Wheat

Wheat is an annual grass, usually 60 to 120 centimetres tall in traditional varieties and shorter in modern semi-dwarf types, with seed heads composed of spikelets, each holding several grains. The grain, called a wheat berry, is an oval kernel with a crease on one side, made up of bran, germ and starchy endosperm. Colours range from amber to red and white. Wheat proteins form gluten when mixed with water, giving dough its elasticity. Bread wheat is the main species grown, but the genus also includes durum, spelt and ancient types such as einkorn and emmer.

Wheat was domesticated in the Fertile Crescent of the Near East roughly 10,000 years ago, first as einkorn and emmer. Bread wheat arose later through a natural hybridisation of cultivated emmer with the wild goat grass Aegilops tauschii, probably in the region south of the Caspian Sea. From there wheat spread across Europe, Asia and North Africa. Today it is grown on more land than any other crop. China, India, Russia, the United States, Canada, France and Australia are among the largest producers.

Wheat was central to the rise of settled agriculture and early civilisations in Mesopotamia and Egypt, where it was used to make bread and beer. The Romans and later Europeans built economies and diets around it, and bread became a symbol of daily life, as in the phrase daily bread. Migrants later introduced wheat to the Americas, Australia and southern Africa, and the great plains of North America became major wheat lands in the nineteenth century.

In the twentieth century, plant breeding transformed the crop. Norman Borlaug and colleagues developed high-yielding, disease-resistant, semi-dwarf wheat varieties in Mexico in the 1940s to 1960s, which contributed to the Green Revolution and helped avert famines in South Asia. Roller milling made white flour cheap and widespread, while concerns about refined grains led to renewed interest in whole wheat and heritage varieties. Wheat is now also a target of research on climate resilience, disease resistance and gluten-related conditions.

Wheat is milled into flour for bread, flatbreads, pastries, pasta, noodles, couscous, crackers and cereals. Whole wheat berries are boiled or soaked to make salads, pilafs and porridge, and bulgur and freekeh are processed wheat foods. Wheat germ and bran are sold as supplements to cereals and baked goods. Wheat is also malted for beer, fermented for spirits, and used for animal feed, straw and starch.

Whole wheat provides carbohydrate, fibre, protein and B vitamins, along with minerals such as manganese, selenium, magnesium and phosphorus. Compared with refined white flour, whole grain wheat retains the bran and germ and therefore contains more fibre and micronutrients. Diets rich in whole grains are associated in population studies with better digestive health and lower risks of several chronic diseases, though such studies cannot prove cause. Refined wheat products are often enriched with iron and B vitamins.