Comparison between varietal purity and zymogram purity in maize

The zymogram purity of 5 inbred lines, 7 single cross hybrids and 7 single cross hybrids mixed with their parental lines was examined by a vertical discontinous polyacrylamide gel electrophoresis. Results indicate that the maize hybrid impurity is mainly composed of three parts:mixed with the seeds from parents or other source, contaminated with the seeds resulting from unknown pollination and variable in genetic background. It was found that the varietal purity is higher than the zymogram purity and they showed a linear relationship. The regression mefficient (γ) between varietal purity and zymogram purity is 0.898 2. There is an average of 3.5 % variable in the field. However, using a known rate of the mixed seeds, their regression mefficient is 0.999 9. It was also found that the examinational mix rate is 0.33% higher than the known mix rate. The seedling rate of the single cross hybrids is 85.71 %, but that of hybrids mixed with their parental lines is only 77%. Therefore, it is reasonable to claim that zymogram purity is lower than the varietal purity.