Maize Genetic Diversity in México: Role of Participatory Landrace Improvement in a Comprehensive Conservation Strategy.

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Genetic diversity has been seen mainly as the foundation for genetic improvement programs. FAO, as integrator of academic opinions, has stated four activities on plant genetic resources: in situ and ex situ conservation, utilization, and capacity-building. This view is applicable to development of strategies for planting improved varieties in massive way. In México –center of origin, domestication and diversification of maize– there are two sorts of maize agriculture: commercial hybrids (20% of the area) and traditional local landraces (80%), where genetic diversity is preserved in situ with evolution under domestication. There have been efforts for maize in situ conservation, but not enough thinking on the fact that maize diversity, cropped under traditional farming, has an additional and locally important role: it is the staple for farmers’ households whose diet depend on maize, and is source of economic income. Besides, due to the broad ecological diversity in Mezico, landraces are well adapted to specific environments. One fact is that maize diversity in a single village is a broad complex of types of maize, diversification determined by cuisine or local market priorities or meteorological risks. Each type of maize should be preserved because to satisfy specific needs; it would maintain the broad genetic diversity in that village. Secondly, there is genetic variation for each type of maize among and within farmers’ maize populations. Based on this stratification, detection of good maize populations and improving the traditional seed selection procedure with farmers in their fields, 20% grain yield gains have been assessed in four years. Implementing this approach requires close participatory collaboration, and ought to be supported locally and nationally.