Abstract:

Aset of isonuclear alloplasmic Japonica CMS lines Liuqianxin A, constructed with four different cytoplasm sources from Hainan Male Sterile Wild Rice (WA type), Hainan Red Awned Wild Rice (HL type), Hunan Chaling Wild Rice (CL type) and India Chinsurah Boro II (BT type) respectively, together with their maintainer line Liuqianxin B, were applied to study their male sterile stability, flowering habits, outcrossingrate and restorable ability. The results showed: (1) Most pollen granules of BT, HL and CL Liuqianxin A were mainly stained-abortion, while those of WA Liuqianxin A weremainly typical-abortion. Selfed seed-setting rate ofBT Liuqianxin A was 0.60%, which would cause application risk in agricultural production. There were no selfed seeds in HL and CL Liuqianxin A,indicating that sterility of them wasbetter than that of BT type. (2) The length of 1st internode to the top was affected by the degree of abortive pollen, which influenced the plant height and the panicle exsertion (i.e. the length of panicle -neckabove the sheath of flag leaf). Namely the more serious abortive degree,the shorter panicle exsertion. Therefore, panicle was enclosed within the sheath of the flag leaf in WA Liuqianxin A, not in BT, HL and CL Liuqianxin A. (3) The flowering habits of WA Liuqianxin A presented assporadicflowering, distinctly lagged flowering time and stretched flowering duration, and were the worst in the four type CMS lines, thus its outcrossing rate was lower. Flowering habits and outcrossing rate between HL, CL CMS lines and BT CMS lines were not significantly different. However it was better in HL, CL CMS lines than in WA CMS lines. (4)BT Liuqianxin A showed the best restorable characteristic,HL was a little worse than BT,WA was the worst. And Japonica restorers for HL or CL CMS lines could be selected from the Japonica restorers for BT CMS lines. HL, CLCMS lines balanced above contradictions well, so an idea of substituting HL, CLCMS lines partly for BTtype was put forward, it can be used to solve the problems of single type sterile cytoplasm in current Japonica hybrid riceand fertility not stable in BTCMS lines.