SNPing Aegilops tauschii genetic diversity and the birthplace of bread wheat.

Towards the end of World War II, McFadden & Sears (1946) published a lengthy and classic paper on the origin of hexaploid or bread wheat. In the appendix to this paper they acknowledged that Kihara (1944) had also independently identified Aegilops tauschii (syn. Ae. squarrosa, Tritcum tauschii) as the D-genome donor of bread wheat. Since then, there have been many studies on the taxonomy, biology, and genetics of this grass to seek answers to many questions, including the center of genetic diversity of Ae. tauschii and the place of origin of bread wheat. In this issue of New Phytologist, a paper by Wang et al. (pp. 925–937) is a culmination of these efforts and in many respects is a landmark contribution. It is a triumph of high-throughput genomics. They used 7815 previously mapped (Luo et al., 2009), single nucleotide polymorphisms (SNPs) providing complete coverage of the genome to interrogate 402 accessions of Ae. tauschii, 75 hexaploid wheats, and seven tetraploid wheats using an Illumina Infinium Platform. But before delving deeper into their findings, letme fill in the key findings of the intervening period.