Fagopyrum esculentum : Différence entre versions

The cultivated races. Cultivated in Tibet, Himalaya area, India, Russia, China, Korea, Japan, Central and W Europe, but also, more recently, in Canada, USA and Cuba. Common buckwheat is used as a vegetable, as animal feed, as a green manure and as a source for buckwheat honey. But most important for human consumption are the grains, used cooked like rice or as flour for the preparation of pancakes, biscuits, noodles. In eastern Europe it is used for porridge and soups, in SE Asia an unleavened bread is made from the flour. In Russia, where it is an important crop even today, it was not grown to a larger extent until the 15th cent. In central and western Europe it is now a declining crop. In Canada and the USA an increase of the growing area can be observed. Buckwheat is known to have been cultivated in China as early as the 2nd/1st cent. BC. Other sources date the cultivation back to earlier times. It is believed to have been introduced into Japan already about 3.000 years ago, via the Korean peninsula. It is known in Central Europe since the 13th cent. probably introduced via E Europe. The centre of origin is obviously in southern China, where several other Fagopyrum species occur (F. homotropicum Ohnish in Fagopyrum 15 (1998); F. statice Gross; F. urophyllum (Bur. & Franch.) Gross; F. leptopodum (Diels) Hedb.; F. lineare (Sam.) Haralds. Most recently new species closely related to cultivated buckwheat have been described from Sichuan (F. megaspartamium Q.-F. Chen in Bot. J. Linn. Soc. 130 (1999) 62) and Tibet (F. zuogangense Q.-F. Chen, l.c. and F. pilus Q.-F. Chen, l.c.). Some of them may have been involved in the evolution of F. esculentum; but the true wild progenitor is F. esculentum subsp. ancestrale from the north-west corner of Yunnan province. Fagopyrism may occur in animals with light skin after feeding larger amounts of buckwheat. Fagopyrin sensibilizes the skin to light. Also observed in humans after consumption of honey from buckwheat. Buckwheat is a rather variable crop. The most important morphological races are var. esculentum, mainly cultivated in Europe and the New World and var. emarginatum (Roth) Alef. (Landw. Fl., 1866, 286) mainly cultivated in the eastern part of the cultivation area (China, Japan, India), for the infraspecific variation compare also Krotov (1975). Occasionally natural crosses have been occured between this and the following species. The hybrids are amphidiploid and have been described as Fagopyrum giganteum Krotov (in Kul't. Fl. SSSR 3, 1975, 16).