Reply to Rieseberg and Burke, Heiser, Brown, and Smith: Molecular, linguistic, and archaeological evidence for domesticated sunflower in pre-Columbian Mesoamerica

Abstract

In response to Rieseberg and Burke's comment (1), we have no objection to the assessment that eastern North American landraces and modern cultivars are most closely related to wild populations of Helianthus annuus L. in the central Mississippi Valley region. We are familiar with both of the relevant molecular studies because we (D.L.L. and R.B.) collaborated on the first of those studies (2) and provided the wild sunflower germplasm from Mexico. The two Mexican domesticated samples used in the study, also used in the Wills and Burke study (3), were originally purchased in Jalisco markets. At least one of those samples, maiz negro, is believed to have been hybridized with modern varieties (4), and the maiz de teja specimens may have been genetically contaminated as well. During our field work in Mexico we visited hundreds of marketplaces from Chiapas to Chihuahua and encountered only commercially produced sunflower seeds. We wish to promote molecular studies that will adequately address questions relating to independent sunflower domestication in Mexico. The use of two samples purchased in marketplaces, as occured in the previous molecular studies, provides an inadequate test of the Mexican sunflower domestication hypothesis. This hypothesis will be tested most effectively by collecting sunflower germplasm directly from indigenous people in Mexico and running the same experiments with well provenienced and thoroughly documented material.