Morphometric Analysis of Sunflower (Helianthus annuus L.) Achenes from Mexico and Eastern North America1

• Published in: Economic botany Vol. 65; no. 3; pp. 260 - 270
• Main Authors: Tarighat, Somayeh S., Lentz, David L., Matter, Stephen F., Bye, Robert
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01.09.2011
• Subjects: Biomedical and Life Sciences; Life Sciences; Plant Anatomy/Development; Plant Ecology; Plant Physiology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; shape factors; Cueva del Gallo; sunflower; San Andres
• ISSN: 0013-0001; 1874-9364
• DOI: 10.1007/s12231-011-9165-0

Morphometric Analysis of Sunflower ( Helianthus annuus L.) Achenes from Mexico and Eastern North America. Sunflower ( Helianthus annuus L . ) has played a major role in the evolution of agricultural systems in the Americas. The discovery of ancient domesticated remains from archaeological deposits in pre-Columbian Mexico offers new dimensions to widely accepted viewpoints on the domestication pattern of H. annuus . Although American sunflower populations north of Mexico have been examined extensively, Mexican indigenous domesticated landraces have not been studied in any detail. In this study, we morphologically assessed wild and domesticated sunflower achenes from Mexico and compared them to similar datasets from eastern North America. Additionally, we evaluated the utility of four computer-assisted shape measurements in discriminating between wild and domesticated sunflower achenes (fruits) and compared variation in achene size among modern wild and cultivated populations from both Mexico and the U.S. We found that, of the shape parameters tested, none were informative in distinguishing wild achenes from domesticated varieties. Subsequent size analysis, using conventional parameters of length, width, and thickness, showed that modern wild populations from Mexico had smaller achenes compared to modern populations from eastern North America. Domesticated achenes unearthed from Mexican archaeological sites, however, were significantly larger than the early domesticated specimens recovered from eastern North America. Our methodological results indicate that variation in archaeological sunflower achenes is better described by conventional size parameters rather than computerized shape analysis.