Source: UNIV OF HAWAII submitted to
FLOWERING CONTROL OF TROPICAL ORNAMENTALS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
REVISED
Funding Source
Reporting Frequency
Annual
Accession No.
0073302
Grant No.
(N/A)
Project No.
HAW00856-H
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2012
Project End Date
Sep 30, 2017
Grant Year
(N/A)
Project Director
Kim, H. J.
Recipient Organization
UNIV OF HAWAII
3190 MAILE WAY
HONOLULU,HI 96822
Performing Department
Tropical Plant & Soil Science
Non Technical Summary
The values of Hawaii's floriculture and nursery products, and out-of-State sales are continuously declining. Of greatest importance are those crops for which significant export occurs such as cut orchids (principally dendrobium), anthuriums, and bold tropicals. However, many of these crops face seasonal production constraints despite Hawaii's favorable climate, and the values of products and out-of-State sales may decline even further without establishing proper production systems to provide constant supplies of ornamental crops throughout the year. Not much research has been done on potted tropical plants to target principal holidays and for year-around flowering. It can be achieved by the use of photoperiod, temperature manipulation and/or plant growth regulators. Potted Dendrobium orchid plants have 2nd ranked among floriculture and nursery products although the production value has been declining since 2004, which may be partially due to the increased shipping cost to the mainland. Some of the most popular new orchids today are miniatures and many different species and hybrids of dwarf dendrobiums are entering the market. Miniature dendrobiums may attract new consumers as well as existing consumers in Hawaii by creating a new market sector. They can be easily shipped to mainland and other countries, promoting out-of state sales of Hawaii. The espected outcomes include the establishement of protocols for manipulation of flowering of tropical cut and potted tropical flowering plants, publications in peer-reviewed journals and trade journals, and presentations of the results at local, national, and international meetings. The new management practices will also help increase the values of product and out-of-State sale.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2042121102010%
2042122102040%
2052121102010%
2052122102040%
Goals / Objectives
The 2010 preliminary value of Hawaii's floriculture and nursery products is estimated at $75.6 milion, which is 2 percent lower than the value in 2009 and declining for the third consecutive year (NASS, 2011). Hawaii's cut flower crops including anthurium, orchid, protea, bold tropicals, and traditional cuts were valued at $9.3 million, while potted flowering crops including potted orchids, anthurium, bromeliad, and poinsettia were valued at 20.8 million dollars (NASS, 2011). The value of out-of-State sales of flowers and nursery products (including wholesale and retail sales) during 2010 is estimated at $32.0 million, declining 10 percent from 2009. Of greatest importance are those crops for which significant export occurs such as cut orchids (principally dendrobium), anthuriums, proteas, and bold tropicals including gingers. However, many of these crops face seasonal production constraints despite Hawaii's favorable climate, and the values of products and out-of-State sales may decline even further without establishing proper production systems to provide constant supplies of cut flowers or potted flowering crops. Therefore, it is essential to understand the flowering physiology of tropical ornamentals in order to better control of flowering of the crops. Hawaii's dendrobium orchids, largely a product of the University of Hawaii breeding program, move into a cycle of flowering after their first year and produce fewer flowers in the high demand January to April time period (Kamemoto et al., 1997; Paull et al., 1995; and Sakai et al., 1998). Injection of plant growth regulator induced inflorescences in October and November, indicating the possibility of the off-season flowering in dendrobium orchids (Sakai et al., 1998). Anthuriums, produced outdoors under saran shade, have a lower production during winter months, but this is true also of protected cultivation in glasshouses, as in the Netherlands (van Herk et al., 1998) and reflects both lower winter air temperatures and less sunlight (Leffring, 1975; Klapwijk and van der Spek, 1988). Seasonal flower production has been demonstrated in many tropical ornamentals (Criley, 1989, Fuss and Sedgley, 1990, Malan and Jacobs, 1990 & 1994, Rieger and Sedgley, 1996). Overall, this project utilizes the strategy of producing high value specialty crops for niche markets. The results of this work will increase the productivity and efficiency of floriculture and nursery operations that produce cut and tropical flowering potted plants by providing new knowledge and applying new and existing technologies. Expected outputs include production guidelines for year-round production systems. In addition to presentations to local industry organizations and professional meetings and conferences, findings will be published in leading journals, trade journal articles, and extension bulletins.
Project Methods
For Objective 1. 1.Lighting, temperature and PGRs on dendrobium orchids. Selected varieties of dendrobium orchids will be grown on the benches under the High Pressure Sodium Lamps . The Daily Light Integral (DLI) will be measured with WeatherTracker units (Spectrum Technologies, Inc., Plainfield, IL) positioned at plant height. Days to flowering will be recorded and the flowering responses will be quantified by spray number, spray length, and floret count. Similar experiments that also allow for temperature variation can be carried out in growth chambers. The results will be compared to non-lighted controls. PGRs will be applied at different plant developmental stages. Various concentrations and application methods of PGRs including drench and spray will be employed. Timeline: Continuous 2.Shortening the flowering cycle of potted dendrobium orchids. UH potted dendrobium hybrids as well as grower-recommended selections including miniature dendrobiums will be grown under extended photoperiods provided by HPS lighting in the glasshouse. Recent publication of responsiveness of orchids to gibberellins and cytokinins (Matsumoto, 2006; Miguel et al., 2006) suggest examination of these factors, as well. Growth chambers will allow us to introduce cool temperatures as a factor in flowering. Measurements of plant size at first flowering, flower spray size and floret count, time to flower from start of treatment, and numbers of inflorescence-supporting pseudobulbs will be determined. Timeline: Continuous upon acquisition of selected dendrobium orchid varieties. For Objective 2. 1.Daylength modification or plant growth application on Leucospermum. This experiment is based on observations by Malan and Jacobs (1990, 1994) that suggest some of the species of Leucospermum initiate inflorescences under short daylengths of high light intensity. Leucospermum hybrids will be placed in a greenhouse with shading unit and will be managed to produce potted plants or cut flowers. The daylength-controlling device will operated to provide 9-hour daylengths from mid-July until late September. Control plants will be given the same cultural practices but without the short day lengths. Flower initiation and development and flowering times will be recorded. Positive results would include earlier flowering of the plants given SD. A various ranges of plant growth regulators (PGRs) will be applied at different stages of plant development to determine the proper timing and concentration for earlier flowering. Timeline: Continuous 2.Flowering control of ornamental gingers. Grower harvest records indicate seasonal flowering for these genera of tropical gingers (Criley and Maciel, 2002). Large tubs of these species will be subjected to artificial short days and long days to determine whether SD or LD is responsible for stimulating flower initiation. Data to include time to flower from imposition of day length conditions, productivity per starting unit, and keeping quality in response to cytokinins. Timeline: Continuous

Progress 10/01/12 to 09/30/13

Outputs
Target Audience: Hawaii cut flower and potted flowering plant operations and nursery growers. Changes/Problems: We have identified issues related to usingdendrobium orchids asplant materials.Dendrobium orchidsare seed-propaged in Hawaii (not clone), and therefore,postharvest evaluation may be a challenge due to the variation in flowering time even among the same variety. In order to provide similar outcomes as described in the objectives and goals, we used 20 varieties of Oncidium orchids instead. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? The results were presented at the following conferences. American Society for Horticultural Science, Palm Desert, California. July 21-25, 2013. The published abstracts can be easily accessible online for the communities of interest. What do you plan to do during the next reporting period to accomplish the goals? We will continuously collect datafor the second year and finalize our evaluation on the seasonal behavior and overall performance of Oncidium intergenerics in the greenhouse. Meanwhile, we are evaluating vase life of Oncidium cut flowers in a simulated consumer environment. Variation in cut flower longevity has been observed, and as a result, promising varieties will be identified throughout thiscut flower trial. Tissue analysis will be conducted in the leaves of 'Sharry Baby' Oncidium and possible nutrient element will be identified in relation to brown spot development. Based on the information, plants will be grown with various concentration of the nutrient element.The results willprovide critical informationonthe causes of brown spot development and how to prevent it. Rooted cuttings of two varieties of Leucospermum were transplanted in 1 gallon pots, and sprayed with Bonzi at various concentrations to determine the optimal concentration for plant growth. Bonzi effects varied depending on a variety. We are currently making observations to finalize the results.

Impacts
What was accomplished under these goals? Oncidium intergenerics are popular potted flowering plants with showy flowers and diverse color variations. Despite the huge availability of intergeneric hybrids, only a few varieties of Oncidiums have been used as cut flowers. The objective of this study was to evaluate Oncidium intergenerics as potential new cut flowers. We have identified several promising cut varieties with long flower spike, higher number of flowers per spike and higher longevity of the spike. This research will help growers choose proper varieties for the production of cut Oncidium varieties. Sharry Baby is one of the most popular Oncidium varieties, however, the development of brown spots during production is a significant problem negatively affecting the quality of the product. Although its economic impact is significant, the causes of brown spots have not been fully understood. Our results indicate that the development of brown spot is closely related to the production temperature and the age of the Oncidium plants – older plants grown under higher growing temperature develop more brown spots. The results will provide critical information on the conditions induce brown spots, so that growers can take preventative measures.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Kim, H.J., Kim, M.H., Li, X.X., and Leonhardt, K. 2013. Temperature affects the development of brown spots on the leaves of Oncidium Sharry Baby. HortScience 48(9): S381.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Kim, M.H., Leonhardt, K., and Kim, H.J. 2013. Evaluation of Oncidium intergenerics as potential cut flowers. HortScience 48(9): S382.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Kim, M.H., Li, X.X., Leonhardt, K., and Kim, H.J. 2013. Temperature affects the development of brown spots on the leaves of Oncidium Sharry Baby. CTAHR Student Research Symposium 25:39.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Kim, M.H., Karki, Y., Leonhardt, K., and Kim, H.J. 2013. Evaluation of Oncidium intergenerics as potential cut flowers. CTAHR Student Research Symposium 25: 24.


Progress 10/01/11 to 09/30/12

Outputs
OUTPUTS: Results of the year-round planting of Siam Tulip (Curcuma alismatifolia) were reported at the VIIth Symposium on New Floriculture Crops in Buenos Aires, Argentina in November 2011. The M.S. thesis research of Ms. Kauahi Perez on plumeria pollen viability was reported at the same meeting. The progress of shoots of 10 protea cultivars and species from the time of pruning to flower bud initiation was reported to the Joseph H. Hill Memorial Foundation via a 6-month progress report and closing summation. PARTICIPANTS: Kauahi Perez, M.S. candidate, conducted the plumeria pollen studies. Maintenance of the plants was carried out by the farm crew at the Waimanalo Research Station. The Joseph H. Hill Memorial Foundation supported the study on manipulating protea flowering through a grant awarded by the International Cut Flower Growers Association. Pamela Shingaki of the Maui Agricultural Research Station supported the study in between visits by the principal investigator. TARGET AUDIENCES: Scientists at the VIIth International Symposium on New Floricultural Crops, potted plant and cut flower producers in Hawaii (ONGA, BIAN, MAN). Plumeria hobbyists who are interested in plumeria breeding (So. Calif. Plumeria Society). Protea growers in Hawaii PROJECT MODIFICATIONS: Project was terminated 30 September 2012

Impacts
The serial planting results of the 2010-2011 year were confirmed by fall plantings in 2011. These showed that the tropical ginger could be grown for out-of-season flowering for Valentine's Day, Easter, and other spring holidays by planting dormant rhizomes in late September through November and providing long days through the winter/spring months. Since this crop is available in both cut flower and potted varieties, this research adds variety to the winter/spring markets and an additional product for Hawaii growers. The protea study at the Maui Agricultural Research Center provided initial evidence that off-season flowering of cultivars within Protea neriifolia and hybrids 'Sylvia' and 'Niobe' may be achieved by stimulating flower bud initiation on 2 and 3 flush shoots treated with the cytokinin N-6-benzylaminopurine. This would create a larger marketing period for Hawaii protea growers. However, P. obtusifolia and P. lorifolia do not respond well to the pruning and cytokinin treatments.

Publications

  • Criley, R. A. 2011. Blueprint programming for year-around forcing of Curcuma alismatifolia. Scientific Program and Abstracts, VIIth International Symposium on New Floricultural Crops, 22-25 November 2011, Buenos Aires, Argentina. Abstr. No. O3-02.
  • Perez, K. and Criley, R.A. 2011. Assessing Plumeria pollen viability. Scientific Program and Abstracts, VIIth International Symposium on New Floricultural Crops, 22-25 November 2011, Buenos Aires, Argentina. Abstr. No. P4-23.


Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: The majority of Curcuma alismatifolia rhizomes forced beginning 1 December 2010, 1 January 2011, 1 February 2011, and 1 March 2011 sprouted 26 to 36 days after planting. From sprout to first flower required an average of 92 days for the first three planting dates but only 75 days for the March planting. These numbers are in good agreement with the previous forcing series and round out times of year that were not included in the earlier studies. A 4-hr light break in the middle of the night was required to prevent dormancy and for the plants to flower in winter. At the Maui Agr. Research Center eleven species and cultivars of the genus protea were included in a manipulation of flowering via pruning and application of cytokinin. Stems on the bushes were cut back on 20 September 2010 and 10 November 2010 and 11 January 2011. Cytokinin treatment (400 ppm N-6-BA) was timed for when the third flush from pruning occurred. As of September 2011, only a few stems on different plants had reached the desired stage of growth, a not-unexpected outcome as three growth flushes often take more than a year according to South African reports. Two reports were filed with the Joseph H. Hill Memorial Foundation, grantors for this research. A graduate student's MS thesis project on pollen biology to support a future breeding effort with plumeria for rust resistance showed that osmotic concentration, sucrose level, and pH of a pollen germination medium needed adjustment for each cultivar examined. Percent germination and pollen tube length were not always optimized in the same germination medium. Fluorescein diacetate staining was a good stain to assess in vitro plumeria pollen viability. The thesis was filed with the University of Hawaii Graduate Division. Ms. Perez presented her work at the 2011 American Society for Horticultural Science meetings: "Adjustment of media pH improves in vitro pollen germination in plumeria" PARTICIPANTS: Kauahi Perez, M.S. candidate, conducted the plumeria pollen studies. Maintenance of the plants was carried out by the farm crew at the Waimanalo Research Station. A $1000 scholarship for Ms. Perez was provided by the Southern California Protea Society. The Joseph H. Hill Memorial Foundation supported the study on manipulating protea flowering. The grant was funded through the International Cut Flower Growers Association (Hazlett, MI). Pamela Shingaki of the Maui Agricultural Research Station supported the study in between visits by the principal investigator. TARGET AUDIENCES: For the Curcuma work: potted plant producers in Hawaii (ONGA, BIAN, MAN) For the Protea work: cut flower protea growers (Maui, Hawaii) -- but nothing to report to them this period. For the plumeria study: plumeria breeders (one on Oahu) and plumeria hobbyists in California, Texas, and Florida. PROJECT MODIFICATIONS: The PI for this project retired 31 December 2010. Dr. Hye-Ji Kim will take over the project until its September 30, 2012 termination and will either renew the project or terminate it.

Impacts
The prospect of availability for flowers of Curcuma alismatifolia in spring flower markets was demonstrated using a series of planting and forcing dates beginning in early December and continuing through March. The rhizomes need to be sent into dormancy, dug, dried, and prepared for planting earlier than they are available from the usual Thailand sources, This requirement opens opportunities for either southern hemisphere production of rhizomes or for an enterprising grower to manipulate growing conditions for rhizome production. Studies on plumeria pollen showed good viability for several species/cultivars, leading to possibilities of hybridizing rust resistant cultivars. However, successful transfer of pollen to a stigma remains a challenge because of the very small pistil and the latex that floods the receptacle when the corolla is removed.

Publications

  • Criley, R. A. 2011. Enhancing protea flowering in Hawaii. Research Progress Report July-December 2010. Intern. Cut Flower Growers Assoc. Bulletin Oct-Dec. 2011. pg 13-15.
  • Perez, B. K. 2011. Aspects of Plumeria pollen viability in support of breeding for rust resistance. M.S. Thesis, University of Hawaii, Honolulu, HI.


Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: Forcing of rhizomes of Curcuma alismatifolia that were held dormant at 15C for varying periods of time showed plant to sprout times of approximately 30 days, and sprout to flower times of 65 to 100 days, depending on season of forcing. Shortest time from plant to flower occurred for rhizomes forced during long, warm days of summer, while fall-planted rhizomes, which flowered in December-January required longer time periods. A 2-week heat treatment at 30 C following removal from cold storage enhanced sprouting and development to anthesis. High pressure sodium lighting of Oncidium Sharry Baby from November through March brought flowering forward into March-April, while plant held under natural day lengths flower from late July through early October. Attempts to shorten the inflorescence stem with paclobutrazol (PBZ) drenches were not successful. Potted Thunbergia erecta were treated with foliar applications of 5 to 20 ppm of paclobutrazol. When compared to untreated controls, treated plants had about 20% growth reduction, and appeared to have slightly more flowers on plants receiving the higher PBZ treatment. Caricature plants (Graptophyllum pictum) treated with PBZ were more compact, and offered better display qualities than untreated plants. PARTICIPANTS: The Joseph H. Hill Memorial Foundation supported cultural and post-harvest studies on two tropical ginger species, Etlingera corneri and Zingiber spectabile. The grant was funded through the International Cut Flower Growers Association (Hazeltt, MI). TARGET AUDIENCES: Nurseries that produce potted plants for sales through garden centers and big box outlets can benefit from cultural practices identified in the work with Curcuma, Thunbergia, Graptophyllum, and Oncidium Sharry Baby. PROJECT MODIFICATIONS: The PI, Richard Criley, is retiring at the end of 2010. A determination is being made whether to terminate the project or to pass it along to new faculty (being recruited). The present project period runs through September 2012. Three graduate students are completing thesis research under this project.

Impacts
Year around flowering of Curcuma alismatifolia is possible with rhizomes held in cold storage for up to 12 weeks after digging. Forcing during the short day period of fall requires extension of the photoperiod to achieve good quality potted plants. Similar treatment could also be applied to cut flower varieties of C. alismatifolia. The target for flowering of Oncidium Sharry Baby, which has a fragrance like chocolate, is late January and early February, but our lighting treatment may not have begun early enough to achieve this goal. Success would place this cultivar into the desirable Valentine's Day marketing period. Ornamental shrubs of the Acanthaceae family, such as Thunbergia erecta and Graptophyllum pictum, are quite responsive to the growth retardant paclobutrazol, and can be grown as attractive potted plants. These add to the palette of color offering for garden center sales.

Publications

  • Criley, R. A. 2010. New Tropical Ginger Cut Flowers. Research Progress Report. Intern. Cut Flower Growers Assoc. Bulletin Mar-Apr 2010. pg 19-22.
  • Criley, R. A. 2010. New tropical ginger cut flowers. Final Report. Intern. Cut Flower Growers Assoc. Bulletin July-Sept. 2010 pg 14-17.
  • Criley, R. A. 2010. New Tropical Ginger Cut Flowers. Research Progress Report. Intern. Cut Flower Growers Assoc. Bulletin Jan-Feb 2010. pg 22-26.


Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Faster plant production from tissue culture was the objective of an expt in which carbon dioxide was injected into closed community pots of anthurium hybrid UH 2555. After 8 wk, 4 of 10 pots receiving CO2 had plantlets touching the plastic enclosure versus only 2 pots with no CO2. While leaf numbers were equal (avg 5.5) leaflet size was greater for plantlets given CO2 ( 3.2 vs 2.1 cm long; 2.2 vs 1.7 cm wide) and stem diameter was thicker (3.3 mm vs 2.9 mm). The data suggest that higher quality plantlets with potentially faster post-transplant growth may be achieved using CO2 pulses following transfer from agar to a growing medium, and that time to flower producing size may be shortened. The cooperating grower, however, did not keep records on the plant following transplant. Stimulation of winter flowering of plumeria was the objective of an expt conducted on 20 field-grown plumeria trees. One half of each tree received a growth regulator applied to terminal and the other half received none. The chemicals were commercial formulations of ethephon (800 ppm), N-6-BA (500 ppm), PMA (800 ppm), and a combination of GA4+7 and PMA (each at 540 ppm). A single application was applied to 10 tips per plant (5 plants per treatment) on October 30, 2008, and the initial appearance of the inflorescence bud and first open flower were determined at 2 week intervals. Ethephon has been previously used to enhance inflorescence appearance in winter, and it caused the earliest bud appearance (12/22/08 versus 2/27/09 for the control portion of the trees) of any of the chemicals. Results were mixed for the PMA + GA4+7 with some inflorescences failing to develop and some in the PMA alone treatment developing as nubs with no flowers. The BA treatment was promising in that a high proportion of terminals did flower, but first inflorescence buds were 6 to 8 wk later than for ethephon-treated terminals and represented no improvement over the ethephon treatment. Manipulation of flowering time for two tropical cut flower gingers using photoperiod successfully demonstrated a short day requirement for Etlingera corneri and a likely short day - long day response for Zingiber spectabile as continued long day lengths during winter prevented flowering in Etlingera and delayed it in Zingiber. Keeping quality of Etlingera inflorescences was slightly improved by a dip in GA4+7 and PMA 200 ppm (14.5 days vs 13 days for water only), but inflorescence maturity was a more important factor with inflorescences with more unfurled bracts lasting about 2 days longer than less mature ones. Zingiber inflorescences similarly showed longer vaselife when harvested at a larger size. Holding in water yielded longer vaselife than did a 3% sucrose pulse or 200 ppm GA4+7 (14 days vs 11 or 8 days, respectively). As part of basic information leading to breeding of plumeria, pollen of Plumeria rubra cultivars and plumeria species was stored at room temperature and germinated on Brewbaker and Kwack medium. Following storage at 0, 8, and 22 C, only 22 C for up to 72 hr permitted subsequent germination. P. rubra cultivar pollen had slightly better viability than pollen from species. PARTICIPANTS: Green Point Nurseries (Kurtistown, Hawaii) provided the space for growing the University of Hawaii anthurium hybrid 2555 that was used in the CO2 pulse to community pots. They provided routine maintenance, while UH research technician, Joanne Lichty monitored the experiment and recorded the data. The Waimanalo Research Farm was the site for the plumeria winter-flowering studies in which the PI was assisted by Peter Maher, a paid student helper, to record data from 400 growing points every two weeks. The plumeria germplasm plot was also the locus of sampling for pollen studies by TPSS graduate student Kauahi Perez whose M.S. thesis will deal with pollination biology of plumeria. The cut flowers for vase life studies with Etlingera and Zingiber were provided by the Lyon Arboretum with assistance in locating flowering plants from Mr. Ray Baker. The flowering studies on Etlingera and Zingiber were funded by the Joseph H. Hill Memorial Foundation through a grant administered by the International Cut Flower Growers Association (Hazlett, MI). TARGET AUDIENCES: The target audience for the CO2 work on anthurium plantlets from tissue culture would be commercial anthurium growers who obtain their planting material via tissue cultured. Since there was plantlet loss due to salinity build-up, the experiment should be repeated in order to provide the growers with a protocol for enhancing early plantlet development. Commercial plumeria growers would have been the target audience for the PGR studies attempting to enhance flowering, but since the gibberellin and cytokinin materials did not bring flowering forward, there is nothing to communicate to them. Reports were made at 6 month intervals to the ICFGA on progress with manipulating tropical cut flower ginger flowering. A final report was prepared and submitted after the no-cost extension of funding to 30 September 2009. This report will appear in the bulletin of the ICFGA. PROJECT MODIFICATIONS: Renovation of the TPSS greenhouses prevented activity from October 2008 through August 2009 on the project objective dealing with potted plants. Lack of a suitable irrigation and fertilization system negatively impacted the study on flowering of Etlingera and Zingiber as a number of plants grew poorly because of uneven water distribution. The loss of many control anthurium plantlets in the CO2 experiment as a result of salinity build-up, requires repeating the experiment so that effective controls are in place.

Impacts
Many years after we reported on a long day response for Hedychium coronarium flowering, a local ginger grower asked for our paper to help him initiate his own winter-flowering program. A Big Island plumeria grower expressed interest in our winter flowering plumeria papers, but this was after the optimum time to apply it in fall 2009, and he indicated he'd take a look at it next year. A earlier study on heliconia flowering productivity was republished by the Heliconia Society International and adapted for publication in a Brazilian journal at the request of the editor. Harold Tanouye of Greenpoint Nurseries expressed great interest in the outcome of the CO2 injection into community pots of anthuriums as it yielded a greater percentage of plantlets from the community pots as well as stronger plantlets.

Publications

  • Criley, R. A. 2008. New tropical ginger cut flowers. Hill Foundation Research Progress Report. Intern. Cut Flower Growers Bulletin Nov.-Dec. 2008. pg. 29-30.
  • Criley, R. A. 2008. Heliconia cut flower production: a 2-year study in Hawaii. Revista Brasiliera de Horticultura Ornamental 14(2): 109-113.
  • Criley, R. A. 2009. Plumeria rubra: an old ornamental, a new crop. Acta Hort. 813:183-190.
  • Criley, R. A. 2009. Heliconia cut Flower Production: a 2 year study in Hawaii. Bulletin Heliconia Society International 15(4):9-12.


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Obj. #1. Rhizomes of Etlingera corneri and Zingiber spectabile collected from the Lyon Arboretum in October 2007 were established in 50 x 20 cm tubs in January 2008. Natural day lengths were provided one half of the plants while the other half received supplemental illumination from 00 W HPS lamps to provide a 16 hr day. In April 2008, 10 plants of each species from each day length condition were subjected to 15 hour long nights until June 21 when all plants were returned to natural day lengths. No plants produced inflorescences under these conditions, but Zingiber plants from the long night conditions began to produce inflorescences about 10 weeks after they were returned to natural long days of summer. Etlingera plants did not flower under any day/night combination. Oncidium Sharry Baby plants were drenched with cytokinin, GA4+7, or a combination of cytokinin and GA4+7 in January 2008. Spiking occurred on 71% of plants treated with GA4+7 commencing 4 weeks after treatment. The cytokinin treatments began to spike at the same time as the control plants while the cytokinin + GA4+7 treated plants were only slightly earlier than the controls, which began to spike in late May - early June. Flowers were normal in appearance but the floral spikes were longer and weaker than on the control plants. Obj. #2. Potted Thunbergia erecta plants treated with 400 ppm benzyladenine developed many side branches, but these remained low and the inflorescences were hidden in the foliage. Obj. #3. Foliar sprays of cytokinin, ethephon, or a combination of cytokinin and GA4+7 and Plumeria trees were applied in mid October and mid November 2007 to evaluate their potential to force early inflorescence development. Earliest bud break was on ethephon treated plants followed by plants receiving benzyladenine. Due to papaya mealybug infestations prior to treatments, only 40 to 60% terminals developed flowers. Thus, the comparisons did not have a good statistical validation. PARTICIPANTS: Richard A. Criley, Principal Investigator. Department of Tropical Plant and Soil Sciences, University of Hawaii. Etlingera and Zingiber work is being conducted under a grant from the Joseph H. Hill Memorial Foundation. Plant growth regulator compounds employed in the Plumeria and Oncidium work were supplied by Fine Americas, Inc., Walnut Creek, CA. TARGET AUDIENCES: Potted orchid growers are the target audience for the manipulation of flowering of Oncidium Sharry Baby, a seasonal bloomer that would be desirable as a late winter-spring offering to consumers. Producers of bold tropical cut flowers are the target audience for the research that attempts to manipulate flowering of these two seasonal blooming tropical gingers. Lighting is a potential trigger for earlier bloom that may be feasible for some growers. Plumeria flower growers already can employ ethephon to enhance early flowering in Plumeria for the winter tourist trade in Hawaii, but this year's research with cytokinin and cytokinin- gibberellin plant growth regulators showed promise despite interference by the insect pest, papaya mealybug. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The seasonal flowering of Zingiber spectabile may be manipulated by photoperiod as flower initiation appeared to develop under long days following a period of long nights. This may extend the marketing period for this ginger. While cytokinin may increase branching of woody shrubs, the plants need to be grown to near marketable size before its application. With more branches, the flower display will be more attractive and salable. The existing recommendation for ethephon to force winter flowering in Plumeria is still valid, but cytokinin application may substitute or be used as a supplement to force development. The adverse impact of an insect infestation made this study inconclusive. While gibberellins have been used to induce flowering on other orchid species, the preliminary results of GA4+7 application on Oncidium Sharry Baby show promise to manipulate flowering. The peak flowering for this cultivar has normally been in mid to late summer, while a desirable marketing period for this chocolate-scented orchid is at the Valentine's Day holiday.

Publications

  • Criley, R. A. 2008. Ornamentals -- More than just beautiful. Acta Hortic. 788:23-28
  • Criley, R. A., K. W. Leonhardt, D. Oka, P. N. Shingaki. 2008. Extending the flowering period of Leucospermum hybrids through disbudding. Acta Hortic. 766:183-186
  • Criley, R. A., M. S. Roh, M. Kikuchi, and R. M. Manshardt. 2008. A comparison of Gardenia Augusta cultivars using isozymes and RAPD markers. Acta Hortic. 766:461-468


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: Obj.#1. Dendrobium Uniwai Pearl orchid plants were lighted from 8 December 2006 to 30 March 2007 with 400W HPS or Metal halide (MH) lights during 4:00 to 11:00 pm. Since UH-bred dendrobiums like Uniwai Pearl do not flower well during the January-April time period, the positive effect of light was determined by comparison with the May-August period when production is heaviest. A comparison of dry weight/fresh weight ratios of 1 cm leaf disks taken before lighting started and 10 weeks later showed that lighted plants had gained an average of 7.3% since lighting began. The HPS-lighted plants produced an average of 1 sprays per plant and the MH-lighted plants 2.5 sprays per plant during the January-April time period. The same plants averaged 1.7 and 4.2 sprays during May-August. While the winter period production was less than that of the high light period of summer, there were, at least some harvestable flowers. Lighting boosted the daily light integral (DLI) to between 8 and 10 Mol.day.m2 from the normal 4-5 Mol.day.m2 for wintertime. Removal of 30% saran shade cloth brought natural light levels up to about 6 Mol.day.m2 in the glasshouse. The research suggests that 8 to 10 Mol.day.m2 is necessary to achieve winter flower production for Uniwai Pearl. The results should also be applicable to other UH-bred dendrobium orchids. Obj.#2 Shading of Curcuma alismatifolia plants in the late summer as they were becoming dormant and forming tuberous storage roots, and ground heating using clear plastic sheets over one-half of shaded and full sun plants after the tops had died down was employed to determine if such pre-digging strategies would produce rhizomes that would sprout faster the following spring. No sprouting was observed before normal end-of-March sprouting occurred, but sprouting was slightly earlier for the rhizomes that had been under clear plastic sheets than for those in bare ground. Potted Oncidum Sharry Baby orchids were given foliar sprays of growth regulators in January 2007 in an effort to bring about flowering by Mother's Day 2007. Treatments with 100 ppm Fresco [1.8% N-(phenylmethyl)-1H-purine-6-amine + 1.8% GA4+7] or 100 ppm Novagib 10L (0.95% GA4+7) both yielded slightly more plants that produced flower spikes than control plants (77.8% in both treatments versus 33.3% for controls), but flowering missed the Mother's Day target. Obj.#3 Single foliar applications of N-6BA, Fresco (1.8% N-(phenylmethyl)-1H-purine-6-amine + 1.8% GA4+7), or Exillis Plus [2% N-(phenylmethyl)-1H-purine-6-amine] at rates of 500, 540 + 600, and 500 ppm respectively, were made to shoots of plumeria OP#3 in the field on 17 November 2006. Emergence of the terminal inflorescence bud and first open flower in each inflorescence was recorded. The earliest emergences were recorded 6 weeks after treatment with all 3 growth regulators, with the Fresco treatment earliest by 2 weeks. N-6-BA alone stimulated the most inflorescence bud emergences and follow-through to open flowers. Since inflorescences had already been initiated at the time of treatment, the growth regulator effect was one of forcing bloom rather than causing initiation. PARTICIPANTS: Richard A. Criley, Principal investigator. Department of Tropical Plant and Soil Sciences, University of Hawaii. Dendrobium research was conducted under Federal Floriculture grant Award No. 2002-34199-12347 (concluded 9-30-2007). Plant growth regulator compounds employed in Oncidium and plumeria studies were provided by Fine Americas, Walnut Creek, CA 94596. Ma Li Ping, graduate student. Conducted trial with cytokinin materials provided by Fine Americas in an attempt to influence flowering of Oncidium Sharry Baby. Her report was poorly analyzed and written and the results require follow-up to verify them. TARGET AUDIENCES: Cut flower orchid growers are the target audience for the lighting studies with dendrobium orchids. Reports on this research have been presented to grower meetings and published in the Fourth Floriculture Conference hosted by the University of Hawaii. Potted orchid growers are interested in manipulating flowering of their potted orchid varieties to provide a broader period during which they can market some of their seasonal materials. They would prefer something that does not require a lot of environmental manipulation such as chemical treatments. Success with the gibberellin and cytokinin materials in other species has been reported elsewhere so the present research was targeted to a selection grown by many Hawaii growers. Nursery grower are the principal target for manipulation of flowering of Curcuma as flowering occurs in a relatively short time span during summertime in Hawaii. At present, the main means of manipulation is by varying the time of planting, but the ability to flower plants for spring holidays is being investigated using a variety of approaches. Plumeria flower growers already can employ ethephon to enhance early flowering in plumeria, a desired lei flower material for the winter tourist trade in Hawaii. Additional tools such as the cytokinin and cytokinin-gibberellin plant growth regulators offer promise as well. The main barrier to the use of the PGRs is that plumeria growers do not have the sprayers available to apply the compounds efficiently. PROJECT MODIFICATIONS: A revision to Project 00856-H has been approved effective October 1, 2007 for a 5-year period. The objectives stated for this revision are: Objective 1. To determine the relationships between environmental factors and yield and rates of development of tropical cut flowers. a. To determine flowering response of orchids to supplemental winter lighting. b. To determine if photoperiod manipulation can be applied to manage earlier flowering in field-grown Leucospermum. c. To manipulate flowering of Etlingera and Zingiber gingers to extend their flowering seasons. Objective 2. To develop information on control of flowering and cultural practices in the production of new potted flowering plants. a. To develop protocols for flowering of woody tropical ornamentals so that they can be used in the seasonal container plantings popular in mainland markets. b. To select and develop species of Leucadendron for use as potted plants. c. To determine the influence of supplemental radiation and growth regulators on the flowering cycles of potted orchids in order to meet market demands. Objective 3. To develop information on manipulation of flowering in lei plants. a. To manipulate flowering in Plumeria hybrids in the field through growth regulators.

Impacts
Improved winter flower production of dendrobium orchids requires higher light levels than usually provided by growers as they do not remove shade coverings employed during the summer months. This research under a Federal Floriculture grant has demonstrated that providing an extra 4 to 5 Mol/day/sq m of light can accomplish the desired goal. Growers can achieve such light levels, as well, by removal of extra shading in mid-October, but may still encounter a low daily light integral during the December-January time period. Modification of the previous season growing environment for Curcuma alismatifolia does not appear to influence time of natural season sprouting the next year. Growth regulator use on Oncidium orchids may have potential to bring about out-of-season flowering, but both timing and choice of chemical require further exploration beyond this first year's promising result. As with successful use of ethephon to bring about earlier flowering of plumeria, new cytokinin and cytokin-gibberellin materials offer a means to manipulate flowering to the benefit of the winter tourist season lei industry.

Publications

  • No publications reported this period


Progress 10/01/05 to 09/30/06

Outputs
A lack of nutritional guidelines and reported examples of leaf chlorosis and necrosis on Globba gingers lead to two studies on nutrient deficiency and sufficiency with Globba magnifica White Dragon. In both experiments, marginal necrosis developed from the basal foliage acropetally towards the inflorescence in all levels of macro and minor elements, and this necrosis could not be correlated with foliar element content. Since plants not under experiment but growing in lower light conditions did not express this symptom as severely, high light levels may contribute to stress conditions. After removal from aseptic media, tissue-cultured anthurium plantlets often grow slowly in a more natural medium, requiring up to 4 months to reach transplant size. Plantlets of two seedling populations of UH experimental hybrids in community pots were provided enhanced CO2 levels and additional light from 4:00 to 8:00 am in an enclosed growing units. CO2 was injected via timer mechanism for 15 seconds at 20 minute intervals, reaching approx. 20,000 ppm. After 8 weeks, CO2-treated plants were 1.25 larger than control plantlets. Destructive sampling at 16 weeks showed 100% survival in CO2-treated plants versus 80% in controls, larger leaves and greater plantlet dry weights, and more extensive root systems in the CO2 plants than the controls. A difference in responsiveness was observed between the two hybrids, but CO2 plants would have been transplantable about a month earlier than control plants. Hawaii orchid growers have noted lower cut flower production in some UH dendrobium hybrids during the winter months into early spring (December - April). Previous work showed that providing supplemental light would overcome some of this low productivity and increase spray quality. The normal practice is to provide shade against summer high light intensity, but that shade is not removed in the winter. By comparing outside light intensities against a 50% shade condition, light levels under shade provided less than 5 Mol/sq M/day during many winter days when outside conditions were 22 to 25 Mol/sq M/day. Addition of supplemental light from HPS lamps to provide an additional 4 Mol/sq M/day of light from late October through mid-December and 5 Mol/sq M/day from mid-December through March brought flower production levels on UH 306 dendrobium up to 3 sprays per plant (versus none under non-lighted conditions), with 80% of these sprays longer than 60 cm and averaging 20.8 florets per spray. Stem strength was very good with 56% of the stems equaling stem thicknesses that would be expected during summer production.

Impacts
Until the proper light level for producing Globba White Dragon is determined, medium to low nutritional levels (100 to 200 ppm each N and K) appear to produce plants of similar size and inflorescence quality as the higher levels (300 ppm N and K), but the marginal leaf necrosis problem will limit the potential of this plant as a potted plant or cut flower. Anthurium plantlets respond to enhanced CO2 levels with stronger growth and are transplantable up to a month earlier than plants not provided extra CO2. This represents a savings in nonproductive bench use as plantlets can be moved up faster to standard growing conditions. Enthusiasm over this work has led to a request to try it out at a commercial grower operation on the Island of Hawaii. The study on orchid lighting suggests that orchid growers need to increase their winter light regimes either by removal of shade cloth or by the more expensive alternative of adding supplemental light. This was particularly important during Hawaii's low light conditions during 6 weeks of rain in February-March 2006 when outside light levels often were less than 10 Mol/sq M/day when growers were reporting no spray production, and our lighted plants were performing happily on 8 to 10 Mol/sq M/day.

Publications

  • Criley, R. A. 2006. Ethephon defoliation of Plumeria rubra for winter flowering. Proc. 32nd Ann. Mtg. Plant Growth Regulator Society of America. pp 65-68
  • Roh, M. S., R. Lawson,, J. S. Lee, J. K. Suh, R. A. Criley, and P. Apavatjrut. 2006. Evaluation of Curcuma as potted plants and cut flowers. J. Hort.Sci. Biotech. 81:63-71.
  • Paz, M. del P., J. S. Kuehny, G. McClure, C. Graham, and R. Criley. 2005. Effect of rhizome storage duration and temperature on carbohydrate content, respiration, growth and flowering of ornamental ginger. Acta Hortic. 673(2):737-744.


Progress 10/01/04 to 09/30/05

Outputs
A series of sowing dates (7/04 to 7/05) for 4 varieties of sunflower was initiated to determine characteristics and potential for year round flowering in Hawaii. Seed was sown directly into a field soil amended with nitrogen at 1.18 kg/100 m2. Stem length, node count, and flower diameter were recorded at harvest. The most uniform cut flowers were from Procut Orange and Procut Lemon with greater variation in the Bicolor and Golden Cheer varieties. Plant to harvest means averaged 54 days for the first two, 59 days for Bicolor and 72 days for Golden Cheer as year round averages, with 7 to 10 days more required for winter crops. Hawaii's short winter photoperiods and lower daily light integrals decreased stem lengths, flower diameters, and node numbers for seed sown in Oct. through Jan., while heavy winter rains washed out the Dec. 04 planting. Ten cultivars of Leucospermum hybrids selected for their limited duration of flowering were disbudded during the fall development period to determine if the flowering period could be extended in the next spring. Removal of the terminal inflorescence bud was carried out on 10/18, 11/15, and 12/15, 2004. Varietal differences were observed, but in general, the Oct. and Nov. disbudding dates provided mean flowering times that were similar to non-disbudded plants, with delays of up to 10 days for first flowering of November disbuds, while the Dec. disbudding date extended mean flowering times by 4 to 5 weeks. For some cultivars, both Nov. and Dec. disbudding provided greater delays in flowering. Disbudding prior to October does not extend the flowering period as lateral buds develop at the same rate as existing terminal buds. Ethephon treatment of plumeria for winter flowering was repeated as the previous years treatments were inconclusive due to heavy rainfall. Foliar sprays of 800 ppm ethephon were made 10/23 and 11/30, 2004 to trees of Plumeria rubra Graveyard Yellow. Oct.-treated trees flowered, on average, about 45 days before non-treated controls with about 50% of the trees flowering by 1/9/05. Nov.-treated trees flowered, on average, about 5 days in advance of the controls with 50% of the trees flowering by 2/24/05. Controls reached 50% flowering on 3/3/05. Only trees treated by 10/23 produced much flowering for the Christmas to New Years tourist period. Later treatment was less effective in producing flowers for the peak winter tourist season both because of less time for flower development and less foliage was on the trees to receive the foliar sprays.

Impacts
It is concluded that single stem sunflower production is viable year round as a cut flower although stems and flower sizes may be smaller for crops grown during the winter months. The disbudding approach can effectively extend the flowering period in Leucospermum without negatively impacting stem length or flower diameter. This enables growers to produce varieties with a limited flowering duration over a longer period of time, thus extending their marketing period. Defoliation of plumeria in the September-October time period advances the time of flowering for plumeria. This enables growers to produce flowers for plumeria lei during the peak winter tourist season. As flowers traditionally associated with Hawaii's floral greeting becomes more available, fewer alternative flowers would have to be imported for leis.

Publications

  • Criley, R.A., Meyer, J., del Pilar Paz, M. and Kuehny, J.S. 2005. Tropical gingers as new flowering potted plants. pp 28-32. Proc. 2004 Hawaii Floriculture Conference. Leonhardt, K. W. and P. Nakao (Eds.), Coll. Trop. Agric. Human Resources, Univ. Hawaii. CTAHR Proc. P-04/05.
  • Criley, R.A. 2005. Heliconia productivity study 1999-2001. pp 31-35. Proc. 2004 Hawaii Floriculture Conference. Leonhardt, K. W. and P. Nakao (Eds.), Coll. Trop. Agric. Human Resources, Univ. Hawaii. CTAHR Proc. P-04/05.
  • Criley, R.A. and Maciel, N. 2005. Seasonal production among some tropical cut flowers. pp 36-44. Proc. 2004 Hawaii Floriculture Conference. Leonhardt, K. W. and P. Nakao (Eds.), Coll. Trop. Agric. Human Resources, Univ. Hawaii. CTAHR Proc. P-04/05.
  • Criley, R.A. 2005. Response of Dendrobium Jaquelyn Thomas Uniwai Pearl (UH 306) to supplementary lighting. Pp 45-49. Proc. 2004 Hawaii Floriculture Conference. Leonhardt, K. W. and P. Nakao (Eds.), Coll. Trop. Agric. Human Resources, Univ. Hawaii. CTAHR Proc. P-04/05.
  • Criley, R.A and Uchida, J.Y. 2005. That twisted Heliconia X rauliniana Bull. Heliconia Soc. Intern. 12(2):10-12.
  • Criley, R.A. 2005. Creating a potted, flowering Hedychium with growth retardants. Acta Horticulturae. 683:201-205.
  • Kuehny, J., Criley, R.A. and Paz, M.P. 2005. The joy of gingers. Ornamental Outlook. 14(8):16-17.
  • Kuehny, J.S., Criley, R.A. and Paz, M.P. 2005. Jump-starting ginger. Ornamental Outlook. 14(7):18-19.


Progress 10/01/03 to 09/30/04

Outputs
Obj. 1. Plants of Leucospermum Hybrid No. 24, developed by the University of Hawaii breeding program, were subjected to disbudding and pruning treatments in an effort to delay flower maturation and extend the season of bloom. Disbudding of the largest terminal bud, disbudding plus treatment of the top remaining bud with N-6-BA (200 ppm) approx. 1 week later, and pruning of shoots to the topmost vegetative bud were carried out at 3 weeks interval from mid-October 2003 through mid-January 2004. Non-disbudded controls were harvestable in early January 2004 while disbudded terminals were delayed in flowering until mid February (10/21/03) and late March (11/10/03 through 12/24/03). Only a few terminals disbudded in January developed flowers and these appeared in April 2004. N-6-BA application improved the number of terminals that developed flowers and narrowed the range of harvest days while bringing forward mean harvest dates for the October to November treatments and slightly delaying the December to January treated terminals. Pruning after October 21 reduced the number of stems that returned an inflorescence and delayed flowering into March 2004. Obj. 2. Effects of 2003 growth retardant drench but not spray treatments on scape length of Curcuma alismatifolia were seen when plants were forced in 2004. Scapes on plants treated with paclobutrazol (20 mg) and uniconazole (10 mg) drenches were 42 and 40 cm long, compared to 51 cm long non-treated controls. The results suggest previous season retardant treatments might be used to produce better proportioned potted curcuma plants. Sequential plantings from mid-April 2004 to late June 2004 of curcuma selected for potted plant use showed differences in time to sprout, but little difference in plant to flower time. Planting to sprout required about 50 days (dark pink) and 56 days (light pink) for the earliest plantings, decreasing to 33 and 42 days, respectively, for later plantings. Both cultivars required about 125 days from plant to flower at the early planting date, decreasing to about 100 days for the latest planting dates. The data confirm that holding rhizomes dry for long periods can hasten flowering after planting. Obj. 3. Plants of plumeria Celadine were defoliated with 800 ppm ethephon 9/30/03 or 10/30/03 to force winter flowering. Shoot tips were enclosed in plastic bags for 4 or 8 weeks with the goal of providing extra heat to speed flowering. Unfortunately a wet cool autumn prevented a marked effect of bagging. Inflorescences developed to first flower approximately 120 days following each spray, thus providing flowers during the normally low production January-February periods. The earliest flowers appeared in late December.

Impacts
Previous defoliation work with ethephon demonstrated the potential for obtaining winter flowering of plumeria, and this use was added to the label. Two growers on the North Shore of Oahu have made use of this technology to produce flowers for the lei flower trade. Concurrent with the disbudding work on Leucospermum at the Maui Agricultural Research Station, a Maui protea grower tried the disbudding technique on High Gold Leucospermum and found it extended his spring harvest into the high market period.

Publications

  • Criley, R.A. 2004. Heliconia. p. 574-581. IN Floriculture. Principles and Species. Second Edition (J.M. Dole and H. F. Wilkins Eds.) Pearson/Prentice Hall. Upper Saddle River, NJ.
  • Criley, R.A. 2004. Strelitzia. p. 868-873. IN Floriculture. Principles and Species. Second Edition (J.M. Dole and H. F. Wilkins Eds.) Pearson/Prentice Hall. Upper Saddle River, NJ.
  • Criley, R.A. 2003. Plumeria. Genetic fingerprinting. Plumeria Potpourri. The Plumeria Society of America, Houston, TX. Oct. 2003 p 4-5.
  • Paz, M.P., Kuehny, J.S. and Criley, R. 2003. Effect of rhizome storage time and temperature on growth and carbohydrate content of ornamental ginger. Acta Hort. 624:103-109.
  • Pilar Paz, M. del, Kuehny, J.S. and Criley, R.A. 2004. Ornamental gingers as flowering potted plants. OFA Bull. 883:6-9.
  • Criley, R.A. and Uchida, J. 2004. Hot Rio Nights in Hawaii. Heliconia Soc. Intern. 11(1):9-11.
  • Meerow, A.A. and Criley, R. 2004. Microsatellite DNA studies in Plumeria cultivars. Plumeria Potpurri. The Plumeria Society of America, Houston, TX March 2004. p. 7-9.


Progress 10/01/02 to 09/30/03

Outputs
A 2nd yr of lighting of dendr K306 was initiated 9/1/02 and discontinued 4/30/03. Trts were daylength extensions (4:00 to 10:00 pm) of HPS, HPS + red light pulsing, MH, and controls in a greenhouse or outdoors under 30% saran with no additional lighting. Flower yields in the critical Jan - April period compared to the greenhouse control were 136% for HPS, 116% for HPS + red, 148% for MH, and 176% for the saranhouse control. Stem lengths were similar when considered across all trts in the early months of the year, but the 2 control trts had higher percentages of stems >52 cm through 9/30/03. Floret counts were greatest for sprays harvested from saranhouse control plants. However, no trts approached the floret counts achieved in the previous year. Lower light intensity under glasshouse shading may have caused poorer quality. Curcuma rhizomes receiving 2 wk storage at 4 or 24 C died (4C) or sprouted in 45 days (24C), with little difference between Hawaii-grown and Thai rhizomes. Curcuma rhizomes subjected to 24 hr dark, or 9 or 16 hr photoperiods following planting sprouted at 86.5 days for darkness and 9 hr, but a comparison could not be made for the 16 hr rhizomes due to overheating of the growth chamber. The unintended heat shock delayed sprouting. The influence of light quality on sprouting showed a delay with a filter that excluded red radiation (80 days) versus natural light and daylength (61 days), but with a daylength extension from white or red incandescent lamps, sprouting times were 40 and 79 days respectively. Three Curcuma cvs selected for shorter stature as potted plants required 102 to 110 days from planting to flowering. Flower stalks averaged 62 cm in length in shade versus 12 cm in full sun, demonstrating significant effects of shading on extension growth.

Impacts
The earlier flowering found for dendrobium cut flowers under HPS lights may enable Hawaii growers to produce flowers for their markets in the low production period of January through April. This would enable them to retain their markets than they now yield to Thai-produced orchids. Investigations into dormancy of Curcuma rhizomes have a potential to enable dormancy manipulations to force flowering of rhizomes as potted plants for spring holiday markets. Warm storage temperatures coupled with lighting appear to force rhizomes earlier than normal cool storage temperatures and the short days of spring. This is a new potted crop for spring holidays.

Publications

  • Parvin, R.A., Criley, R.A. and Coetzee, J.H. 2003. Proteas - a dynamic industry. Acta Hort. 602:123-126.
  • Maciel, N. and Criley, R.A. 2003. Morphology, growth and flowering behavior of Curcuma zedoaria. Acta hort. 624:111-116.
  • Criley, R.A., Uchida, J.Y. and Fu, Z. 2003. Productivity and periodicity of flowering in Heliconia orthotricha cultivars. Acta Hort. 624:207-212.


Progress 10/01/01 to 09/30/02

Outputs
UH306 dendrobium orchid plants were provided supplemental lighting from 4 to 10 pm from 11/1/01 to 4/30/02 using 400W HPS or 400W MH lamps suspended 1.2 M above the plants in a glasshouse environment. HPS-lighted plants were superior to controls, which, in turn, were superior to MH-lighted plants for all indices: earliness to flower (early vs late March), yields per plants (7.5, 7.2 and 6.7 respectively), spray lengths (62.6, 57.8, and 58.5 cm resp.), florets per spray (15.8, 13.3, 14.4 resp.), % of sprays exceeding 52 cm length, which is the minimum for Hawaii Fancy grade (76.5, 74.7, and 73.2 resp.) and percent of sprays with > 15 florets (64.8, 56.9, and 56.8 resp.). HPS plants also produced slightly more basal stems per plant (8.2 vs 8.0 for control and 7.4 for MH). An automated shading system was installed over 6-year old plants of 6 cv of Leucospermum in the field at the Maui Agr. Expt. Res. Ctr. SD were provided from mid-July until the end of September 2002 with the objective to induce earlier flower bud initiation. At this time flower bud initiation could not be determined for either the SD-plants or the controls. White Dragon Globba rhizomes planted 3 units per 15 cm pot were forced with different growth retardant treatments applied either as pre-plant rhizome soaks (2 mg a.i./L) or as drenches (0.5 or 1.0 mg/pot) upon shoot emergence. Uniconazole and flurprimidol rhizome soaks delayed shoot emergence and held plant size to about 53 and 59% (resp.) of control plant height (53 cm), while paclobutrazol-treated rhizomes were 90% of the control plant heights. As drenches, flurprimidol (36%) and uniconazole (42%) were more effective than paclobutrazol (51%) at both concentrations. No results to report for Obj. 3.

Impacts
The response of dendrobium to supplemental light can be put to immediate use by growers who have access to electricity in their growing facilities. The higher quality product should command higher prices in the market. Should SD treatment of Leucospermum be effective in inducing earlier flowering, new markets could open for Hawaii growers during a time that the product is not normally available in either the northern or southern hemispheres. As a long-lived potted plant, White Dragon Globba ginger offers an exciting new material that is easy to grow and force. However, normal forcing produces plants that are too tall. The use of growth retardants applied at shoot emergence can shorten the plants to about 50% of the height of untreated plants and improve marketability.

Publications

  • Agboka, D. and Criley, R.A. 2002. Control of vegetative growth and flowering in white ginger Hedychium coronarium Koenig. Bull. Heliconia Soc. Intern. 10(4):7-8.
  • Criley, R.A. and Maciel, N. 2002. Seasonal flower production among Zingiberales -- Some examples from a commercial cut flower grower in Hawaii. Bull. Heliconia Soc. Intern. 10(4):10-13.


Progress 10/01/00 to 09/30/01

Outputs
1) Shoot production data for 17 heliconia clones in the T-STAR grant 98-34135-6783 were tabulated for the first year following planting while inflorescence harvest was continued into the year ending 31 August, 2001. Small-flowered hybrids Keanae, Guadeloupe, and New Yellow Parrot averaged 183, 176, and 136 shoots per plant respectively. Low shoot productivity characterized 2 H. chartacea cultivars Sexy Pink and Maroon Sexy and the presumed hybrid Temptress, which averaged 91.4, 23, and 23 shoots per plant respectively. H. bihai and H. orthotricha varieties and H. rostrata '10 Day,' H. X rauliana, H. stricta 'Red Stricta,' and H. dmitri 'Hot Rio Nights' were intermediate, in the 40 to 90 shoot range. Days from planting to first bloom were determined, with the very productive small hybrids ranging from 182 to 210 days, the H. orthotricha varieties 'Garden of Eden' and 'Candy Cane' flowering 6 months after planting, while 'Eden Pink' and 'Macas Pink' and the H. chartacea varieties required nearly one year. Production patterns ranged from highly seasonal for H. bihai 'Claw No. 2,' H. X rauliana, H. rostrata '10 Day,' and 'Incredible Orange' to scattered and continuous for most of the other varieties. 2) Cuttings of a pink selection of Rhododendron christianae (USDA Acc. No. 489747) were propagated and potted into 15 cm pots in March 2000, and drenched with 0, 1, 2, or 4 mg paclobutrazol (PBZ) or uniconazole (UNI) in November 2000. During the following 200 days, control plants failed to flower but grew to twice the size of retardant-treated plants. All treated plants produced flower buds and flowered in June 2001 over a period of about 4 weeks. The best plant quality ratings, based on floriferousness and plant shape were for plants that received a drench of 1 mg UNI per pot. Heliconia 'Andromeda' plants grown from rhizomes given one or two drenches of PBZ during culture were very short in comparision to plants that received no PBZ or that received only one drench. Flowering was inhibited in plants receiving the highest rates. Desirable plants with flowers were achieved with a single early drench of 5 or 10 mg PBZ/12.5 cm pot, then dividing the rhizomes and replanting the ones showing the most retardation. Hedychium coronarium plants were treated with PBZ during propagation and/or following potting up. Control plants flowered 133 days after potting and culture under long days, but the inflorescence stalks were 135 cm tall. PBZ-treated plants were delayed 1 to 2 weeks but flowered at about one-third the size of controls. 3) No progress to report on Obj. #3.

Impacts
The heliconia productivity experiment offers an indication of the potential flower yields of a number of commercially-marketable varieties, as well as a means to anticipate flowering times. The growth rate data also enable advisers to recommend suitable plant spacings. Retardant use on Rhododendron christianae stimulated flower bud initiation and marked this material as a species with potential for programmed flowering. Different species will, however, require different time periods following treatment for initiation and development of the flowers. Two growers on the island of Hawaii have requested information on treatments to apply to crops they are growing. The heliconia retardant work offers potential for some of the more than 40 colorful H. psittacorum cultivars to be grown as potted plants. Rhizomes from treated plants may contain enough of the retardant that they can be used to start pots that will finish as well-proportioned flowering plants. A grower from Hawaii expressed interest in this research during a recent visit. While the fragrance of Hedychium coronarium is an attractant in its use as lei and cut flowers, its size has previously been a factor against growing it as a potted plant. Using long days and a growth retardant drench, it is possible to produce well-proportioned flowering plants. Growers who have seen the flowering retarded plants feel they offer potential, especially if we can extend the work to some of the pastel hybrids developed at the Lyon Arboretum.

Publications

  • Criley, R.A. 2000. Seasonal flowering for heliconia shown by grower records. Acta Horticulturae. 541:159-165.
  • Criley, R.A. 2000. Lighting of field-grown stephanotis for winter flowering. p 9-10. In: Proc. Fourth Hawaii Flor. Ind. Conf. 1994-95. K. W. Leonhardt and L. L. Burnham-Larish (Eds.) CTAHR, Univ. Hawaii, CTAHR Proc. P-12/00
  • Criley, R.A. 2000. Ethephon forces plumeria for winter flowering. p. 11-13. In: Proc. Fourth Hawaii Flor. Ind. Conf. 1994-95. K. W. Leonhardt and L. L. Burnham-Larish (Eds.) CTAHR, Univ. Hawaii, CTAHR Proc. P-12/00
  • Criley, R.A. 2001. Proteaceae: Beyond the big three. Acta Horticulturae. 545:79-85.
  • Criley, R.A. 2001. Vireyas: new Rhododendron varients for use as potted plants. Ohio Flor. Assoc. Bull. 855:4-6.
  • Criley, R.A., Maciel, N., Fu, Z. and Uchida, J. 2001. Productivity of three Heliconia hybrids. Bull. Heliconia Soc. Intern. 10(3):1-3.


Progress 10/01/99 to 09/30/00

Outputs
1) All but 3 heliconia varieties established in 1999 as part of a productivity study (TSTAR 98-34135-6783) came into flower during the report period. The most productive varieties, with more than 125 flowers cut per plant were 'New Yellow Parrot' and 'Keanae.' followed by H. bihai cultivars 'Peachy Orange,' 'Claw #2,' and 'Incredible Orange.' Some heliconias were seasonal in their productive patterns, including 'Claw #2,' H. X rauliniana, H. rostrata '10-Day,' and H. dmitri 'Hot Rio Nights.' The 4 H. orthotricha cultivars have a long period of production and are representative of medium-sized, lighter weight marketable varieties. Data are being summarized for the timeframe of shoot emergence to harvest for 17 varieties, and show variation with season. For example, 'New Yellow Parrot' and 'Keanae' inflorescences require 21 weeks to flower from shoot emergence in late summer but only 15 weeks for spring shoots. PhD student Norberto Maciel completed his studies on manipulation of flowering of H. rostrata '5-Days' using short daylengths. He noted that failure of flowers to develop was most probably due to crowding and competition among daughter rhizomes. 2) A series of experiments funded by the American Rhododendron Society provided a basis for the production of the tropical vireya rhododendrons as potted plants. Paclobutrazol-treated plants flower 22-23 weeks after being drenched and returned another burst of flowers 22-25 weeks later, indicating a long-term efficacy of the treatment. Of four growth retardants applied as drenches to Ruspolia hypocrateriformis (a potential potted plant), only uniconazole at 0.25 or 0.50 mg/pot successfully controlled plant height. More flower clusters developed on paclobutrazol, uniconazole and ancymidol -treated plants than the control or chlormequat-treated plants. 3) No progress to report on Obj. #3.

Impacts
The heliconia productivity evaluation provides a basis for selecting varieties to cover the whole year's market period. Varieties can be selected for overlapping blooming period and a means for predicting blooming times and production at those times is being developed by following shoot development rates. This information will assist Hawaii growers to increase their export of these bold tropical flowers. The ability to manipulate flowering through daylength offers a means for heliconia growers to extend flowering seasons and reap the economic benefit of higher prices for out-of-season blooms. A niche market for the export of rooted vireya rhododendron cuttings or pre-finished potted rhododendrons could develop from the increased interest in these species as potted flowering plants. Hawaii growers could produce and root cuttings year around for mainland finishers.

Publications

  • Maciel, N. 2000. Flowering in Heliconia rostrata Ruiz & Pavon. PhD dissertation. Univ. of Hawaii, Manoa.
  • Criley, R.A. 2000. Growth regulators in the control of flowering in a vireya rhododendron hybrid. J. Amer. Rhodo. Soc. 54:64-69.
  • Maciel, N. and Criley, R.A. 2000. Effects of natural and simulated short-day on the flowering of Heliconia rostrata Ruiz & Pavon. Bul. Heliconia Soc. Intern. 10(1-2):12-16.
  • Criley, R.A. 2000. A review of floriculture production research in Hawaii. Proc. Interamer. Soc. Trop. Hort. 42:1-20.
  • Criley, R.A. 2000. Tropical rhododendrons as potted plants. Acta Hort. 513:123-128.


Progress 10/01/98 to 09/30/99

Outputs
Obj. 1: Heliconia rostrata plants provided with 3 short daylengths (SD) (9.5, 10.5 and 11.5 hours of light) for differing numbers of SD cycles (4, 5, 6, 7 and 8 weeks) all flowered, demonstrating that the critical daylength for flowering is at least 11.5 hours, and perhaps longer, but 13 hr. photoperiods prevented flowering. Although flowering occurred after 4 weeks of SD treatment, the intensity of flowering, as shown by bract number, was greater with cycles of 6 weeks or longer. H. rostrata could be prevented from flowering by providing a light interruption between 11:30 pm and 2:30 am as with a daylength extension with incandescent light from 5:30 pm to 8:30 pm. Plants prevented from flowering by lighting until February 1, when natural SD were initiated, came into bloom 23 weeks later, in July. Obj. 2: Interrupted nights stimulated flowering in Hedychium coronarium, confirming its designation as a long day plant. Potted Hedychium coronarium treated with a drench of paclobutrazol were much shorter than untreated plants, but still capable of flowering when given LD. Obj. 3: No progress to report.

Impacts
The use of lights to prevent or delay flowering of Heliconia rostrata and to promote it in Hedychium coronarium (white ginger) enable commercial growers to manipulate flowering times for their crops to obtain flowers at times when prices are better due to lack of competition from natural season flowering. The use of growth retardants on potted white ginger may lead to the development of a new potted plant with attractive fragrance.

Publications

  • Criley, R.A. 1999. Landscaping with heliconias, gingers, and their relatives. Acta Horticulturae. 486:247-253.
  • Criley, R.A., Sakai, W.S., Lekawatana, S. and Kwon, E. 1999. Photoperiodism in the genus Heliconia and its effect upon seasonal flowering. Acta Horticulturae. 486:323-327.
  • Leonhardt, K.L. and. Criley, R.A 1999. Proteaceae floral crops: cultivar development and underexploited uses. IN Perspectives on New Crops and New Uses. J. Janick (Ed.) ASHS Press, Alexandria, VA. pp. 410-433.


Progress 10/01/97 to 09/30/98

Outputs
Heliconia species that are photoperiod responsive often require a minimum leaf number before flower initiation can occur in response to inductive conditions. Efforts to understand the requirement have included leaf removal or partial deblading and limiting shoot number in the container. In Heliconia rostrata, partial deblading did not influence final leaf count or flowering, while in Heliconia 'Golden Torch,' flowering was delayed by leaf removal as the plant produced an additional number of leaves to compensate for the lost leaves. Shoot density influenced inflorescence abortion, as all clumps in which only one shoot per generation was allowed to grow produced an inflorescence and showed low abortion rates, while high abortion and clumps lacking flowers were observed when all shoots were retained. The results may be useful in manipulating flowering time in certain heliconias. Hedychium coronarium plants in containers were subjected to daylength treatments of 8, 10, 12, 13, and 14 hours using incandescent lamps to extend the natural light period, as well as the natural daylength. Artificial short days were imposed on another group of plants. The plants subjected to 13 and 14 hour daylengths flowered at the rates of17% and 50% respectively. Since daylengths in Hawaii do not exceed 14 hours of light, including civil twilight, longerhotoperiods were not evaluated. The work suggests that Hedychium coronarium is a long day plant, and studies are continuing using interrupted nights to confirm this conclusion. The impact of the work allows producers of white ginger blossoms to produce them during the short day period of the year for lei makers and may allow the development of Hedychium as potted plants with targeted flowering times. The tropical rhododendron hybrid (R. aurigeranum X R. herzogii) was induced to set inflorescence buds and bloom approximately 150 days following drench treatment with 2 mg paclobutrazol/15 cm pot. The drench was applied as a flush of growth was finishing elongation.The subsequent growth flush was compressed, and the inflorescence bud developed next. Application of a high phosphorus fertilizer did not enhance floral initiation. Control plants and phosphorus fertilizer-only plants continued to produce vegetative growth flushes and had not begun to initiate flower buds when the paclobutrazol-treated plants had completed flowering. The combination of phosphorus and paclobutrazol was not superior to paclobutrazol alone. Some control of flowering in tropical rhododendrons may be achieved through the use of growth retardants to make possible the production of flowering potted tropical rhododendrons for garden centers, florists, and mass markets.

Impacts
(N/A)

Publications

  • CRILEY, R.A. 1998. Leucospermum: Botany and horticulture. Hort. Rev. 22:27-90.
  • CRILEY, R.A. 1998. Plumeria. Univ. Hawaii, CTAHR, CES, Orn. and Flowers OF-24.


Progress 10/01/96 to 09/30/97

Outputs
Samples of Heliconia rostrata, which has a seasonal blooming period from late Feb to early June in Hawaii, were collected at biweekly intervals from fall through flower emergence. At one site, flower initiation had commenced by Nov. 28, while at the other site, it was still not detectable by dissection of the apical tissues. By mid-Jan, however, 2 to 5 bracts were initiated. Unfurled leaf count at initiation was at least 3, while total leaf count at flower emergence ranged from 5 to 9. Understanding the time of natural floral initiation and the timeframe for flower emergence will enable the manipulation of flowering time to extend the availability of this species. Paclobutrazol-treated (PBZ) plants of 5 Heliconia psittacorum cultivars responded with more shoots per pot and shorter stalks as the concentration of PBZ increased from 0 to 5 to 10 mg a.i. per 3.8 L pot. Compared to the untreated controls, varietal sensitivity to the 10 mg treatment as measured by shoot length was Petra (74%), Barbara (58%), Andromeda (42%), Sassy (33%) to Lady Di (17%). The first 3 cvs are well-known for their vigor while the latter 2 offer potential as potted flowering plants. Flowering was not inhibited at the 2 PBZ concentration used and flower stalks were shorter. Microscopic examination of shoot tips from a hybrid of Rhododendron aurigeranum x R. herzogii treated with a soil drench of PBZ showed the earliest transitions from vegetative to reproductive status 6 weeks after treatment. The earliest anthesis was reached 5 months after treatment. A pink form of dwarf Ixora treated with flurprimidol at the rates of 10, 15, or 20 ppm as foliar sprays produced inflorescences 7 wks later while untreated plants and plants receiving foliage sprays of PBZ at 25 and 50 ppm showed produced no inflorescences. The treatment could be used to enhance flowering of this plant material as a potted plant. The rare gesneriad, Chirita moonii, produces large purple flowers on vigorous upright stalks but is too tall at flowering to be proportional to its container. A survey of several growth retardants was conducted to determine which, if any, would retard this species. Plant height and flower count for plants treated with foliar sprays of daminozide (2500 ppm), ancymidol (25 ppm), and flurprimidol (25 ppm) or a drench of PBZ (0.5 mg/12 cm pot) were compared against untreated plants. Five wks after treatment, only the PBZ treatment had significantly controlled plant height and improved visual appearance when compared to the control. Although other concentrations or application methods of the other retardants could be evaluated, the PBZ treatments offers a good starting point for additional experimentation. Potted Leucospermum conocarpodendron were treated with PBZ or ethephon as a flush of growth was completing elongation to determine if either compound could enhance inflorescence formation. Plant compactness was enhanced by the PBZ but not with ethephon. Ethephon caused partial abortion of developing florets. Neither treatment increased the number of terminals setting flower buds.

Impacts
(N/A)

Publications

  • CRILEY, R. A and SAKAI, W. S. 1997. Heliconia wagneriana Petersen is a short-day plant. HortScience. 32:1044-1045.
  • CRILEY, R. A. 1997. Height control of Dendrobium orchid. CTAHR. CES, Hort. Res. Note 4.
  • CRILEY, R. A. 1997. Bougainvillea. In Tips on Growing Specialty Potted Crops. Ohio Florists' Assoc. Columbus, OH. 28-32p.


Progress 10/01/95 to 09/30/96

Outputs
Obj 1: Design and construction of a daylength controlling unit for Leucospermum flowering has been partially completed by my cooperator, Dr. Loren Gautz. Plants of 6 Leucospermum cultivars have been established in the field at the Maul Agr. Res. Stn. Obj. 2: The growth retardant, paclobutrazol (PBZ), at 2 mg al per 15 cm pot 1 mon. after pruning, caused flower bud initiation under LD on Rhododendron christianae after 2 flushes of growth. Flower anthesis began about 6 mon. after treatment with the retardant. On a hybrid of R. aurigeranum x R. herzogii, flowering was reached about 5 mon. after treatment with PBZ. Drenches of PBZ at 10 and 20 mg/L applied to potted Heliconia psittacorum reduced pseudostem length without preventing flowering. Although promising, the treatments must be refined to lead to proportionally-sized potted flowering plants. Obj 3: Based on research performed under this project, an SLN registration of ethephon to force winter flowering of plumeria was sought and achieved by two manufacturers of the chemical. Use of PBZ and flurprimidol drenches on seedling Fagreaea berteriana plants in the field did not reduce the juvenile period and bring about earlier flowering.

Impacts
(N/A)

Publications

  • CRILEY, R.A. 1995. Propagation of Zingiberaceae and Heliconiaceae . Rev. Bras. Hort. Orn. (Campinas) (Reprinted in Bul. Heliconia Sec. Intern. 8(2):3-6).
  • CRILEY, R.A. 1995. Techniques of cultivation in the ornamental Zingiberaceae. Rev. Bras. Hort. Orn. 1(1):22-32. (Reprinted in Bul. Heliconia Sec. Intern. 8(2):7-11).
  • CRILEY, R.A. 1995. Culture profile: Heliconia psittacorum Cut Flower Quart. 7(4):7-10.


Progress 10/01/94 to 09/30/95

Outputs
Obj. 1: No progress this period. Obj. 2: Growth retardant applications to a dwarf pink Ixora were effective in controlling vegetative growth. Flurprimidol and ancymidol stimulated production of more flower clusters than did daminozide or paclobutrazol. The retardant, uniconazole, was effective as a drench at 0.5 to 2.0 mg/pot in controlling vegetative growth of Allamanda cathartica, but it failed to stimulate early or uniform flowering. A foliar spray of the cytokinin, PBA, or the application of a 7-40-6 fertilizer to potted Christmas cactus resulted in three times as many flower buds as on control plants. Slightly more flowers were produced when PBA and phosphorus were combined. Obj. 3: The effectiveness of foliar sprays of ethephon on defoliation and flowering of six plumeria cultivars was determined during fall-winter 94-95. Cultivars responding with earlier flowering were Acc. # 18-41, Celadine, Donald Angus, Kimo, and Lurline, while Scott Pratt produced early inflorescence structures but no flowers. Proposals for special use labels under Section 24(c) SLN were submitted to two firms marketing ethephon. A preliminary experiment comparing pruned versus non-pruned and lighted versus non-lighted Stephanotis showed little effect of pruning upon winter flowering, but the use of night break lighting advanced flowering by approx. one month.

Impacts
(N/A)

Publications


    Progress 10/01/92 to 09/30/93

    Outputs
    The stress of Hurricane Iniki in September 1992 was a more significant factor influencing winter flowering in plumeria than the ethephon treatments applied in October, November or December. All trees showed a similar flowering progression January through March, but higher proportions of blooming inflorescences occurred in December than is normal. Treatments were reapplied commencing September 1993 to evaluate effects in winter 93-94. Alpinia purpurata plants subjected to irrigation regimes replacing weekly pan evaporation factors of 0.3, 0.67, 1.0, 1.3, and 1.67 showed an increased proportion of Fancy grade flowers in the highest irrigation treatment, but yields were not affected. Accessions of Heliconia thomasiana, H. esterii, and H. orthotricha were received from plant materials collected in Ecuador and established on Kauai. The accessions will be evaluated for their capacity to flower in containers as potential potted plants. Growth retardants ethephon and uniconazole effectively controlled vegetative growth on potted Allamanda cathartica 'Thai Dwarf' during the first 4 wks but by 8 wks, treated plants were nearly as tall as the controls. Uniconazole inhibited flowering more than did ethephon, and both were delayed when compared to the control. The Plumeria Society of America visited the plumeria germplasm collection and documented 42 cultivars for their registry.

    Impacts
    (N/A)

    Publications


      Progress 10/01/91 to 09/30/92

      Outputs
      Production of plumeria flowers for the winter tourist trade was successfully achieved in a field trial. Applications of ethephon were made once a month during 1991 to Plumeria rubra ommon Yellow' to force defoliation and release floral buds from dormancy. Applications earlier than August had no effect on flowering. August and September treatments enhanced floral bud appearance in October and November, while October and November treatments caused flowering in December through February. December treatment was only marginally effective because natural leafdrop had left too little foliage to receive the foliar sprays. As the 1991-92 winter was relatively warm, treatments must be evaluated over several seasons to determine the best timing for winter bloom. A model of flowering was developed for Heliconia angusta based on Honolulu daylength conditions using the critical daylengths for initiation and development previously determined. The model was validated with data collected from commercial growers. Harvestable flowers should be produced between September 1 and February 20 under natural conditions. Use of artificial lighting should make it possible to extend the blooming season later into the year and improve sales opportunities for the growers. Increasing night temperature in the range between 14 and 22 C increased stalk length and time to flower and decreased the number of flowering stems.

      Impacts
      (N/A)

      Publications


        Progress 10/01/90 to 09/30/91

        Outputs
        During a 3-yr period, field-grown Heliconia chartacea averaged 44.8 wk from shoot emergence to flower with a range of 35 to 63. About 1/2 of the development time was vegetative with flower development commencing when 4 leaves had appeared. On average, 6.4 leaves subtend the inflorescence with a range of 5.8 to 7.3. Flower initiation occurs year-round, but fewer than 20% of shoots emerging during May-July actually mature their inflorescences. Of shoots emerging during the winter months 40% to 60% flower, but losses due to aborted flower buds were high. A modeling approach will be undertaken to compare normal and non-flowering shoots in an effort to identify the time of flower abortion and to relate it to environment. For H. angusta plants grown under 12.5 to 16 hr days, the minimum day length for initiation was 13.5 hr. Anthesis occurred 23 wks after the start of treatment. Plants of H. stricta 'Dwarf Jamaican' grown under different combinations of light and temp. had their greatest flower bud abortion under high temp. and high light intensity. Pakalana (Telosma cordata) initiated and develop flower clusters at 21 and 24C under 16-hr daylengths. Development times were about 4 and 5 wks respectively. Under 8-hr days at the same temps, flower did not develop. Development required 6-7 wks at 18 C under LD, but this temp. limited development at daylengths of 12 hr or less. These results will enable winter production of pakalana using lights where nights are warm.

        Impacts
        (N/A)

        Publications


          Progress 10/01/89 to 09/30/90

          Outputs
          H. wagneriana plants were given 13 wk of 8-hr days (SD) and compared with similar plants grown under natural (13.5-11.5 hr) days (ND) or with a nightbreak (NB) of 25 W/m2 from 10 pm to 2 am. The SD and NB trts began 8/29/89. Uniform flowering occurred on the SD plants at the end of December, averaging 17.3 wk from the start of treatment. ND plants began to bloom at the end of February 1990, averaging about 10 wk delay. Plants from the NB treatment did not flower during the normal season, but 2 inflorescences bloomed in July, probably as a result of delayed initiation on young shoots when the lights were turned off at the end of February. It appears that H. wagneriana naturally initiates its inflorescences in late October. After 2.5 years of tracking growth and flowering in H. chartacea, a pattern of longer development periods for summer-emerging pseudostems was evident when compared to winter- and spring-produced pseudostems. A temperature model accumulating degree days correlated well with development through the appearance of 5 leaves, but the final stages including floral development were more variable. Lanolin pastes of cytokinins, ethephon, or TDZ were applied to the cut surfaces of soft-pinched plumeria shoots to stimulate branch development. Treated, pinched branches developed fewer shoots than normally occur when a shoot flowers. Ethephon did stimulate more shoots than on the control following pinching, but growth was retarded.

          Impacts
          (N/A)

          Publications


            Progress 10/01/88 to 09/30/89

            Outputs
            Growth rates of Heliconia chartacea were recorded to determine effect of season on time from shoot emergence to flowering. Shoots emerging in late summer and fall took longer to develop, but the overall average was 10 +/- 2 mon. H. chartacea produces about 1 leaf/mon., and after 7-9 leaves, the inflorescence appears, reaching harvestable size in 3-5 weeks. As flower initiation has occurred when 5-6 leaves have appeared, it may be possible to shift some flowering from mid-summer to desirable spring and fall market periods. The microscopic development of flower buds of Leucospermum cordifolium 'Vlam' was recorded from 10/1/88 to peak flowering at 2/15/89. Plotting Log bud length against heat and solar units accumulated at Kula (Maui) from 9/1/88 yielded a good fit to a straight line. Against this baseline, developmental rates of other cvs. can be compared, but additional seasons of data collection are needed to improve predictability. Thiadiazuron and PBA (cytokinin) were applied to cut branches of 5-year old, field-grown plumeria 'Common Yellow' to induce greater bud break. After 8 weeks, there were no differences between control (2.8 buds/branch) and those treated with up to 800 mg/L thiadiazuron, but an average of 1 and 1.5 more buds were present on 400 and 800 mg/L PBA treatments than for controls (2.5 buds/branch). Enhanced branching through selective pruning and growth regulator applications may increase the harvest potential of this lei flower.

            Impacts
            (N/A)

            Publications


              Progress 10/01/87 to 09/30/88

              Outputs
              Experiments were conducted in an effort to determine the cause of little-leaf disorder in poinsettia. Plants of 'Glory' subjected to heat, drought, salinity, nitrogen type, and combinations of these failed to produce symptoms consistently. Ca and Mo uptake were greatest in plants supplied N0(subscript 3) and low in NH(subscript 4) plants, but significant leaf distortion was not prevalent in plants with low Mo or Ca. Na tungstate was applied to determine if it would interfere with Mo function and cause leaf distortion, but at the rates used, no distortion was found. The greatest incidence of distortion was associated with foliar sprays of Dursban insecticide. As heliconia shoot tips collected in 1986 had not revealed inflorescence development by 10/86, shoot tips of H. rostrata, H. chartacea, H. wagneriana, and H. bihai 'Kamehameha' were collected from 11/87 through 2/88. Evidence for floral initiation was found: December, H. wagneriana; February, H. bihai, H. chartacea, H. rostrata. Potted H. angusta plants grown under LD and SD with 10, 15, and 20C NT for 6 weeks began to flower about 5 months after the start of treatment. Flowering was observed for all conditions of daylength and night temperature. H. psittacorum responded to growth retardant drenches in the same way as the species reported in the 1987 CSRS Progress Report. These results offer an opportunity to use heliconia as potted plants as well as cut flowers. Telosma cordata (pakalana) initiated flowers under LD at both 15 and 20C NT. A 0.

              Impacts
              (N/A)

              Publications


                Progress 10/01/86 to 09/30/87

                Outputs
                The use of leaf temperature for degree-day accumulation increased the precision of a model of flower development for Strelitzia. A field misting system cooled Strelitzia foliage by nearly 5C and shifted the seasonal flowering pattern towards greater winter production. Examination of slides prepared from apical tissues of 7 Heliconia species collected in 1986 revealed that flower initiation had not occurred by late October, and all pseudostems were still producing leaves. Euphorbia leucocephala plants grown under 9 hr SD developed well-formed bracts at 20C NT in 8 wk and at 15C NT in 10 wks. Plants grown at 10C NT remained vegetative. Heliconia stricta and H. angusta plants in 3.5 L pots were drenched with the retardants ancymidol, paclobutrazol and flurprimidol. While ancymidol was less effective than the others, all 3 retardants controlled plant height at concn of 2 mg/pot or less. The potential for heliconia pot culture is improved by this ability to control plant height. Early October applications of paclobutrazol and flurprimidol were very effective in controlling height of the tall-growing poinsettia cv Eckespoint C-1. Some axillary branching was observed on plants given foliar sprays of paclobutrazol but not with drenches. Less paclobutrazol is required than for standard application of chlormequat. A medium of 1:1 peat:perlite was compared with a less expensive medium of 1:1 peat:volcanic cinders in the production of 'V-10' poinsettias.

                Impacts
                (N/A)

                Publications


                  Progress 10/01/85 to 09/30/86

                  Outputs
                  Automated application of mist to bird of paradise plants during summer months of1984-1985 reduced leaf temperature by 5C when compared to controls without mist or grown under 30% saran shade. The cooler plants grew more slowly and shifted their seasonal flowering pattern towards a winter production period. The results may enable established low-elevation plantings to produce flowers during the high demand winter months. A series of experiments with Heliconia stricta and H. angusta examined growth and flowering responses to photoperiod. Longitudinal sections through H. stricta apical meristems confirmed that flower initiation occurs after 6 leaves have developed-when 3 or 4 have expanded and the remainder are still furled in the pseudostem. This appears to be a critical stage also in H. angusta, although sections were not made of this species. Apical tissue was collected from field-grown plants of 7 species to determine the time of natural initiation of the inflorescence. It is expected that these studies will improve our ability to manage these plants for controlled cropping. A 5-year fertilization experiment was concluded for 6 plumeria cv. Foliar application of microelements had no effect but increasing amounts of P did produce a small, but significant, increase in in the number of inflorescence-bearing terminals. The 6 cv showed different percentages of inflorescence-bearing terminals.

                  Impacts
                  (N/A)

                  Publications


                    Progress 01/01/85 to 09/30/85

                    Outputs
                    Monitoring of vegetative growth and flower production of Strelitzia under conditions of full sun, shade, and leaf cooling was begun during summer 1985. As flower development requires 6 months, results are expected during January - March, 1986. Plants of Heliconia stricta grown in 15 cm pots at minimum night temperatures of 15, 20 and 25C for 4 weeks with 8-hr daylengths yielded more flowers at the cooler temperature 3 months after treatment termination. A leaf count of 3 at the start of treatment was significantly superior to 1 or 2 in terms of flower yield. Seasonal patterns of flowering in heliconia spp were identified through sales records of a local wholesale shipper. Scutellaria offers potential as a new potted plant if flower drop can be controlled. Developing inflorescences were sprayed with silver thiosulfate (STS) to reduce flower drop. STS-treated inflorescences averaged 2 abscised flowers to 15 for untreated control plants during the first 10 days after the first flower opened. Significant foliar phytotoxicity was observed and late-developing flowers were distorted at 1X and 2X rates but less at 1/2X. Leaf tissue of poinsettia cv. Amy grown in a 5x5x3 K-Mg-Ca factorial showed a classical K-depression of Ca and Mg uptake at high K levels. However, foliar chlorosis symptoms did not develop to the extent that they could be associated with Ca or Mg. deficiencies. It suggests, however, that high K fertilization could contribute to chlorosis problems observed by growers.

                    Impacts
                    (N/A)

                    Publications


                      Progress 01/01/84 to 12/30/84

                      Outputs
                      Due to prolonged drought, field experiments were held at maintenance levels. A 4th set of data were collected on plumeria flowering with results similar to 1983. Heliconia stricta plants were grown in tubs inside to evaluate the effect of SD on flowering. After exposure to SD, plants were grown under LD until flowering. Inflorescence length and bract No. increased significantly as No. wk SD increased from 3 to 5. Of stalks bearing 4 or more expanded leaves at the start of SD, 67% flowered 84 to 96 days after the start of SD; ultimately 91% of these stalks flowered with an average stem + inflor. length of 68 cm. Inflor. abortion was observed in a portion of nonflowering stalks. Rhizomes of H. stricta were planted 1, 2, or 3/15 cm pot to investigate suitability of the 'Dwarf Jamaican' clone for potted plant use. Due to crowding, no more shoots were produced by 2 or 3 rhizomes than by a single one. More 1-rhizome pots developed inflor. than with 2 or 3 under natural daylengths. In attempts to produce compact potted plants, pseudobulb elongation in Dendrobium was controlled by ancymidol and EL500, but growth was deformed and flowering did not occur on these stalks in the next 9 months. Appln of silver thiosulfate to developing inflor. of Scutellaria costaricensis prevented flower abscission but caused damage to the foliage and petals.

                      Impacts
                      (N/A)

                      Publications


                        Progress 01/01/83 to 12/30/83

                        Outputs
                        Successful propagation of a grower-selected compact form of Euphorbia leucocephala was achieved in 4 to 6 wk using 10% soln of a commercial rooting hormone (Dip 'N Grow). Stock plantings were established to permit more rapid release of this clone when culture and management expts have been completed. Foliage of poinsettia cv Amy can be a darker green than is usual for the variety if the amount of iron provided is increased. This cv takes up more Mn than other cvs, and the light green foliage is thought to be a result of a Mn-Fe imbalance. Since 'Amy' accounts for 48% of the Hawaii crop, this work may improve the quality of desirability of the crop. After 3 years of evaluating differential P applicatio and minor element foliar sprays to 6 cv of plumeria, no differences in inflorescence production due to fertilized treatment have been identified. The percentage of inflorescence-bearing branches has increased from 30.6% to 41.3% as the trees have grown. Such information may be useful in predicting the potential yields of a plumeria operation. The minimum number of weeks of short days to stimulate flower initiation and development on the dwarf Jamaican heliconia, H. humilis, is 4, and the stalk should have at least one expanded leaf at the time treatment is initiated. Return flowering of this heliconia from winter cutback peaked in May for November and December cutbacks and was very low although also peaking in May for January cutbacks.

                        Impacts
                        (N/A)

                        Publications


                          Progress 01/01/82 to 12/30/82

                          Outputs
                          Further refinement of a Strelitzia growth and flowering model was achieved usinga stochastic model of time-series analysis with maximum temperature as the variable function. A dwarf clone of Euphorbia leucocephala received from a commercial grower is being evaluated for use as a flowering potted plant. Vegetative plants of 3 poinsettia cv received 3 appln of 13 insecticides at 2X concn to determine phytotoxicity. Highly toxic were Cygon 2.67, Ficam 76WP, Kelthane 1.6EC, Lannate L, malathion 5EC, Orthene 75SP. Zero or slight phytotoxicity occurred from appln of Enstar 5EC, Resmethrin 2EC, Thiodan 3EC, and Vendex 50WP. Vydate L caused slight phytotoxicity on 'C-1' and 'V-10' but moderate toxicity to 'V-14'. 'V-14' showed greater sensitivity to insecticide appln than did the other 2 cv. Soil drenches of a new growth retardant, EL-500, were more effective than drenches of ancymidol or chlormequat in controlling elongation of Clerodendrum plants. In a cooperative experiment with a commercial grower on propagation of 3 difficult-to-root hibiscus cv, the best results were achieved with 4000 ppm. IBA alone for 'California Gold', but pretreatment of the cutting in 2500 ppm. daminozide or 300 ppm. ethephon before treatment with 4000 ppm. IBA gave the best results for 'Crown of Bohemia'. The results are important to the development of new cultivars of hibiscus for export as potted liners for mainland finishing as Hawaii has a large resource of hybrid hibiscus from years of amateur hybridizing.

                          Impacts
                          (N/A)

                          Publications


                            Progress 01/01/81 to 12/30/81

                            Outputs
                            Computer analysis of flower stalk emergence rates for Strelitzia showed most rapid development of flower stalks occurred during the summer months, however, dissection of the crown also revealed a high incidence of flower bud abortion at the 20 mm stage during the same time period. The interval between appearance of leaves varied by 30 days between summer and winter with a range of 6 to 8 leaves added per fan per year. Evidence for a short-day response in a heliconia species locally known as the Dwarf Jamaican heliconia was revealed in two experiments. Further research is needed to determine if this is an obligate or facultative response and to examine the cause of flower bud abortion under long days. Following growth retardant experiments, Scutellaria costa-ricana was released for use as a potted plant. Scutellaria responded to chlormequat and ancymidol drenches and sprays. Slow release and soluble minor element sources affected floral maturation and number of breaks on poinsettia. Cv. Amy was found to accumulate more Mn than 'Glory' or 'R-13'. Early application of Mo to rooted cuttings of 'Eckespoint C-1 Red' poinsettias reduced leaf distortion on lateral breaks following a pinch.

                            Impacts
                            (N/A)

                            Publications


                              Progress 01/01/80 to 12/30/80

                              Outputs
                              Foliage & calyx tissue sampling of 'Impr. Wh. Sim' carnation growing at 4 soil potassium levels & 3 irrigation regimes revealed little difference in foliar K over the range of soil K levels. By the late spring flowering flush, calyx tip-dieback was associated with a fusarium problem which weakened the vascular system. k levels in the calyx tissue of affected plants showing dieback were only 20-25% that of the foliage. The level of K was lowest in calyz tissue from plants on the medium & low irrigation frequencies. Since disbudding is not practiced by Hawaii growers, competition among flowers for K may lead to a deficient condition which, under stress, may cause the calyx tip dieback. Modelling of Strelitzia yields by fitting a curve toa sine wave function appeared to give a good fit when lagged 4 to 5 weeks behind max. temperature and solar radiation. However, difficulties in relating this to the onset of flower initiation and development have caused us to review this model. Dissection of stem apices revealed no flower buds during te winter months but there were 8 to 9 leaves which could be dissected out. Given a plastochron of 56 days, the youngest leaves will be 448 to 504 days in emerging and the flower in the axil will appear 180 + 10 days later. The weather prior to flower emergence must be studied to determine its effect on subsequent yields. A computerized screening of 98 Strelitzia platns using 15 variables was carried out to determine superior plants.

                              Impacts
                              (N/A)

                              Publications


                                Progress 01/01/79 to 12/30/79

                                Outputs
                                A study of plumeria flowering using 18 plots each containing 2 plants each of 6 cv. was initiated. Preliminary yield analyses from Strelitzia plots showed no significant effect of fertilizer rate but increasing plant density decreased per plant yields by an avg. of 26.3%. At the high plant density, yields were depressed 21.2% vs. 42.9% for high and low fertilizer rates, respectively. Final records were taken for an internationsl study on Strelitzia flowering. Leaves emerging during winter months had a higher percentage of flowering than those emerging in spring or early summer. Regression analysis using temperature, rainfall, and solar radiation gave a closer relationship for days to flower with max. daily temp. than the other variables. Tissue samples of carnations grown at 3 irrigation frequencies and 4 potash levels showed differences in elemental content associated with age and crop maturity but little effect of differential potash fertilization. Crop maturation was earliest with the highest irrigation frequency. So far, calyx tip die-back has not been observed. Potted flowering crops: Poinsettia--amendments to increase water retention delayed wilting while not altering plant quality. Plumbago indica coccinea flowered readily on short days and can be retarded by chlormequat. Pachystachys coccinea showed retardation with chlormequat but a low percentage of flowering.

                                Impacts
                                (N/A)

                                Publications


                                  Progress 01/01/78 to 12/30/78

                                  Outputs
                                  An additional year's data were collected on flowering behavior of selected Strelitzia plants. Preliminary examination of these data shows a pattern similar to the preceding year. Relating the rate of flower emergence and development to meteorological conditions has been impeded by a lack of support for processing the meteorological data. Analysis of the flowering of Alpinia purpurata shows that approximately 4 months elapse between the emergence of the flower stalks and its harvestable stage. The rate of elongation seems related to solar radiation, but the critical period is during the last 5-7 weeks prior to harvest. A number of tropical species are being examined for their suitability as flowering potted plants. These include a Pachystachys spp., Plumbago indica, Heliconia spp., Gardenia radicans, Hibiscus spp., and a double Allamanda spp. Results of 1977 lighting trials on the 1978 harvest of 3 clones of Leucospermum suggest that photoperiod is not a strong modifying factor in the initiation of flowers.

                                  Impacts
                                  (N/A)

                                  Publications


                                    Progress 07/01/77 to 12/30/77

                                    Outputs
                                    Basic studies to analyze flowering behavior in Strelitzia show that approximately 6 months elapse between the emergence of a leaf and the flower in that leaf axil. The period between flower emergence and cut ranges from 55 days during the summer to 65 days during the winter. Since temperature is not a significant influence in Hawaii, explanations for differences are being sought by examination of solar radiation data. Flowering in Jasminum sambac can be modified by light intensity and temperature but not by photoperiod. Flowers are borne terminally on new growth only. A preliminary study of flower development in Leucospermum cordifolium suggests that average daily temperatures following initiation may control the rate of development and thus the peak harvest season.

                                    Impacts
                                    (N/A)

                                    Publications