scholarly journals Timing and Concentration of Hydrogen Cyanamide Affect Blueberry Bud Development and Flower Mortality

HortScience ◽  
2001 ◽  
Vol 36 (5) ◽  
pp. 922-924 ◽  
Author(s):  
J.G. Williamson ◽  
B.E. Maust ◽  
D.S. NeSmith
Keyword(s):  
Growth Stages ◽  
Flower Bud ◽  
Time Intervals ◽  
Vaccinium Ashei ◽  
Hydrogen Cyanamide ◽  
Bud Development ◽  
Mild Winter ◽  
Fruit Maturity ◽  
Bud Growth ◽  
Southern Highbush

The effects of hydrogen cyanamide (H2CN2) sprays on vegetative and reproductive bud growth and development were evaluated for `Climax' rabbiteye (Vaccinium ashei Reade) and `Misty' southern highbush blueberry (V. corymbosum L. hybrid). `Climax' plants were sprayed with 0% or 1% H2CN2 (v/v) at each of several time intervals or flower bud growth stages following either 270 or 600 hours of artificial chilling. `Misty' plants were sprayed with 0%, 1%, or 2% H2CN2 (v/v) immediately after exposure to 0, 150, or 300 hours of artificial chilling. H2CN2 application to `Climax' plants at 3 days after forcing (DAF) and at 10% to 30% stage 3 flower bud development dramatically accelerated leafing, and only minimal flower bud damage was observed at these application times. For `Misty', vegetative budbreak was increased and advanced by both H2CN2 spray concentrations, regardless of pretreatment chilling levels; the number of vegetative budbreaks per plant increased with increased concentration. Timing of anthesis did not appear to be affected by H2CN2, but fruit maturity was hastened. Increased pretreatment chilling also hastened fruit development. This effect on maturity appears to be due primarily to increased and accelerated vegetative budbreak, which probably increased leaf: fruit ratios. Greater flower bud mortality from H2CN2 occurred in nonchilled plants than in those chilled for 150 or 300 hours, especially at 2% H2CN2. These results indicate that H2CN2 has potential value in stimulating vegetative bud development, which potentially hastens maturity in blueberries grown under the mild winter conditions of the Southeast. However, spray concentration and timing of application will be critical to successful use of this compound.

Hydrogen Cyanamide Increases Leafing and Reduces Fruit Development Period of Southern Highbush Blueberry

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 529c-529
Author(s):  
J.G. Williamson ◽  
B.E. Maust ◽  
R.L. Darnell
Keyword(s):  
Fruit Development ◽  
Fruit Size ◽  
Highbush Blueberry ◽  
Flower Bud ◽  
North Central ◽  
Hydrogen Cyanamide ◽  
Central Florida ◽  
Fruit Thinning ◽  
Fruit Maturity ◽  
Southern Highbush

Mature, field-grown `Misty' southern highbush blueberry plants were sprayed to drip with 0, 20.4, and 10.2 g·L–1 concentrations of hydrogen cyanamide in north-central Florida on 20 Dec. and 7 Jan. 1996–97. Plants were dormant and leafless, with slightly swollen flower buds, at the time of spray applications. All hydrogen cyanamide sprays increased the extent and earliness of vegetative budbreak and canopy establishment. The number of vegetative budbreaks per centimeter of shoot length increased linearly with increasing spray concentration of hydrogen cyanamide. Hydrogen cyanamide-treated fruit had greater average fresh weights and shorter average fruit development periods than non-treated fruit. On 15 Apr., 40% ti 60% of hydrogen cyanamide-treated fruit were ripe compared to about 10% of control fruit. Some flower bud damage and subsequent fruit thinning was observed from the 20.4 g·L–1 spray, especially at the later spray date. Hydrogen cyanamide shows potential for increasing early fruit maturity and fruit size of some southern highbush blueberry cultivars in Florida.

Budbreak of Rabbiteye Blueberry Enhanced by Hydrogen Cyanamide

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 529b-529
Author(s):  
Melvin R. Hall ◽  
Max E. Austin
Keyword(s):  
Flower Buds ◽  
Flower Bud ◽  
Vaccinium Ashei ◽  
Hydrogen Cyanamide ◽  
Bud Development ◽  
Chilling Temperatures ◽  
Stage 1 ◽  
Flower Bud Development

Few flower buds on pot grown `T-227' rabbiteye blueberry (Vaccinium ashei Reade) advanced past stage 1 (tight bud) when exposed to 0 or 200 h of chilling temperatures (4 °C), regardless of treatment with hydrogen cyanamide. However, 0.25%, 0.5%, 1%, and 2% sprays on plants chilled 400 h advanced flower bud development through stage 6 (open). Sprays were less effective on plants chilled for 600 h or longer, and 1% and 2% sprays caused some phytotoxicity regardless of chilling.

scholarly journals The Effect of Timing of Dormex Application on Blueberry Leafing and Flower Mortality

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 601e-601 ◽  
Author(s):  
D. Scott NeSmith ◽  
Gerard Krewer
Keyword(s):  
Fruit Crops ◽  
Flower Buds ◽  
Calendar Time ◽  
Vaccinium Ashei ◽  
Hydrogen Cyanamide ◽  
Bud Development ◽  
Floral Buds ◽  
Stage 4 ◽  
Southern Highbush ◽  
Floral Bud

Leaf bud development is a problem on many blueberry cultivars grown throughout the Southeast. Dormex (50% hydrogen cyanamide) has shown potential in accelerating leaf and floral bud development of some fruit crops, but its usage on blueberries has not been thoroughly explored. A greenhouse experiment was conducted to examine the effects of timing Dormex applications on `Climax' rabbiteye blueberry (Vaccinium ashei) and `Oneal' southern highbush blueberry (V. corymbosum). Plants were subjected to low and moderate chilling conditions and were forced under greenhouse conditions. Dormex timings were: 1)1 day after forcing (DAF), 2) 3 DAF, 3) at 10% stage 3 floral buds, 4) at 30% to 50% stage 3 floral buds, 5) at 10% to 30% stage 4 floral buds, 6) control (no Dormex). All Dormex applications were applied at a rate of 2% product. Results showed that Dormex both increased and accelerated leaf bud break as compared to the control. However, flower buds at stage 3 of development or beyond were very susceptible to chemical burn by the product. The data indicate that timing of Dormex applications on blueberries should be based on rate of plant development rather than calendar time. Additional research is needed to most effectively use the product to aid blueberry leaf development.

scholarly journals Evaluation of Flower Bud Removal Treatments on Growth of Young Blueberry Plants

HortScience ◽  
2007 ◽  
Vol 42 (3) ◽  
pp. 571-573 ◽  
Author(s):  
Jeffrey G. Williamson ◽  
D. Scott NeSmith
Keyword(s):  
Growth Index ◽  
Dry Weight ◽  
Growth Cycle ◽  
Santa Fe ◽  
Flower Bud ◽  
Vaccinium Ashei ◽  
Hydrogen Cyanamide ◽  
Total Plant ◽  
Southern Highbush ◽  
Bud Removal

The effects of flower bud removal treatments on growth of young rabbiteye (Vaccinium ashei Reade) and southern highbush (V. corymbosum hybrids) blueberry plants were evaluated. Treatments consisted of pruning, hand stripping, and hydrogen cyanamide applications. The growth index of rabbiteye plants after the first spring growth cycle was unaffected by any of the flower bud removal treatments. However, the effects of flower bud thinning were cultivar specific for southern highbush blueberry plants. ‘Misty’ plants showed increases in total plant dry weight and in root, leaf, and stem dry weights from hand thinning and hydrogen cyanamide sprays. Conversely, ‘Santa Fe’ showed no increased growth response from any of the flower bud removal treatments. Flower bud mortality increased as hydrogen cyanamide spray concentration increased and was greater when applications were delayed so that flower buds were more advanced. Hydrogen cyanamide may have potential as an alternative to labor-intense flower bud removal practices such as hand stripping or pruning on young blueberry plants during establishment.

A Leaf Bud Development Scale for Rabbiteye Blueberry

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 455f-456 ◽  
Author(s):  
D. Scott NeSmith ◽  
Gerard Krewer ◽  
Jeffrey G. Williamson
Keyword(s):  
Reproductive Development ◽  
Developmental Differences ◽  
Research Management ◽  
Growth Stages ◽  
Vaccinium Ashei ◽  
Bud Development ◽  
Dormant Bud ◽  
Mouse Ear ◽  
Highbush Blueberries ◽  
Winter Chilling

Crop vegetative and reproductive development are frequently divided into stages to describe progression of development. Such a description is useful in denoting developmental differences between cultivars, for making crop management decisions based on growth stages, and for clear communication among individuals concerned with research, management, and production of the crop. We have developed such a scale for leaf bud development in rabbiteye blueberry (Vaccinium ashei Reade). Our scale has six stages briefly described as follows: 1) dormant bud; 2) early green tip; 3) late green tip; 4) unfolding stage; 5) mouse-ear stage; 6) fully opened bud. Categorizing buds in this manner has proven useful in comparing rates of leaf development between cultivars and in response to winter chilling. The stages appear to be relevant to highbush blueberries (V. corymbosum) as well.

scholarly journals UAV-Based Heating Requirement Determination for Frost Management in Apple Orchard

2021 ◽  
Vol 13 (2) ◽  
pp. 273
Author(s):  
Wenan Yuan ◽  
Daeun Choi
Keyword(s):  
Apple Orchard ◽  
Growth Stages ◽  
Flower Bud ◽  
Critical Temperatures ◽  
Mapping Algorithm ◽  
Aerial Vehicle ◽  
Bud Growth ◽  
Frost Protection ◽  
Map Resolution ◽  
Temperature Maps

Frost is a natural disaster that can cause catastrophic damages in agriculture, while traditional temperature monitoring in orchards has disadvantages such as being imprecise and laborious, which can lead to inadequate or wasteful frost protection treatments. In this article, we presented a heating requirement assessment methodology for frost protection in an apple orchard utilizing unmanned aerial vehicle (UAV)-based thermal and RGB cameras. A thermal image stitching algorithm using the BRISK feature was developed for creating georeferenced orchard temperature maps, which attained a sub-centimeter map resolution and a stitching speed of 100 thermal images within 30 s. YOLOv4 classifiers for six apple flower bud growth stages in various network sizes were trained based on 5040 RGB images, and the best model achieved a 71.57% mAP for a test dataset consisted of 360 images. A flower bud mapping algorithm was developed to map classifier detection results into dense growth stage maps utilizing RGB image geoinformation. Heating requirement maps were created using artificial flower bud critical temperatures to simulate orchard heating demands during frost events. The results demonstrated the feasibility of the proposed orchard heating requirement determination methodology, which has the potential to be a critical component of an autonomous, precise frost management system in future studies.

scholarly journals Natural and Artificial Chilling of Southern Highbush Blueberry

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 825B-825
Author(s):  
Donna A. Marshall* ◽  
Stephen J. Stringer ◽  
James M. Spiers
Keyword(s):  
Bud Break ◽  
Delivery Method ◽  
Flower Bud ◽  
Bud Development ◽  
Chilling Requirements ◽  
Highbush Blueberries ◽  
Southern Highbush ◽  
Chilling Hours ◽  
Floral Bud ◽  
Vegetative Bud

A study was initiated in November, 2002 to determine the effects of exposing two Southern Highbush blueberries (Vaccinium corybosum L) to artificial chilling hours on initiation of bud break and advancement of floral and vegetative bud maturity. Plants of `Jubilee' and `Misty' were divided into 2 groups in which one was left outdoors, allowing chilling to occur and accumulate naturally, while the other group was placed in a growth chamber set at a constant artificial temperature of 4 °C. Five plants of each cultivar were then placed into a heated greenhouse after 0, 200, 400, 600, or 800 hours of chilling (total hours of exposure to <5 °C) had accumulated for forcing of flower bud development. The progression of floral bud development of the terminal three buds on five tagged stems was observed at 7-10 day intervals for 30 days. At the end of the forcing period observations were also made on total percent vegetative and floral bud break. Prior to accumulating sufficient chilling requirements, chilling delivery method did not appear to influence the rate of floral bud development since none advanced past stage 3 regardless of chilling regime used. However after chilling requirements were met, flower buds of plants that were allowed to chill naturally developed more quickly than did those chilled by artificial means.

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

HortScience ◽  
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.

scholarly journals Flower Bud Load Influences Blueberry Vegetative and Fruit Development

HortScience ◽  
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.

scholarly journals Metabolomics Analysis Reveals the Mechanism of Hydrogen Cyanamide in Promoting Flower Bud Break in Blueberry

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 102
Author(s):  
Hao Wang ◽  
Xiuying Xia ◽  
Lijia An
Keyword(s):  
Soluble Sugars ◽  
Fruit Trees ◽  
Fruit Production ◽  
Bud Break ◽  
Dormancy Release ◽  
Flower Bud ◽  
Hydrogen Cyanamide ◽  
Mild Winter ◽  
Deciduous Fruit ◽  
Bud Breaking

Bud dormancy of deciduous fruit trees is a complex process that allows trees to survive long periods in adverse conditions during winter. Dormancy is a major obstacle for both fruit production in mild winter areas and off-season culture of fruit trees in protection facilities. It is very economically advantageous to be able to control the time point of bud break and consequently harvest in crops with high returns and short harvest seasons like blueberry (Vaccinium spp.). Hydrogen cyanamide (H2CN2 (HC)) treatment is an effective method to promote dormancy release and synchronize bud break in perennial deciduous fruit trees, including blueberry. However, there are few systematic studies of the metabolic changes that occur during HC-induced bud breaking. In this study, the metabolome of blueberry buds under forced conditions following HC and water treatment (control) was analyzed using gas chromatography paired with time-of-flight mass spectrometry (GC–TOFMS) technology. A total of 252 metabolites were identified and 16 differential metabolites (VIP > 1, p < 0.05) were detected. The levels of several soluble sugars (fructose, glucose, maltose), organic acids (citric acid, alpha-ketoglutaric, succinic acid), and amino acids (aspartic acid, glutamic acid, phenylalanine) were upregulated, while tyrosine, tryptophan, and asparagine were significantly downregulated in HC-treated buds when compared with control buds. The synthesis and accumulation of phenylpropanoids (salicin, 4-vinylphenol, neohesperidin) were also promoted by HC. These results suggest that alteration of carbohydrate and amino acid metabolism, tricarboxylic acid (TCA) cycle increase, and phenylpropanoid accumulation were crucial in HC-promoted bud breaking in blueberry. This research extends our understanding of the mechanisms involved in dormancy release induced by HC and provides a theoretical basis for applying HC to accelerate bud break.

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