Mapping the Diversity of Maize Races in Mexico

Traditional landraces of maize are cultivated throughout more than one-half of Mexico's cropland. Efforts to organize in situ conservation of this important genetic resource have been limited by the lack of knowledge of regional diversity patterns. Authors used recent and historic collections of maize classified for race type to determine biogeographic regions and centers of landrace diversity. They also analyzed how diversity has changed over the last sixty years. They found no evidence of rapid overall decline in landrace diversity for this period. However, several races are now less frequently reported, and two regions seem to support lower diversity than in previous collection periods. Their results are consistent with a previous hypothesis for diversification centers and for migration routes of original maize populations merging in western central Mexico