Pea (Pisum sativum L.) Domestication - The History of Peas and Humans

Pea (Pisum satifum) by Giglioli E., 0th Century Ink and Watercolor on Paper
Pea (Pisum satifum) by Giglioli E., 0th Century Ink and Watercolor on Paper. Electa / Hulton Fine Art Collection / Getty Images

Pea (Pisum sativum L.) is a cool season legume, a diploid species belonging to the Leguminosae family (aka Fabaceae). Domesticated about 11,000 years ago or so, peas are an important human and animal food crop cultivated throughout the world.

Key Takeaways: Domesticated Peas

  • Peas are one of several legumes, and a "founder crop" domesticated in the Fertile Crescent about 11,000 years ago. 
  • The earliest human consumption of wild peas was at least 23,000 years ago, and perhaps by our Neanderthal cousins as long ago as 46,000 years ago. 
  • There are three modern species of peas, and they are very complex genetically and their precise domestication process has yet to be figured out.  

Description

Since 2003, global cultivation has ranged between 1.6 to 2.2 million planted hectares (4–5.4 million acres) producing 12–17.4 million tons per year.

Peas are a rich source of protein (23–25%), essential amino acids, complex carbohydrates, and mineral content like iron, calcium, and potassium. They are naturally low in sodium and fat. Today peas are used in soups, breakfast cereals, processed meat, health foods, pasta, and purees; they are processed into pea flour, starch, and protein. They are one of the eight so-called "founder crops" and among the earliest domesticated crops on our planet.

Peas and Pea Species

Three species of peas are known today:

  • Pisum sativum L. extends from Iran and Turkmenistan through anterior Asia, northern Africa, and southern Europe
  • P. fulvum is found in Jordan, Syria, Lebanon, and Israel
  • P. abyssinicum is found from Yemen and Ethiopia

Research suggests that both P. sativum and P. fulvum were domesticated in the Near East about 11,000 years ago, likely from P humile (also known as Pisum sativum subsp. elatius), and P. abyssinian was developed from P. sativum independently in the Old Kingdom or Middle Kingdom Egypt about 4,000–5,000 years ago. Subsequent breeding and improvements have resulted in the production of thousands of pea varieties today.

The oldest possible evidence for people eating peas is that of starch grains founded embedded in the calculus (plaque) on Neanderthal teeth at Shanidar Cave and dated about 46,000 years ago. Those are tentative identifications to date: the starch grains are not necessarily those of P. sativum. Undomesticated pea remains were found at Ohalo II in Israel, in layers dated about 23,000 years ago. The earliest evidence for the purposeful cultivation of peas is from the Near East at the site of Jerf el Ahmar, Syria about 9,300 calendar years BCE [cal BCE] (11,300 years ago). Ahihud, a Pre-Pottery Neolithic site in Israel, had domestic peas in a storage pit with other legumes (fava beans, lentils, and bitter vetch), suggesting they had been cultivated and/or used for the same purpose.

Pea Domestication

Pisum sativa (Sugar Snap Peas)
Pisum sativa (Sugar Snap peas). Jenny Dettrick / Moment / Getty Images

Archaeological and genetic research indicates that the pea was domesticated by people purposefully selecting for peas that had a softer shell and ripened during the wet season.

Unlike grains, which ripen all at once and stand up straight with their grains on predictably sized spikes, wild peas put out seeds all over their flexible plant stems, and they have a hard, water-impermeable shell that allows them to ripen over a very long period of time. While long producing seasons may sound like a great idea, harvesting such a plant at any one time is not terrifically productive: you have to return time and time again to collect enough to make a garden worthwhile. And because peas grow low to the ground and seeds arise all over the plant, harvesting them isn't particularly easy either. What a softer shell on the seeds does is allow the seeds to germinate in the wet season, thereby allowing more peas to ripen at the same, predictable time.

Other traits developed in domesticated peas include pods that don't shatter on maturity—wild peapods shatter, scattering their seeds out to reproduce; we would prefer that they wait until we get there. Wild peas have smaller seeds, too: wild pea seed weights range between .09 to .11 (about 3/100ths of an ounce) grams and domesticated ones are larger, ranging between .12 to .3 grams, or 4/100th to a tenth of an ounce.

Studying Peas

Peas were one of the first plants studied by geneticists, starting with Thomas Andrew Knight in the 1790s, not to mention the famous studies by Gregor Mendel in the 1860s. But, interestingly enough, mapping the pea genome has lagged behind other crops because it has such a large and complex genome.

There are important collections of pea germplasm with 1,000 or more pea varieties located in 15 different countries. Several different research teams have begun the process of studying pea genetics based on those collections, but the variability in Pisum has continued to be problematic. Israeli botanist Shahal Abbo and his colleagues built wild pea nurseries in several gardens in Israel and compared the grain yield patterns to those of domesticated pea.

Selected Sources