Plant 139

Beta vulgaris L. (Amaranthaceae)



Look around waste places, beaches and cliffs on the coasts of western Europe and the Mediterranean and you are likely to find a plant with thick, glossy green, diamond-shaped leaves and ridged stems flecked with beetroot-red pigment; sea beet. Despite its appearance, sea beet has been harvested from the wild for more than eight millennia; its leaves are one of the most frequently collected wild food plants around the Mediterranean. In northern Europe, in addition to the leaves, sea beet's roots were also significant foods. However, more important than its use as 'wild food' were the decisions different peoples took to select sea beet features and bring them into cultivation.

Sea beet was probably brought into domestication in the Near East some eight thousand years ago. Initially, people selected the wild plants for their leaves, producing crops such as spinach beet and chard. Beetroots, with their swollen underground parts started to appear about 500 BCE, although their precise origin is unknown. In Europe, during the Middle Ages, a variant with large, swollen roots was developed, and became the magnificently named fodder mangelwurzel.

The sixteenth-century agriculturalist Olivier de Serres observed French cooks making sweet syrups from beetroot. About 150 years later the German physicist Andreas Marggraf showed beetroot sugar and cane sugar were identical (sucrose). By 1784, Franz Achard used these two observations to start selectively breeding sugar beet from 'White Silesian' mangolds. The Napoleonic Wars saw France blockaded and food supplies diminish. The French chemist Antoine-Augustin Parmentier became convinced sugar beet could fill the gap. Napoleon ordered French farmers to plant sugar beet, and French industrialists had invented a commercial process for extracting sugar from beets; the import of Caribbean sugar was banned. By 1837, France had more than 500 sugar-processing factories and was the world's largest sugar beet producer, a position she held until 2010. During the nineteenth century, sugar beet cultivation gradually spread across the temperate world but it only became part of the British agricultural landscape after the First World War.

Sugar beet vividly illustrates the power of plant breeding to change plants. In fewer than ten human generations, through the application of selective breeding, the sucrose content of sugar beet, unknown in antiquity, rose from c. 5% dry weight to c. 20% dry weight in modern varieties. Today, sugar beet provides almost one third of the world's annual sugar production and is an important animal feed.

Further reading

Dohm JC et al. 2014. The genome of the recently domesticated crop plant sugar beet (Beta vulgaris). Nature 505: 546-549.

Fischer HE 1989. Origin of the 'Weisse Schlesische RĂ¼be' (white Silesian beet) and resynthesis of sugar beet. Euphytica 41: 75-80.

Rivera D et al. 2006. Gathered Mediterranean food plants - ethnobotanical investigators and historical development. In Heinrich M et al. (eds) Local Mediterranean food plants and nutraceuticals. Karger, pp 18-74.

Stephen Harris