Rye - The Domestication History of Secale cereale

What Science Knows of the Weedy History of Domesticating Rye

Field of Rye (Secale cereale)
Field of Rye (Secale cereale). Charlotta Wasteson

Rye (Secale cereale subspecies cereale) was likely fully domesticated from its weedy relative (S. cereale ssp segetale) or perhaps S. vavilovii, in Anatolia or the Euphrates River valley of what is today Syria, at least as early as 6600 BC, and perhaps as early as 10,000 years ago. Evidence for domestication is at Natufian sites such as Can Hasan III in Turkey at 6600 cal BC (calendar years BC); domesticated rye reached central Europe (Poland and Romania) about 4,500 cal BC.

Today rye is grown on about 6 million hectares in Europe where it is mostly used for making bread, as animal feed and forage, and in the production of rye and vodka. Prehistorically rye was used for food in a variety of ways, as animal fodder and for straw for the thatched rooves.

Characteristics

Rye is a member of the Triticeae tribe of Pooideae subfamily of the Poaceae grasses, meaning it is closely related to wheat and barley. There are around 14 different species of the Secale genus, but only S. cereale is domesticated.

Rye is allogamous: its reproductive strategies promote outcrossing. Compared to wheat and barley, rye is relatively tolerant to frost, drought, and marginal soil fertility. It has an enormous genome size (~8,100 Mb), and its resistance to frost stress appears to be a result of the high genetic diversity among and within rye populations.

The domestic forms of rye have larger seeds than wild forms as well as a non-shattering rachis (the part of the stem that holds the seeds onto the plant).

Wild rye is free-threshing, with a tough rachis and loose chaff: a farmer can free the grains by a single threshing since straw and chaff are eliminated by a single round of winnowing. Domestic rye maintained the free-threshing characteristic and both forms of rye are vulnerable to ergot and to munching by pesky rodents while still ripening.

Experimenting with Rye Cultivation

There is some evidence that Pre-Pottery Neolithic (or Epi-Paleolithic) hunters and gatherers living in the Euphrates valley of northern Syria cultivated wild rye during the cool, arid centuries of the Younger Dryas, some 11,000-12,000 years ago. Several sites in northern Syria show that increased levels of rye were present during the Younger Dryas, implying that the plant must have been specifically cultivated to survive.

Evidence discovered at Abu Hureyra (~10,000 cal BC), Tell'Abr (9500-9200 cal BC), Mureybet 3 (also spelled Murehibit, 9500-9200 cal BC), Jerf el Ahmar (9500-9000 cal BC), and Dja'de (9000-8300 cal BC) includes the presence of multiple querns (grain mortars) placed in food processing stations and charred wild rye, barley, and einkorn wheat grains.

In several of these sites, rye was the dominant grain. Rye's advantages over wheat and barley are its ease of threshing in the wild stage; it is less glassy than wheat and can be more easily prepared as food (roasting, grinding, boiling and mashing). Rye starch is hydrolyzed to sugars more slowly and it produces a lower insulin response than wheat, and is, therefore, more sustaining than wheat.

Weediness

Recently, scholars have discovered that rye, more than other domesticated crops has followed a weedy species type of domestication process--from wild to weed to crop and then back to weed again.

Weedy rye (S. cereale ssp segetale) is distinctive from the crop form in that it includes stem shattering, smaller seeds and a delay in flowering time. It has been found to have spontaneously redeveloped itself out of the domesticated version in California, in as few as 60 generations.

Sources

This article is part of the About.com guide to Plant Domestication, and part of the Dictionary of Archaeology

  • Hillman G, Hedges R, Moore A, Colledge S, and Pettitt P. 2001. New evidence of Late Glacial cereal cultivation at Abu Hureyra on the Euphrates. The Holocene 11(4):383-393.
  • Li Y, Haseneyer G, Schön C-C, Ankerst D, Korzun V, Wilde P, and Bauer E. 2011. High levels of nucleotide diversity and fast decline of linkage disequilibrium in rye (Secale cerealeL.) genes involved in frost response. BMC Plant Biology 11(1):1-14. http://dx.doi.org/10.1186/1471-2229-11-6 (Springer link is currently not working)