In a review paper published in the journal Frontiers in Plant Science, researchers followed ancient arts and recent genetics to trace the evolutionary origin of the saffron crocus (Crocus sativus), a triploid flower crop and source of the spice and colorant saffron.
From Greece to Iran, from paintings and dyes to spice and perfumes, flavor and sparkly yellow color of saffron — the world’s most expensive spice — has made its trail in human history.
Saffron is extracted from the flowers of the saffron crocus, a species of flowering plant of the Crocus genus in the iris family Iridaceae.
Between 15,000 and 16,000 flowers, requiring between 370 and 470 person-hours to collect, yield a single kilo of saffron, worth between $1,300 and $10,000.
The Mediterranean is considered as the emergence site of many Crocus species, with Greece and Turkey possessing the highest number. Investigating ancient texts and artworks in these regions can help finding more information on early saffron domestication.
The first use of the word ‘saffron’ dates back to the 12th century to the old French term safran that consecutively originated from the Latin safranum, the Arabic za’farān, and the Persian zarparan with the meaning ‘gold strung.’
As folk taxonomies were used to differentiate plant species prior to the formalization of the Linnaean system, different species of purple, autumn-flowering crocuses were not distinguished before the 18th century.
Hence, at the time, most crocuses were considered as one and we cannot rely on texts for clear species information. Nevertheless, scientists suggested that Crocus cartwrightianus, Crocus thomasii, or Crocus hadriaticus were the most likely species that were cited by ancient historians.
Regarding ancient arts, images can be categorized into two types: on one hand, those that are painted using pigments derived from crocus and on the other hand, those that depict saffron crocus flowers.
While the use of crocus-based pigments can be traced back about 50,000 years ago to prehistoric cave paintings in northwestern Iran (today’s Iraq), early signs of cultivation and domestication were found later, at about 1700 BCE, during the time of the Minoan civilization in Crete.
As saffron’s high medicinal value and antioxidant ability were recognized, its commercial value as a spice increased over the next eras, leading to its spread across the Mediterranean.
“Both ancient artworks and genetics point to Bronze Age Greece, in approximately 1700 BCE or earlier, as the origin of saffron’s domestication,” said Ludwig Mann, a Ph.D. student at Technische Universität Dresden.
“Finding out where and when saffron was first domesticated isn’t straightforward: the species is difficult to study genetically, because it has three copies of every chromosome instead of the usual two, and a large genome containing a high percentage of difficult-to-sequence repetitive DNA,” added Seyyedeh-Sanam Kazemi-Shahandashti, a Ph.D. student at the Institute of Bio- and Geosciences of the Forschungszentrum Jülich.
“As there are no ancient crocus remains preserved from ancient times, we here revisit ancient artworks that depict saffron-like plants. We expected that these could point us to specific regions.”
“Artworks from the Minoan civilization are likely the oldest to depict domesticated saffron,” the scientists said.
“For example, the dense patches of crocus flowers on the fresco ‘The Saffron Gatherers’ from the island of Santorini (approximately 1600 BCE) suggest cultivation.”
“Another fresco on the same island, ‘The Adorants,’ shows flowers with long, dark-red stigmas which overtop dark violet petals, typical of domesticated saffron.”
“Flowers with these traits are also depicted on ceramics and cloth from Bronze Age Greece, and symbolically rendered in the ideogram for saffron in the ancient Linear B script.”
“In Egypt, tombs from the 15th and 14th centuries BCE depict how ambassadors from Crete brought tribute in the form of textiles dyed with saffron.”
An origin in Bronze Age Greece agrees with results from genetic studies from 2019, which showed that Crocus cartwrightianus, which only occurs in mainland Greece and Crete, is saffron’s closest wild relative.
“The modern saffron crocus with its three genomes arose naturally from the wild, either exclusively from Crocus cartwrightianus or from hybrids between Crocus cartwrightianus and another crocus species,” the authors said.
“The saffron crocus would then have been retained by the Bronze Age Greeks because of its superior qualities as a spice.”
“We will continue to trace saffron’s properties,” said Dr. Tony Heitkam, leader of the Plant Genomics group at Technische Universität Dresden.
“Around the globe today, all saffron crocuses are effectively clones dating back to saffron’s emergence in ancient Greece.”
“Nevertheless, despite sharing the same genome, saffron can have different properties depending on the region.”
“We have started to investigate the molecular causes, in particular so-called ‘epigenetic’ differences, for this regional variation.”
Seyyedeh-Sanam Kazemi-Shahandashti et al. Ancient Artworks and Crocus Genetics Both Support Saffron’s Origin in Early Greece. Front. Plant Sci, published online February 25, 2022; doi: 10.3389/fpls.2022.834416