Botany Photo of the Day

Connor had originally written this as an entry for Monday, but I had already posted the Ouratea before he sent me this write-up — so I've altered Connor's write-up to reflect this.

Happy belated St. Patricks Day! Recognized worldwide by people wearing green, eating green, and drinking green, March 17 is the national holiday of Ireland. Among the many acts people perform to celebrate Saint Patrick, drinking Irish beer seems to be the activity exercised most piously. The quintessential Irish beer is most certainly Guinness, and its most important ingredient is malted barley.

Barley, or Hordeum vulgare, is a member of the Poaceae. Its genus, Hordeum, has a worldwide distribution. Barley is also a member of the same tribe as wheat, Triticum spp. and rye, Secale cereale — the Triticeae (note: this is not a family name, as it does not end in -aceae). Barley is the fourth most important cereal crop in the world, grown most abundantly in Canada, Germany, and Russia (from Biodiversity International). Its main uses are for livestock feed, beer, and human consumption, in the forms of bread, cereal, and —my favorite— miso. As with most other cereal crops, barley has been part of many breeding programs designed to increase crop quality and yield. In breeding programs, crosses are made between lines with desired traits (e.g., resistance to a particular pathogen or drought tolerance) with the aim of producing a new cultivar. Chemical and radiation-induced mutations are also used to produce new, more resistant barley lines (a review of biotechnology and barley in Turkey (PDF)). Barley is already more tolerant of harsh physical conditions than any other cereal crop. It can be found in artic and alpine latitudes, as well as very dry places such as Yemen and parts of North Africa. Interestingly barley is also a very productive host for mycorrhizal fungi as shown by Chaurasia and Khare (Hordeum vulgare: A suitable host for mass production of mycorrhizal fungi (PDF)). This symbiotic ability may give barley an advantage over other cereal crops in less than favorable conditions.

Barley was domesticated around 10,000 years ago from Hordeum spontaneum in the area known as the Fertile Crescent. It is possible to trace its origins by looking at the genotypes of cultivated plants and comparing them to the genotypes of wild plants of a particular site; the more similar they are, the more likely it is that the cultivar came from that wild line. The article On the origin and domestication history of barley outlines the development of barley as a cultivated crop in the Fertile Crescent by genetic analysis and suggests that Hordeum vulgare is the product of only one domestication. A second article, Genetic evidence for a second domestication of barley (PDF), provides evidence for a second domestication east of the Fertile Crescent, accounting for barley lines in central and east Asia.

Thanks to stephenbuchan@flickr for the photograph (original via the UBCBG BPotD Flickr pool), even though it was taken in Scotland and not Ireland.