Rye is a cereal, which played a major role in the feeding of European populations throughout the Middle Ages owing to its considerable winter hardiness. Recently the world production amounts about 30 Mio tons. The cultivated rye resulted from crossbreeding between Secale vavilovii and the perennial species, S. anatolicum and S. montanum (cf. chapter 4.10). It is part of the quite young cultivated plants. It is called a secondary crop, which originated as a weed in emmer and barley fields of the Near East. First cultivation began in Persia, Central Anatolia and north of Black Sea region about 3,000 years ago. The domestication probably happened at several locations but, presumably, within the general area defined below. Rye grains found in Neolithic sites in Austria and Poland are considered to be of "wild" origin. The earliest seed finds of cultivated rye in central Europe came from Hallstatt period 1,000-500 BC. From there the cropping of rye moved northwest toward Sweden from 2,500 to 2,000 BC. During the 16th century rye cultivation subsequently increased, and at the beginning of the 20th century it succeeded even wheat in acreage.
Original was rye a meter-high grass. The long straw was used in particular also for roofing of buildings. Meanwhile rye became a modern crop plant with all the technological and agronomic advantages. There is a subsequent increase in rye grain yield caused by improvement of agronomy and new (hybrid) varieties (Fig. 1.1).
Although the rye acreage decreased by more than one-half during the last four decades, the cool temperate zones of Europe remained the major growing areas. About 94 % of the world production is harvested in Russia (37 % of the total acreage), Belarus (9 % of the total acreage), Poland (22 % of the total acreage), and Germany (9 % of the total acreage; Tab.1.1, 1.2). Acreage in USA has been decreasing as well. All rye of USA is winter rye, mostly used for grain production. The leading states are South Dakota, Georgia, Minnesota and North Dakota.
About 50-75 % of the yearly harvest is used for bread making, resulting in rich, dark bread that holds its freshness for about a week. The rest is used for feeding and the production of alcohol for industrial and consuming purposes.
