Weed Technology (1998) 12, 27-31

Leon J. Scott, Corinna L. Lange, Glenn C. Graham and David K. Yeates (1998)
Genetic diversity and origin of siam weed (Chromolaena odorata) in Australia
Weed Technology 12 (1), 27-31
Abstract: Asynchronous flowering was noted in a recently discovered infestation of siam weed in north Queensland. This may indicate some genetic diversity in the infestation, increasing concerns about the origin of the infestation. Internal transcribed spacer 1 (ITS1) sequence data were obtained for siam weed individuals from north Queensland, Indonesia, Thailand, South Africa, Ivory Coast, Brazil, Colombia, and the U.S. The ITS1 region is 258 base pairs long, and the populations that flower at different times in north Queensland differ by four base substitutions. The genotype common in north Queensland is also reported throughout the native and introduced ranges. The other genotype is reported only in north Queensland and southern Brazil. These data, in conjunction with prior investigations into possible origins, indicate that Brazil is the most likely source of the infestation in Australia.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
surveys/sampling/distribution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Chromolaena odorata (weed)		Indonesia
	Chromolaena odorata (weed)		Thailand
	Chromolaena odorata (weed)		Ivory Coast
	Chromolaena odorata (weed)		South Africa
	Chromolaena odorata (weed)		Brazil (south)
	Chromolaena odorata (weed)		Colombia
	Chromolaena odorata (weed)		Australia (NT+QLD)