Plant 248

Avena sativa L. (Poaceae)


Common oats

Oats are part of a group of closely related species that have been variously named depending on morphological, breeding and genetic criteria. Wild oat species are primarily distributed around the Mediterranean and Near East. The main crop species is common oats, which is now widely cultivated across northwest Europe.

Oats were domesticated much later than other temperate cereal crops that originated in the Near East, such as wheat and barley. It is likely Palaeolithic and Neolithic hunter-gathers collected wild oats together with other wild grasses. However, wheat and barley were probably favoured over oats because their grains are larger, heavier and less prone to dormancy. During the gradual domestication of these other crops, oats were present as weeds in the fields. As wheat and barley migrated across Europe, cooler, moister conditions probably favoured oat cultivation. The transition from a minor weed to a domesticated crop had been made by c. 4000 years BP.

As with other cereals, the main trait associated with oat domestication is the breakdown of the grain dispersal mechanism. Wild and weedy oats release their grains immediately after maturation. Furthermore, the grains are tightly surrounded by bracts with a specialist drill-like structure capable of driving the mature fruit into the soil. Domesticated oats retain their mature grains on the plant until harvest, whilst the surrounding bracts are readily detached.

Before the mid-seventeenth century, weeds were widely believed to be produced spontaneously from soil. Pliny the Elder went further, taking the ancient belief that useful grasses, such as wheat and barley, could be transformed into apparently useless grasses: 'the first of all forms of disease in wheat is the oat. Barley also degenerates into oats'.

Samuel Johnson, in his Dictionary (1755), defined oats as 'a grain, which in England is generally given to horses, but in Scotland supports the people'. Often taken as a slur on the Scots, the statement emerges from the ancient belief of degeneration and the social cache associated with the consumption of wheat. It failed to recognise oats as a quality cereal grain that sustained all Britain's rural poor, and her horses. Only by the end of the eighteenth century was wheat an affordable food for most Britons.

Oats remains an important protein- and fat-rich human and livestock food. Oat bran is used as a dietary fibre and oatmeal is used in cosmetics. Furfural, extracted from oats, is used in the manufacture of nylon.

Further reading

Murphy D. 2007. People, plants & genes. The story of crops and humanity. Oxford University Press.

Preece C et al. 2017. How did the domestication of Fertile Crescent grain crops increase their yields? Functional Ecology 31: 387-397.

Zohary D et al. 2013. Domestication of plants in the Old World. Oxford University Press.

Stephen Harris