Preceramic maize from Paredones and Huaca Prieta, Peru

Area of Science:

• Archaeobotany
• Paleoethnobotany
• Crop domestication and evolution

Background:

• Maize (Zea mays ssp. mays) is a globally significant ancient domesticated crop with a complex history of dispersal.
• Previous research clarified maize domestication and dispersal chronology but lacked details on early morphological evolution and diversification due to poor macrofossil preservation.
• Obligate dispersal routes in tropical forests, particularly before 5000 calibrated years before present, are underrepresented in the fossil record.

Purpose of the Study:

• To investigate the early morphological evolution and racial diversification of maize in South America.
• To shed light on the chronology, land race evolution, and cultural contexts of maize's early movements into South America.
• To understand maize adaptation to new environments and its role in early human societies.

Main Methods:

• Discovery and analysis of macrobotanical and microbotanical maize remains from coastal Peruvian sites (Paredones and Huaca Prieta).
• Dating of remains from the middle and late preceramic and early ceramic periods (ca. 6700–3000 calibrated years before present).
• Accelerator mass spectrometry radiocarbon dating directly on preserved maize plant structures, comparing burned and unburned cobs for reliability.

Main Results:

• Discovery of some of the earliest known maize cobs, husks, stalks, and tassels in South America.
• The macrobotanical record indicates the emergence of diverse Andean racial complexes during the preceramic era.
• Radiocarbon dating suggests burned cobs are more reliable for dating than unburned cobs.

Conclusions:

• The findings provide crucial insights into the early diffusion of maize into South America and its adaptation.
• The study contributes to understanding the emergence of Andean maize diversity and its cultural contexts.
• The results have broader implications for comprehending the development of early preindustrial human societies and agricultural systems.