Genetic variation in drought damage in Eucalyptus globulus was studied in a sublined trial series across four neighbouring sites in Western Australia linked by ten common families. The trials included approximately 400 open-pollinated families, encompassing 51 native stand collection localities and 19 subraces from throughout the geographic range of the species. Data were analysed using mixed models, with spatial analysis used to better identify genetic effects. Significant subrace differences in drought damage were detected, with both broad-scale, regional and localised clines evident. The quantitative genetic differentiation between subraces as measured by QST (0.39±0.091) was significantly greater than the FST for neutral marker expectations and consistent with diversifying selection shaping the patterns of subrace divergence in drought susceptibility. This conclusion is supported by the significant association of subrace drought susceptibility with bioclimatic parameters, particularly those associated with temperature seasonality. Less drought damage was observed in subraces originating from areas with more temperature seasonality, but also less radiation and rainfall seasonality, less winter rainfall, higher radiation and higher temperatures in the warmest month. Significant additive genetic variation in drought damage was detected within subraces, with narrow-sense heritabilities ranging from 0.14 to 0.20. We argue that spatial genetic variation in drought susceptibility of E. globulus has been shaped by natural selection acting at multiple scales and discuss opportunities for exploiting this genetic variation in breeding and deployment programs.

Item Type:	Refereed Article
Keywords:	drought Eucalyptus globulus eucalypt genetics adaptation
Research Division:	Biological Sciences
Research Group:	Genetics
Research Field:	Population, Ecological and Evolutionary Genetics
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Forestry
Objective Field:	Hardwood Plantations
Author:	Dutkowski, GW (Mr Greg Dutkowski)
Author:	Potts, BM (Professor Brad Potts)
ID Code:	82213
Year Published:	2012
Funding Support:	Australian Research Council (LP0884001)
Web of Science® Times Cited:	31
Deposited By:	Plant Science
Deposited On:	2013-01-21
Last Modified:	2015-09-01
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