Landraces of maize in Central Mexico an altitudinal transect

Conservatwn of crop genetw resources is now considered an important component of sustainable agricultural development. If conservation of genetic resources for agriculture is to be successful, a more complete understanding of the dynamws affecting tradmonal (landrace) crop populatwns ts needed. We conducted a study of maize-based agrwulture in the Central Highlands of Mexico in communities at 2400, 1700, 1400, and 1200 masl to assess the status of traditional varieties in an area characterized by thorough integration into the national economy Our research contradwts the view that modem varietws perstst because of marginal conditions, deficient infrastructure, weaker markets, or tradittonal attitudes. One or two landraces dominated htghland maize populations and farmers appeared to be more conservative in terms of their emphasis on traditional maize varieties than at lower elevations. The dominance of traditional varieties in the highlands is well known but poorly explained, and the coexistence of traditional and modem varieties in the mid-elevattons was unexpected. Our highland study area has good roads, is near Mexwo City, and Is less than 50 km away from four major crop research institutes that have done maize breeding since 1950"s. We suggest that in sita conservation of maize genetic resources in the htghlands ts sustained because the landraces there have good agronomw performance and are highly valued by farmers for their end-use qualities. At the mid-elevations, competition between local and modem maize was sharpest, and farmers have found that both landraces and tmproved varietws suit their needs, hence enhancing genetic diversity. Interventions and incenttves would approprtately be carrwd out here to assure m sltu conservation of locally adapted landraces of maize.