| Abstract: |
"Maize, the second most globally important staple crop after wheat, originated
in Mexico, where it is typically grown as part of a set of associated crops
and practices called the milpa system. This ancient mode of production is
practiced today in ways that vary by cultural context and agro-environment.
Milpas generate private economic value, in terms of food security, diet
quality and livelihoods, for the two-million farm households who manage them.
Furthermore, milpas generate public economic value by conserving
agrobiodiversity, especially that of maize landraces, which have the potential
to contribute unique traits needed by plant breeders for future crop
improvement. In this way, milpas contribute to global food security in maize.
However, the sustainability of the milpa system has been threatened by
off-farm employment opportunities, long-distance migration, the increasing
commercialization and intensification of maize production. Most recently, the
milpa system has been negatively impacted by the contamination of maize
landraces by genetically modified (GM) maize, cultivation of which is
currently prohibited in Mexico. Here, we employ a choice experiment to
estimate Mexican farmers' valuation of three components of agrobiodiversity
(crop species richness, maize variety richness and maize landraces), and
examine their interest in cultivating GM maize. Choice experiment data,
household level social, economic and demographic data, community level
economic development data, and information on milpa production
characteristics, and farmers' attitudes and perceptions with regards to GM
food and crops were collected from 420 farm households across 17 communities
in three states of Mexico. Using these data, we analyzed the heterogeneity of
farmer preferences using a latent class model, which can be used to
simultaneously identify sample segments having homogenous preferences for
milpa attributes, as well as farmer characteristics affecting preferences. We
further identified the characteristics of farmers who are most likely to
continue growing maize landraces and managing milpa systems, as well as those
least likely to accept GM maize. Specifically, we identified three distinct
segments of farmers: (i) Landrace Conservationists derive the highest private
economic value from continued management of landraces and the highest economic
loss from the possible adoption of GM maize. These farmers are young, dislike
GM foods and crops, and are mainly located at the Oaxaca site, where
transgenic constructs have been found in maize landraces. (ii) Milpa Diversity
Managers derive the highest economic value from managing all of the
agrobiodiversity components of the milpa, and suffer fewer losses from
management of GM maize. These are older farmers, who are curious and like to
experiment with maize varieties. (iii) Marginalized Maize Producers derive
little value from crop species and maize variety richness, receive minimal
value from maize landraces, and also experience the smallest negative impact
from the adoption of GM maize. These farmers are located in the most isolated
communities, have the lowest level of productivity, and oversee the largest
milpa areas. They are also the most tightly integrated into the maize output
markets. These novel findings have implications for debates concerning the
adoption of GM maize in Mexico and its associated costs and benefits, as well
as for the design of targeted, cost-effective conservation programs on farms."
from Author's Abstract |