The cost of in situ conservation of maize landraces in the Sierra Norte de Puebla, Mexico

摘要

Major crop landraces contain valuable genetic resources and they have been conserved in gene banks for decades. Policies to promote conservation of landraces in their place of origin by local subsistence growers ( in situ conservation) has been opposed by those who considered in situ conservation infeasible, unaffordable, or undesirable. Today, in situ conservation is regarded as a required complement to gene banks and widely advocated, but planning and implementation await. The integration of rural markets and economic development are expected to hinder in situ conservation of landraces in the long run, raising conservation costs. The integration of maize markets under the North American Free Trade Agreement (NAFTA) raised concern for in situ conservation of Mexican maize landraces. Although, seven years into NAFTA, rain-fed maize growers have not reacted as expected to falling maize prices, advocates believe that low prices are an imminent threat to landrace conservation. Current economic explanations for the resilience of maize agriculture in Mexico, based on transaction costs, suggest that a downturn in production can be expected if prices decrease further. This study examines the threat to maize conservation in the milpa system in Zoatecpan, a village in the Sierra Norte de Puebla, and assesses the potential cost of an in situ conservation program. Although the market value of maize has dropped following NAFTA, it appears that factors other than transaction costs have kept the shadow value of milpa above its opportunity cost. Responses to price and income changes, estimated using a contingent behavior approach, show that the elasticity of household supply is positive for price increases, on average, but it is nil for price decreases. Analysis of individual household responses suggests that different factors, including liquidity constraints and non-market benefits influence production decisions. Village-wide responses to policy and market shocks, simulated using a computable general equilibrium model, suggest that price decreases promote a shift from commercial to subsistence maize production and an increase in varietal diversity within the household. It is concluded that NAFTA does not pose a threat to in situ conservation of maize landraces in the region.