Development of SCAR markers linked to the Pm21 gene conferring resistance to powdery mildew in common wheat

Powdery mildew is an important disease in most of the wheat production areas of the world. The resistance gene Pm21 (6AL/6VS trans-location) derived from Haynaldia villosa confers resistance to all available isolates of Erysiphe (Blumeria) graminis f. sp. tritici in China and Europe. The objective of this study was to develop fast and reliable sequence characterized amplified region (SCAR) markers linked to the Pm21 gene. A random amplified polymorphic DNA (RAPD) marker for Pm21, OPH171400, was converted to SCAR markers after sequencing the two ends of the polymorphic DNA fragment. Two SCAR markers, SCAR1265 and SCAR1400, were developed to detect the Pm21 gene in different genetic backgrounds. The specific SCAR1265 marker enable large-scale accurate screening for the presence/absence of Pm21 allele.