Genome-Wide Characterization of Exotic Alleles for Increased Yield from Primary Synthetic Bread Wheat

To address the loss of genetic diversity due to domestication and breeding of modern wheat cultivars, exotic alleles from bread wheat progenitors Triticum dicoccum and Triticum tauschii have been captured in primary synthetic bread wheat lines developed by CIMMYT. The primary synthetics carry resistance and tolerance to a range of biotic and abiotic stresses. Selected lines from double haploid (DH) and recombinant inbred line (RIL) populations between an elite CIMMYT cultivar (Opata) and six different primary synthetics were evaluated for grain yield, agronomic, and physiological traits.  Field trials were conducted at Cd. Obregon, Mexico over several years in full-irrigation, heat, and drought-stressed environment. Several synthetic derived lines outperformed the elite parent Opata in all environments indicating that the primary synthetics contribute alleles increasing yield. Whole genome profiles were generated using genotyping-by-sequencing (GBS) to identify yield promoting genomic regions inherited form the primary synthetics. We will apply specifically developed genomic selection (GS) models to rapidly introgress valuable alleles and develop high-yielding breeding lines. New populations derived from crosses between the highest yielding lines in the existing DH populations are under development and will be evaluated under optimal and stress conditions in yield trials at CIMMYT. Testing of multiple types of synthetic derivatives including DH lines and breeding lines will provide rigorous validation of alleles for increased yield and the predictive power of our GS models. This pioneering study takes a whole genome approach to characterize, improve and utilize exotic germplasm to increase yield.