100-1 Mapping Powdery Mildew and Leaf Rust Resistance Introgressed From Aegilops Speltoides Into Soft Red Winter Wheat.
Poster Number 100
The wheat germplasm line NC09BGTS16 (NC-TS16) was found to hold resistance to both PM and LR introgressed from Aegilops speltoides. Greenhouse and field evaluations of 144 F2:3 families derived from a cross between NC-TS16 and the susceptible cultivar ‘Coker68-15’ indicated that a single gene conferred resistance to PM. Bulked Segregant Analysis and linkage analysis showed that the resistance gene in NC-TS16 was closely linked to SSR markers Xgwm499 and Xwmc759 on chromosome 5BL at distance 0.7cM. Additionally, the resistance gene in NC-TS16 was flanked by SNP markers IWA_6024 and IWA_2454 at distances of 0.7 and 1.4 cM, respectively. Detached leaf tests with over 80 different PM isolates were set up to differentiate the Pm gene in NC-TS16 from Pm36, which also has been located to chromosome 5BL. NC-TS16 had a different response to at least three of the isolates compared to a line containing Pm36. In addition, the NC-TS16 Pm gene and Pm36 have been introgressed from two different alien species, and it is therefore reasonable to believe that the NC-TS16 Pm gene is a novel Ae. speltoides derived PM resistance specificity.
Evaluations of the same 144 F2:3 families for LR in the greenhouse and field indicated that at least one gene was conferring resistance to LR. Using the Bulked Segregant Analysis method, a gene conferring resistance to LR was mapped to chromosome 6BL. Differential tests and additional mapping is currently being done in order to determine whether this resistance gene is novel.