Mapping of Ug99 stem rust resistance in Canadian durum wheat

Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), has potential to cause major yield losses in durum wheat. Development of cultivars with improved resistance stem rust is a sustainable option for effective control this disease. This study was conducted identify genomic regions associated Ug99-derived Pgt races using doubled haploid (DH) mapping population produced from cross between the resistant experimental line A9919-BY5C and moderately susceptible cultivar ‘Strongfield’. The parents DH lines were phenotyped adult plant disease severity infection response at Njoro, Kenya, four years, seedling reaction race TTKSK containment facility near Morden, Canada. Composite interval 612 SNP DArT markers indicated significant QTL on chromosomes 1B, 4A, 5B, 6A. A stable identified short arm chromosome 6A (6AS), which accounted 71% variation explained up 46% field resistance. mapped Sr8 locus may be Sr8155B1, or novel gene same location. Another 1B that 14% phenotypic likely Sr14. Two minor ‘Strongfield’ 4A 5B inconsistent over years. Markers 6AS can used proactively stack into Canadian