Genetic variation in frost resistance of Eucalyptus globulus ssp. globulus assessed by artificial freezing in winter
Wayne N. Tibbits A B F , Timothy L. White C , Gary R. Hodge C D and Nuno M. G. Borralho A EA Cooperative Research Centre for Sustainable Production Forestry, School of Plant Science, University of Tasmania, GPO Box 252–255 Hobart, Tas. 7001, Australia.
B Present address: Trees, Research and Environmental Solutions, 17 George Street, Ulverstone, Tas. 7315, Australia.
C School of Forest Resources and Conservation, University of Florida, 138 Newins-Ziegler Hall, Gainesville, FL 32611-0410, USA.
D Present address: Central American and Mexico Coniferous Resources Cooperative, North Carolina State University, Box 8002, Raleigh, NC 27695, USA.
E Present address: RAIZ, Centro de Investigacao Florestal, Quinta da Torra Bella Apartado 15, 2065 Alocentre, Portugal.
F Corresponding author. Email: tresolutions@vision.net.au
Australian Journal of Botany 54(6) 521-529 https://doi.org/10.1071/BT02061
Submitted: 15 July 2002 Accepted: 14 February 2006 Published: 15 September 2006
Abstract
A study of genetic variation in freezing tolerance of Eucalyptus globulus was conducted in winter by subjecting leaf discs from nursery-grown seedlings to artificial freezing at temperatures ranging from –5.5 to –10.0°C. A total of ~6200 seedlings from 477 open-pollinated families from the full natural range were assessed in three separate experiments. Patterns of frost tolerance with race were not clear and consistent in all three experiments, although inland south-eastern Tasmanian and West Coast Tasmanian races were usually the more frost tolerant (T50 = –8.8°C, cf. overall mean of –8.3°C). Poor correlations between experiments also made clear identification of superior localities difficult. Winter-frost tolerance was a trait with considerable variation and also under strong additive genetic control. Estimated heritabilities of the relative electrical conductivity following a set freezing temperature and the calculated trait T50 were in the range of 0.27–0.71, with small standard errors. Predicted breeding values in all experiments indicated that the best families were tolerant of ~1.4°C colder temperatures than average. Seedlings appeared equally capable of rapid dehardening, when average T50 cold hardiness changed from –10.5 to –5.7°C during a 10-day period, or ~3–4°C per week. The issue of more thoroughly assessing the genetic basis of frost tolerance in E. globulus through field-testing is discussed.
Acknowledgments
This work was supported by a Federal Government research grant under the National Afforestation Program. A fellowship under the Winston Churchill Memorial Trust enabled the senior author to travel to the University of Florida where much of the analysis was undertaken. Many employees of the Gunns Ltd (then APPM Forest Products) assisted with seedling maintenance and freeze assessment, including Mr Ian Ravenwood, Dr David de Little, Mr Milton Savva and Ms Wendy Hodgetts. Mr Greg Powell of the University of Florida and Professor Brad Potts of the University of Tasmania are also acknowledged for their support.
Borralho NMG, Potts BM
(1996) Accounting for native stand characteristics in genetic evaluations of open pollinated progeny from a Eucalyptus globulus base population. New Forests 11, 53–64.
Dutkowski GW, Potts BM
(1999) Geographic patterns of genetic variation in Eucalyptus globulus ssp. globulus and a revised racial classification. Australian Journal of Botany 47, 237–263.
| Crossref | GoogleScholarGoogle Scholar |
Jordan GJ,
Borralho NMG,
Tilyard P, Potts BM
(1994) Identification of races in Eucalyptus globulus ssp. globulus based on growth rates in Tasmania and geographic distribution. Silvae Genetica 43, 292–298.
Kirkpatrick JB
(1974) The numerical intraspecific taxonomy of Eucalyptus globulus Labill. Botanical Journal Linnaean Society London 69, 84–104.
Martin D
(1948) Eucalypts in the British Isles. Australian Forestry 12, 63–74.
Meyer K
(1991a) Estimating variances and covariances from multivariate animal models by restricted maximum likelihood. Genetic Selection Evolution 23, 67–83.
Nelder JA, Mead R
(1965) A simplex method for function minimisation. Computer Journal 7, 303–333.
Potts BM, Jordan GJ
(1994) The spatial pattern and scale of variation in Eucalyptus globulus ssp. globulus: variation in seedling abnormalities and early growth. Australian Journal of Botany 42, 471–492.
| Crossref | GoogleScholarGoogle Scholar |
Raymond CA,
Harwood CE, Owen JV
(1986) A conductivity method for screening populations of eucalypts for frost damage and frost tolerance. Australian Journal of Botany 34, 377–393.
| Crossref | GoogleScholarGoogle Scholar |
Raymond CA,
Owen JV, Ravenwood IC
(1992) Genetic variation for frost tolerance in a breeding population of Eucalyptus nitens. Silvae Genetica 41, 355–362.
Tibbits WN, Hodge GR
(2003) Genetic parameters for cold hardiness in Eucalyptus nitens (Deane & Maiden) Maiden. Silvae Genetica 52, 89–97.
Tibbits WN, Reid JB
(1987a) Frost resistance in Eucalyptus nitens (Deane & Maiden) Maiden: physiological aspects of hardiness. Australian Journal of Botany 35, 235–250.
| Crossref | GoogleScholarGoogle Scholar |
Tibbits WN, Reid JB
(1987b) Frost resistance in Eucalyptus nitens (Deane & Maiden) Maiden: genetic and seasonal aspects of variation. Australian Forest Research 17, 29–47.
Volker PW,
Owen JV, Borralho NMG
(1994) Genetic variances and covariances for frost tolerance in Eucalyptus globulus and E. nitens. Silvae Genetica 43, 366–372.