Crocus sativus

''Crocus sativus'', commonly known as saffron crocus or autumn crocus, is a species of flowering plant in the iris family Iridaceae. A cormous autumn-flowering cultivated perennial, unknown in the wild, it is best known for the culinary use of its floral stigmas as the spice saffron. Human cultivation of saffron crocus and the trade and use of saffron have endured for more than 3,500 years and span different cultures, continents, and civilizations.

Common names

The plant is most commonly known as the saffron crocus. The alternative name autumn crocus is also used for species in the ''Colchicum'' genus, which are not closely related but strongly resemble the true crocuses; in particular, the superficially similar species ''Colchicum autumnale'' is sometimes even referred to as ''meadow saffron''. However, the true crocuses have three stamens and three styles, while colchicums have six stamens and one style; and belong to a different family, Colchicaceae. Colchicums are also toxic, making it particularly crucial to distinguish them from the saffron crocus.

Morphology

''Crocus sativus'' develops as an underground corm, which produces leaves, bracts, bracteole, and the flowering stalk. It generally blooms with purple flowers in the autumn. The plant grows about 10 to 30 cm high.Mollazadeh, Hamid "Razi's Al-Hawi and saffron (Crocus sativus): a review". Iranian Journal of Basic Medical Sciences, Dec 2015.

Genetics

Saffron crocus is a triploid with 24 chromosomes (2''n'' = 3''x'' = 24), making the plant sexually sterile due to its inability to pair chromosomes during meiosis. Its most probable ancestor is the wild species ''Crocus cartwrightianus''. Although ''C. thomassi'' and ''C. pallasii'' are still being considered as potential predecessors or genetic contributors, these hypotheses have not been successfully verified by chromosome and genome comparisons.

Domestication

It is thought that the domesticated saffron crocus most likely arose as a result of selective breeding from the wild ''C. cartwrightianus'' in the southern portion of mainland Greece. An origin in Western or Central Asia, although often suspected, is not supported by botanical research.

Use

The stigmas of the flower are used as the culinary spice saffron. Depending on the size of harvested stigmas, the flowers of between 50,000 and 75,000 individual plants are required to produce about 1 pound of saffron; each corm produces only one or two flowers, and each flower produces only three stigmas. Stigmas should be harvested mid-morning when the flowers are fully opened.

Cultivation

As a sterile triploid, ''C. sativus'' is unknown in the wild and relies upon manual vegetative multiplication for its continued propagation. Because all cultured individuals of this plant are clonal, there is minimal genetic diversity from the single domestication event, making it quite hard to find cultivars with new, potentially beneficial properties, let alone combine them by breeding. Cultivars of saffron are nevertheless produced by a number of means:

* Clonal selection. Any plant with a desirable mutation is kept and further grown. This is the traditional approach.
* Mutation breeding. Mutagenesis can be used to cause a wide range of mutations to select from. The traditional clonal process follows.
* Sexual reproduction. Breeding for desirable features is much easier in fertile plants.
** Although the plant is not self-fertile, some wild relatives can be successfully cross-pollinated with saffron pollen ''in vitro'' and form seeds. This creates fertile diploid plants containing genomic material from ''C. sativus'', allowing new traits to be explored via further cross-pollination.
** Chromosome doubling could in principle also create a fertile hexaploid plant. Such a change may be possible via colchicine.

Corms of saffron crocus should be planted apart and in a trough deep. The flower grows best in areas of full sun in well-drained soil with moderate levels of organic content. The corms will multiply after each year, and each corm will last 3–5 years.

Gallery

File:Crocus sativus - Köhler–s Medizinal-Pflanzen-194.jpg, Illustration from '' Köhler's Medizinal-Pflanzen'' (1897)
File:Safrà de perfil.jpg, Flower's profile, Serra de Casteltallat, Catalonia, Spain
File:Pollen of Crocus sativus.jpg, Pollen, Afghanistan
File:Safran-Weinviertel Niederreiter 2 Gramm 8285.jpg, Saffron threads are the dried styles and stigmas of ''C. sativus''.
File:Saffronfarm-860808.jpg, Saffron harvesting, Torbat-e Heydarieh, Iran

See also

'' Topics related to saffron:''
* History of saffron
* Trade and use of saffron

References

External links

*

{{Authority control

Plants described in 1753
Taxa named by Carl Linnaeus
sativus

Medicinal plants