Georgia, the South Caucasus as the homeland of the hexaploid wheat

Abstract

The importance of the local wheats of the South Caucasus for the evolution of the hexaploid wheat is largely overlooked. The South Caucasus and, especially, Georgia is the only country where all suitable conditions (on a very small territory are created for the origin of hexaploid wheat: 1) high diversity of local flora of wild and cultivated plants; 2) ancient Neolithic farming society confirmed by numer- ous archeological findings, which included nine species of wheat in Arukhlo and eight domesticated wheat species in each of Shulaveri and Khramis Didi Gora (southeast Georgia) dated as 8000 BP; 3) highest diversity and endemism of ancient hulled wheats represented with all seven hulled species; 4) highest diversity and endemism of free-threshing wheats; 5) presence of all tetraploid wheats - po- tential donors of AABB-genome; 6) presence of the of D-genome donor - all linages of Aegilops tauschii subsp. strangulata including the ancient, late flowering forms; 7) the presence of the endemic T. timopheevii - T. zhukovskyi lineage (AAGG-AAGGAA genomes); 8) The representation of the T. turgidum – Tr. aestivum lineage (AABB-AABBDD) genomes with two sub-linages: i) endemic hulled T. turgidum subsp. palaeocolchicum – T. aestivum subsp. macha and ii) free-threshing T. turgidum subsp. carthlicum – T. aestivum.