Broomcorn (Panicum miliaceum) - History of Domestication

When and Where Was Broomcorn Millet First Domesticated?

Broomcorn Millet in a Montana Roadside
Broomcorn Millet in a Montana Roadside. Matt Lavin

Broomcorn or broomcorn millet (Panicum miliaceum), also known as proso millet, panic millet, and wild millet, is today primarily considered a weed suitable for bird seed. But it contains more protein than most other grains, is high in minerals and easily digested, and has a pleasant nutty taste. Millet can be ground up into flour for bread or used as a grain in recipes as a replacement for buckwheat, quinoa or rice.

Broomcorn History

Broomcorn was a seed grain used by hunter-gatherers in China at least as long ago as 10,000 years. It was first domesticated in China, probably in the Yellow River valley, about 8000 BP, and spread outward from there into Asia, Europe, and Africa. Although the ancestral form of the plant has not been identified, a weedy form native to the region called P. m. subspecies ruderale) is still found throughout Eurasia.

Broomcorn domestication is believed to have taken place about 8000 BP. Stable isotope studies of human remains at sites such as Jiahu, Banpo, Xinglongwa, Dadiwan, and Xiaojingshan suggest that while millet agriculture was present ca 8000 BP, it did not become a dominant crop until about a thousand years later, during the Middle Neolithic (Yangshao).

Evidence for Broomcorn

Broomcorn remains which suggest a highly developed millet-based agriculture have been found at several sites associated with Middle Neolithic (7500-5000 BP) cultures including the Peiligang culture in Henan province, the Dadiwan culture of Gansu province and the Xinle culture in Liaoning province.

The Cishan site, in particular, had more than 80 storage pits filled with millet husk ashes, totaling an estimated 50 tons of millet.

Stone tools associated with millet agriculture include tongue-shaped stone shovels, chisel-edged sickles and stone grinders. A stone millstone and grinder was recovered from the early Neolithic Nanzhuangtou site dated to 9000 BP.

By 5000 BC, broomcorn millet was flourishing west of the Black Sea, where there are at least 20 published sites with archaeological evidence for the crop, such as the Gomolava site in the Balkans. The earliest evidence in central Eurasia is from the site of Begash in Kazakhstan, where direct-dated millet seeds date to ca 2200 cal BC.

Recent Archaeology Studies of Broomcorn

Recent studies comparing the differences of grains a broomcorn millet from archaeological sites often vary a great deal, making them difficult to identify in some contexts. Motuzaite-Matuzeviciute and colleagues reported in 2012 that millet seeds are smaller in response to environmental factors, but relative size also can reflect immaturity of the grain. depending on charring temperature, immature grains can be preserved, and such size variation should not rule out identification as broomcorn.

Broomcorn millet seeds were recently found at the central Eurasian site of Begash, Kazakhstan, and Spengler et al. (2014) argue that this represents evidence for the transmission of broomcorn outside of China and into the broader world. See also Lightfoot, Liu and Jones for an interesting article on the isotopic evidence for millet across Eurasia.

Sources and Further Information

Foxtail millet (Setaria italica L.) is an important grain crop in the world today, thought to have been domesticated from the wild species green foxtail (S. viridis) at least 11,000 calendar years ago (cal BP) in northern China. Grown world-wide, foxtail millet is cultivated as a dietary staple in arid and semiarid regions of China and India. Nearly 1,000 diverse foxtail millet varieties exist in the world today, including both traditional landraces and modern cultivars.

Unfortunately, its smaller size, relative to rice and broomcorn millet, may have led to a lower chance of preservation in the archaeological record, and it wasn't until modern flotation methods were used in excavations that foxtail seeds were regularly recovered. Data for the origin sites is still limited, and ongoing research is studying the points of origin as well as foxtail's fairly rapid spread.

Domestication of Foxtail

Scholars agree that incipient, low-level millet agriculture began about 8,700 cal BP in the upland foothill sandy deserts along the upper Yellow River--a recent identification of millet starch grains has pushed the likely date back to 11,000 cal BP (see Yang et al. 2012). The theory is that specialized hunter-gatherers experiencing increasing climatic instability began tending plants to provide a stable food source.

Why Foxtail?

Foxtail millet has a short growing season and an innate ability to tolerate cold and arid climates.

These characteristics lend themselves to adaptation in different and difficult environments, and in Neolithic contexts, foxtail is often found as a package with paddy rice. Researchers argue that by the 6000 cal BP, foxtail was been planted either alongside rice during the summer seasons, or planted in the fall as a late season supplement after the rice harvests were collected.

Either way, foxtail would have acted as a hedge for the riskier but more nutritious rice crops.

Flotation-supported studies (such as Lee et al) have shown that the arid- and cool-adapted foxtail was dominant in the Yellow River valley beginning about 8,000 years ago (Peiligang culture) and remained dominant throughout the Neolithic into the early Shang Dynasty (Erligang, 1600-1435 BC), roughly 4,000 years.

Agricultural systems based entirely on millet were present in the foothills of western Sichuan province and the Tibetan Plateau by 3500 BC, and evidence from central Thailand suggests that the millet moved in first before rice: the terrain in these places is quite steep, and the terraced paddies seen there today are much more recent.

Archaeological Evidence

Early sites with evidence for foxtail millet include Nanzhuangtou (starch grains, 11,500 cal BP), Donghulin (starch grains, 11.0-9,500 cal BP), Cishan (8,700 cal BP), Xinglonggou (8,000-7,500 cal BP), in Inner Mongolia; Yeuzhuang in the lower Yellow River (7870 cal BP), and Chengtoushan in the Yangtze River (ca. 6000 cal BP).

The best data concerning foxtail millet comes from Dadiwan, where over the next 1,000 years (a very brief gestation stage for agriculture), foxtail millet, broomcorn millet and rice developed into intensive agriculture.

Called the Laoguantai food production system, this hunter-gatherer adaptation required the reduction of mobility, and the fragmenting into small groups adapted to plant use, storage and tending. Eventually, at the start of the Banpo period (6800-5700 cal BP), millet agriculture developed into an intensive pattern with settled, larger populations.

Millet spread into the southwestern China highlands as a package with rice, both plants having the characteristics of versatility and capacity for intensification.