ibclogo XVI International Botanical Congess


Abstract Number: 2850
Session = 20.18.4


PHASEOLUS:AMS RADIOCARBON DATES AND THEIR SIGNIFICANCE FOR PRE-COLOMBIAN AGRICULTURE


Kaplan, Lawrence (U.of Mass. Boston, MA 02125)& Thomas F. Lynch (Brazos Valley Mus. of Nat. Hist. 3232 Briarcrest Dr.,Bryan,TX 77802).


Radiocarbon dates on charcoal associated with Phaseolus in archaeological sites in Mexico and Peru have indicated the presence of domesticated beans by 10,000 years ago. Direct dates on the beans and pods by accelerator mass spectrometry (AMS) do not provide evidence for the cultivation in Mexico of common beans, P. vulgaris, and teparies, P. acutifolius, before ca 2500 B.P. in the Tehuacán Valley, and of common beans ca 1300 years ago in Tamaulipas and 2100 years ago in the Valley of Oaxaca. AMS dates support the presence in the Peruvian Andes of domesticated common beans by ca 4400 B.P. and lima beans by ca 3500 B. P. and lima beans by ca 5600 B.P. in the coastal valleys of Peru. We discuss the significance of these dates for Precolumbian agriculture and cultivated bean migrations.


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