Screening and identification of the AFLP markers linked to a new powdery mildew resistance gene in wheat cultivar Brock.

Wheat cultivar Jing 411 which is susceptible to powdery mildew, wheat cultivar Brock and near isogenic lines (NILs) of Jing411, which are resistant to powdery mildew were analysized for polymorphisms using 225 pairs of AFLP primers Only two pairs of primers Pst+GAC/Mse+ TCT (P1) and Pst+AGC/Mse+ACC (P2) stably produced polymorphic bands between the resistant and susceptible plants. Two specific fragments were obtained. By cloning and sequencing these two specific fragments, it was showed that the specific fragment amplified by primer P1 had 268bp, and the fragment amplified by P2 had 227bp. They were named AFLP marker P1(268) and P2(227) respectively. Linkage analysis of these two markers revealed that the polymorphism existed in a 106 F2 segregating population. These two markers closely linked to a powdery mildew resistance gene in wheat cultivar Brock, linkage distance were 3.6 and 1.9 cM respectively. These two markers will be useful for marker-assisted selection and gene pyramiding in wheat resistance breeding.