In Amazonia most indigenous horticulturists prefer to cultivate the more toxic forms of manioc as a staple crop, despite the increased processing required to render them safe for consumption. This phenomenon has long intrigued anthropologists. In this chapter we describe the agricultural practices of the Tukanoan Indians in the North-west Amazon and explore their reliance on toxic varieties of manioc from agronomic, ecological, organoleptic, and ethnographic perspectives. Our findings indicate that the puzzling preference for a toxic staple crop may be explained by the higher yields produced by the more toxic forms, and also that the most salient factor in variety selection by Tukanoan women is the food into which the roots will be made. This suggests a multifaceted explanation. Moreover, we propose that present-day lack of concern about yield is a recent luxury due to artificial selection of sufficiently high-yielding manioc varieties during the development of this crop.
Artificial selection of stable rhizosphere microbiota leads to heritable plant phenotype changes
