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Origins and diversity of rush Skeletonweed (Chondrilla juncea) from three continents

Gaskin, J.; Kinter, C. L.; Schwarzlander, M.; Markin, G. P.; Novak, S.; Smith, J. F. 2013. Origins and diversity of rush Skeletonweed (Chondrilla juncea) from three continents. In: Wu, Yun; Johnson, Tracy; Sing, Sharlene; Raghu, S.; Wheeler, Greg; Pratt, Paul; Warner, Keith; Center, Ted; Goolsby, John; Reardon, Richard, eds. Proceedings of the XIII International Symposium on Biological Control of Weeds; September 11-16, 2011; Waikoloa, Hawaii, USA. Session 4: Target and Agent Selection. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Forest Health Technology Enterprise Team. Online:

Rush skeletonweed (Chondrilla juncea L.) is an invasive apomictic perennial plant in Australia, South- and North America, accidentally introduced from Eurasia, which shows differential resistance/tolerance to some herbicides and classical biological control agents. Rush skeletonweed biotypes have been locally described using morphology, phenology, isozyme patterns, and resistance to control agents, but studies comparing invasions on different continents and determining exact origins of invasive genotypes do not exist or are lacking in detail. Commonly available molecular tools and bulk analysis capacity now make it possible to determine genetic diversity within invasions and their origins. We investigated over 1000 plants from three invaded continents using highly variable AFLP (Amplified Fragment Length Polymorphism) markers, and found 13 distinct genotypes (three from Australia, three from Argentina, and seven from North America). No genotypes were shared between continents. Certain regions in North America, such as California, contain only one genotype of the weed. We then investigated over 1000 plants from the native Eurasian range to determine, as accurately as possible, origins of the invasive genotypes, including those that are currently resistant to strains of rust (Puccinia chondrillina Bubak & Syd.) used in biological control programs. This information can be used to screen for pathogens and other agents that will not be resisted or tolerated by certain rush skeletonweed genotypes. Understanding global intraspecific diversity and exact origins can improve management of differentially-resistant/tolerant weed biotypes, enhance efficacy of future agent selection, and increase cooperation between invaded regions.

Keywords: rush skeletonweed, Chondrilla juncea

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Title: RMRS Other Publications: Origins and diversity of rush Skeletonweed (Chondrilla juncea) from three continents
Electronic Publish Date: September 25, 2013
Last Update:
September 25, 2013

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