Source: CORNELL UNIVERSITY submitted to
FLOWERBULB GROWTH AND DEVELOPMENTAL PHYSIOLOGY
Sponsoring Institution
State Agricultural Experiment Station
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0187694
Grant No.
(N/A)
Project No.
NYC-145301
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2000
Project End Date
Sep 30, 2009
Grant Year
(N/A)
Project Director
Miller, W. B.
Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
HORTICULTURE
Non Technical Summary
Flower bulb crops suffer from a variety of problems during greenhouse production, ranging from physiological problems in the greenhouse to post-harvest concerns in the retail and consumer environment. We propose to ultimately generate useful information on the growth and development of bulb crops to allow more efficient and profitable bulb production, as well as lead to improved quality of these products for the consumer.
Animal Health Component
60%
Research Effort Categories
Basic
40%
Applied
60%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2062120102050%
2052120102050%
Goals / Objectives
The work described falls into two major areas: 1) growth and development of flowerbulbs in the greenhouse environment, where major objectives include 1a) determining factors associated with development of upper leaf necrosis (a putative calcium deficiency) in oriental hybrid lilies, 1b) determining protocols for optimum cold duration, and physiological/biochemical changes associated with cold exposure dormancy of selected flowerbulb species and 1c) determining mechanisms and practical solutions for stress-related chlorophyll loss in Lilium; 2) maintenance of flower bulb quality in warm-storage (retail) environments, with major objectives of 2a) determining phenological and biochemical responses to sub-ambient oxygen levels, and 2b) evaluation of the role of moisture in this process.
Project Methods
Obj. 1a) will involve time course determinations of leaf calcium level as the disorder progresses, by developing a system for hydroponic culture, allowing plants to be grown with varying calcium levels, and by environmental manipulation to increase or reduce transpiration and calcium uptake. Obj. 1b) will be addressed by exposing bulbs to varying temperatures and durations prior to greenhouse forcing and by determination of carbohydrate pools (soluble sugars, soluble polymeric sugars, e.g. fructan or glucomannan, and starch). Objective 1c) by evaluation of anti-senescence treatments (e.g. gibberellin application, etc.) for both whole-plant and biochemical response (including stress enzymes and chlorophyll fluorescence studies).

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

Outputs
OUTPUTS: This project identifies and approaches problems affecting the use and performance of flowerbulbs and similar plants when used for forcing (flower or plant production) or landscape purposes. Studies in this project range from near market greenhouse and landscape trials to more in-depth laboratory investigations into the physiology and biochemistry of flowerbulbs. Specific research topics are identified through many channels including interviews and correspondence with producers and industry members who are aware of specific and important problems, through out own understanding of forcing and landscape problems of flower bulbs and perennials and from consultation with a panel of international experts (mainly from The Netherlands) who are aware of many topics worthy of research. Projects may range from a single year, or may last for 4 or more years. Outputs and results are communicated in a variety of ways, including a web site (a major revision of this site was initiated late in this reporting period, and is currently ongoing), newsletters, trade journal and industry articles, verbal presentations at industry meetings, and or course national and international scientific venues. PARTICIPANTS: Three Ph.D students at Cornell University contributed to and were a major part of, this project. Approximately 6 Cornell undergraduate students were involved in various aspects of this project throughout the calendar year. The undergraduates gained experience in plant biology research, instrumentation operation (especially gas chromatography), outdoor experimental trial design and conduct, greenhouse studies and general laboratory procedures and techniques. While a number of commercial firms contributed to this project (plant materials, knowledge, financial support), they are not listed here. At the conclusion of our fall "planting season", we always have bulbs left over. Many of these bulbs are donated to local schools and/or regional community groups for use in their specific situations. While not quantifiable, undoubtedly a number of individuals gain some degree of training or professional development as a result of participation with their local leader in planting and maintaining these bulbs. TARGET AUDIENCES: The main target audience for the distilled findings of this project is the national and world industry concerned with floriculture crop production, more specifically those producing and using bulbous and related plants (e.g., herbaceous perennials). Specific industry segments relating to this project include production greenhouses and nurseries, retail garden centers, landscape installation and maintenance firms, wholesalers (distributors), importers (into the US) and the growers and handlers of these bulbs in foreign countries (e.g., The Netherlands, Israel, New Zealand, etc. as just a few examples). The industry is reached primarily through our website (which is undergoing revision at the present time), through our annual CD of research results that is widely distributed, through our quarterly newsletters, verbal presentations and finally by individual communication (email, mainly). While the "industry" is the key audience, private citizens and homeowners are also an audience, especially in the realm of landscape activities. Unplanned activities such as the work of 2005-2006 on "The use of alcohol to reduce stem length of paperwhite narcissus" resulted in very visible and significant homeowner/private citizen contact and outreach. Throughout the year, I receive and answer many (estimate 100-150 per year) emails from homeowners and/or garden writers, media, etc. These emails usually revolve around use and success of flower bulbs and perennials in the landscape or home garden situation. The revised website will have more homeowner/gardener based information related to flowerbulbs. A third audience is the scientific community, an audience reached mainly from scientific publication, seminars, etc. PROJECT MODIFICATIONS: None, as defined

Impacts
A paper was published based on several years' work on vole feeding on flower bulbs. It is thought that vole feeding preference is similar to that of deer, and this paper provided the first sound scientific documentation of the differences in animal predation on flower bulbs. In 2009, we continued studies into the mechanisms of Fusarium-induced ethylene production in tulip bulbs. Infection by Fusarium oxysporum is a serious problem in the world tulip industry. Fusarium causes direct loss of the infected bulb, but more importantly, it produces the gaseous plant hormone ethylene that can injure non-infected bulbs. While we know from our earlier work that that tulip cultivars vary greatly in ethylene production upon infection, we determined that color mutants of tulips support similar levels of ethylene production upon inoculation with Fusarium as do the parent cultivar. In other words, sports of cultivars supporting high ethylene production are also high ethylene producers. Fusarium-induced ethylene production was assessed on ca. 30 major tulip cultivars (based on acreage and commercial importance) to develop groupings of ethylene production by cultivar. Oxalis regnelli is a specialty bulbous crop grown for the St. Patrick's Day holiday. It suffers from leaf chlorosis, reminiscent of iron deficiency. Initial efforts to culture the crop hydroponically were made in 2008, and were expanded in 2009. A study was completed assessing leaf nutrient content as a function of nitrate-N to ammonium-N ratio, representing the first information published on the nutrient requirements of this crop. First data from a study on landscape perennialization of tulips as a function of planting depth were taken, and a second planting was made in fall 2009. This study will be on going for the next three years (completion in spring, 2012). A paper summarizing several years' effort in carbohydrate analysis in bulbous crops was published which should prove useful to the world geophyte research community. Studies were completed and published on the use of benzyladenine and gibberellin as anti-leaf and flower senescence agents in tulips. Results of research in oxalis (mentioned above) and storage of dry Ranunculus tuberous roots were accepted for publication in an International journal.

Publications

  • Curtis, P. D., G. B Curtis and W. B. Miller. 2009. Relative resistance of ornamental flowering bulbs to feeding damage by voles. HortTechnol. 19:499-503.
  • Ranwala, A. P. and W. B. Miller. 2009. Comparison of the dynamics of non-structural carbohydrate pools in cut tulip stems supplied with sucrose or trehalose. Postharv. Biol. Technol. 52:91-96.
  • Kim, H.-J. and W. B. Miller. 2009. GA4+7 plus BA enhances postproduction quality in pot tulips. Postharv. Biol. Technol. 51:272-277.
  • Miller, W. B. 2009. 2009 Annual Report of the Cornell Flower Bulb Research Program. (This report was issued as a CD). 687 pages.
  • Miller, C. T., B. Lockhart, M. Daughtrey and W. B. Miller. 2009. Keeping shamrocks green. Greenhouse Product News 19(12):24-29.
  • Miller, W. B. 2009. Topflor and Bulb Crops. Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 19. March 2009. pp. 1-8.
  • Miller, W. B. 2009. Cornell's NEW bulb labyrinth makes it's debut! Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 20. May 2009. pp. 3-4.
  • Miller, W. B. 2009. Mechanical stress and cold water reduce growth in lilies. Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 20. May 2009. pp. 4-5.
  • Miller, W. B. 2009. Ethylene, Fusarium and tulip color sports. Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 20. May 2009. pp. 5-6.


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

Outputs
OUTPUTS: This project identifies and studies problems affecting the use and performance of flowerbulbs and similar plants. Studies in this project range from practically oriented greenhouse and landscape trials to more in-depth laboratory investigations into the physiology and biochemistry of flowerbulbs. Infection of tulip bulbs by Fusarium oxysporum is a serious problem in the world tulip industry. Fusarium causes direct loss of the infected bulb, but more importantly, it produces the gaseous plant hormone ethylene. Our earlier work has shown that tulip cultivars vary greatly in their ability to support ethylene production by Fusarium. In 2008, we continued studies into the mechanisms of Fusarium-induced ethylene production in tulip bulbs. We determined that color mutants of tulips support similar levels of ethylene production upon inoculation with Fusarium as does the parent cultivar. In other words, sports of cultivars supporting high ethylene production are also high ethylene producers. Fusarium-induced ethylene production was assessed on ca. 30 major tulip cultivars (based on acreage and commercial importance) to develop groupings of ethylene production by cultivar. Ranunculus asiaticus is sold as dried tuberous roots. While these underground parts can withstand very low moisture levels, to ca. 8% (as dry as most seeds), reduced tuber viability can occur. Tubers were submerged in distilled water from 5 to 35C and weighed hourly until fully hydrated. Water uptake by the tubers begins immediately upon submersion and is most rapid during the first 12 hours, leveling off and remaining relatively constant for the next 24 to 48 h. Studies on relative humidity (RH) in storage showed that very high RH and very low RH can be detrimental to storage. Oxalis regnelli is a specialty bulbous crop grown for the St. Patrick's Day holiday. It suffers from leaf chlorosis, reminiscent of iron deficiency. Initial efforts to culture the crop hydroponically were made in 2008, with the goal of refining nutrient availability for induction and curing the chlorosis. A study was completed to assess the reliability of the SPAD-502 meter for estimating chlorophyll levels in oxalis. Total chlorophyll concentrations from DMSO extractions were compared to SPAD readings. There was a strong a positive correlation between SPAD-502 meter readings and total chlorophyll concentrations, indicating SPAD readings can be a useful nondestructive technique for this research. Studies on landscape perennialization of tulips as a function of planting depth were initiated. This study will be on going for the next three years (completion in spring, 2011). A paper summarizing several years' effort in carbohydrate analysis in bulbous crops was published which should prove useful to the world geophyte research community. Studies were completed and published on the use of benzyladenine and gibberellin as anti-leaf and flower senescence agents in tulips. PARTICIPANTS: Three Ph.D students at Cornell University contributed to and were a major part of, this project. A number (approximately 8) of Cornell undergraduate students also were involved in various aspects of this project throughout the calendar year. These undergraduates gained experience in plant biology research, instrumentation operation (especially gas chromatography), outdoor experimental trial design and conduct, greenhouse studies and general laboratory procedures and techniques. While a number of commercial firms contributed to this project (plant materials, knowledge, financial support), they are not listed here. TARGET AUDIENCES: The main target audience for the distilled findings of this project is the national and world industry concerned with floriculture crop production, more specifically those producing and using bulbous and related plants (e.g., herbaceous perennials). Specific industry segments relating to this project include production greenhouses and nurseries, retail garden centers, landscape installation and maintenance firms, wholesalers (distributors), importers (into the US) and the growers and handlers of these bulbs in foreign countries (e.g., The Netherlands, Israel, New Zealand, etc. as just a few examples). While the "industry" is the key audience, private citizens and homeowners are also an audience, especially in the realm of landscape activities. Unplanned activities such as the work of 2005-2006 on "The use of alcohol to reduce stem length of paperwhite narcissus" resulted in very visible and significant homeowner/private citizen contact and outreach. A third audience is the scientific community, an audience reached mainly from scientific publication, seminars, etc. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The major outcome of this project in 2008 was completion and publication of studies concerned with the plant hormones cytokinins and gibberellin as anti-senescence agents in tulip. The commercial product, Fascination (a mixture of benzyladening anf gibberellin 4+7) was shown to be a effective as an anti-senescence (maintaining greener leaves and causing longer lasting flowers) in many tulip cultivars. Cultivars showed varied responses to the treatment, depending on their senescence syndrome (cultivars showing petal "wilting" responded better than cultivars senescing by petal abscission). It remains to be seen what will be the commercial impact of this finding. While commercial products are available, the required timing of the treatment (very close to flowering) is inconsistent with commercial shipping and handling requirements (with tulip, plants should optimally be in the retail chain before the optimum treatment time occurs!). During the life of this project, a safe and effective method for reducing excessive leaf and stem growth in the paperwhite narcissus has been developed. This method, while aimed at non-commercial audiences may nevertheless prove to be useful in the commercial greenhouse industry as well. Non-chemical methods to reduce sprouting of ornamental lily bulbs during retail sales have been identified, and will hopefully lead to a commercial application. The causes of a persistent leaf nutritional problem in oriental hybrid lilies have been identified, and simple measures, such as increasing airflow around the plants can significantly reduce the problem. Effective postharvest treatments for cut flower lilies leading to vastly improved leaf and flower longevity have been developed, and are increasingly being used in the industry (based on personal observation, and inquiry with producers as I visit with them). New studies on minor bulb crops (oxalis and ranunculus) have been initiated, and should prove fruitful in coming years.

Publications

  • Ranwala, A. P. and W. B. Miller. 2008. Analysis of non-structural carbohydrates in storage organs of thirty ornamental geophytes by high-performance anion-exchange chromatography with pulsed amperometric detection. New Phytologist 180:421-433.
  • Ranwala, A. P. and W. B. Miller. 2008. Gibberellin-mediated changes in carbohydrate metabolism during flower stalk elongation in tulips. Plant Growth Regul. 55:241-248.
  • Kim, H.-J. and W. B. Miller. 2008. Effects of GA4+7 and BA application on postproduction quality in 'Seadov' pot tulip flowers. Postharv. Biol. Technol. 47:416-421.
  • Miller, W. B., J. Atkins and J. R. Preece. 2008. Propagating Selected Flowerbulb Species. Plant Propagation Concepts and Laboratory Exercises. CRC Press. P. 311-316.
  • Atkins, J. and W. B. Miller. 2008. Storage organs. Plant Propagation: Concepts and Laboratory Exercises. CRC Press. P. 303-309.
  • Kim, H.-J. and W. B. Miller. 2008. Characterizing cold-storage-induced bud necrosis in 'Mona Lisa' Lilies. Acta Hortic. 768:463-467.
  • Chang, Y.-C., J. P. Albano and W. B. Miller. 2008. Oriental hybrid lily cultivars vary in susceptibility to upper leaf necrosis. Acta Hortic. 766:433-440.
  • Kuehny, J. S. and W. B. Miller. 2008. Storage duration and temperature affect dormancy of Hippeastrum. Acta Hortic. 766:169-174.
  • Cerveny, C. and W. B. Miller. 2008. Ranunculus asiaticus dried tubers imbibe water through a physical process. HortScience. 43(4):1286.
  • Miller, C., W. B. Miller and J. Sparks. 2008. Comparison of total chlorophyll content with chlorophyll meter readings in Oxalis regnellii. HortScience. 43(4):1097.
  • Miller, W. B. 2008. Boron Deficiency in Tulip. Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 15. Feb. 2008. pp. 1-2.
  • Miller, W. B. 2008. Update on 1-MCP. Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 15. Feb. 2008. p. 3.
  • Miller, W. B. 2008. Topflor dips for hyacinth height control. Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 15. Feb. 2008. pp. 3-4
  • Miller, W. B. 2008. Easter lilies: Target date April 12. GrowerTalks. 72(8):42.
  • Miller, W. B. 2008. 2008 (v. 2) Annual Report of the Cornell Flowerbulb Research Program. (This report was issued as a CD). 554 pages.
  • Miller, W. B. 2008. 2006 and 2007 Annual Reports of the Cornell Flowerbulb Research Program. (These reports were issued on a CD entitled "2008 Annual Report"). 339 and 222 pages, respectively.
  • Miller, C. T. and W. B. Miller. 2008. Evaluations of planting mix, planting depth and growth regulators on forcing of Dutch grown calla lilies (Zantedeschia). Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 18. Dec. 2008. pp. 1-7.
  • Miller, W. B. 2008. Potential technologies to reduce ethylene injury in tulips. Research Newsletter, Dutch Wholesalers' Association for Flowerbulbs and Nursery Stock. No 17. August 2008. pp. 1-3.
  • Miller, W. B. 2008. One from the archive: Postharvest leaf yellowing and it's control in oriental hybrid lilies. Research Newsletter, Dutch Wholesalers' Association for Flowerulbs and Nursery Stock. No 16. May 2008. pp. 1-4.


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

Outputs
This project identifies and studies problems affecting the use and performance of flowerbulbs and similar plants. Studies in this project range from practically oriented greenhouse trials to more in-depth laboratory investigations into the physiology and biochemistry of flowerbulbs. Infection of tulip bulbs by Fusarium oxysporum is a serious problem in the world tulip industry. In addition to causing direct loss of the infected bulb, the Fusarium fungus also produces the gaseous plant hormone ethylene. Our earlier work has shown that tulip cultivars vary greatly in their ability to support ethylene production by Fusarium. In the past year, we have isolated a variety of Fusarium strains from tulips and have demonstrated wide variation in ethylene production by these strains when grown on defined media. Such variation probably holds when isolates are grown on different tulip cultivars, and this work is currently in progress. These findings have fundamental implications for ethylene management in tulip bulb storages and during transportation. In the last year, we have refined an in-vitro assay based on freeze-dried bulb tissue that will allow year-round experimentation to test hypotheses addressing the mechanism of the variability between cultivars. Work on flower bud necrosis (FBN), a relatively new disorder reported by industry, was completed in 2007. To summarize, FBN occurs during (not after) cold storage, and is initially characterized by small brown spots on the bud. We have found that the greenhouse production environment plays a role in susceptibility to this disorder. High growth temperatures (over ca. 23C) or high light levels (not defined with accuracy, yet) are associated with the problem, even if given only in the last 2 weeks of forcing. Storage of plants (after forcing) at 3C caused much more injury than storage at 7 or 9C. Work is beginning on a postharvest storage problem with Ranunculus asiaticus tuberous roots. In this crop, the underground parts can withstand very low moisture levels, to ca. 8% (as dry as most seeds). Problems on viability and regrowth vigor have been reported. Techniques are being developed to non-destructively assess tuber viability. Oxalis regnelli is a minor bulbous crop grown for the St. Patricks Day holiday. It suffers from a leaf chlorosis problem, that is reminiscent of iron deficiency. Initial studies indicate there is not a close correlation between the extent of leaf chlorosis and leaf tissue iron level.

Impacts
During the life of this project, a safe and effective method for reducing excessive leaf and stem growth in the paperwhite narcissus has been developed. This method, while aimed at non-commercial audiences may nevertheless prove to be useful in the commercial greenhouse industry as well. Non-chemical methods to reduce sprouting of ornamental lily bulbs during retail sales have been identified, and will hopefully lead to a commercial application. The causes of a persistent leaf nutritional problem in oriental hybrid lilies have been identified, and simple measures, such as increasing airflow around the plants can significantly reduce the problem. Effective postharvest treatments for cut flower lilies leading to vastly improved leaf and flower longevity have been developed, and are increasingly being used in the industry (based on personal observation, and inquiry with producers as I visit with them). New studies on minor bulb crops (oxalis and ranunculus) have been initiated, and should prove fruitful in coming years.

Publications

  • Kim, H.-J. and W. B. Miller. 2007. Causes and Control of Cold-Storage-Induced Bud Necrosis in Mona Lisa Lilies. Research Newsletter, Dutch Wholesalers Association for Flowerbulbs and Nursery Stock. July 2007. 4 pages.
  • Chang, Y. C. and W. B. Miller. 2007. Using Florel to Control Upper Leaf Necrosis and Reduce Height in Pot Oriental Hybrid Lilies. Research Newsletter, Dutch Wholesalers Association for Flowerbulbs and Nursery Stock. February 2007. 4 pages.
  • Miller, W. B. 2007. Fusarium, tulips and ethylene: Not as simple as you thought. Research Newsletter, Dutch Wholesalers Association for Flowerbulbs and Nursery Stock. May 2007. 4 pages.


Progress 01/01/06 to 12/31/06

Outputs
This project identifies and studies problems affecting the use and performance of flowerbulbs and similar plants. Studies in this project range from practically oriented greenhouse trials to more in-depth laboratory investigations into the physiology and biochemistry of flowerbulbs. Infection of tulip bulbs by Fusarium is a serious problem in the world tulip industry. In addition to causing direct loss of the infected bulb, the Fusarium fungus also produces the gaseous plant hormone ethylene. In the last two years, we have established that tulip cultivars vary enormously (more than 2 orders of magnitude) in the level of ethylene produced by Fusarium after infection of the bulb. To further probe this problem, we developed in the last 12 months an in-vitro assay based on freeze-dried bulb tissue that will allow year-round experimentation to test hypotheses addressing the mechanism of the variability between cultivars. A plant pathologist and expert in Fusarium, Dr. Gary Bergstrom, is providing expertise to this project. Experiments investigating the response of tulip cultivars to ethylene or hear stress were completed. Bulbs were exposed to ethylene gas (ca. 10 ppm for 2 weeks) or heat stress (35C for 4 to 7 days). As in previous experiments we have conducted in this area, there are clearly differences between cultivars in heat and ethylene susceptibility. Resistance to one stress does not relate to resistance to the other, although cultivars may be found that are resistant (or susceptible) to both stresses. 2005 trials with 1-methylcyclopropene (1-MCP), a gaseous inhibitor of ethylene action, have lengthened our estimate of effectiveness (previously 7 days) to as long as 28 days after application. The length of protection from ethylene will be greatly affected by storage temperature, time of year (reflecting developmental state of the bulb), and undoubtedly many other factors. This work is the basis of a Ph.D. student's dissertation, and papers will be submitted in 2006. In 2005, an inquiry from the New York Times led us to investigate effects of ethanol on growth of certain bulb crops. Experiments conducted in 2005 showed conclusively that dilute ethanol (ca. 3-5%) is indeed a useful and safe growth regulator for paperwhite narcissus. In 2006, we continued experiments on ethanol and paperwhite narcissus, and conducted some initial trials with other bulb crops. In 2005, we began work on a new disorder reported (by industry) on oriental hybrid lily flower buds during cold storage of plants in a cooler. We call the problem flower bud necrosis, or FBN. FBN occurs during (not after) cold storage, and is initially characterized by small brown spots on the bud. Initial experiments in 2005 suggested that the greenhouse production environment plays a role in susceptibility to this post harvest disorder. Work in 2006 confirmed this. High growth temperatures (over ca. 23C) or high light levels (not defined with accuracy, yet) are associated with the problem, even if given only in the last 2 weeks of forcing. Storage of plants (after forcing) at 3C caused much more injury than storage at 7 or 9C.

Impacts
During the life of this project, a safe and effective method for reducing excessive leaf and stem growth in the paperwhite narcissus has been developed. This method, while aimed at non-commercial audiences may nevertheless prove to be useful in the commercial greenhouse industry as well. Non-chemical methods to reduce sprouting of ornamental lily bulbs during retail sales have been identified, and will hopefully lead to a commercial application. The causes of a persistent leaf nutritional problem in oriental hybrid lilies have been identified, and simple measures, such as increasing airflow around the plants can significantly reduce the problem. Effective postharvest treatments for cut flower lilies leading to vastly improved leaf and flower longevity have been developed, and are increasingly being used in the industry (based on personal observation, and inquiry with producers as I visit with them). New studies on minor bulb crops (oxalis and ranunculus) are also being initiated, and should prove fruitful in the coming years.

Publications

  • Legnani, G. C. B. Watkins and W. B. Miller. 2006. Tolerance of dry-sale lily bulbs to elevated carbon dioxide in both ambient and low oxygen atmospheres. Postharv. Biol. Technol. 41:198-207.
  • Miller, W. B. and E. Finan. 2006. Root zone alcohol is an effective growth retardant for paperwhite narcissus. HortTechnology. 16(2):294-296.
  • Miller, W. B. 2006. Using alcohol to reduce stem and leaf growth in Narcissus. FloraCulture International. 16(2):16-17.
  • Miller, W. B. 2006. Pickling your paperwhites. Ginning the narcissus with alcohol to reduce growth, flopping over. NAFWA News, winter 2006 page 4.
  • Carver, S. A. 2006. Ask the Doctor: Review of lily upper leaf necrosis research at Cornell. OFA Bulletin 894:28-29 (Jan. 2006. This summary highlighting our work was prepared by Dr. Carver, with our input).
  • Miller, W. B. 2006. Using Alcohol to Reduce Growth of Paperwhite Narcissus, TopFlor, a New Growth Regulator, Registered in the US, and Hyacinth Height Control: Avoiding Floppy Stems. (3 articles). Research Newsletter, Dutch Wholesalers Association for Flowerbulbs and Nursery Stock. No. 9, February 2006. 4 pp.
  • Miller, W. B. 2006. Many Cultivars of Cutflower Hybrid Lilies Make GREAT Garden Plants! Research Newsletter, Dutch Wholesalers Association for Flowerbulbs and Nursery Stock. No. 10, May 2006. 4 pp.
  • Miller, W. B. 2006. Combining Flowerbulbs and Perennials: Increasing the Market for Both. Research Newsletter, Dutch Wholesalers Association for Flowerbulbs and Nursery Stock. No. 11, September, 2006. 4 pp.
  • Miller, W. B. 2006. 2005 Annual Report of the Cornell Flowerbulb Research Program. (This report is issued on a CD).


Progress 01/01/05 to 12/31/05

Outputs
This project identifies and studies problems affecting the use and performance of flowerbulbs and similar plants. Studies in this project range from practically-oriented greenhouse trials to more in-depth laboratory investigations into the physiology and biochemistry of flowerbulbs. In the past year, research on lily upper leaf necrosis (ULN), a physiological problem caused by calcium deficiency, has been completed, and the papers of the graduate student author (Chang) were published. Infection of tulip bulbs by Fusarium is a serious problem in the world tulip industry. In addition to causing direct loss of the infected bulb, the Fusarium fungus also produces the gaseous plant hormone ethylene. In the last two years, we have established that tulip cultivars vary enormously (more than 2 orders of magnitude) in the level of ethylene produced by Fusarium after infection of the bulb. We are presently developing an assay based on freeze-dried bulb tissue that would allow year-round experimentation to test hypotheses addressing the mechanism of the variability between cultivars. A plant pathologist and expert in Fusarium, Dr. Gary Bergstrom, is providing expertise to this project. Experiments investigating the response of tulip cultivars to ethylene or hear stress were completed. Bulbs were exposed to ethylene gas (ca. 10 ppm for 2 weeks) or heat stress (35C for 4 to 7 days). As in previous experiments we have conducted in this area, there are clearly differences between cultivars in heat and ethylene susceptibility. Resistance to one stress does not relate to resistance to the other, although cultivars may be found that are resistant (or susceptible) to both stresses. 2005 trials with 1-methylcyclopropene (1-MCP), a gaseous inhibitor of ethylene action, have lengthened our estimate of effectiveness (previously 7 days) to as long as 28 days after application. The length of protection from ethylene will be greatly affected by storage temperature, time of year (reflecting developmental state of the bulb), and undoubtedly many other factors. This work is the basis of a Ph.D. students dissertation, and papers will be submitted in 2006. In 2005 a new area of research opened up with an inquiry from the New York Times asking whether the observed growth-reducing effect of gin on the fragrant winter-flowering bulb, paperwhite narcissus, were real, and if so, is it due to 'essential oils' from the gin. Experiments were conducted that showed conclusively that dilute ethanol (ca. 3-5 percent) is indeed a useful and safe growth regulator for paperwhite narcissus, and in a homeowner context. Experiments continue to dissect the mechanism of this effect. We began work on a new disorder reported (by industry) on oriental hybrid lily flower buds during cold storage of plants in a cooler. We call the problem flower bud necrosis, or FBN. FBN occurs during (not after) cold storage, and is initially characterized by small brown spots on the bud. Initial experiments suggest the greenhouse production environment plays a role in susceptibility to this post harvest disorder, and that buds may vary in susceptibility to the problem.

Impacts
A safe and effective method for reducing excessive leaf and stem growth in the paperwhite narcissus has been developed. This method, while aimed at non-commercial audiences may nevertheless prove to be useful in the commercial greenhouse industry as well. Non-chemical methods to reduce sprouting of ornamental lily bulbs during retail sales have been identified, and will hopefully lead to a commercial application. The causes of a persistent leaf nutritional problem in oriental hybrid lilies have been identified, and simple measures, such as increasing airflow around the plants can significantly reduce the problem. Effective postharvest treatments for cut flower lilies leading to vastly improved leaf and flower longevity have been developed, and are increasingly being used in the industry (based on personal observation, and inquiry with producers as I visit with them).

Publications

  • Miller, W.B. 2005. Plant High! A lesson in the planting depth of perennials. Perennial Plants (Quarterly Newsletter of the Perennial Plant Association). vol. 3:6-21.
  • Miller, W.B. 2005. A North American view of forcing potted spring bulbs. FlowerTECH 8(4):20-22.
  • Miller, W.B. 2005. Update on Bulb Crops. OFA Bulletin. 890:23-26.
  • Miller, W.B. 2005. Handling bareroot perennials. 2005. Perennial Plants. vol. 2:7-19.
  • Miller, W.B. New Research: 2005. Plant High. GrowerTalks 69(1):34.
  • Miller, W.B. and R.O. Miller. 2005. How do I make my hydrangeas blue? OFA Bulletin. 889(March-April): 4-5.
  • Chang, Y.C. and W.B. Miller. 2004. Upper leaf necrosis in Oriental hybrid lilies (I): The causes. Taiwan Flower Industry 206: 47-53. (in Chinese)
  • Chang, Y.C. and W.B. Miller. 2004. Upper leaf necrosis in Oriental hybrid lilies (II): Factors affecting symptom development. Taiwan Flower Industry 207: 48-53. (in Chinese)
  • Chang, Y.C. and W.B. Miller. 2004. Upper leaf necrosis in Oriental hybrid lilies (III): Control methods. Taiwan Flower Industry 208: 46-50. (in Chinese)
  • Web site describing use of dilute ethanol as a growth retardant for indoor-forced paperwhite narcissus. 2005. http://www.hort.cornell.edu/department/faculty/wmiller/bulb/Pickling_ your_Paperwhites.pdf
  • Chang, Y.-C. and W.B. Miller. 2005. The development of upper leaf necrosis in Lilium 'Star Gazer'. J. Amer. Soc. Hort. Sci. 130:759-766.
  • Ranwala, N.K.D., A.P. Ranwala and W.B. Miller. 2005. Paclobutrazol and uniconazole solutions maintain efficacy after multiple lily bulb dip events. HortScience 15:551-553.
  • Ranwala, A.P. and W.B. Miller. 2005. Effects of cold storage on postharvest leaf and flower quality of potted oriental-, Asiatic- and LA-hybrid lily cultivars. Sci. Hortic. 105:383-392.
  • Okubo, H., W.B. Miller and G.A. Chastagner (eds). 2005. Proceedings of the Ninth International Symposium on Flower Bulbs. Vol. 1 and 2. 780 pages.
  • Watkins, C.B. and W.B. Miller. 2005. 1-Methylcyclopropene (1-MCP) based technologies for storage and shelf life extension. Acta Hortic. 687: 201-207.
  • Miller, W.B., M. Verlouw, S.S. Liou, H.O. Cirri, C.B. Watkins and K. Snover-Clift. 2005. Variation in Fusarium-induced ethylene production among tulip cultivars. Acta Hortic. 673:229-235.
  • Liou, S.S., C.B. Watkins and W.B. Miller. 2005. Post-heat stress respiration pattern of tulip bulbs in storage. Acta Hortic. 673:237-242.
  • Kamenetsky, R., H. Okubo, H. Imanishi, and W.B. Miller. 2005. The IXth international symposium on flowerbulbs: Concluding remarks. Acta Hortic. 673:775-776.
  • Miller, W.B. 2005. Section Ornamental Plants: report on the Ninth Int'l Symposium on Flower Bulbs. Chronica Hortic. 45(2):33-34.
  • Miller, W.B. 2005. Easter lily guidelines 2006. GrowerTalks 69(7): 50-56.
  • Miller, W.B., N.K.D. Ranwala and A.P. Ranwala. 2005. PGR bulb dips. Greenhouse Product News. 15(10):54-60.


Progress 01/01/04 to 12/31/04

Outputs
A number of sub-projects are on-going within this project on Flowerbulb growth and physiology. One area of active investigation has been that of 'upper leaf necrosis' in oriental hybrid lilies. Our work has shown that this is a calcium deficiency that occurs due to a combination of low bulb calcium levels in vivo, as well as certain environmental factors that inhibit transportation from young, developing leaves. Most of the work in this project was completed, and in 2004 final scientific manuscripts were published or submitted (see list below). We also published information in national and international greenhouse industry journals for access by growers and the floriculture trade. Another sub-project has involved postharvest handling of lily bulbs for garden-center sales. The problem under study is premature sprouting of these bulbs, and the aim pf the project is to evaluate low-oxygen atmospheres as a means of reducing this growth. In 2004, two manuscripts were published in Postharvest Biology and Technology. The research shows that low-oxygen atmospheres of ca. 2-4 percent, are very effective in reducing shoot growth while bulbs are held at warm (ca. 20C) temperatures. Additional work in the biochemistry has continued, with experiments looking at organic acid and carbohydrate metabolism under these atmospheres. In a third sub-project, the relationship of tulip cultivar to ethylene production by Fusarium oxysporum is being studied. Colonization of tulip bulbs by Fusarium is a serious problem in the world tulip industry. In addition to causing direct loss of the infected bulb, the Fusarium fungus also produces the gaseous plant hormone ethylene. We have established that tulip cultivars vary enormously (more than 2 orders of magnitude) in the level of ethylene production after colonization by Fusarium. Experiments with living bulbs continue, and we hope to develop an assay based on freeze-dried bulb tissue that would allow year-round experimentation to test hypotheses addressing the mechanism of the variability between cultivars. Experiments investigating the response of tulip cultivars to ethylene or hear stress were conducted. Bulbs were exposed to ethylene gas (ca. 10 ppm for 2 weeks) or heat stress (35C for 4 days). Results indicated large variation in cultivar response to both stresses. Several cultivars were resistant to both stresses, while others were sensitive. Experiments with 1-methylcyclopropene (1-MCP), a gaseous inhibitor of ethylene action, suggested that 1-MCP remains active as an inhibitor of ethylene for at least 7 days after application. Due to limitations in facilities, we were unable to conduct more detailed work in this areas in 2004.

Impacts
Non-chemical methods to reduce sprouting of ornamental lily bulbs during retail sales have been identified, and will hopefully lead to a commercial application. The causes of a persistent leaf nutritional problem in oriental hybrid lilies have been identified, and simple measures, such as increasing airflow around the plants can significantly reduce the problem. Effective postharvest treatments for cut flower lilies leading to vastly improved leaf and flower longevity have been developed, and are increasingly being used in the industry (based on personal observation, and inquiry with producers as I visit with them).

Publications

  • Chang, Y.-C. and Miller, W. B. 2004. Upper leaf necrosis on oriental lilies: A calcium deficiency disorder. FloraCulture Intl. 14(5):pp. 30-31.
  • Verlouw, M. and Miller, W. B. 2004. A student's view of American flowerbulb research. Bloembollen Visie. No. 41, 22 July.
  • Miller, W. B. 2004. Trichoderma in tulips. The Mayflower (newsletter of the Massachusetts Flower Growers' Association). 1:1-2.
  • Miller, W. B. and Bestic, A. 2004. Handling bareroot perennials. GrowerTalks 68(1):38-46.
  • Miller, W. B. 2004. 2005 Easter lily schedule. GrowerTalks. 68(7):50-54. (November 2004).
  • Miller, W. B. 2004. Leaf counting guidelines. GrowerTalks. 68(7):55. (November 2004).
  • Miller, W. B. 2004. Potted flowerbulbs popular in North America. FlowerTECH 7(7):26-28.
  • Chang, Y.-C. and Miller, W. B. 2004. Upper leaf necrosis on lilies. GrowerTalks 67(12): 38-50. (April 2004).
  • Chang, Y.-C. and Miller, W. B. 2004. The relationship between leaf enclosure, transpiration, and upper leaf necrosis on Lilium cv. Star Gazer. J. Amer. Soc. Hort. Sci. 129:128-133.
  • Legnani, G., Watkins, C. B. and Miller, W. B. 2004. Low oxygen affects the quality of Asiatic hybrid lily bulbs during simulated dry-sale storage and subsequent forcing. Postharv. Biol. Technol. 32:223-233.
  • Chang, Y.-C., Grace-Martin, K, and Miller, W. B. 2004. Efficacy of exogenous calcium applications for reducing upper leaf necrosis in Lilium cv. Star Gazer. HortScience 39:272-275.
  • Legnani, G., Watkins, C. B. and Miller, W. B. 2004. Light, moisture, and atmosphere interact to affect the quality of dry sale Asiatic hybrid lily bulbs. Postharv. Biol. Technol. 34:93-103.
  • Miller, W. B. 2003. 2004 Easter lily schedule. GrowerTalks 67(7):88-93.


Progress 01/01/03 to 12/31/03

Outputs
The project on calcium deficiency on oriental hybrid lilies has been completed, and several manuscripts were published in 2003 (see list below). Our work has shown that a disorder, upper leaf necrosis, in oriental hybrid lilies is a calcium deficiency. Measures to improve transpiration of young, upper leases can reduce the occurrence of the problem (increased airflow, slightly reduced growth rate, and manual bending of the leaves to reduce boundary layer effects). An alternative method explored in 2003 was to use an ethylene-releasing agrichemical, ethephon, as a way to induce a mild, and temporary leaf penalty. Our initial experiments with this technique were very encouraging, and may lead to a novel and creative way to combat this problem. Initial experiments to assess the potential of a proteomics approach to questions of bulb development and physiology were conducted cooperatively with the Ted Thannhausers USDA-ARS lab at Cornell. We were able to repeatibly extract proteins from non-chilled (dormant) and chilled (dormancy removed) tulip bulbs. 2-D gel electrophoresis results were also repeatable. A number of substantially up-regulated and down-regulated protein spots were chosen, excised, digested, and sequences with mass spectroscopy. Sequence data were obtained and compared against known sequences in on-line databases. In many cases, known proteins were returned. At this point, we are evaluating the next step in this work,. In the area of postharvest handling of summer flowering bulbs, experiments to assess the extent of anaerobic metabolism are currently underway. Two approaches: analysis of organic acids by HPLC, and volatiles by GC, are being used. A preliminary experiment to assess variation in ethylene production resulting from Fusarium infection was conducted with a number of tulip cultivars. Results are very preliminary, but there appears to be a dramatic range of response to Fusarium infection: some cultivars respond with a massive production of ethylene, and others seem to produce very little, if any, additional ethylene with Fusarium infection. Further experiments on the efficacy of gibberellin4+7 as an anti-senescence agent for additional cut flower lily cultivars were conducted. Results indicate that all cultivars respond favorably, with essentially no phytotoxity or other problems associated with the treatment. Work over the last 2 years has indicated that concentrations as low as 5 mg/L gibberellin4+7 is effective when applied to cut lily stems overnight. If treatment times need to be shorter (down to 2 hours), then an increase in concentration to 25 mg/L maintains effectiveness. These treatments are effective at temperatures ranging from 3 to 20C. This will give producers a wide range of flexibility for treating their product with this chemical.

Impacts
Non-chemical methods to reduce sprouting of ornamental lily bulbs during retail sales have been identified, and will hopefully lead to a commercial application. The causes of a persistent leaf nutritional problem in oriental hybrid lilies have been identified, and simple measures, such as increasing airflow around the plants can significantly reduce the problem. Effective postharvest treatments for cut flower lilies leading to vastly improved leaf and flower longevity have been developed, and are increasingly being used in the industry (based on personal observation, and inquiry with producers as I visit with them).

Publications

  • Kamenetsky, R., H. Zemah, A. P. Ranwala, F. Vergeldt, W. B. Miller, H. van As and P. Bendel. 2003. Water status and carbohydrate pools in tulip bulbs during dormancy release. New Phytologist 158:109-118.
  • Langens-Gerrits, M., W. B. Miller, A. Croes, and G.-J. de Klerk. 2003. Effect of low temperature on dormancy breaking and growth after planting in lily bulblets regenerated in vitro. Plant Growth Regul. 40:267-275.
  • Chang, Y.-C. and W. B. Miller. 2003. Growth and calcium partitioning in Lilium cv. Star Gazer in relation to leaf calcium deficiency. J. Amer. Soc. Hort. Sci. 128(6):788-796.
  • Watkins, C. B. and W. B. Miller. 2003. Implications of 1-methylcyclopropene registration for use on horticultural products. (NATO Symposium, May 2002, presented by CBW). In: M. Vendrell et al. (eds). Biology and Bioptechnology of the Plant Hormone Ethylene III. IOS Press. pp. 385-390.
  • Miller, W. B. Commercial Flower Production Methodology. 2003. In: B. Thomas, D. Murphy and B. Murray (eds). Encyclopedia of Applied Plant Sciences. Elsevier. pp. 942-948.
  • Miller, W. B. 2003. Lilium x hybrida. In: D. Hamrick (ed). Ball RedBook. 17th ed. Vol 2. pp 487-491.
  • Miller, W. B. 2003. Lilium longiflorum (Easter lily) In: D. Hamrick (ed). Ball RedBook. 17th ed. Vol 2. pp 492-506.
  • Liou, S. C. and W. B. Miller. 2003. Quantifying sensitivity of tulip cultivar susceptibility to heat. HortScience 38:721.
  • Ogutu, R. A. and W. B. Miller. 2003. Growth regulation of Lachenalia aloides cultivars. HortScience 38:727.
  • Ranwala, A. P. and W. B. Miller. 2003. Minimizing stem elongation during spray applications of gibberellin4+7 and benzyladenine to prevent leaf chlorosis in Easter lilies. HortScience 38:1210-1213.
  • Ranwala, N. K., A. P. Ranwala and W. B. Miller. 2003. Studies on plant growth regulator (PGR) uptake by lily bulbs. HortScience 38:727.
  • Liou, S. C. and W. B. Miller. 2003. Increasing length of precooling increases sensitivity to heat injury in tulip. HortScience 38:753.
  • Chang, Y.-C. and W. B. Miller. 2003. Effects of solution calcium level and bulb calcium level on the development of upper leaf necrosis on Lilium cv. Star Gazer. HortScience 38:848.
  • Legnani, G., A. P. Ranwala, C. B. Watkins, and W. B. Miller. 2003. Low oxygen storage affects the carbohydrate status of Asiatic hybrid lily bulb scale and shoot tissues. HortScience 38:858.


Progress 01/01/02 to 12/31/02

Outputs
Major findings from this year's work are that upper leaf necrosis in Oriental hybrid lilies is a calcium deficiency disorder. The bulb, as planted, has very low levels of calcium (ca. 0.05 pct. on a dry weight basis), far less than that needed to support calcium needs of the developing shoot. Horticultural treatments that reduce boundary layer effects on the upper leaves (e.g., artificial leaf unfolding, wind, etc) all improve calcium movement to upper leaves and minimize occurrence of the disorder in the greenhouse. Work has progress on identification of carbohydrate types and pool sizes in a range of bulbous species. We sampled storage organ tissues from 30 cultivars or species in 14 genera (Allium, Arum, Camassia, Chionodoxa, Colchicum, Crocus, Fritillaria, Galanthus, Hyacinthus, Iris, Muscari, Narcissus, Scilla, and Tulipa). Due to the complexity of samples (containing a range of soluble sugars, starch, fructan, and glucomannan), methodologies needed to be worked out to reliably quantify such varied pools in the various taxa. Starch was present in large quantities (greater than ca. 25 pct. on a dry weight basis) in all species except Allium, where no starch was detected. Fructans were detected in all species except Crocus, Arum, Colchicum, and Fritillaria. In species with fructan, three main groups could be distinguished: a: those where fructan was a minor component, generally less than 5 pct. of the dry weight; 2) those species where fructans were of a similar pool size as starch, and 3) the Alliums, where fructan was the only storage carbohydrate. Glucomannan was detected in 5 of the genera, and accounted for ca. 15 pct. of the dry weight in Camassia. In the area of postharvest handling of summer flowering bulbs, additional experiments to assess the potential for developing a modified atmosphere package were conducted. Marketing of these bulbs is necessarily at warm temperatures (ca. 20C and above) in the spring months, and a major problem occurs with unwanted shoot growth (sprouting) in the retail environment. Asiatic hybrid lily bulbs were held in 1 pct. oxygen (a treatment previously shown to be effective in reducing shoot growth and inhibiting floral development) at 20-23C, and a range of carbon dioxide concentrations, ranging from 0 to 16 pct. Elevated carbon dioxide concentrations had no effect on shoot length during storage, and no effect on days to flower, height at flowering, flower bud number and total number of leaves. Thus, carbon dioxide levels in the range to be expected in a modified atmosphere package will not be problematic. Further experiments on the efficacy of gibberellin4+7 as an anti-senescence agent for cut flower lilies were conducted. This year's work indicated that much lower concentrations can be used with excellent results. For example, as little as 5 mg/L gibberellin4+7 is effective when applied to cut lily stems overnight. If treatment times need to be shorter (down to 2 hours), then an increase in concentration to 25 mg/L maintains effectiveness. These treatments are effective at temperatures ranging from 3 to 20C.

Impacts
Non-chemical methods to reduce sprouting of ornamental lily bulbs during retail sales have been identified, and will hopefully leaf to a commercial application. The causes of a persistent leaf nutritional problem in oriental hybrid lilies have been identified, and simple measures, such as increasing airflow around the plants can significantly reduce the problem. Effective postharvest treatments for cut flower lilies leading to vastly improved leaf and flower longevity have also been developed.

Publications

  • Chang, Y.-C. 2002. Upper leaf necrosis on Lilium cv. Star Gazer - A calcium deficiency disorder. Ph.D. Diss., Cornell University.156 pp.
  • Ranwala, A.P., G. Legnani, M. Reitmeier, B.B. Stewart. and W.B. Miller. 2002. Efficacy of plant growth retardants as pre-plant bulb dips for height control in LA and oriental hybrid lilies. HortTechnology. 12(3):426-431.
  • Legnani, G. C. B. Watkins and W. B. Miller. 2002. Use of low-oxygen atmospheres to inhibit sprout elongation of dry-sale Asiatic lily bulbs. Acta Hortic. 570:183-189.
  • Ranwala, A. P. and W. B. Miller. 2002. Effects of gibberellin treatments on flower and leaf quality of cut hybrid lilies. Acta Hortic. 570:205-210.
  • Miller, W. B., A. Chang, G. Legnani, N. Patel, A. P. Ranwala, M. Reitmeier, S. S. Scholl, and B. B. Stewart. 2002. Pre-plant bulb dips for height control in LA and Oriental hybrid lilies. Acta Hortic. 570:351-357. Ranwala, A. P., D. Ranwala, W. B. Miller and R. Kamenetsky. 2002. Cold-induced changes in non-structural carbohydrates in tulip bulbs. XXVIth Intl. Hortic. Congr Abstract 479.
  • Chang, Y.C. and W.B. Miller. 2002. Foliar calcium sprays reduce the severity of upper leaf necrosis on Lilium cv. Star Gazer. XXVIth Intl. Hortic. Congr Abstract 494.


Progress 01/01/01 to 12/31/01

Outputs
Experiments were conducted in the three main areas of this project. Experiments designed to probe the nature of the specific upper leaf necrosis disorder in 'Star Gazer' lilies indicated convincingly that the disorder is indeed a calcium deficiency. Leaf nutrient analysis, leaf shading, sand culture growth in minus-calcium solutions, and canopy turbulence (wind) experiments all pointed to calcium deficiency at the cause of the symptoms. Treatments encouraging transpiration reduced the disorder. A number of initial experiments aimed at suppressing the disorder on a practical level are in progress, including foliar calcium application, pre-plant bulb soaking in calcium solutions, etc. Additional data on cultivar response to gibberellin 4+7 as an anti-leaf senescence treatment on hybrid lily cut flowers were collected. Results indicate that there is wide cultivar variability and proper cultivar selection can greatly reduce occurrence of the problem for commercial growers. Post-harvest stem dips or short term (less than 3 hours) pulses in solutions of gibberellin 4+7 and benzyladenine (i.e., the commercial product, Fascination) are also very effective. Additional studies evaluating details such as treatment duration, temperature, concentration, etc. all will be worked on in the upcoming year. Experiments have indicated clearly that low oxygen atmospheres are effective in reducing unwanted shoot elongation in lily bulbs destined for retail marketing in the springtime. Experiments are currently underway to assess interactions with carbon dioxide concentrations.

Impacts
Results generated from this project have already been used to support the registration of a new plant growth regulator, Fascination. This product is a gibberellin and cytokinin combination, and does an excellent job of reducing leaf chlorosis problems in the lily forcing industry. Results from other avenues of investigation in this project are too tentative for defined impact.

Publications

  • Legnani, G. and W. B. Miller. 2001. Short photoperiods induce fructan accumulation and tuberous root development in Dahlia seedlings. New Phytologist 149:449-454.