Efficiency of marker–assisted selection for a russian wheat aphid resistant gene in wheat

DNA markers have provided valuable tools for plant breeding and beneficial for germplasm characterization and indirect selection. Marker-assisted selection has the potential to deploy favorable gene combinations for disease and pest control as well as the quality of some crop products. However, practical application of molecular marker revealed that a successful MAS program depends on inheritance of the trait, number of individuals subjected to analysis and the genetic background. In this study, microsatellite (SSR) markers linked to the Russian wheat aphid (RWA) resistant gene (Dn4) and glume-color gene (Rg2) in wheat using a population of F2–derived F3 families derived from F2 single plants originating from a cross between the susceptible line (synthetic hexaploid-11) and the resistance cultivar (Halt) are reported. Two flanking microsatellite markers Xgwm106 and Xgwm337 are linked with Dn4 on the short arm of wheat chromosome 1D at 5.9 cM and 9.2 cM, respectively. The accuracy (AMAS) and efficiency (EMAS) of marker-assisted selection were calculated for homozygous RWA resistant genotypes of Dn4 gene in the F2 generation. Dominant morphological marker, Rg2, was also used for marker-assisted selection of Dn4 gene individually and in combination with microsatellite markers. EMAS of 100% for Xgwm337 marker and AMAS of 100% for bracketing markers Xgwm337-Xgwm106 and Xgwm337-Rg2 and non-bracketing markers Xgwm106-Rg2 were obtained.