About 5000–10,000 years ago, domestication of crop plants
resulted in conversion of plants from wild to cultivated
forms. As humans selected fruits and crop plants on the
basis of sweeter fruits or prolific seed production, so
these random selections led to genetic erosion of many
crop species. Most crops grown worldwide are the direct
result of selection in that era. It is thought that more
than 900 cultivated plant species were lost during the
domestication process as these crops were not preferred
by the people of those times (Hammer and Khoshbakht,
2005). For example, quinoa (Chenopodium quinoa) and
maca (Lepidium meyenii Walp.) were not domesticated
in those times, but their recent domestication has found
them very useful crops for their nutrition and medicinal
benefits, respectively (wan de Wouwet al., 2009). The
green revolution led to the development of new cereal
types that had dwarfism and fertilizer responsiveness as
their most prominent traits. However, genes conferring