Every saffron crocus on Earth is a sterile clone that needs human hands
The saffron crocus cannot make seeds. It has three sets of chromosomes, no wild populations, and survives only because people dig up its bulbs, split them and replant them. A kilogram of the spice takes roughly 150,000 flowers picked by hand, which is why the best grades sell for over 5,000 dollars.
Crocus sativus is a triploid with 24 chromosomes, eight per set, and its flowers are male sterile and incompatible with themselves. It is unknown in the wild and probably descends from Crocus cartwrightianus, a wild saffron native to mainland Greece, Crete and several Aegean islands. Each underground corm lasts a single season but can split into as many as ten cormlets, and that manual divide-and-replant cycle has carried the same genetic clone across Eurasia, to North Africa and North America, and even to Fiji with Indian migrants.
The spice itself is the dried crimson stigma, the thread. Flowers open at dawn and wilt within the day, and a whole field blooms inside one or two weeks, so harvests are frantic. It takes about 440,000 stigmas to fill a kilogram, and forty hours of labour to pick 150,000 flowers. A single fresh bloom yields around 7 milligrams once dried. The plants want full sun, cope with frost down to minus 10 Celsius, and grow in Kashmir's wet climate as well as in Spain, where rainfall is only 400 millimetres.
Three molecules define quality, and the ISO 3632 standard measures them in the lab. Crocin, a water-soluble carotenoid that can exceed 10 percent of dry mass, gives the golden colour that suits rice dishes. Picrocrocin, up to 4 percent, supplies the bitter taste, and safranal, split from it, carries the hay-like aroma. More dark red stigma and less yellow style means a higher grade.
Saffron likely began in Iran, especially Khorasan, and has been grown and traded for over 3,500 years; an Assyrian plant text from the seventh century BC already mentions it. Persian kitchens use it in tahdig and in the dessert sholeh-zard. The English word arrived through French around 1200 from Persian zafaran, rooted in an older term meaning gold-strung. The unrelated, toxic meadow saffron is not a source of the spice.
Source: Saffron
