Concurrent detection and introgression of novel loci controlling yield component traits and stem rust resistance from Triticum turanicum into T. aestivum

Abstract

Common wheat (Triticum aestivum L.) is the most widely grown crop in the world with over 220million hectares harvested annually. Currently yield gains in wheat average ~1.1% per year, which is not enough to continue to fulfill caloric and nutritional demands of a growing population. Closing this yield gap is not only a matter of making drastic improvements to genetic yield potential, but it also requires deliberate efforts to protect yields from an ever-shifting list of pests and pathogens, including stem rust caused by Puccinia graminis f. sp. tritici. (Pgt). Accomplishing these goals are hindered by a relative lack of genetic diversity among elite wheat germplasm. However, hexaploid common wheat has a myriad of wild relatives and progenitor species with untapped genetic diversity. Realization of the expanded gene pools’ potential by plant breeders has been stifled by several factors including biological factors such as linkage drag and meiotic instability, as well as financial barriers and logistical challenges. Plant breeders are hesitant to incorporate diverse materials into their programs as it naturally draws resources away from routine breeding operations. Rather than reporting novel loci directly detected in related species, a population was developed to simultaneously identify and introgress novel loci from tetraploid Khorasan wheat (T. turgidum ssp. turanicum) into hexaploid wheat. An initial study was conducted to develop a rapid and straightforward method to identify genetically stable progeny developed from interspecific hybridization. Second, novel quantitative trait loci for yield component traits were detected and introgressed into hexaploid lines. A third study demonstrated the potential to develop mapping and introgression populations for multiple target traits by identifying novel sources of adult plant resistance to the Ug99 lineage of Pgt. Additional studies should be conducted to further refine and characterize these loci in order to promote their utilization.