Sequence divergence between spelt and common wheat.

KEY MESSAGE: Sequence comparison between spelt and common wheat reveals that the former has huge potential in enriching the genetic variation of the latter. Genetic variation is the foundation of crop improvement. By comparing genome sequences of a Triticum spelta accession and one of its derived hexaploid lines with the sequences of the international reference genotype Chinese Spring, we detected variants more than tenfold higher than those present among common wheat (T. aestivum L) genotypes. Furthermore, different from the typical 'V-shaped' pattern of variant distribution often observed along wheat chromosomes, the sequence variation detected in this study was more evenly distributed along the 3B chromosome. This was also the case between T. spelta and the wild emmer genome. Genetic analysis showed that T. spelta and common wheat formed discrete groups. These results showed that, although it is believed that the spelt and common wheat are evolutionarily closely related and belong to the same species, a significant sequence divergence exists between them. Thus, the values of T. spelta in enriching the genetic variation of common wheat can be huge.