Abstract only

A panel of 183 elite durum accessions suitable for association mapping was characterized for stem rust response in four artificially inoculated field trials in Ethiopia using race Ug99 and a bulk of other highly virulent Ethiopian Pgt races. The seedling responses of the accessions were determined using several Pgt races at CDL, St. Paul MN. The phenotypic distributions indicated that the overall genetics of resistance is complex. Twenty-five resistant accessions were identified (DSS below 20%). The molecular genotypes of the accessions using 300 SSR and 900 DArT markers were subjected to association mapping analysis. Several chromosome regions putatively involved in stem rust response, both under field conditions and at the seedling stage, were identified. Genotypes at the Sr13 locus (chromosome 6AL) were involved in both field and seedling tests and a resistant haplotype tagged by a series of SSRs was often present (wmc580, gwm427 and barc104). Significant associations were also detected on chromosomes 1B (gwm11, wmc128 and gpw3013) and 2B (wmc257, gwm1300 and wmc356) as well as other regions. These results suggest that durum has several genes for resistance to Ethiopian races, including Ug99, and that there is potential to exploit some of them in breeding.

Genetic Resources Program|Global Wheat Program

English

Lucia Segura

INT2585|CCJL01