Abstract：Abstract Purity identification for hybrid seeds is very important in oilseed rape seed production. Analysis of peroxidase (POD) isozyme of Brassica napus hybrid.-Zhongyouza 12 and its parental lines indicated that one specific band with a relative mobility (Rf) of 0.41 presented in hybrid and male parent, but absent from female parent. So this specific band could be used to identify hybrid of seeds produced from sites where the male parent plants were strictly removed after flowering. For more precise identification, 173 pairs of SSR primers were screened for polymorphic amplification between the parental lines of Zhongyouza 12. Among those primers, six pairs amplified clear specific bands to either of the parents, with no difference among individual plants within lines. Four pairs of the primers, P052, P130，P131 and P154, amplified specific bands of both parents in F1 hybrid plants. Primer combination P131+P154 could create additive band profiles in one reaction system as which amplified by P131 and P154, respectively. In case of seeds produced from difficult conditions where the pollen source out of control, the use of P131 + P154 primer combination could improve the detection sensibility of unknown pollen, and more accurately identify the seed purity of Zhongyouza 12 under the condition of using the same workload. One hundred DNA samples from Zhongyouza 12 single plants were analyzed by using primers P131, P154 and P131+P154, respectively. The results of seed purity were fully consistent, and were very close to the results of field identification.
