Progress 10/01/02 to 09/30/07
Outputs
During 2006 Professor Hammer retired.
Impacts
X
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
We studied the production characteristics of 110 poinsettia cultivars in 2004. Of those cultivars, 23 were new introductions. We conducted comparison trials with North Carolina State University and the University of Florida. We also conducted a consumer preference survey of the poinsettia cultivars at White River Gardens in Indianapolis, Indiana.
Impacts
Our research has a significant impact on growers' selection of poinsettia cultivars they choose to grow. We also greatly impact what cultivar characteristics breeders use for selection. We have also impacted the quality of the poinsettia cultivars for US consumers.
Publications
- Dole, John, Allen Hammer, and Jim Barrett. 2005. 2004 National Poinsettia Trial. GPN 15(2):23-24,26,27,31-32.
- Hammer, Allen, John Dole, and Jim Barrett. 2005. Best of the Trials. GPN 15(2):35-36.
- Hammer, Allen, John Dole, and Jim Barrett. 2005. Recommended Cultivars. GPN 15(2):38,40,42.
- Dole, John, Jim Barrett, and Allen Hammer. 2005. Picking Popular Poinsettias. GPN 15(3):32,34,36,38.
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Progress 10/01/03 to 09/30/04
Outputs
As poinsettias are the number one potted crop in the U.S., we continue to cooperate with the University of Florida and North Carolina State University to help growers determine which new poinsettia cultivars are best for production. We are also conducting consumer information studies that help growers select cultivars that have the highest sales appeal. The poinsettia data we collect are quickly put on a web site that growers use for information on poinsettia cultivars. We continue to develop labortory procedures to determine lime requirements for soil-less root media used in greenhouse production.
Impacts
With the poinsettia data we collect, growers are able to make informed decisions on the most profitable poinsettia cultivars for their market. Our data are useful in improving the quality of poinsettias in the U.S. Our root medium pH research will have a significant impact on U.S. greenhouse production by reducing pH problems that account for significant production losses each year.
Publications
- Hammer, Allen, Jim Barrett, and John Dole. 2004. National Poinsettia Trials 2003. GPN14(2):20,22,24,25-29,31-32,34,38.
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Progress 10/01/02 to 09/30/03
Outputs
As poinsettias are the number one potted crop in the U.S., we continue to cooperate with the University of Florida and North Carolina State University to help growers determine which new poinsettia cultivars are best for production. We are also conducting consumer information that also helps growers select cultivars that have highest sales appleal. The poinsettia data we collect is quickly put on a web site that growers use for a quick information on poinsettia cultivars. We continue to develop labortory procedures to determine lime requirements for soil-less root media used in greenhouse production.
Impacts
With the poinsettia data we collect, growers are able to make informed decisions on the most profitable poinsettia cultivars for their market. Our data is useful in improving the quality of poinsettias in the U.S. Our root medium pH research will have a significant impact on U.S. greenhouse production by reducing ph problems that account for significant production losses each year.
Publications
- Ludena, C., McNamara, K., Hammer, P.A., and Foster, K. Development of a Stochastic Model to Evaluate Plant Growers' Enterprise Budgets. Selected Paper, American Agricultural Economics Association Annual Meeting, Montreal, Canada, July 27-30, 2003. 31P.
- Barrett, .J. and .A. Hammer. 2002. 2001 Poinsettia Trials: Regionally Recommendded Cultivars. GPN. 12(2):10, 12, 14-15.
- Hammer, .A., .J. Barrett, .T. Nell and .R. Larson. 2002. 2001 Poinsettia Trials: New at the Trials. GPN. 12(2):16-18, 20, 22-23
- Barrett, .J. and .A. Hammer. 2002. Best of Best 2001 Poinsettia Trials. GPN. 12(2):24, 25, 27.(published/completed)
- Barrett, .J. and .R. Schoelhorn .A. Hammer. 2002. Which Poinsettias do Consumers Prefer? GPN. 12(4):46, 48, 50-51,53,56.
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Progress 10/01/01 to 09/30/02
Outputs
In cooperation with the University of Florida and North Carolina State we are trialing and collecting production data on available poinsettia cultivars. We are developing production guidelines for the available cultivars useful to greenhouse growers in the United States., We are developing models to predict lime requirements for the various highly organic root media used in greenhouse production. The development of a reliable lime requirement model for a specific root medium pH does not presently exist.
Impacts
Greenhouse producers will maximize poinsettia profits with proper cultivar selection and using the correct production techniques for individual poinsettia cultivars. Root media at the proper pH will greatly reduce production problems and plant losses.
Publications
- Barrett, Jim and Allen Hammer. 2002. Regionally Recommended Cultivars. Greenhouse Product News 12(2): 10, 12, 14-15.
- Barrett, Jim and Allen Hammer. 2002. Best of the Best: 2001 Poinsettia Trials. Greenhouse Product News 12(2): 24, 26, 28.
- Hammer, P. Allen, Jim Barrett, Terril A. Nell, and Roy A Larson. 2002. New at the Trials. Greenhouse Product News 12(2): 16-18, 20, 22-23.
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Progress 10/01/00 to 09/30/01
Outputs
DIF (difference between day and night air temperature) is used by the greenhouse industry as a method of controlling plant height. Our research has shown that the DIF temperatures are related to total plant water relations. Warm night/cool day temperatures reduce early morning plant turgor, a driving force in plant elongation growth. Temperature and watering techniques can be combined to manipulate plant growth.
Impacts
Greenhouse growers will be better able to use greenhouse temperatures to control plant height and plant quality. These are also useful non-chemical approaches that provide higher quality plants to consumers.
Publications
- Ranwala, Anil P., William B. Miller, Terri I. Kirk, and P. Allen Hammer. 2000. Ancymidol Drenches, Reversed Greenhouse Temperatures, Post-Greenhouse Cold Storage and Hormone Sprays Affect Post-Harvest Leaf Chlorosis in Easter Lily. J. Amer. Soc. Hort. Sci. 125(2):248-253.
- Kaufmann, Pauline Helen, Robert J. Joly and P. Allen Hammer. 2000. Influence of Day and Night Temperature Differentials on Root Elongation Rate, Root Hydraulic Properties, and Shoot Water Relations in Chrysanthemum. J. Amer. Soc. Hort Sci. 125(3):383-389.
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Progress 10/01/98 to 09/30/99
Outputs
We continue to work on research problems significant to the greenhouse industry. The compaction of root media by greenhouse operations of potting, movement, and watering of plants has significant affect on root growth. We have quantified these affects. We have shown that many greenhouse operations such as reverse temperatures and chemical growth retardant applications can significantly increase postharvest leaf yellowing in Easter lilies.
Impacts
Significant improvements have been made in the postharvest longevity of Easter lilies for the consumer for our joint research.
Publications
- Kampf, Atelene, P. Allen Hammer, and Terri Kirk. 1999. Effect of packing density on the mechanical impedance of root media. Proceedings of the International Symposium on Growing Media and Hydroponics. A.P. Papadopoulos, Editor. Volume 2. Acta Horticulturae, Number 481. pp. 689-694.
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Progress 10/01/97 to 09/30/98
Outputs
We have determined that the DIF response is related to the internal water potential. Plants grown at high night/low day temperatures have a very different water potential pattern when compared to low night/high day temperatures. Plant stem elongation at the negative and positive DIF conditions is directly correlated to thse internal water potentials. Plants with greatest stem elongation show the greatest turgor potential. We have developed computer video protocols to measure plant elongation over time.
Impacts
(N/A)
Publications
- No publications reported this period
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Progress 10/01/96 to 09/30/97
Outputs
Results from hydroponically grown poinsettias showed an increase in nutrient uptake over time. The plants were grown for a 15 week period from rooted cutting until anthesis. The study showed that increasing the rates of N and K from 100 to 300 ppm did not significantly influence plant dry mass or quality. These results have altered our fertilizer application recommendation for poinsettias. We participated in a national poinsettia trial study with North Carolina State University and the University of Florida. The study, using uniform protocol among the locations, provides data on the regional performance, as well as the average performance, in three distinct growing regions of the United States for over 40 poinsettia cultivars. The collected data is useful in helping the poinsettia breeders and growers choose the best cultivars for production as well as the consumer. We continue studies to understand how plants respond to differences in day/night temperatures (DIF). We
have discovered some important internal plant differences between negative and positive DIF plants.
Impacts
(N/A)
Publications
- Whipker, Brian E. and P. Allen Hammer. 1997. Efficacy of ancymidol, paclobutrazol, and uniconazole on growth of tuberous-rooted dahlias. Hort Technology 7 (3): 269-273.
- Whipker, Brian E. and P. Allen Hammer. 1997. Nutrient uptake in poinsettia during different stages of physiological development. J. Amer. Soc. Hort. Sci. 122(4): 565-573.
- Larson, Roy and P. Allen Hammer. 1997. Trialing cuts through the cultivar clutter. GrowerTalks 60(12):26, 28, 30, 32 34.
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Progress 10/01/95 to 09/30/96
Outputs
Excessive alkalinity in greenhouse irrigation water can increase root medium pH,resulting in reduced micronutrient availability. We developed a computer spreadsheet to calculate the needed addition of nitric, phosphoric, or sulfuric acid required to achieve an endpoint alkalinity of pH. The spreadsheet accounts for the pH dependent chemical reaction to correct alkalinity. We found that nutrient uptake varies during the production stages of Poinsettias. The early and late stages of production showed lower rates of uptake, therefore fertilization practices in the greenhouse can be adjusted to reduce excess fertilizer application, therefore reducing potential fertilizer runoff concerns. The height of dahlias and geraniums can be altered with the use of chemical growth regulators. We conducted a number of studies to determine optimum rates of application of ancymidol, paclobutrazol, and uniconazole to achieve a predictable plant height.
Impacts
(N/A)
Publications
- WHIPKER, B.E., BAILEY, D.A., NELSON, P.V., FONTENO, W. C., and HAMMER, P.A. 199. A novel approach to calculate acid additions for alkalinity control in greenhouse irrigation water. Commun. Soil Sci. Plant Anal. 27(5-8):959-976.
- WHIPKER, B.E. and HAMMER, P.A. 1997 Efficacy of ancymidol, paclobutrazol, and uniconazole on growth of tuberous-rooted dahlias. Accepted for publication, HortTechnology.
- WHIPKER, B.E. and HAMMER, P.A. 1997 Nutrient uptake in poinsettia during different stages of physiological development. Accepted for publication, J. Amer. Soc. Hort. Sci.
- WHIPKER, B.E., HAMMER, P. A., and CONNELL, J. 1997 Vegetatively propagated geranium response to single and multiple applications of chemical growth retardants. Accepted for publication, Plant Growth Regulation Society of AmericaQuarterly.
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Progress 10/01/94 to 09/30/95
Outputs
No narrative reported at this time.
Impacts
(N/A)
Publications
- NO PUBLICATIONS REPORTED THIS PERIOD.
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Progress 10/01/93 to 09/30/94
Outputs
Poinsettia bract damage increased with increasing rates of phosphate fertilizersincorporated into root media. Fluoride levels in leaves and bracts increased as levels of superphosphate and triple superphosphate increased, as did number of bracts burned. Bract fluoride levels were significantly correlated with bract damage. Nutrient solution experiments were conducted to manipulate fluoride levels in the root environment without subsequent changes in P and other elements. In these studies, number of damaged bracts per plant increased dramatically when bract fluoride levels exceeded 7 ppm F. The study also indicated 'Supjibi Red', a cultivar reported as susceptible to bract disorders, was more susceptible to fluoride toxicity than was 'Red Sails'. CaCl(subscript 2) sprays of 377 mg Ca/liter applied to plants growing in 10 mg F(superscript -)/liter solution resulted in significantly fewer bracts with damage, suggesting calcium was limiting in these plants. Changes in the
levels of Ca/Mg ratio applied to poinsettias in irrigation water did not result in bract damage, though it could be shown that Mg reduced the uptake of Ca when present at greater concentrations. Bract damage occurred in this study following anthesis which was not treatment-specific, but cultivar-specific. 'Supjibi Red' showed much greater K uptake into bracts than other cultivars, resulting in ionic toxicity. Though symptoms could be distinguished from nutritional bract disorders, pesticide applications also resulted in bract damage.
Impacts
(N/A)
Publications
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Progress 10/01/92 to 09/30/93
Outputs
Easter Lilies Easter lilies were grown with positive or negative DIF's (/+-/10F)to give equal 24-hour temperature averages. There was no effect of negative DIF on flower longevity, but negative DIF increased by 6-fold the number of aborted flower buds. Negative DIF reduced leaf carbohydrate level, and significantly increased postharvest leaf yellowing. For example, after 6 days in the postharvest room, negative DIF plants had 3 times more yellowed lower leaves compared to positive DIF controls (36% vs. 12%). Lower leaves had much less carbohydrate than upper leaves at any time during the postharvest period. Further, leaf yellowing was negatively correlated to leaf sucrose level. These results indicate that temperature stresses which reduce leaf carbohydrate levels contribute to postharvest leaf yellowing. Poinsettia The uptake of N, P, and K are being studied in poinsettias grown in solution cultures. Uptake of these elements change significantly over time. We are
developing mathematical models that will allow us to predict uptake as related to growth stage. This will allow us to optimize application of fertilizer with uptake by the plant.
Impacts
(N/A)
Publications
- MILLER, W.B., HAMMER, P.A. and KIRK, T.L. 1992. Reversed Greenhouse Temperature Alter Carbohydrate Status in Lilium longiflorum, Thumb. `Nellie White'. Journal paper #13495. J. Amer. Soc. Hort. Sci. (in-press).
- WHIPKER, B.E. and HAMMER, P.A. 1993. Determination of Injurious Phosphorus Levels in Poinsettias. Journal paper #13707. HortScience (in-press).
- WHIPKER, B.E. and HAMMER, P.A. 1993. Growth and Yield Characteristics of Field-grown Limonium sinatum. Journal paper #13925. HortScience (in press).
- WHIPKER, B.E., EDDY, R.J. and HAMMER, P.A. 1993. Growth Regulator Height Control of Ornamental Kale. Journal paper #13805. HortScience (in press).
- HOPPER, D.A., HAMMER, P.A. and WILSON, J.R. 1993. Dynamic Growth Model of Rosa hybrida L. Response to Irradiance and Day/Night Temperatures. Journal paper #13002. J. Amer. Soc. Hort. Sci. (in-press).
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