PHOTOPERIOD EFFECTS ON REPRODUCTIVE DEVELOPMENT OF RABBITEYE BLUEBERRY

Containerized `Climax' and `Beckyblue' rabbiteye blueberry plants (Vaccinium ashei Reade) were exposed to 5 weeks of natural daylengths (i.e. gradually decreasing daylengths from 12 to 11 hr) or shortened daylengths (i.e. gradually decreasing daylengths from 10 to 8 hr) starting October 1. `Beckyblue' initiated twice as many flower buds under short days compared to longer days. The following spring, `Beckyblue' plants exposed to shortened photoperiods the previous fall had a greater percentage of floral budbreak (based on the number of flower buds formed within each treatment) and a shorter, more concentrated bloom period than did plants exposed to longer photoperiods the previous fall. Fresh weight per berry increased following the short fall photoperiod treatment, despite the fact that fruit number was higher. `Climax' did not respond to the photoperiod treatments in any way. Leaf carbon assimilation rates of both cultivars increased under short days, but there was no detectable effect of photoperiod on current carbon partitioning in either cultivar, suggesting that flower bud initiation is not limited by current source leaf assimilate supply under these conditions.

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Photoperiod, Carbon Partitioning, and Reproductive Development in Rabbiteye Blueberry

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.116.5.856 ◽

1991 ◽

Vol 116 (5) ◽

pp. 856-860 ◽

Cited By ~ 13

Author(s):

Rebecca L. Darnell

Keyword(s):

Carbon Fixation ◽

Carbon Assimilation ◽

Reproductive Development ◽

Carbon Partitioning ◽

Stem Tissue ◽

Flower Buds ◽

Vaccinium Ashei ◽

Bloom Period ◽

Short Days

Containerized `Climax' and `Beckyblue' rabbiteye blueberry plants (Vaccinium ashei Reade) were exposed to 5 weeks of natural daylengths or shortened daylengths starting 30 Sept. `Beckyblue' plants exposed to short daylengths in the fall initiated more flower buds and had a shorter, more concentrated bloom period than did plants exposed to natural fall daylengths. Reproductive development of `Climax' was not influenced by photoperiod treatments. Leaf carbon assimilation of both cultivars increased under short days. Partitioning of translocated 14C-labeled assimilates to stem tissue increased under short photoperiods for `Beckyblue'; however, partitioning patterns in `Climax' were not affected. Increased carbon fixation and increased partitioning of carbon to stem tissue under short days may contribute to the observed effect of short days on enhancing reproductive development in `Beckyblue'.

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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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Reproductive Development in Evergreen vs. Deciduous Blueberry Production System

HortScience ◽

10.21273/hortsci.32.3.443d ◽

1997 ◽

Vol 32 (3) ◽

pp. 443D-443

Author(s):

Peter A.W. Swain ◽

Rebecca L. Darnell

Keyword(s):

Production System ◽

Reproductive Development ◽

Vaccinium Corymbosum ◽

N Fertilization ◽

Highbush Blueberry ◽

Fresh Weight ◽

Flower Buds ◽

Flower Bud ◽

Active Growth ◽

Southern Highbush

Two cultivars of southern highbush blueberry (Vaccinium corymbosum interspecific hybrid) were grown in containers under the traditional deciduous production system, or the dormancy-avoiding evergreen production system. In the dormancy-avoiding system, plants are maintained evergreen and do not enter dormancy in the winter. This alleviates the chilling requirement, thus extending the potential growing area of blueberries into subtropical regions. Plants in the evergreen production system were maintained in active growth through weekly or biweekly N fertilization (≈21–23 g N/ plant per year). Keeping foliage through the year lengthens the duration of the photosynthetic season of the plant and is hypothesized to improve the carbohydrate (CHO) status of the evergreen plants. This, in turn, may decrease source limitations to reproductive development and potentially increase fruit number and/or size. In both cultivars, the evergreen production system advanced the time of anthesis by 3 to 4 weeks compared to the deciduous production system. Plants in the evergreen system initiated 10% to 25% more flower buds than plants in the deciduous system, depending on cultivar. Average leaf area, leaf fresh weight, total above-ground fresh weight, bud density, and cane length were greater in the evergreen plants than deciduous. The evergreen production system increased plant fresh weight and flower bud number compared to the deciduous system, and may ultimately increase yield.

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Low Night Temperature Increases Ovary Size in Sweet Pepper Cultivars

HortScience ◽

10.21273/hortsci.46.3.396 ◽

2011 ◽

Vol 46 (3) ◽

pp. 396-401 ◽

Cited By ~ 6

Author(s):

Nicacio Cruz-Huerta ◽

Jeffrey G. Williamson ◽

Rebecca L. Darnell

Keyword(s):

Production Systems ◽

Sweet Pepper ◽

Bell Pepper ◽

Fresh Weight ◽

Night Temperature ◽

Flower Buds ◽

Flower Bud ◽

Bud Initiation ◽

Cool Night

Cool night temperatures have been reported to induce ovary swelling and consequent fruit deformation in bell pepper (Capsicum annuum L.), resulting in unmarketable fruit. This response is a serious limitation to the success of winter production systems for bell pepper. Limited work has been done with other types of sweet pepper, so it is unknown how universal this response is. Furthermore, most prior work has examined effects on ovary diameter only, and there is limited characterization of other ovary traits in response to cool night temperature. The objectives of the present study were to determine the effects of low night temperature on ovary characteristics in different sweet pepper cultivars and to determine the parts of the ovary that are most affected by these factors. Three types of sweet pepper (bell, long-fruited, and cherry) were exposed to 22/20 or 22/12 °C day:night temperatures and flowers at anthesis were continuously harvested throughout the experiments. Ovary fresh weight (FW), diameter, and length across all types (and cultivars within type) were greater under 22/12 °C compared with 22/20 °C. The increase in ovary FW was the result of increases in both ovary wall and placenta FW. In general, all cultivars exhibited increases in ovary size under 12 °C compared with 20 °C night temperature. Differences in ovary FW resulting from night temperature became more pronounced with time. These results indicate that low night temperature effects on ovary swelling may be a universal response among sweet pepper types. Three to 4 weeks are required for maximum swelling response, suggesting that flower buds must be exposed to low night temperatures within the first week after flower bud initiation, because previous work found that flower bud initiation in bell pepper takes ≈4 weeks. However, the duration of low night temperatures necessary for this response remains unknown.

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

HortScience ◽

10.21273/hortsci.38.2.192 ◽

2003 ◽

Vol 38 (2) ◽

pp. 192-195 ◽

Cited By ~ 8

Author(s):

Timothy M. Spann ◽

Jeffrey G. Williamson ◽

Rebecca L. Darnell

Keyword(s):

Interspecific Hybrids ◽

Highbush Blueberry ◽

Flower Buds ◽

Flower Bud ◽

Vaccinium Darrowi ◽

Southern Highbush ◽

Vegetative And Reproductive Growth ◽

Bud Initiation ◽

Short Days ◽

Flower Bud Development

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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Different Summer and Autumn Water Deficit Affect the Floral Differentiation and Flower Bud Growth in Apricot (Prunus armeniaca L.)

Agronomy ◽

10.3390/agronomy10060914 ◽

2020 ◽

Vol 10 (6) ◽

pp. 914

Author(s):

Susanna Bartolini ◽

Ermes Lo Piccolo ◽

Damiano Remorini

Keyword(s):

Water Deficit ◽

Water Availability ◽

Water Status ◽

Prunus Armeniaca ◽

Stem Water Potential ◽

Flower Buds ◽

Flower Bud ◽

Fruit Species ◽

Floral Differentiation ◽

Bud Initiation

In deciduous fruit species, floral bud initiation, differentiation and organogenesis take place during the summer–autumn season that precedes anthesis. Among factors able to modify the regularity of these processes, water availability represents a crucial aspect. This investigation aimed to assess the influence of different summer and autumn water deficit and re-watering treatments on floral morphogenesis, xylem vessel differentiation and quality of flower buds. Trials were carried out on two-year-old potted apricot trees (cv. ‘Portici’) which were submitted to different regimes: (i) fully irrigated plants; (ii) stressed plants in June (S1), July (S2) and October (S3) followed to re-watering. Midday stem water potential was used to determine water status, and leaf gas exchanges were measured during trials. Histological analyses on floral differentiation, xylem progression within flower buds and biological observations were carried out. Both summer water stress periods affected the floral differentiation leading to a temporary shutdown. The S1 trees were able to recover the development of meristematic apices while S2 had a strong delay. All drought treatments caused a slower xylem progression, variations in bud size, blooming entity and flower anomalies. Results particularly highlights the importance of water availability also in early autumn.

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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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444 Forcing Requirements of Seed-propagated Easter Lilies

HortScience ◽

10.21273/hortsci.35.3.470c ◽

2000 ◽

Vol 35 (3) ◽

pp. 470C-470 ◽

Cited By ~ 1

Author(s):

Neil O. Anderson

Keyword(s):

Plant Height ◽

Disease Transmission ◽

Cold Treatment ◽

Leaf Number ◽

Stem Height ◽

Flower Buds ◽

Flower Bud ◽

Hybrid Treatment ◽

Easter Lily ◽

Bud Initiation

Seed-propagated lilies have the potential to revolutionize Easter lily production, eliminating clonal disease transmission, costly production and shipping. Five F1 interspecific hybrids, Lilium × formolongo (L. longiflorum × L. formosanum), were evaluated to establish an initial forcing schedule. The hybrids included `Raizan Herald', `Augusta F1', `Raizan No. 1', `Raizan No. 2', and `Raizan No. 3'. Two hundred seeds/hybrid were sown in early July in plug trays. Ten weeks after sowing, seedlings were transplanted into 3-inch pots. At the 20-week stage, the seedlings were repotted into 6-inch standard pots for the final production phase. All hybrids had low germination rates (<20%). Hybrids were grown under two photoperiod treatments (short, long days) at 21 °C with n = 10 reps/hybrid/treatment. Plants were evaluated for no. days to visible bud, leaf unfolding rate, final plant height, leaf number, bud count, flowering dates, and the no. of shoots/bulb. Ten weeks after sowing, hybrids had one to four leaves/plant. At 20 weeks, the leaf number had increased to as many as 40. Despite the lack of a cold treatment, most hybrids initiated flower buds. Visible bud date occurred as early as 20 weeks after sowing. Photoperiod had no effect on leaf number, stem height, and flower bud initiation. Plant height exceeded 15 inches by week 16 in most hybrids, indicating the need for plant growth regulator applications. The next steps in product development for seed-propagated Easter lilies will be outlined.

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CONTROLLING HEIGHT AND FLOWERING IN HYPOESTES PHYLLOSTACHYA

HortScience ◽

10.21273/hortsci.27.11.1178g ◽

1992 ◽

Vol 27 (11) ◽

pp. 1178g-1178

Author(s):

Chi Wang ◽

Kevin L. Grueber

Keyword(s):

Plant Growth ◽

Plant Height ◽

Shoot Growth ◽

Internode Elongation ◽

Flower Buds ◽

Flower Bud ◽

Plant Seed ◽

Leaf Distortion ◽

Flower Bud Abortion ◽

Short Days

Control of plant height and flowering are two major problems associated with the production of Hypoestes phyllostachya Bak. (polka-dot plant). In seed-propagated cultivars, sprays of ancymidol (A-Rest), chlormequat (Cycocel), paclobutrazol (Bonzi), and uniconazole (Sumagic) were effective in inhibiting shoot growth and internode elongation at 100, 1000, 33, and 10 mg·l-1, respectively. Daminozide (B-Nine), even at 6000 mg·l-1, was ineffective compared to untreated controls. Ethephon (Florel) was effective in retarding plant growth at 500 mg·l-1, but at 1500 mg·l-1 resulted in leaf distortion and horizontal shoot growth. H. phyllostachya was determined to be a quantitative (facultative) short day plant. Seed-propagated plants with 16 or more nodes flowered regardless of photoperiod, but flowering was more rapid under short days (SD) than under long days (LD). Application of ethephon significantly inhibited shoot elongatioo and number of flower buds formed and also increased the incidence of flower bud abortion. In seed-propagated plants, 500 mg·l-1 ethephon did not adversely affect flowering when applied at any time during the first seven weeks after the start of SD. At 1500 or 2500 mg·l-1, ethephon applied at any time during the first five weeks after the start of SD maximized the number of vegetative buds and minimized the number of viable flower buds. When applied more than six weeks after SD began, ethephon did not promote the formation of vegetative axillary buds but did promote flower bud abortion.

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Inhibition of Root Formation in Cuttings from Flowering Stock Plants of Chrysanthemum

HortScience ◽

10.21273/hortsci.30.4.836b ◽

1995 ◽

Vol 30 (4) ◽

pp. 836B-836

Author(s):

Carrie DeVier ◽

Robert L. Geneve

Keyword(s):

Flower Development ◽

Root Formation ◽

Flowering Plants ◽

Separate Experiment ◽

Flower Buds ◽

Flower Bud ◽

Gradual Reduction ◽

Rooted Cutting ◽

Short Days ◽

Bud Removal

The influence of flowers on root formation in mum cuttings was evaluated for stock plants grown under long (LD) or short (SD) days. SD plants showed visible flower buds after 20 days and color after 30 days. Cuttings were taken from LD or SD plants at 10-day intervals until flowers were fully open. Cuttings from LD plants rooted at 100% throughout the study, with 24 or more roots per cutting. Cuttings from SD plants showed a gradual reduction in rooting percentage and number as flower development increased. After 30 days, roots per cutting for SD plants was reduced by 85% compared to LD cuttings and only 30% of SD cuttings rooted. In a separate experiment, cuttings were taken from stock plants after 40 long or short days. Partial or all flower buds were removed from SD plants prior to sticking. SD cuttings (regardless of flower bud removal) rooted at <47%. LD cuttings rooted between 23.6 to 43.8, while SD cuttings rooted between 3.1 and 8.5 roots per rooted cutting. The data indicates that cuttings taken from flowering plants show reduced potential for rooting and that this effect was not influenced by removal of flowers prior to sticking cuttings.

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