Society for Economic Botany/BSA Economic Botany Section
Bradbury , Elizabeth Jane , Tay, David , Emshwiller, Eve .
Understanding Domestication Resulting in Opposing Crop Phenotypes: (2) Organic Acid Accumulation in Oca (Oxalis tuberosa Molina) Tubers.
Crops displaying directly opposing domesticated biochemical phenotypes could provide valuable insight to the effects on the domestication process of conflicting selective pressures in the agricultural ecosystem. One relatively well-known example is cassava (Manihot esculenta Crantz), which has high-cyanide and low-cyanide varieties that are grouped into two distinct use-categories, those cassava that are processed prior to consumption and cassava that are consumed after cooking without processing. Small-scale studies conducted by Bradbury and Emshwiller (2011) revealed that Oxalis tuberosa Molina,"oca", may represent another example of such a crop system, with opposing high oxalic acid and low oxalic acid cultivars. Each cultivar set ("use-category") also has different cultural food preparation practices. In order to establish a more thorough understanding of the biochemical basis for the different use-categories of oca, we conducted a common garden experiment in the Mantaro River Valley in the JunÃ£n Department of Peru. In September 2009, we planted 45 unique cultivars replicated five times throughout the field using a randomized block design. Tubers were harvested June 2010 and organic acid extractions were conducted following the hot 2M HCl protocol outlined by Ross and colleagues (1999). Six organic acids were quantified using HPLC analysis: oxalic, malic, tartaric, succinic, ascorbic, and glutaric acids. Our results indicate that there is a statistically significant difference in organic acid accumulation between the oca use-categories, demonstrating that oca displays what we are referring to as "opposing crop phenotypes" with high-acid cultivars processed prior to consumption and low-acid cultivars consumed after cooking without prior processing.
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1 - University of Wisconsin-Madison, Botany, 430 Lincoln Drive , Birge Hall, Madison, WI, 53706, USA
2 - El Centro Internacional de la Papa, Division 2, Av. La Molina 1895, La Molina, Lima, Peru
3 - University Of Wisconsin-Madison, Botany Dept, 321 Birge Hall, 430 Lincoln Drive, Madison, WI, 53706-1313, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Maryland Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 1:30 PM