
D. Scott NeSmith
Keyword(s):  
Gibberellic Acid ◽  
Growth Regulator ◽  
Fruit Set ◽  
Total Yield ◽  
Control Treatment ◽  
Single Application ◽  
Treatment Results ◽  
Vaccinium Ashei ◽  
Berry Size ◽  
Mature Field

Experiments were conducted during 1999 and 2000 at Griffin, Ga., with rabbiteye blueberries (Vaccinium ashei Reade) to determine how the growth regulator CPPU affected fruit set, berry size, and yield. CPPU (applied at two different timings) was used alone, and in conjunction with GA3 on mature, field-grown `Tifblue' plants. A control treatment without either growth regulator was also included. The CPPU concentration used was 10 mg·L-1 (a single application per treatment), and the GA3 concentration used was 200 mg·L-1 (two applications per treatment). Results from both years showed a positive benefit of CPPU with respect to fruit set and berry size, especially in the absence of GA3. Depending on timing, berry number per plant was increased by more than 200% in 1999 using CPPU. Berry size increases of more than 30% occurred in 2000 when CPPU alone was applied at 17 d after flowering (DAF). CPPU did not increase berry size of GA3-treated plants in either year. Total yield per plant during 2000 was 5.0, 7.1, and 8.3 kg for control, CPPU applied 7 DAF, and CPPU applied 17 DAF treatments, respectively, without GA3. While CPPU did substantially increase fruit set, berry size, and yield of `Tifblue', there was a notable delay in fruit ripening. These results suggest that CPPU may be useful for increasing yield of rabbiteye blueberries under conditions of inadequate fruit set (such as occurs in much of the Southeast), but a delay in ripening will likely result. Chemical names used: N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU); gibberellic acid (GA3).

scholarly journals Salvaging a Rabbiteye Blueberry Crop with GA3 following Sub-freezing Temperatures

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 575d-575
Author(s):  
D. Scott NeSmith ◽  
Gerard Krewer ◽  
Orville Lindstrom
Keyword(s):  
Gibberellic Acid ◽  
Cold Exposure ◽  
Fruit Set ◽  
Temperature Limit ◽  
Flower Buds ◽  
Vaccinium Ashei ◽  
Growth Chambers ◽  
Freezing Temperatures ◽  
Flower Damage

Recent research in Georgia indicated gibberellic acid (GA3) could possibly be used to induce fruit set of freeze damaged rabbiteye blueberry (Vaccinium ashei) blooms. This research was conducted to determine the subfreezing temperature limit at which GA3 could be expected to be of use in salvaging a crop with freeze-damaged flowers. Rabbiteye blueberries with flower buds at stages 5 to 6 of development (fully elongated corollas and open blooms) were exposed to temperatures of 0, –1, –3, and –4.5°C in growth chambers to simulate overnight freezing events. After cold exposure, plants were placed in a greenhouse with a hive of bumblebees. Half of the plants were treated with GA3 and half were not. The number of flowers and subsequent fruit were recorded in order to calculate fruit set. Temperatures of –1°C and below caused fruit set resulting from pollination by bees to decline compared to control plants; whereas, flowers treated with GA3 had fruit set comparable to control plants down to –3°C. Plants exposed to –3°C had 50% to 80% fruit set when treated with GA3 compared to 5% to 19% fruit set for untreated plants. Temperatures of –4.5°C caused severe flower damage, and fruit set by pollination or GA3 was very poor (<2%). These results indicate that GA3 should be useful in salvaging a blueberry crop exposed to temperatures of – 1 to –3.5°C during bloom.

scholarly journals GIBBERELLIC ACID ENHANCES FRUIT SET OF PHYSICALLY DAMAGED BLUEBERRY FLOWERS

HortScience ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 430c-430
Author(s):  
Gerard Krewer ◽  
Scott NeSmith ◽  
Mark Rieger ◽  
Ben Mullinix
Keyword(s):  
Gibberellic Acid ◽  
Fruit Development ◽  
Fruit Set ◽  
The Other ◽  
Vaccinium Ashei ◽  
Freeze Damage ◽  
Corroborative Evidence ◽  
Better Than

Rabbiteye blueberry (Vaccinium ashei R.) flowers often suffer slight freeze damage that prevents fertilization and fruit development. To determine if gibberellic acid (GA3) might be useful in rescuing freeze-damaged flowers the following treatments were applied before anthesis to two cultivars at different locations: 1) undamaged control, 2) approximately two-thirds of the corolla and most of the style removed, 3) approximately half of the style removed, and 4) ovules lanced with an insect pin by driving it through the equator of the undeveloped berry until the point came out the other side. Half the bushes were not sprayed, and half were sprayed with GA3 (312 ppm, v/v) the night following treatment. `Climax' at Chula, Ga., had good fruit set for treatment 1 with and without GA3 (70% to 85%). Good fruit set also occurred for treatment 2, 3, and 4 where GA3 was applied (47% to 54%), but poor fruit set without GA3 (4% to 16%). `Tifblue' at Chula had significantly better fruit set for treatment 1 with GA3 (54% vs. 27%). Excellent fruit set occurred for treatment 2, 3, and 4 where GA3 was applied (81% to 96%), and poor fruit set without GA3 (6% to 7%). `Tifblue' fruit set by GA3 sized better than `Climax' fruit set by GA3. The experiments provide corroborative evidence that flowers that have suffered freeze damage to the stigma, style, corolla, and perhaps ovules can be set with GA3.

scholarly journals EFFECT OF PLANT GROWTH REGULATORS FOR INDUCTION OF PARTHENOCARPIC FRUIT IN KAKROL (Momordica dioica Roxb.)

2007 ◽  
Vol 20 (2) ◽  
pp. 17-22 ◽  
Author(s):  
R. N. Chowdhury ◽  
M. G. Rasul ◽  
A. K. M. Aminul Islam ◽  
M. A. K. Mian ◽  
J. U. Ahmed
Keyword(s):  
Plant Growth ◽  
Gibberellic Acid ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Plant Growth Regulator ◽  
Fruit Set ◽  
Fruit Weight ◽  
Parthenocarpic Fruit ◽  
Three Stages ◽  
Fruit Diameter

An experiment was conducted to find out the suitable plant growth regulator(s) for inducing parthenocarpic fruit in kakrol (Momordica dioicia Roxb). Four plant growth regulators, viz. NAA and 2, 4-D (Auxins), Fulmet (Cytokinine) and GA3 (Gibberellic acid) were sprayed at three stages (a day before anthesis, at anthesis, a day after anthesis). Out of four growth regulators 2, 4-D and fulmet induced parthenocarpic fruit development. Fruit set percent, final fruit weight, fruit length and fruit diameter varied significantly with different treatment combinations. 2, 4-D at 50 ppm when applied at anthesis showed better performance in inducing parthenocarpy.DOI: http://dx.doi.org/10.3329/bjpbg.v20i2.17030

scholarly journals Benzyladenine and Gibberellic Acid (GA3) Increase Runner Production in Day-neutral Strawberries

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 831D-831
Author(s):  
A. Dale ◽  
D.C. Elfving ◽  
C. Chandler
Keyword(s):  
Gibberellic Acid ◽  
Field Trials ◽  
Series Of Experiments ◽  
Greenhouse Tests

Day-neutral strawberries produce runners less freely than June-bearing strawberries, which leads to reduced production in nursery fields. To alleviate this, a series of experiments were done to test how effectively benzyladenine (BA) and gibberellic acid (GA3) increased runner production. In greenhouse tests with the varieties `Tribute' and `Selva' and in field trials with `Selva', the combination of BA and GA3 consistently increased runner production in day-neutral strawberries, but not alone. Runner production increased linearly with BA dosage to 1800 ppm. GA3 produced very elongated internodes at high dosages, which led to fewer daughter plants in the field. Twelve-hundred ppm BA and 300 ppm GA3 are recommended as suitable concentrations to induce runnering both in the field and greenhouse.

scholarly journals Fruit Set of Rabbiteye Blueberry (Vaccinium ashei) after Subfreezing Temperatures

1999 ◽  
Vol 124 (4) ◽  
pp. 337-340 ◽  
Author(s):  
D. Scott NeSmith ◽  
Gerard Krewer ◽  
Orville M. Lindstrom
Keyword(s):  
Gibberellic Acid ◽  
Cold Exposure ◽  
Fruit Set ◽  
Vaccinium Ashei ◽  
Different Temperatures ◽  
Freeze Damage

Plants of `Brightwell' and `Tifblue' rabbiteye blueberry (Vaccinium ashei Reade) were subjected to 0, -1, -3, or -4.5 °C for 1 hour during flowering. After treatment, half of the plants were exposed to bees (Bombus sp.) only, and half were exposed to bees and received applications of GA3. Fruit set of both `Brightwell' and `Tifblue' pollinated by bees declined sharply after exposure to -1 °C for 1 hour, but there was no visible damage to corollas, styles, and ovaries. Fruit set of GA3-treated plants of both cultivars equaled that of control plants (plants having no cold exposure) at temperatures ≥+-3 °C. Both pollinated and GA3-treated plants had ≤2% fruit set after exposure of flowers to -4.5 °C. Both prefreeze and postfreeze applications of GA3 were beneficial for fruit set. Assessment of flower part damage at the different temperatures indicated corollas were most sensitive to freeze damage, followed by styles, and then ovaries. Results suggest fertilization and fruit set of pollinated rabbiteye blueberries can be greatly impaired by even mild freezes (-1 to -2 °C), whereas, appropriately timed applications of GA3 can result in little reduction in fruit set even after moderate freezes (-3 to -4 °C) of blueberries during bloom. Chemical name used: gibberellic acid (GA3).

scholarly journals DELAYING BLOOM OF `LORING' PEACH BY FALL APPLICATION OF GIBBERELLIC ACID, ETHEPHON, AND GIBBERELLIC ACID PLUS ETHEPHON

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 735b-735
Author(s):  
A. Caylor ◽  
W. Dozier ◽  
D. Himelrick ◽  
J. Pitts ◽  
L. Chapman
Keyword(s):  
Gibberellic Acid ◽  
Fruit Set ◽  
Fruit Weight ◽  
Fruit Yield ◽  
Flower Bud ◽  
Fruit Maturity ◽  
Peach Trees ◽  
Fall Application

Four year old `Loring' peach trees on `Lovell' rootstock were treated with single applications of 0, 50, and 100 ppm GA3 alone and in combination with 100 ppm ethephon on 15 November 1988, 1989, and 1990 to determine the effect on bloom delay the following spring. Flower bud number was not affected by any of the treatments the next spring. Ethephon had the greatest effect on bloom delay the following spring. The 50 and 100 ppm GA3 treatments resulted in a slight delay of bloom. The combination of 50 and 100 ppm GA3 and 100 ppm ethephon resulted in less of a bloom delay than ethephon alone but greater than the GA3 treatments alone. Fruit set was increased by ethephon treatments in 1989 and 1991 but not in 1990. Ethephon treatments delayed fruit maturity whereas GA3 did not. Total fruit yield for 1989, 1991, and the three year average was not effected by treatments. However, in 1990 50 ppm GA3 resulted in the highest yields. Ethephon treatments reduced the average fruit weight in 1990 and 1991 but not in 1989 or the three year average.

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