Society for Economic Botany/BSA Economic Botany Section
Walsh, Brian M. , Emshwiller, Eve .
Phylogeny of American Chenopodium species with focus on origins of the domesticated taxa.
The edible seeds of Quinoa (Chenopodium quinoa, Amaranthaceae) have gained popularity worldwide, based on nutritional qualities and ease of growing. Most people do not know quinoa is one of four cultigens of Chenopodium domesticated in the Americas: C. quinoa and C. pallidicaule from South America, C. berlandieri ssp. nuttalliae from Mesoamerica, and the extinct C. berlandieri ssp. jonesianum recovered from archaeological sites throughout eastern North America. Despite nearly 100 years of debate researchers still do not agree on the relationship among these domesticates. Conflicting hypotheses have been proposed asserting whether cultigens were domesticated independently or represent introductions into neighboring regions. Alternative hypotheses suggest two, three, or four independent domestications of Chenopodium in the Americas, and proposed several putative wild progenitors of the cultigens. To investigate the relationships among cultigens of Chenopodium and assess potential wild progenitors, a phylogenetic framework of the genus emphasizing New World species is required. Phylogenetic analyses of DNA sequences of non-coding loci, both nuclear (SOS1 intron 17, COS at103, ITS) and plastid (trnQ-rps16, trnL-trnT, ndhJ-trnF-trnL, psbD-trnT, and psbM-ycf6), were conducted using parsimony, maximum likelihood, and Bayesian analyses. Taxon sampling includes 19 Chenopodium species from North and South America, with focus on the extant cultigens and subspecific taxa within C. berlandieri.
Findings include the following: Chenopodium pallidicaule is genetically distinct from other extant cultigens.
Sampled cultivars of the Mesoamerican cultigen, C. berlandieri ssp. nuttalliae, unite in a single subclade, nested within, but distinct from wild C. berlandieri.
Chenopodium quinoa is nested within the C. berlandieri complex, but not within the C. berlandieri ssp. nuttalliae clade. Interestingly, the southern-most range of wild C. berlandieri is southern Mexico,where as Quinoa is cultivated in Eduador, Peru, and Bolivia. These findings are consistent with independent domestications of the extant cultigens. Using nucleotide markers unique to C.berlandieri ssp. nuttalliae, ancient-DNA analyses will be conducted to determine the relationship of the extinct cultigen, C. berlandieri ssp.jonesianum.
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1 - University of Wisconsin - Madison, Botany, 430 Lincoln Dr., Madison, WI, 53706, USA
2 - University Of Wisconsin-Madison, Botany Dept, 321 Birge Hall, 430 Lincoln Drive, Madison, WI, 53706-1313, USA
Presentation Type: Poster:Posters for Sections
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:45 PM