Genetic Mapping Of Quantitative Trait Locifor Heading Date And Stigma Exsertion Of Male Sterile Line In Rice

Heading date is one of the key elements for the rice yield; Rice stigma exsertion is an important agronomic trait, which not only affects the outcrossing rate of male sterile line for hybrid rice combinations, but also is an important entry point for research in rice domestication. Therefore, to investigate the genetic basis of heading date and stigma exsertion is of great significance for breeding. The main results were showed as follows:1. In this study, a recombinant inbred line(RILs) population derived from a cross of Zhongguo Xiangdao(ZX) and Chuanxiang 29B(CX29B), was used to map QTL for heading date. A total of nine QTL, namely q Hd1 a, q Hd1 b, q Hd4, q Hd6 a, q Hd6 b, q Hd6 c, q Hd7, q Hd8 a and q Hd8 b, were detected in two years, which were located on chromosomes 1, 4, 6, 7 and 8, respectively, and accounted for the phenotypic variance ranging from 3.31% to 26.64%. Among that, q Hd1 a, q Hd6 b, q Hd6 c, q Hd7 and q Hd8 b were all repeatedly detected in two years. q Hd1 a, flanked by RM3746 and RM259 on chromosome 1, is a novel minor QTL for heading date, explaining 8.21% of the phenotypic variance. A BC3F2 near isogenic lines(NILs) population for q Hd1 a was developed using the method of marker-assisted selection(MAS), and used to analyze its genetic effect. Compared with the NIL carrying homozygous q Hd1 a region from CX29B(NIL(q Hd1aCX29B)), the NIL carrying homozygous q Hd1 a region from ZX(NIL(q Hd1aZX)) showed 7 days longer before heading, which was significant. Therefore, q Hd1 a could be of great use in regulating heading date during rice breeding.2. A F2 population derived from a cross of Dodda(indica)×Guangzhan63S(indica, Photosensitive male sterile line), was constructed and used to map QTL for heading date. A total of six QTL, namely q Hd1-1, q Hd1-2, q Hd1-3, q Hd2-1, q Hd4-1 and q Hd5-1, for heading date were detected, which were located on chromosomes 1, 2, 4 and 5, respectively, and accounted for the phenotypic variance ranging from 1.77% to 18.58%. Among that, q Hd1-1 is co-located with q Hd1 a from the CX29B/ZX RIL population, demonstrating the truth of QTL.3. The experiment was conducted using a F2 population derived from a cross of Dodda(indica)×Guangzhan63S(indica, Photosensitive male sterile line), two parents exhibiting high and low percentage of exserted stigma respectively, which was used to map QTL for stigma exsertion. A total of six QTL, namely q SPES-1, q SPES-5, q SPES-6-1, q SPES-6-2, q SPES-11-1 and q SPES-11-2, for SPES(%) and a total of five QTL, namely q DPES-1, q DPES-5, q DPES-6-1, q DPES-6-2 and q DPES-11-2, for DPES(%) were detected, which were located on chromosomes 1, 5, 6 and 11, respectively. These QTLs explained 0.26%~15.32% and 1.40%~13.09% of the phenotypic variations for SPES(%) and DPES(%), respectively.