Eggplant Domestication History and Genealogy

Eggplant (Solanum melongena), also known as aubergine or brinjal, is a cultivated crop with a mysterious but well-documented past. Eggplant is a member of the Solanaceae family, which includes its American cousins potatoes, tomatoes, and peppers).

But unlike the American Solanaceae domesticates, eggplant is believed to have been domesticated in the Old World, likely India, China, Thailand, Burma or someplace else in southeast Asia. Today there are approximately 15-20 different varieties of eggplant, grown primarily in China.

Using Eggplants

The first use of eggplant was probably medicinal rather than culinary: its flesh still has a bitter after-taste if it is not treated properly, despite centuries of domestication experimentation. Some of the earliest written evidence for the use of eggplant is from the Charaka and Sushruta Samhitas, Ayurvedic texts written about 100 BC that describe the health benefits of eggplant.

The domestication process increased the fruit size and weight of eggplants and altered the prickliness, flavor, and flesh and peel color, a centuries-long process which is carefully documented in ancient Chinese literature. The earliest domestic relatives of eggplant described in Chinese documents had small, round, green fruits, while today's cultivars feature an incredible range of colors.

The prickliness of the wild eggplant is an adaptation to protect itself from herbivores; the domesticated versions have few or no prickles, a trait selected by humans so that we omnivores can pluck them safely.

Eggplant's Possible Parents

The progenitor plant for S. melongena is still under debate. Some scholars pinpoint S. incarnum, a native of North Africa and the Middle East, that developed first as a garden weed and then was selectively grown and developed in southeast Asia.

However, DNA sequencing has provided evidence that S. melongena is likely descended from another African plant S. linnaeanum, and that that plant was dispersed throughout the Middle East and into Asia before becoming domesticated. S. linnaeanum produces small, round green-striped fruit. Other scholars suggest that the true progenitor plant has not been identified yet, but was probably located in the savannas of southeast Asia.

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The real problem in trying to resolve the domestication history of eggplant is that archaeological evidence supporting any eggplant domestication process is lacking--evidence for eggplant simply hasn't been found in archaeological contexts, and so researchers must rely on a set of data that includes genetics but also a wealth of historical information.

Ancient History of the Eggplant

Literary references to eggplant occur in Sanskrit literature, with the oldest direct mention dated from the third century AD; a possible reference may date as early as 300 BC. Multiple references have also been found in the vast Chinese literature, the earliest of which is in the document known as the Tong Yue, written by Wang Bao in 59 BC.

Wang writes that the one should separate and transplant eggplant seedlings at the time of the Spring equinox. The Rhapsody on Metropolitan of Shu, 1st century BC-1st century AD, also mentions eggplants.

Later Chinese documentation records the specific changes that were deliberately wrought by Chinese agronomists in domesticated eggplants: from round and small green fruit to large and long-necked fruit with a purple peel.

Illustrations in Chinese botanical references dated between the 7-19th centuries AD document the alterations in eggplant's shape and size; interestingly, the search for a better flavor is also documented in Chinese records, as the Chinese botanists endeavored to remove the bitter flavor in the fruits.

Eggplant is believed to have been brought to the attention of the Middle East, Africa and the West by Arabic traders along the Silk Road, beginning around the 6th century AD.

However, earlier carvings of eggplants have been found in two regions of the Mediterranean: Iassos (within a garland on a Roman sarcophagus, ​the first half of the 2nd century AD) and Phrygia (a fruit carved on a grave stele, 2nd century AD). Yilmaz and colleagues suggest a few samples may have been brought back from Alexander the Great's expedition to India.

Sources

Doğanlar, Sami. "High resolution map of eggplant (Solanum melongena) reveals extensive chromosome rearrangement in domesticated members of the Solanaceae." Amy FraryMarie-Christine Daunay, Volume 198, Issue 2, SpringerLink, July 2014.

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_{Liao Y, Sun B-j, Sun G-w, Liu H-c, Li Z-l, Li Z-x, Wang G-p, and Chen R-y. 2009. AFLP and SCAR Markers Associated with Peel Color in Eggplant (Solanum melongena). Agricultural Sciences in China 8(12):1466-1474.}

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