Origin place of maize is

Concept: A crop's place of origin is determined by where its wild ancestor species grows and where the archaeological and genetic record shows domestication first occurred -- not by which country produces or consumes the crop most today. Modern production volume reflects trade, colonization, and later agronomic adoption, and can be completely disconnected from where the plant was first domesticated.

Application: Maize (Zea mays) was domesticated from the wild grass teosinte in the Balsas River valley of southern Mexico roughly 9,000 years ago -- a single domestication event established by genetic and archaeobotanical research (USDA-ARS studies; Matsuoka et al., PNAS). Mexico lies within the American landmass, so the Americas are maize's true center of origin. The crop reached Asia, Africa, and Europe only after the Columbian Exchange that followed 1492, when Spanish and Portuguese traders carried it across the Atlantic.

Cross-check (why the other regions do not fit):

• India -- today one of the world's major maize-producing and maize-consuming countries, but the crop reached the subcontinent only after European contact; no wild ancestor of maize is native to South Asia.

• China -- currently the world's second-largest maize producer by volume, yet this reflects large-scale cultivation adopted well after the crop's introduction from the Americas; teosinte, maize's only wild progenitor, does not occur in East Asia.

• Russia -- grows maize only in its warmer southern regions using modern cold-tolerant hybrid varieties developed through recent plant breeding; this is a 20th-century agronomic adaptation, not the site where the species was first domesticated.

Since the wild ancestor and the earliest domestication evidence both trace to Mesoamerica, the Americas -- not any of the present-day major producers -- is the region correctly identified as maize's place of origin.