Photoperiodic Effects on Vegetative and Reproductive Growth of Vaccinium darrowi and V. corymbosum Interspecific Hybrids

Experiments were conducted with V. darrowi and two cultivars of southern highbush blueberry, `Sharpblue' and `Misty,' to test whether V. darrowi and cultivars derived from it are photoperiodic with respect to flower bud initiation. Plants of each cultivar were grown under three different photoperiod treatments [long days (LD) = 16-hour photoperiod; short days (SD) = 8-hour photoperiod; and short days + night interrupt (SD-NI) = 8-hour photoperiod with 1-hour night interrupt] at constant 21 °C for 8 weeks. Vegetative growth was greatest in the LD plants of both cultivars. Flower bud initiation occurred only in the SD treatments, and the lack of flower bud initiation in the SD-NI treatment indicates that flower bud initiation is a phytochrome mediated response in Vaccinium. Previously initiated flower buds on the V. darrowi plants developed and bloomed during the LD treatment, but bloom did not occur in the SD and SD-NI treatment plants until after those plants were moved to LD. These data indicate that flower bud initiation in both V. darrowi and southern highbush blueberry is photoperiodically sensitive, and is promoted by short days, while flower bud development is enhanced under long days.

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625 Early Fall Defoliation of Southern Highbush Blueberry Inhibits Flower Bud Initiation and Retards Flower Bud Development

HortScience ◽

10.21273/hortsci.35.3.505b ◽

2000 ◽

Vol 35 (3) ◽

pp. 505B-505 ◽

Cited By ~ 3

Author(s):

Jeffrey G. Williamson ◽

E.P. Miller

Keyword(s):

Unit Length ◽

Highbush Blueberry ◽

Similar Response ◽

Block Designs ◽

Flower Buds ◽

Flower Bud ◽

Bud Development ◽

Early Fall ◽

Southern Highbush ◽

Flower Bud Development

In 1998, representative canes of mature, field-grown, `Misty' and `Sharpblue' southern highbush blueberry were hand-defoliated on 4 Sept., 2 Oct., 6 Nov., 7 Dec., or not defoliated. The experiment was repeated in 1999. Randomized complete-block designs with 11 (1998) or 10 (1999) replications were used. The early defoliation treatments (4 Sept. and 2 Oct.) resulted in reduced flower bud number per unit length of cane for `Misty', but not for `Sharpblue', when compared with later defoliation treatments or controls. A similar response to early defoliation was found both years for both cultivars. The later defoliation treatments (6 Nov. and 7 Dec.) had no significant effect on flower bud number compared to controls. Early defoliation had a negative effect on flower bud development for both cultivars. Flower buds that developed on canes defoliated on 4 Sept. or on 2 Oct. had smaller diameters than flower buds on canes defoliated on 6 Nov., 7 Dec., or on non-defoliated canes. Fruit fresh weight per unit cane length was less for the September and October defoliation treatments than for the December defoliation treatment or controls. These results support the need for summer pruning and a effective summer spray program to control leaf spot diseases that often result in early fall defoliation of southern highbush blueberries grown in the southeastern United States.

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Cold Injury of Southern Blueberries as a Function of Germplasm and Season of Flower Bud Development

HortScience ◽

10.21273/hortsci.26.1.18 ◽

1991 ◽

Vol 26 (1) ◽

pp. 18-20 ◽

Cited By ~ 8

Author(s):

Kim Patten ◽

Elizabeth Neuendorff ◽

Gary Nimr ◽

John R. Clark ◽

Gina Fernandez

Keyword(s):

Frost Damage ◽

Vaccinium Corymbosum ◽

Highbush Blueberry ◽

Flower Buds ◽

Flower Bud ◽

Bud Development ◽

Stage Of Development ◽

Cold Damage ◽

Southern Highbush ◽

Flower Bud Development

The relative tolerance of flower buds and flowers of southern highbush blueberry (Vaccinium spp.) to cold damage was compared to rabbiteye (Vaccinium ashei Reade) and highbush blueberry (Vaccinium corymbosum L.). For similar stages of floral bud development, southern highbush and highbush cultivars had less winter freeze and spring frost damage than rabbiteye cultivars. Cold damage increased linearly with stage of flower bud development. Small fruit were more sensitive to frost damage than open flowers. Rabbiteye blueberry flower buds formed during the fall growth flush were more hardy than buds formed during the spring growth flush, regardless of cultivar or stage of development.

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Inflorescence Bud Initiation, Development, and Bloom in Two Southern Highbush Blueberry Cultivars

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.140.1.38 ◽

2015 ◽

Vol 140 (1) ◽

pp. 38-44 ◽

Cited By ~ 4

Author(s):

Alisson P. Kovaleski ◽

Jeffrey G. Williamson ◽

James W. Olmstead ◽

Rebecca L. Darnell

Keyword(s):

Interspecific Hybrids ◽

Shoot Growth ◽

Late Summer ◽

Vaccinium Corymbosum ◽

Highbush Blueberry ◽

Bud Development ◽

Late Fall ◽

Southern Highbush ◽

Bud Initiation ◽

The Relationship

Blueberry (Vaccinium spp.) production is increasing worldwide, particularly in subtropical growing regions, but information on timing and extent of inflorescence bud development during summer and fall and effects on bloom the next season are limited. The objectives of this study were to determine time of inflorescence bud initiation, describe internal inflorescence bud development, and determine the relationship between internal inflorescence bud development and bloom period the next spring in two southern highbush blueberry [SHB (Vaccinium corymbosum interspecific hybrids)] cultivars. ‘Emerald’ and ‘Jewel’ SHB buds were collected beginning in late summer until shoot growth cessation in late fall for dissection and identification of organ development. Inflorescence bud frequency and number, vegetative and inflorescence bud length and width throughout development, and bloom were also assessed. Inflorescence bud initiation occurred earlier in ‘Emerald’ compared with ‘Jewel’. Five stages of internal inflorescence bud development were defined throughout fall in both cultivars, ranging from a vegetative meristem to early expansion of the inflorescence bud in late fall. ‘Emerald’ inflorescence buds were larger and bloomed earlier, reflecting the earlier inflorescence bud initiation and development. Although inflorescence bud initiation occurred earlier in ‘Emerald’ compared with ‘Jewel’, the pattern of development was not different. Timing of inflorescence bud initiation influenced timing of bloom with earlier initiation resulting in earlier bloom.

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FLOWER BUD HARDINESS OF SOUTHERN HIGHBUSH BLUEBERRY CULTIVARS

HortScience ◽

10.21273/hortsci.30.3.430d ◽

1995 ◽

Vol 30 (3) ◽

pp. 430d-430

Author(s):

John R. Clark ◽

Robert Bourne

Keyword(s):

Incubation Period ◽

Minimum Temperature ◽

Gulf Coast ◽

Highbush Blueberry ◽

Blue Ridge ◽

Flower Buds ◽

Flower Bud ◽

Cape Fear ◽

Southern Highbush

The southern highbush blueberry (Vaccinium spp.) `Blueridge', `Cape Fear', `Cooper', `Georgiagem', `Gulf Coast', and `O'Neal'; the rabbiteye (V. ashei Reade) `Climax'; and the highbush (V. corymbosum L.) `Bluecrop' were evaluated for ovary damage following exposure of flower buds to 0 to 30C in a programmable freezer in Dec. 1993 and Jan. and Feb. 1994. The plants sampled were growing at the Univ. of Arkansas Fruit Substation, Clarksville. Damage was based on oxidative browning of the ovaries following an incubation period after removal from the freezer. With the exception of `Climax', a minimum temperature of –15C was required before bud damage was sufficient enough to differentiate among cultivars. All southern highbush cultivars and `Bluecrop' had superior hardiness compared to `Climax' at –15C in December, –20C in January, and –15C in February. Maximum hardiness of all cultivars was found in January. The hardier southern highbush cultivars were `Cape Fear' and `Blue Ridge'. Less hardy cultivars were `Gulf Coast, `Cooper', `Georgiagem', and `O'Neal', although the date of sampling affected the ranking of these clones for hardiness, especially for the February sample date. `Bluecrop' was not consistently hardier than the hardier southern highbush cultivars, except at the February sample date.

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Flower Bud Density Affects Vegetative and Fruit Development in Field-grown Southern Highbush Blueberry

HortScience ◽

10.21273/hortsci.34.4.607 ◽

1999 ◽

Vol 34 (4) ◽

pp. 607-610 ◽

Cited By ~ 17

Author(s):

B.E. Maust ◽

J.G. Williamson ◽

R.L. Darnell

Keyword(s):

Leaf Area ◽

Fruit Development ◽

Fruit Size ◽

Dry Weight ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Highbush Blueberry ◽

Flower Buds ◽

Flower Bud ◽

Southern Highbush

Floral budbreak and fruit set in many southern highbush blueberry (SHB) cultivars (hybrids of Vaccinium corymbosum L. with other species of Vaccinium) begin prior to vegetative budbreak. Experiments were conducted with two SHB cultivars, `Misty' and `Sharpblue', to test the hypothesis that initial flower bud density (flower buds/m cane length) affects vegetative budbreak and shoot development, which in turn affect fruit development. Flower bud density of field-grown plants was adjusted in two nonconsecutive years by removing none, one-third, or two-thirds of the flower buds during dormancy. Vegetative budbreak, new shoot dry weight, leaf area, and leaf area: fruit ratios decreased with increasing flower bud density in both cultivars. Average fruit fresh weight and fruit soluble solids decreased in both cultivars, and fruit ripening was delayed in `Misty' as leaf area: fruit ratios decreased. This study indicates that because of the inverse relationship between flower bud density and canopy establishment, decreasing the density of flower buds in SHB will increase fruit size and quality and hasten ripening.

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Hydrogen Cyanamide Stimulates Early Foliation of `Misty' Southern Highbush Blueberry

HortScience ◽

10.21273/hortsci.32.3.537c ◽

1997 ◽

Vol 32 (3) ◽

pp. 537C-537

Author(s):

J.G. Williamson ◽

R.L. Darnell

Keyword(s):

Vegetative Growth ◽

Fruit Set ◽

Small Diameter ◽

Highbush Blueberry ◽

Full Bloom ◽

Flower Buds ◽

Flower Bud ◽

Hydrogen Cyanamide ◽

Southern Highbush ◽

Chilling Treatment

Two-year-old, container-grown `Misty' southern highbush blueberry plants were sprayed to drip with two concentrations of hydrogen cyanamide (HCN) (20.4 g·L–1 and 10.2 g·L–1) after exposure to 0, 150, or 300 hr of continuous chilling at 5.6°C. All plants were sprayed immediately after chilling and placed in a greenhouse for several weeks. The plants were moved outdoors during flowering to increase cross-pollination from nearby `Sharpblue' blueberry plants. HCN sprays killed some of the more advanced flower buds on shoot terminals and on small-diameter wood from the previous spring growth flush. Significantly greater flower bud mortality occurred for the 20.4 g·L–1 HCN sprays than for the 10.2 g·L–1 sprays. Flower buds subjected to 0 hr of chilling were more susceptible to spray burn than flower buds receiving 150 or 300 hr of chilling. Very little flower bud death occurred with the 10.2 g·L–1 HCN rate on plants receiving 300 hr of chilling. Vegetative budbreak was advanced for both HCN treatments compared to controls, regardless of chilling treatment. HCN-treated plants were heavily foliated at full bloom, while non-treated plants had very few to no leaves during bloom. HCN may be useful for stimulating vegetative growth in some southern highbush blueberry cultivars that suffer from poor foliation during flowering and fruit set.

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Flower Bud Load Influences Blueberry Vegetative and Fruit Development

HortScience ◽

10.21273/hortsci.31.4.682e ◽

1996 ◽

Vol 31 (4) ◽

pp. 682e-682

Author(s):

B.E. Maust ◽

J.G. Williamson ◽

R.L. Darnell

Keyword(s):

Leaf Area ◽

Fruit Development ◽

Reproductive Development ◽

Dry Weight ◽

Highbush Blueberry ◽

Fresh Weight ◽

Flower Buds ◽

Flower Bud ◽

Fruit Maturity ◽

Southern Highbush

A field experiment was conducted in Gainesville, Fla., with two southern highbush blueberry cultivars, `Misty' and `Sharpblue', to investigate the influence of varying flower bud load on the timing and extent of vegetative and reproductive development. Flower bud load was adjusted on three different canes on ten plants by removing none, one-third, or two-thirds of the flower buds. Vegetative budbreak, leaf area, fruit number, and fruit fresh weight and dry weight were measured. Vegetative budbreak was delayed with increasing flower bud load. Vegetative budbreak, leaf area, and leaf area: fruit ratio decreased with increasing flower bud load. Fruit maturity was delayed and average berry fresh weight and dry weight declined with decreasing leaf area:fruit ratio. Responses were similar for both cultivars although `Misty' was more adversely affected by high flower bud load and low leaf area: fruit ratio.

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Flower bud initiation in southern highbush blueberry cv. O’Neal occurs twice per year in temperate to warm-temperate conditions

Journal of Applied Horticulture ◽

10.37855/jah.2011.v13i01.02 ◽

2011 ◽

Vol 13 (01) ◽

pp. 8-12 ◽

Cited By ~ 2

Author(s):

Maria Pescie ◽

Marcelo Lovisolo ◽

Alberto De Magistris ◽

Bernadine Strik ◽

Cesar Lopez

Keyword(s):

Highbush Blueberry ◽

Flower Bud ◽

Southern Highbush ◽

Bud Initiation ◽

Warm Temperate

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Photoperiod and Temperature Effects on Growth and Carbohydrate Storage in Southern Highbush Blueberry Interspecific Hybrid

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.129.3.0294 ◽

2004 ◽

Vol 129 (3) ◽

pp. 294-298 ◽

Cited By ~ 9

Author(s):

Timothy M. Spann ◽

Jeffrey G. Williamson ◽

Rebecca L. Darnell

Keyword(s):

High Temperature ◽

Interspecific Hybrid ◽

Vaccinium Corymbosum ◽

Highbush Blueberry ◽

Flower Bud ◽

Experimental Conditions ◽

Carbohydrate Concentration ◽

Southern Highbush ◽

Bud Initiation ◽

Carbohydrate Status

Experiments were conducted with `Misty' southern highbush blueberry (Vaccinium corymbosum L. interspecific hybrid) to test the effects of high temperature on flower bud initiation and carbohydrate accumulation and partitioning. Plants were grown under inductive short days (SDs = 8 hour photoperiod) or noninductive SDs with night interrupt (SD-NI = 8 hour photoperiod + 1 hour night interrupt), at either 21 or 28 °C for either 4 or 8 weeks. Flower bud initiation occurred only in the inductive SD treatments and was significantly reduced at 28 °C compared with 21 °C. The number of flower buds initiated was not significantly different between 4- and 8-week durations within the inductive SD, 21 °C treatment. However, floral differentiation appeared to be incomplete in the 4-week duration buds and bloom was delayed and reduced. Although plant carbohydrate status was not associated with differences in flower bud initiation between SD and SD-NI treatments, within SD plants, decreased flower bud initiation at high temperature was correlated with decreased whole-plant carbohydrate concentration. These data indicate that flower bud initiation in southern highbush blueberry is a SD/long night phytochrome-mediated response, and plant carbohydrate status plays little, if any, role in regulating initiation under these experimental conditions.

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Flower and Fruit Load Influence Blueberry Plant Development and CO2 Exchange Rate

HortScience ◽

10.21273/hortsci.32.3.443a ◽

1997 ◽

Vol 32 (3) ◽

pp. 443A-443

Author(s):

B.E. Maust ◽

J.G. Williamson ◽

R.L. Darnell

Keyword(s):

Exchange Rate ◽

Leaf Area ◽

Fruit Ripening ◽

Highbush Blueberry ◽

Plant Canopy ◽

Flower Buds ◽

Flower Bud ◽

Whole Plant ◽

Southern Highbush ◽

Fruit Load

Two southern highbush blueberry cultivars, `Sharpblue' and `Misty', were used to investigate the influence of varying flower bud density and fruit load on vegetative development, whole-plant canopy CO2 exchange rate (CER), and leaf CER. Plants were grown in pots and flower buds were removed so that initial flower bud density (fl ower bud number/total cane length) on a whole-plant basis ranged from 0.05–0.35 flower buds/cm. Vegetative budbreak number, leaf area, and leaf area: fruit ratio decreased with increasing flower bud density. In `Sharpblue', whole-plant canopy CER measured at fruit ripening decreased with increasing flower and fruit load and decreasing leaf area:fruit ratio, while leaf CER increased with increasing fruit load and decreasing leaf area:fruit ratio. In `Misty', whole-plant canopy CER measured 4 weeks after full bloom decreased with increasing flower and fruit load, but whole-plant canopy and leaf CER at fruit ripening were similar among the different fruit loads. Average fruit fresh and dry weights increased and the fruit development period decreased with increased leaf area:fruit ratio in both cultivars. These data suggest that carbohydrate source limitations from reduced leaf area development and whole-plant canopy CER lead to decreased fruit fresh and dry weights and delayed ripening in some southern highbush blueberry cultivars.

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