Abstract: Abstract Common winter wheat (Triticum aestivum) line 99-2439 has shown high resistance to Blumeria graminis sp. tritici in the field in Zhengzhou for 4 years. However, the origin of its powdery mildew resistance genes was unclear. We identified 99-2439 as a Triticum aestivum -Secale cereale 1BL/1RS alien translocation line by chromosome C-banding and 1RS-specific SCAR marker detection. Powdery mildew evaluation and 1RS detection of an F2 segregation population derived from the cross between Chinese Spring wheat and line 99-2439 demonstrated that the powdery mildew resistance gene was located on the 1RS chromosome arm. Inheritance study using a single spore isolate of B. graminis showed that line 99-2439 harbored a racespecific recessive powdery mildew resistance gene. Because 99-2439 was highly resistant to mixed fungi and 5 single spore isolates of B. graminis, the powdery mildew resistance gene of 99- 2439 was different from Pm5a of Hope/8Cc, which was highly susceptible to all 21 isolates of B.graminis in China.

Key words: Wheat (Triticum aestivum), Powdery mildew, Resistance, Inheritance