Cultivated einkorn wheat (Triticum monococcum L. subsp monococcum): the long life of a founder crop of agriculture

The first cultivated wheat, cultivated einkorn (Triticum monococcum L. subsp. monococcum), was domesticated in South-East Turkey during the Pre-Pottery Neolithic period. It then spread to the Middle-East, the Balkans and Caucasus, Turkmenistan, Central and Mediterranean Europe, North-Africa, and finally to Western and Northern Europe. In all these regions, it played an important role in the development of agriculture and was cultivated for several centuries before being replaced by free-threshing wheats. Today, cultivated einkorn is only present in isolated, mountainous areas of a few countries. However, there is renewed interest for this crop due to the nutritional qualities of its grain, its adaptation to low-input agriculture and high level of resistance to pests and diseases that represent advantages for organic farming. Cultivated einkorn is also a valuable reservoir of genes for wheat improvement. Its utilization, limited by its hulledness, low yield and especially by a poor knowledge of its diversity and its low crossability with bread and durum wheat, is expected to increase in the future, particularly with the need for wheat breeding to face newly emerging diseases through the use of genetic resistances. Considering these perspectives, the present review attempts to analyse the current and historical importance of einkorn cultivation and utilization in wheat breeding, tracing back to its origin and diffusion. The main traits of resistance to pest and diseases, and the nutritional qualities and technological characteristics of the grain are described. Einkorn genetic resources diversity exploration is reviewed and successful examples of introgression of useful einkorn traits into cultivated wheat are reported. Lastly, perspectives of einkorn cultivation development in low-input agriculture and use for wheat enhancement are discussed.