Introgression of FHB resistance from Sumai 3-derived hexaploid wheat lines into Canadian durum wheat germplasm

Canadian durum cultivars are susceptible to Fusarium head blight (FHB), and recent epidemics have motivated the use of hexaploid wheat as a source of resistance. Five top-crosses were made between the hexaploid lines Sumai-3, HY644-BE, P89-77-1B (a synthetic wheat derivative) and BW871 and the durum cultivars AAC Marchwell, Transcend, AAC Raymore, AAC Spitfire and Langdon. A population of 380 F7 lines was phenotyped in FHB field nurseries in Morden, MB from 2015 to 2107. FHB incidence, severity, and developmental traits height and maturity (1-4 scale) were recorded and FHB index calculated. Using Spearman’s correlation FHB traits were negatively correlated with height, r2 ranging from -0.2 to -0.37, and maturity with r2 ranging from -0.37 to -0.72 indicating that height maturity explain part of the FHB response. When the reaction of the lines was compared to the checks, 23 of the lines had equal or lower FHB index than Sumai 3 in 2015, 32 in 2016 and 35 in 2017 which translated to 6 to 9% of the population being better than Sumai 3. A core set of 62 lines with low to intermediate FHB ratings over multiple years and with intermediate height and maturity were selected for further study. The exome capture sequencing of the parents is being used to call SNP markers within the confidence interval of three major FHB QTL of Sumai-3, Fhb1, Fhb2 and Qfhs-ifa-5A. The markers will be used to accelerate stacking FHB resistance QTL.