[Screening and study of RAPD markers tightly linked to wheat powdery mildew resistance gene Pm2]

The random amplified polymorphic DNA (RAPD) analysis was made in Pm2 near-isogenic lines (NILs) with 265 random primers. Seventeen out of the 256 tested primers amplified the polymorphic DNA in the NILs. Five of them showed the same discriminating results in more than four replications. The polymorphic bands were assigned to be OPM08(1600), OPI04(1700), OPH19(1100) and OPE09(900), respectively. Using these five polymorphic primers to detect 14 resistant materials with Pm2 and 9 susceptible materials without Pm2, only OPI04(1700) was amplified in 12 of the 14 resistant materials and absent in all of the 9 susceptible materials. Further RAPD analysis of (Chancellor x Ulka/8*Cc) F2 plants by primer OPI04 indicated that the genetic distance of OPI04(1700) to Pm2 was 12.2 +/- 3.3 cM.