Wild Emmer 10.5 Mb Genome Assembly Reveals Insights on Wheat Domestication

The study of plant domestication attempts to answer fundamental biological and cultural questions and is important for present day plant sciences. Domesticated plants, including wheat, differ from their wild ancestors by a suite of traits called the 'domestication syndrome'. For example, the non-brittle rachis and uniform seed germination are important components of the domestication syndrome in wheat. As a step in understanding crop improvement and domestication, we have recently completed the genome assembly of wild emmer wheat (Triticum turgidum ssp. dicoccoides accession Zavitan), the direct progenitor of most domesticated wheat varieties. The scaffolds of our dicoccoides assembly are >100 times longer than any available wheat assembly (L₅₀=7 Mb N₅₀=414) and were ordered along the 14 chromosomes using genetic linkage data from our  recombinant inbred line (RIL) population derived from hybridization of durum wheat (T. turgidum ssp. durum, cv. Svevo) with Zavitan. Genetic analysis using two years of phenotypic evaluations of domestication related traits revealed 15 loci responsible for the morphological differences between Svevo and Zavitan. Gene diversity in these loci was analyzed using resequencing of a core collection of tetraploid wheat and results will be discussed. The wild emmer wheat assembly is expected to accelerate efforts to identify the genetic control over significant polymorphisms between wild and domesticated wheat.