Genome-wide association study in diverse Iranian wheat germplasms detected several putative genomic regions...

Stem rust is one of the most important diseases, threatening global wheat production. Identifying genomic regions associated with resistance to stem rust at the seedling stage may contribute wheat breeders to introduce durably resistant varieties. Genome-wide association study (GWAS) approach was applied to detect stem rust (Sr) resistance genes/QTLs in a set of 282 Iranian bread wheat varieties and landraces. Germplasms evaluated for infection type and latent period in four races of Puccinia graminis f. sp. tritici (Pgt). A total of 3 QTLs for infection type (R² values from 9.54% to 10.76%) and 4 QTLs for the latent period (R² values from 8.97% to 12.24%) of studied Pgt races were identified in the original dataset. However, using the imputed SNPs dataset, the number of QTLs for infection type increased to 10 QTLs (R² values from 8.12% to 11.19%), and for the latent period increased to 44 QTLs (R² values from 9.47% to 26.70%). According to the results, the Iranian wheat germplasms are a valuable source of resistance to stem rust which can be used in wheat breeding programs. Furthermore, new information for the selection of resistant genotypes against the disease through improving marker-assisted selection efficiency has been suggested.