Relationship between Flowering Behavior and Outcrossing Rate of CMS Lines in Japonica Hybrid Rice

Nine japonica CMS lines with different stigma exsertion rate(SER) and spikelet flowering rate before noon(SFRBN)(583A,7740A,77237A,Chunjiang 12A,Chunjiang 16A,Chunjiang 26A,99-44A,Ning 67A and Handao A) and one japonica restorer line(CH89) were used as the materials to conduct the hybrid rice seed production in plots of field.SER,SFRBN and outcrossing rate(OR) of japonica CMS lines were investigated to analyze the relationship between them by using the DPS data processing system.The results showed that the simple correlation coefficient and the partial correlation coefficient between SER and OR and the simple correlation coefficient between SFRBN and OR were significant,and the multiple correlation coefficient of OR was also significant to SER and SFRBN did.The regression equation between SER(x_1),SFRBN(x_2) and OR(y) is: y=26.06+0.51x_1+0.28x_2.Path analysis indicated that SER played a more important part in the OR of japonica CMS lines than SFRBN did.The genetic improvement of japonica CMS lines and the strategy of japonica hybrid rice seed production were also discussed.