Molecular Marker-assisted Selection For Photoperiod Sensitivity In Rice

Rice photoperiod sensitivity (PS) is defined as characteristics of the heading date related with daylight, which is the basic physiological feature in rice. We can obtain rice variety that is suitable for the ecotype of late rice if the photoperiod sensitivity type is selected. In present study, donor materials carrying a pair of PS complementary genes were used to breed cultivated photosensitive lines of hybrid rice by hybridization and backcross combined with marker-assisted selection (MAS). The main results of the study are summarized as follows:1. By marker-assisted backcross breeding, A PS gene was respectively introgressed into maintainer lines Te B, Meng B etc and restorer lines R29etc, and breeding lines with the PS gene were obtained.2. The improved Te B, Meng B lines which carried a PS complementary gene were crossed with the corresponding male sterile lines, respectively, and the improved PS lines, Te A and Meng A, were obtained finally.3. The average of MAS efficiency was84%with the highest100%which was derived from the heading date of progenies with PS marker compared to their recurrent parent.4. Te A with a PS complementary gene was crossed to restorer parents that were not photosensitive in order to study the heterosis of progenies. Three rice lines with significant yield heterosis were obtained.5. Seventeen genetically stable lines with PS complementary gene were obtained from200breeding lines through screening for the PS complementary gene on Chr.8. These lines are being used for hybrid rice breeding.Study results showed that MAS combined PS verification is the most effective method in order to transfer PS complementary gene into good male sterile lines and restorer lines. The achieved results in the stage would set a solid foundation for good photosensitive hybrid rice.