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Bud burst phenology, dormancy release and susceptibility to Dutch elm disease in elms (Ulmus spp.)

Ghelardini, Luisa (2007). Bud burst phenology, dormancy release and susceptibility to Dutch elm disease in elms (Ulmus spp.). Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2007:134
ISBN 978-91-85913-33-6
[Doctoral thesis]

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European elms (Ulmus glabra Huds., U. laevis Pall. and U. minor Mill.) have been damaged and are still threatened by an alien hypervirulent pathogen, Ophiostoma ulmi s.l., the agent of Dutch elm disease (DED). Therefore, several ex situ clone collections were established throughout Europe for breeding and conservation purposes. This thesis was carried out within the RESGEN CT96-78 project, which launched the EU-coordinated evaluation of these collections. The aim of this thesis was to analyse the variation in bud burst date and to acquire basic knowledge on the environmental control of this adaptive trait with regard to DED susceptibility. Bud burst date variation observed among collections and years in European elms was explained by a phenological model based on an inverse exponential relationship between thermal time and chilling to bud burst. According to the fitted curves, European elms have low dormancy and short chilling requirement for dormancy release. Bud burst date in U. minor was directly related to latitude and elevation. The order of bud burst was stable among years. The observed geographic trends were largely determined by difference in chilling requirement for dormancy release which increased with latitude and elevation. The effects of photoperiod and temperature on dormancy release in clones of European and Asian species were studied in partially controlled conditions in Italy. Dormancy was generally low and short in all clones. There was no evidence that photoperiod influenced dormancy release in these elms. Susceptibility to DED was assessed in the Italian clone collection. Susceptibility varied greatly among taxonomic groups and within the most represented species, U. minor. In this species, DED susceptibility was directly correlated with geographic origin and date of bud burst, southern and early flushing clones showing the least symptoms. The results suggest that earliness of bud burst represents a mechanism of disease avoidance owing to an asynchrony between the susceptible period in the host and the time of natural infection by Scolytus insects, the main vectors of DED.

Authors/Creators:Ghelardini, Luisa
Title:Bud burst phenology, dormancy release and susceptibility to Dutch elm disease in elms (Ulmus spp.)
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2007
Number of Pages:52
ALLI. Santini, A., Ghelardini, L., Falusi, M., Bohnens, J., Buron, M., Collin, E., Solla, A. & Van den Broeck, A. 2004. Vegetative bud-burst variability of European elms. In: New approaches to elm conservation. Proceedings of the 2nd International Elm Conference, 20-23 May 2003, Valsaìn, Spain. Investigatión Agraria: Sistemas y Recursos Forestales 13 (1): 37-45. II. Santini, A., Fagnani, A., Ferrini, F., Ghelardini, L. & Mittempergher, L. 2005. Variation among Italian and French elm clones in their response to Ophiostoma novo-ulmi inoculation. Forest Pathology 35: 183-193. III. Ghelardini, L., Falusi, M. & Santini A. 2006. Variation in timing of bud-burst of Ulmus minor clones from different geographical origins. Canadian Journal of Forest Research 36: 1982-1991. IV. Ghelardini, L., Santini, A., Black-Samuelsson, S., Myking, T. & Falusi, M. Bud dormancy release in elm (Ulmus spp.) clones – photoperiod and temperature effects. (Manuscript)
Place of Publication:Uppsala
ISBN for printed version:978-91-85913-33-6
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:ulmus glabra, ulmus laevis, ceratocystis ulmi, fungal diseases, scolytus, buds, sprouting, dormancy, cooling, disease control, photoperiodicity, phenology, time
Keywords:bud burst, chilling, disease avoidance, dormancy, elm, Ophiostoma ulmi, photoperiod, phenology, rest, thermal time, Ulmus glabra, Ulmus laevis, Ulmus minor
Permanent URL:
ID Code:1671
Department:(NL, NJ) > Dept. of Plant Biology and Forest Genetics (until 131231)
Deposited By: Luisa Ghelardini
Deposited On:23 Jan 2008 00:00
Metadata Last Modified:02 Dec 2014 10:13

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