The quadratic general rotary unitized design was used to optimize SRAP-PCR system in pepper(Capsicum spp.) with five key factors(Taq DNA polymerase,Mg2+,dNTPs,primer and template DNA,respec-tively).The results showed that the optimized SRAP-PCR system for pepper was: 0.5 U Taq DNA polymerase,2.3 mmol?L-1 Mg2+,0.2 mmol?L-1 dNTPs,0.8 μmol?L-1 primer,45 ng template DNA in a total of 10 μL reaction solu-tion.The optimized SRAP-PCR system was tested on 18 pepper germplasm and was reliable and steady.Accord-ingly...