scholarly journals Validation of a Model for Simulating the Effect of Daminozide Application on Chrysanthemum

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 500C-500
Author(s):  
J.H. Lieth ◽  
L.R. Oki ◽  
P. Ng ◽  
M.C. Garcia-Navarro ◽  
S.H. Kim ◽  
...  

Daminozide is a growth retardant used in potted plant production as a foliar spray to inhibit shoot elongation. It has its greatest inhibitory effect immediately after application, becoming less pronounced thereafter; continued retardation is accomplished by reapplication at 7to 14-day intervals. A model for this retardation effect is useful in developing decision support tools, as well as in optimizing (perhaps minimizing) the use of this growth retardant. Such a model, as developed and described earlier, simulates the effect of a foliar spray application of daminozide at various concentrations on various days during the production cycle. The objective of this work was to validate this model for various varieties of chrysanthemum. Using the model to simulate the effect of one application of daminozide resulted in predicted plant heights very close to the observed heights for most of the varieties tested. Of four methods used to implement the multiple-application effect, two resulted in very good simulation of the observed plant heights. In summary, the model was shown to be valid for all the varieties of chrysanthemum tested.

1979 ◽  
Vol 59 (4) ◽  
pp. 1161-1163
Author(s):  
G. P. LUMIS ◽  
A. GAIL JOHNSON

A foliar spray application of 0.1% dikegulac-sodium (Atrinal) on Juniperus chinensis L. ’Fairview’ was an effective chemical pruning agent. As the concentration of dikegulac was increased from 0.1 to 0.4% terminal shoot growth was greatly reduced and injury increased while lateral branching was not influenced.


HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1045E-1046
Author(s):  
Roberto G. Lopez ◽  
Erik S. Runkle

Prohexadione-Ca (ProCa) is a relatively new plant growth regulator (PGR) that inhibits internode length in rice, small grains, and fruit trees. However, little is known about its efficacy and potential phytotoxicity on floriculture crops and how it compares to other commercially available PGR chemicals. The effects of two foliar spray applications (2 weeks apart) of ProCa (500, 1000, or 2000 ppm), paclobutrazol (30 ppm), or a tank mix of daminozide plus chlormequat (2500 and 1000 ppm, respectively) were quantified on Dianthus barbatus L. `Interspecific Dynasty Red', Ageratina altissima R. King & H. Robinson (Eupatorium rugosum) `Chocolate', Lilium longiflorum Thunb. `Fangio', and Buddleia davidii Franch. `Mixed.' All plants were forced in a glass-glazed greenhouse with a constant temperature setpoint of 20 °C under a 16-h photoperiod. Two weeks after the second spray application of ProCa at 500, 1000, or 2000 ppm, plant height of Dianthus and Lilium was shorter than control plants by 56%, 60%, and 65% and by 6%, 26%, and 28%, respectively. However, ProCa bleached and reduced the size of Dianthus flowers. ProCa at 2000 ppm and daminozide plus chlormequat were effective at controlling the height of Eupatorium (64% and 53% reduction, respectively); however, leaves of Eupatorium were discolored and showed symptoms of phytotoxicity 1 week after the first ProCa application. Only daminozide plus chlormequat were effective on Buddleia. ProCa is an effective PGR for most of the crops we tested; however, its discoloration of red flowers and foliage may limit its application for commercial use.


2002 ◽  
Vol 19 (2) ◽  
pp. 68-72 ◽  
Author(s):  
Paula M. Pijut

Abstract Eastern white pine (Pinus strobus L.) is an important forestry species in the northeastern and midwestern United States and in eastern Canada. Induction of early and reliable flowering and cone production will shorten the breeding cycle and aid in the development of genetically improved white pine. The objective of this study was to determine if a foliar spray application of gibberellin A4/7 (GA4/7) or ProCone™ would induce both male and female strobili on young grafted eastern white pine selected for white pine blister rust resistance. Trees were sprayed (500 mg L-1) weekly in 1998 during the period of rapid shoot elongation (mid-May through July), for a total of 11 applications. Flowering data were collected June 15, 1999. Twenty-five out of 53 genotypes produced male strobili. For all genotypes studied, the total number of male strobili clusters per tree (and the mean number ± SE of pollen-cones per cluster) produced with GA4/7, ProCone™, or untreated controls were: 643 (7.1 ± 0.3); 574 (7.9 ± 0.3); and 79 (8.3 ± 0.8), respectively. Twenty out of 53 genotypes produced female strobili. For all genotypes studied, the total number of female strobili per tree (and the mean number ± SE of female strobili per shoot) produced with GA4/7, ProCone™, or untreated controls were: 87 (1.1 ± 0.1); 130 (1.3 ± 0.1); and 33 (0.6 ± 0.1), respectively. Eleven genotypes produced both male and female strobili. Control trees that flowered may have been the result of spray drift. The results indicate that a foliar spray application of GA4/7 or ProCone™ at 500 mg L-1 will induce both male and female strobili, but not on all selected genotypes of eastern white pine.


HortScience ◽  
2021 ◽  
pp. 1-6
Author(s):  
Jaser A. Aljaser ◽  
Neil O. Anderson

Gladiolus (Gladiolus ×hybridus) is an asexually propagated, herbaceous perennial and an economically important cut flower crop. In commercial production, gladioli have tall flower stalks, which limit their use to cut flowers and annual garden plants. The gladiolus breeding program at the University of Minnesota has bred and selected rapid generation cycling (RGC) cycle 1 gladiolus, which can flower in <1 year from seed instead of the norm of 3 to 5 years (which are vegetatively propagated as corms). Gibberellin inhibitors, such as ancymidol, are used as plant growth retardants to control height in potted plants. Higher concentrations can inhibit flowering along with other negative side effects. The aim of this study was to investigate the growth, flowering, and corm/cormel production response of cycle 1 gladiolus to the gibberellin inhibitor, ancymidol (0, 100, and 400 mg·L−1 soak) in comparison with noncycle 1 genotypes and commercial cultivars for potted gladiolus production. Cycle 1 genotypes flowered with all ancymidol concentrations while noncycle 1 genotypes had significantly fewer flowers or were completely nonflowering under higher concentrations. All tested genotypes had increased leaf width as ancymidol concentration increased. Conversely, flower stalk heights were shorter as the ancymidol concentration increased while the number of stalks was nonsignificant. Corms, cormel number, and fresh weights decreased in all genotypes except for one cycle 1 genotype, which had an increase in both corm number and fresh weight when treated with 100 mg·L−1 ancymidol. Cycle 1 gladiolus are more resilient to this gibberellin inhibitor even at high concentrations and can potentially be used for gladiolus potted plant production.


2020 ◽  
pp. 323
Author(s):  
Nour Elislam Djedaa ◽  
Abderrezak Moulay Lakhdar

2007 ◽  
Vol 7 (5-6) ◽  
pp. 53-60
Author(s):  
D. Inman ◽  
D. Simidchiev ◽  
P. Jeffrey

This paper examines the use of influence diagrams (IDs) in water demand management (WDM) strategy planning with the specific objective of exploring how IDs can be used in developing computer-based decision support tools (DSTs) to complement and support existing WDM decision processes. We report the results of an expert consultation carried out in collaboration with water industry specialists in Sofia, Bulgaria. The elicited information is presented as influence diagrams and the discussion looks at their usefulness in WDM strategy design and the specification of suitable modelling techniques. The paper concludes that IDs themselves are useful in developing model structures for use in evidence-based reasoning models such as Bayesian Networks, and this is in keeping with the objectives set out in the introduction of integrating DSTs into existing decision processes. The paper will be of interest to modellers, decision-makers and scientists involved in designing tools to support resource conservation strategy implementation.


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