Chromosome-scale genome assembly of bread wheat’s wild relative Triticum timopheevii

Wheat ( Triticum aestivum ) is one of the most important food crops with an urgent need for increase in its production to feed the growing world. Triticum timopheevii (2n = 4x = 28) is an allotetraploid wheat wild relative species containing the A t and G genomes that has been exploited in many pre-breeding programmes for wheat improvement. In this study, we report the generation of a chromosome-scale reference genome assembly of T. timopheevii accession PI 94760 based on PacBio HiFi reads and chromosome conformation capture (Hi-C). The assembly comprised a total size of 9.35 Gb, featuring a contig N50 of 42.4 Mb, and 166,325 predicted gene models. DNA methylation analysis showed that the G genome had on average more methylated bases than the A t genome. The G genome was also more closely related to the S genome of Aegilops speltoides than to the B genome of hexaploid or tetraploid wheat. In summary, the T. timopheevii genome assembly provides a valuable resource for genome-informed discovery of agronomically important genes for food security.