Commensal domestication pathways amongst plants: Exploring segetal and ruderal crop origins

Two commensal pathways to plant domestication - ruderal and segetal - have been proposed. These domestication pathways are detailed here, together with associated archaeobotanical morphometric data for multiple crops within each pathway. The ruderal pathway characterizes how plants adapted to anthropically disturbed habitats, which can be associated with foraging or farming communities, were domesticated by people. Ruderal crops discussed are squash (Cucurbita pepo), aji chili (Capsicum baccatum) and melon (Cucumis melo). The segetal pathway characterizes how weeds in agricultural contexts became crops. Segetal crops discussed are rye (Secale cereale) and kodo millet (Paspalum scrobiculatum). Metric archaeobotanical datasets are used to infer the domestication episode for crops and to calculate rates of change in domestication traits (Haldanes). Although metric archaeobotanical data limits presentation and discussion to seeds, it enables quantitative comparisons of domestication episodes and haldane rates with those of the grain and fruit tree domestication pathways, respectively. We conclude that early ruderals underwent slower domestication processes, whereas segetals and perhaps some later ruderals, underwent faster processes of domestication that probably involved conscious selection. This article is part of the theme issue 'Unravelling domestication: multi-disciplinary perspectives on human and non-human relationships in the past, present and future'.