Mining Novel Genetic Diversity in Aegilops tauschii, the D-Genome Progenitor of Hexaploid Wheat.

Wheat production is threatened by depleting resources, increasing cost of production and climate change.  An estimated 60% increase in wheat production is needed by 2050 to feed the projected population of 9 billion.  Hexaploid wheat, like many other crops, has undergone bottlenecks during polyploidization and domestication resulting in narrow genetic base.  Aegilops tauschii, the D-genome progenitor of bread wheat has remained genetically diverse and is an excellent source for broadening genetic base of wheat. With this vision, we assessed the diversity in Ae. tauschii collections at Wheat Genetics Resource Center at Kansas State University and developed a PowerCore and MiniCore sets.  We genotyped 572 accessions of Ae. tauschii representing the world collection by genotyping-by-sequencing (GBS).  More than 120K SNPs were discovered using TASSEL pipeline.  SNPs with less than 50% missing data were filtered and a random subset of 15K SNPs was selected to identify a PowerCore consisting of 144 Aegilops tauschii accessions retaining most of the genetic diversity and maintaining frequency of alleles in core set similar to the entire collection. Further, the PowerCore was optimized based on genetic distance to represent the major clusters of phylogenetic tree.  A MiniCore set of 52 accessions was selected from the PowerCore set to represent all the major clusters in of phylogenetic tree. The MiniCore set of 52 accessions will be crossed to elite wheat cultivars to produce wheat Ae. tauschii amphiploids.  These amphiploids will be selfed and backcrossed to elite wheat lines to enhance the diversity of bread wheat.