EMPIRICAL VALIDATION OF THE MULTICENTRIC THEORY ON THE ORIGIN AND DIVERSITY OF MAIZE IN MEXICO

Abstract

Mesoamerica is considered as the center of origin and diversity of maize (Zea mays L.). The multicentric theory on the origin and diversity of maize defines five centers of origin-domestication, from which four macro regions or primary centers of diversification of this cereal were conformed, from which the different races and the concentration of diversity emerged. A center of genetic diversity is defined as the geographical area where there is morphological, genetic diversity, or both, for a certain species, characterized by harboring populations of wild relatives and constituting a genetic reserve. The objective of this study was to empirically validate the geographic regions of Mexico that conform to the definition of a center of genetic diversity for maize. Spatial analysis was used to examine the diversity and distribution of 24,126 accessions of native maize and 1,106 records of wild relatives (Teosinte: 692 and Tripsacum: 414) collected during the period 1926 2014, available at germplasm banks and herbaria of national and international agricultural research and education institutions located in Mexico and, through the use of geographic information systems and modeling. In accordance with the criteria and definitions considered in the multicentric theory on maize origin and diversity, 19 geographic regions were empirically defined and validated to be considered as centers of genetic diversity of maize native to Mexico.