How is wheat related to other grains?

Introduction

Wheat belongs to the Triticum genus of plants, and this classification makes it different from many grains. All species of wheat listed below are members of the Triticum plant genus:

• common wheat (Triticum aestivum L.)
• durum wheat (Triticum durum Desf.)
• club wheat (Triticum compactum Host.)
• emmer wheat (also known as farro) (Triticum turgidum L. subsp. dicoccon (Schrank) Thell.)
• semolina (Triticum durum Desf.)
• Einkorn wheat (Triticum monococcum L. subsp. monococcum )

In addition to these wheat species, two other naturally occurring grains—spelt (Triticum spelta L.) and kamut (Triticum polonicum L.) —are members of this same Triticum genus. Triticale (x Triticosecale ssp. Wittm.)—a human crossbred grain created through the hybridization of wheat and rye—is also a Triticum grain. At WHF, we think about wheat, spelt, and kamut as being naturally occurring, closely related grains.

Among the plant foods that we commonly refer to as grains, there are no other members of this Triticum group. In terms of plant evolution, the next closest relatives to the Triticum group of grains are rye (Secale genus) and barley (Hordeum genus).

The chart below show 11 of the most commonly consumed grains in the U.S. and their degree of relationship from a science standpoint. As you read left to right across the chart, the more relationships (family, subfamily, tribe, genus) that are shared by different grains, the closer they are in terms of their make-up.

Grain

Family

Subfamily

Tribe

Genus

wheat

Poaecea

Pooideae

Triticaceae

Triticum

kamut

Poaecea

Pooideae

Triticaceae

Triticum

spelt

Poaecea

Pooideae

Triticaceae

Triticum

barley

Poaecea

Pooideae

Triticaceae

Hordeum

rye

Poaecea

Pooideae

Triticaceae

Secale

oats

Poaecea

Pooideae

Poeae

Avena

rice

Poaecea

Ehrhartoideae

Oryzeae

Oryza

millet

Poaecea

Panicoideae

Paniceae

Pennisetum

corn

Poaecea

Panicoideae

Paniceae

Pennisetum

amaranth

Amaranthaceae

Amaranthoideae

Andropogoneae

Zea

quinoa

Amaranthaceae (Chenopodiaceae)

Chenopodiodeae

Chenopodieae

Chenopodium

buckwheat

Polygonaceae

Polygonoideae

Fagopyreae

Fagopyrum

We would note here that buckwheat, quinoa, and amaranth are so far removed from what have traditionally been referred to as “cereal grains” as to justify our thinking about them in totally different terms. When we think about buckwheat, we should be thinking about foods like rhubarb and sorrel, which belong to the same plant family as buckwheat. For quinoa and amaranth, we should be thinking about spinach, Swiss chard, and beets.

Among our eight grains at WHF, you will find three members of the Tricaceae tribe of plants—namely, wheat, barley, and rye. These three grains are closely related. However, you will also find five additional grains on our website that are not closely related to wheat, and, in some cases, are really best considered in the context of vegetable foods like spinach, Swiss chard, rhubarb, beets, or sorrel. We included this very diverse group of grains on our website to encourage intake across a wide spectrum of grain plants by people who choose to consume grains, rather than an overemphasis on the more closely-related grain group of wheat, barley, and rye.

Related Q&As About Wheat, Grains, and Gluten

• Can you help set the record straight on gluten-free foods, grain-free diets, and the “wheat belly diet?”
• What is gluten?
• Is gluten-free the same as wheat-free?
• Is gluten sensitivity the same thing as wheat allergy?
• Can I still have an unwanted reaction to wheat or grains, even if I always choose whole grains?
• Do you consider grains to be a priority food group for healthy eating?

References

To see the research articles we reviewed in the writing of these articles, see here.