Burning questions: Experiments on the effects of charring on domestic and wild sorghum

Abstract

Sorghum was first domesticated approximately 6000 years ago in the eastern Sahel region of Africa, but our understanding of its agricultural history is uneven due to the paucity of the available archaeobotanical evidence. Despite growing interest in the issue, sorghum response to fire exposure has been little investigated. In this paper, the resistance of six domesticated sorghum varieties (Sorghum bicolor) and one wild specimen (Sorghum arundinaceum) to charring was evaluated under oxidising and reduced oxygen conditions using temperatures ranging from 300 °C to 500 °C for 1–8 h. The experimental study in this work indicates that the maximum temperature wild sorghum can resist without severe distortion is around 300 °C, whereas domesticated varieties could resist up to 350 °C before becoming damaged beyond identification. Our findings suggest that resistance to temperature might represent an important bias for sorghum seed preservation, both in its wild and domesticated forms.