Early generation selection for resistance to wheat stripe rust Puccinia striiformis f.sp. Tritici and Fusarium head blight (FHB) in segregating populations can increase the frequency of resistance among derived lines. This study demonstrates an increase in the frequency of resistance and shifts in associated genomic regions among progeny derived populations undergoing selection. Populations segregating for resistance to stripe rust and FHB were split into an experimental group undergoing selection for resistance and a control without selection. To apply selection for resistance in the selected populations, susceptible genotypes were culled and resistant F2 and F3 plants were retained each generation. All genotypes in control populations were advanced without selection. Both selected and control populations were inoculated at the F4 generation to compare the frequency of resistant individuals. The frequency of resistance was also compared between selected and control-derived recombinant inbred lines (RILs) derived at the F4 generation. Experimental populations undergoing selection showed significantly higher resistance levelscompared to control populations. A significantly higher frequency of resistant genotypes were identified among RILs derived from populations undergoing selection. Signatures of selection for stripe rust were identified on eight unique chromosome regions and twelve for FHB. Selection for resistance during generational advancement results in an increased frequency of stripe rust and FHB resistance among inbred lines derived from segregating populations. The frequency of genomic regions associated with resistance is increased in parallel with phenotypic selection.
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