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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGICAL CONTROL OF INVASIVE PLANTS OF THE NORTHERN GREAT PLAINS Title: The Salsola tragus Complex in California (Chenopodiaceae): Characterization and Status of Salsola australis and the Autochthonous Allopolyploid Salsola ryanii Sp. Nov

Authors
item Hrusa, Fred - CALIF DEPT OF FOOD AND AG
item Gaskin, John

Submitted to: Madrono
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 22, 2008
Publication Date: April 1, 2008
Repository URL: http://hdl.handle.net/10113/44246
Citation: Hrusa, F., Gaskin, J.F. 2008. The Salsola tragus Complex in California (Chenopodiaceae): Characterization and Status of Salsola australis and the Autochthonous Allopolyploid Salsola ryanii Sp. Nov. Madrono. 55(2):113-131.

Interpretive Summary: Since its introduction to North America in the mid 19th century, the invasive weed Salsola tragus (russianthistle), has become a widespread and troublesome plant pest. Early biocontrol attempts had achieved only partial success. Efforts to improve chances for success in renewed biocontrol research efforts revealed that there are actually two distinct entities which comprise what has been called Salsola tragus. We examined Salsola tragus using using DNA sequences and found three species previously listed under one name. We present a taxonomic and morphological characterization of the species. Morphological variation, habitats and dispersal behaviors among these Salsola taxa were examined in the herbarium and in the field. These are compared and discussed from both ecological and biocontrol viewpoints.

Technical Abstract: Since its introduction to North America in the mid 19th century, the invasive weed Salsola tragus sensu auct. (russianthistle), has become a widespread and troublesome plant pest. Early biocontrol attempts had achieved only partial success. Efforts to improve chances for success in renewed biocontrol research efforts revealed that there are actually two distinct, often sympatric, genetic entities which comprise what has been called Salsola tragus. Recent publications have referred to these as Salsola tragus and Salsola ‘type B’. Continued biocontrol efforts required the identification and characterization of ‘type B’. In the process, a third form was recognized and called ‘type C’. We examined Salsola tragus and Salsola ‘type B’ using morphometrics and ‘type C’ using DNA sequence data and morphometrics. Salsola tragus and ‘type B’ were morphologically distinct; ‘type C’ was morphologically intermediate between them and contained a combination of DNA sequence haplotypes mostly exclusive to S. tragus and exclusive to ‘type B’. We present a taxonomic and morphological characterization of Salsola tragus, Salsola ‘type B’ and ‘type C’ using discriminant analysis with DNA sequence genotypes as its taxonomic framework. We provide a pre-existing name, Salsola australis R. Br. for ‘type B’ and propose Salsola ryanii sp. nov. for ‘type C’. Morphological variation, habitats and dispersal behaviors among these Salsola taxa were examined in the herbarium and in the field. These are compared and discussed from both ecological and biocontrol viewpoints.

Last Modified: 10/22/2014
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