Abstract: The combining pattern of japonica male sterile line/widely compatible restorer lines has been widely adopted in Zhejiang Province in recent years. Moreover, hybrid rice purity could be quickly tested with the functional marker of wide compatibility S5-n. To verify the effectiveness of functional marker of wide compatibility S5-n for identifying the F₁ hybrid of the combining pattern of japonica male sterile line/widely compatible restorer lines, field statistics and functional marker of wide compatibility S5-n were conducted for the F₁ hybrid of Changjing 1A and six restorer lines. The results showed that the alien plants resulted from pollen contamination could not be specifically tested; hence, the result of functional marker of wide compatibility S5-n was 1.0%-2.0% higher than that of field statistics. Therefore, we suggested that the specificity of functional marker of wide compatibility gene should be further optimized to improve the accuracy of molecular detection, which had important practical significance for the safety production of hybrid rice.

Key words: rice, wide compatibility gene S5-n, molecular marker, hybrid purity