Effects of Timing of CPPU Applications on Rabbiteye Blueberries

A series of field and greenhouse experiments were conducted at two locations in Georgia to determine how rabbiteye blueberries (Vaccinium ashei Reade) respond to different timings of application of the growth regulator [N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU)]. In all tests, a CPPU rate of 15 mg·L−1 was used, and timings of applications were based on days after flowering (DAF). Overall, results indicate that a positive response in fruit set or berry size can occur with applications of CPPU depending on cultivar and timing of application. As with many growth regulators, the effect can vary, and these experiments indicate that the timing of CPPU application is critical in achieving the most desirable response. Collectively, data suggest an optimum window of application of CPPU to rabbiteye blueberries is between 7 and 21 DAF with the most probable success being from an application made around 14 ± 3 DAF.

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

HortScience ◽

10.21273/hortsci.37.4.666 ◽

2002 ◽

Vol 37 (4) ◽

pp. 666-668 ◽

Cited By ~ 16

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).

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

HortScience ◽

10.21273/hortsci.27.4.316 ◽

1992 ◽

Vol 27 (4) ◽

pp. 316-318 ◽

Cited By ~ 5

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).

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Osmia lignaria (Hymenoptera: Megachilidae) produce larger and heavier blueberries than honey bees (Hymenoptera: Apidae)

10.1101/2020.06.28.176396 ◽

2020 ◽

Author(s):

Christine Cairns Fortuin ◽

Kamal JK Gandhi

Keyword(s):

Apis Mellifera ◽

Honey Bees ◽

Fruit Set ◽

Solitary Bee ◽

Field Cage ◽

Vaccinium Ashei ◽

Osmia Lignaria ◽

Berry Weight ◽

Berry Size

AbstractFruit set, berry size, and berry weight were assessed for pollination by the solitary bee Osmia lignaria (Say) in caged rabbiteye blueberries (Vaccinium ashei Reade, Ericales : Ericaceae), and compared to that of uncaged rabbiteye blueberries which were pollinated largely by honey bees (Apis mellifera L). O. linaria produced berries that were 1.6mm larger in diameter and 0.45g heavier than uncaged blueberries. Fruit set was 40% higher in uncaged blueberries. This suggests that Osmia bees can produce larger and heavier berry fruit, but O. lignaria may be less efficient at blueberry pollination as compared to A. mellifera under field cage conditions.

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Effect of Urea, Some Micronutrients, and Growth Regulator Foliar Sprays on the Yield, Fruit Quality, and Some Vegetative Characters of Washington Navel Orange Trees: Fruit Pedicel Pectin Content, Flowering Aspects, and Fruit Set, and Dropping Percentages

HortScience ◽

10.21273/hortsci.30.4.880b ◽

1995 ◽

Vol 30 (4) ◽

pp. 880B-880

Author(s):

Ahmed M. Akl ◽

Abdel-Fattah M. Eid ◽

Mohamed Y. Hegab

Keyword(s):

Growth Regulators ◽

Fruit Quality ◽

Growth Regulator ◽

Fruit Set ◽

Navel Orange ◽

Fruit Drop ◽

Pectin Content ◽

Washington Navel ◽

Vegetative Characters ◽

Orange Trees

This part of the investigation studied the effect of foliar spraying with urea (0.5%); a mixture of Zn (0.4%), Mn (0.3%), Fe (0.5%), and Cu (0.3%) in sulphates (from 23% Zn, 28% Mn, 19% Fe, and 30% Cu, respectively); and two growth regulators (GA3 at 25 ppm and α-NAA at 10 ppm); as well as number and date of sprays on fruit pedicel pectin content, some flowering aspects, and fruit set and drop percentages. Applying urea, micronutrients, or both significantly increased pectin content in the pedicels of the attached and dropped fruit. The treatment including urea plus micronutrients resulted in the highest values for pectin in fruit stem. Either GA3 or NAA significantly raised pectin content over that of the water-sprayed control. However, NAA was more effective in increasing pectin content in fruit pedicel. The overall treatment including urea and micronutrients with GA3 or NAA was the most effective in producing the highest percentage of leafy inflorescence in 1991–92 and 1992–93 seasons. Any nutrition treatment was significantly effective in increasing fruit set and reducing fruit drop compared with the water-sprayed control; however, the treatment including all sprayed nutrients was the most effective. Application of GA3 or NAA significantly increased fruit set percentage and reduced June and preharvest fruit drop; however, NAA was more effective in reducing fruit drop than GA3.

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Effects of CPPU Applications on Southern Highbush Blueberries

HortScience ◽

10.21273/hortsci.42.7.1612 ◽

2007 ◽

Vol 42 (7) ◽

pp. 1612-1615 ◽

Cited By ~ 8

Author(s):

Jeffrey G. Williamson ◽

D. Scott NeSmith

Keyword(s):

Growth Regulator ◽

Field Experiments ◽

Fruit Set ◽

Vaccinium Corymbosum ◽

Highbush Blueberry ◽

Berry Size ◽

Spray Volume ◽

Highbush Blueberries ◽

Southern Highbush ◽

Spray Timing

Greenhouse and field experiments were conducted to determine the effects of the growth regulator N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) on fruit set, berry size, and yield of southern highbush blueberry (Vaccinium corymbosum hybrids). The experiments were conducted over a period of several years in Georgia and Florida. CPPU sprays were capable of increasing fruit set and berry weight of southern highbush blueberry, although the responses to CPPU treatment were variable and appeared to be influenced by factors such as rate, spray timing, and cultivar. In Florida, high natural fruit set may have prevented increased fruit set from CPPU. A slight delay in berry maturity was noted in several experiments. Spray burn occurred on several occasions and may be related to factors such as cultivar, rate, spray volume, and use of surfactant.

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Effect of Urea, Some Micronutrients, and Growth-regulator Foliar Sprays on the Yield, Fruit Quality, and Some Vegetative Characteristics of `Washington' Navel Orange Trees—Vegetative Growth and Mineral Leaf Content

HortScience ◽

10.21273/hortsci.30.4.774d ◽

1995 ◽

Vol 30 (4) ◽

pp. 774D-774

Author(s):

Ahmed M. Akl ◽

Abdel-Fattah M. Eid ◽

Mohamed Y. Hegab

Keyword(s):

Growth Regulators ◽

Growth Regulator ◽

Fruit Set ◽

Shoot Length ◽

Navel Orange ◽

Pronounced Increase ◽

Leaf Analysis ◽

Washington Navel ◽

Macro And Micronutrients ◽

Orange Trees

This investigation was carried out during the experimental seasons of 1991–92 and 1992–93 on 25-year-old `Washington' navel orange trees grown in an orchard at Beni Suef (≈120 km south of Cairo). This part of the investigation studied the effect of foliar spraying urea (0.5%), a mixture of Zn (0.4%), Mn (0.3%), Fe (0.5%), and Cu (0.3%) in sulfates from 23% Zn, 28% Mn, 19% Fe, and 30% Cu, respectively, and two growth regulators (GA3 at 25 ppm and α-NAA at 10 ppm) on some vegetative aspects and leaf content of some macro- and micronutrients. The investigation also included the effect of number and date of spraying (one spray 3 weeks before flowering, one spray 4 weeks after fruit set, and two sprays at the two dates) on the studied traits. The results showed that the overall treatments included two sprays of urea, micronutrients (Zn, Mn, Fe, and Cu) and NAA at 10 ppm achieved the highest values for average leaf area and shoot diameter in both seasons. The treatment on shoot length was more effective when GA3 replaced NAA. Leaf analysis showed that the application of any of the nutrients was responsible for a pronounced increase in leaf content of that element, but reduced the contents of others. Growth regulator treatments lowered leaf content of the determined elements. However, all other treatments in this study reduced leaf content of P and K.

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Enhanced Germination and Emergence of Dormant Wild Mustard (Sinapsis arvensis) Seed by Two Substituted Phthalimides

Weed Science ◽

10.1017/s0043174500083569 ◽

1985 ◽

Vol 33 (6) ◽

pp. 894-902 ◽

Cited By ~ 10

Author(s):

William W. Donald ◽

Roland A. Hoerauf

Keyword(s):

Triticum Aestivum ◽

Growth Regulators ◽

Soil Surface ◽

Mustard Seed ◽

Greenhouse Experiments ◽

Deep Surface ◽

Surface Application ◽

Wild Mustard ◽

Effect Of Surface

Applications of the substituted phthalimide growth regulators AC-94377 [1-(3-chlorophthalimido)cyclohexanecarboximide] and AC-99524 [1-tetrahydrophthalimido-cyclohexanecarboximide] to the soil surface stimulated germination and emergence of dormant wild mustard seed (Sinapsis arvensisL. ♯4SINAR) shallowly planted in soil in greenhouse experiments. Surface applications of AC-94377 enhanced the germination and emergence of dormant wild mustard seed planted 0.6 cm deep in soil from nine locations as the rates were raised from 0.4 to 3.7 kg ai/ha. Surface application of AC-94377 increased emergence rates and also extended the period of wild mustard emergence. Increasing quantities of wheat (Triticum aestivumL.) straw on the soil surface reduced the effect of surface-applied AC-94377 on shallowly buried dormant wild mustard seed. When dormant wild mustard seed were buried 1.3, 2.5, or 3.8 cm deep, surface applications of AC-94377 also stimulated greater emergence than the dormant controls from these depths, strongly suggesting that the compound moved from the surface to the depth of planting.

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