Data from: Evolutionary and food supply implications of ongoing maize domestication by Mexican campesinos

Maize evolution under domestication is a process that continues today.
Case studies suggest that Mexican smallholder family farmers, known as
campesinos, contribute importantly to this, but their significance has not
been explicitly quantified and analyzed as a whole. Here we examine the
evolutionary and food security implications of the scale and scope under
which campesinos produce maize. We gathered official municipal-level data
on maize production under rainfed conditions and identified campesino
agriculture as occurring in municipalities with average yields of ≤ 3
t/ha. Environmental conditions vary widely in those municipalities and are
associated with a great diversity of maize races, representing 85.3% of
native maize samples collected in the country. We estimate that in those
municipalities around 1.38 x 1011 genetically different individual plants
are subjected to evolution under domestication each season. This implies
that 5.24x108 mother plants contribute to the next generation with their
standing genetic diversity and rare alleles. Such a large breeding
population size also increases the total number of adaptive mutations that
may appear and be selected for. We also estimate that campesino
agriculture could potentially feed around 54.7 million people in Mexico.
These analyses provide insights about the contributions of smallholder
agriculture around the world.