| At Present, mostly rice(Oryza sativa L.) breeding is conventional.It have much potential in breeding of hybrid vice(Oryza sativa L.). Hybrid rice seed production requires man-assisted pollination in order to enhance rate of outcrossing seed. In practice, the blade of flag leaf was cut by 1/2 to 1/3 to eliminate obstacle for outcrossing in CMS lines and restorer lines with small flag leaf angle. This procedure of leaf-cutting requires not only high-intensity laborious work, but also a higher level of operative technique in order to avoid cutting into young panicles being heading. In addition, wounds caused by leaf-cutting also had adverse effect on normal growth of rice plants. Identifiying favorable alleles of flag leaf angle is a foundation for improving the characters relating to outcrossing of male sterile lines through pyramiding merit alleles. Improving flag leaf angle of male sterile lines have important role in increasing yield and lowering cost of hybrid rice seed production. In this thesis, three studies have been conducted. Fistly, R254 was crossed and backcrossed to ningjing 1 and wujing 15. BC2F2 been identified with SSR marker RM5629. Secondly, QTLs for FLA were detected by in the BC1F1 population(9311/A7466//9311) the resuls obtained were as follows:1. Secondly, R254 was crossed and backcrossed to ningjing 1 and wujing 15. BC2F2 been identified with SSR marker RM5629.Three genotype BC2F2 been cross to BT-6427A and BT-9522A. restorer gene has been introduced to ningjing 1 and wujing 15 identified from panicle seed setting rate of F1. Result of agronomic traits in R14-8:plant height95±1.0cm, seed set rate97.0±1.3%, ratio of infected hole 0%, the 8 SSR markers linked with qSTV-11 b and qSTV-11c amplified no difference between R14-8 and ningjing 1.2.106 of polymorphyic SSR primers were found between 9311 (P1) and A7466 (P2), by amplying the total DNA from the two parents among 439 pairs of SSR primers amplified. The rate of polymorphism was 24.1%. With the 106 SSR markers, SSR marker genotypes of the 70 plants were identified. Heterozygosity marker genotype and homozygous marker genotype of 9311 consistent with the 1:1 overall segregation one markers occurred segregation distortion. The recurrent parent genetic material response rate ranged from 60.38%-84.90%,, with an average of 75.82% for 70 plants.Use JoinMap 3.0 software was employed to construct genetic linkage map.The genetic map containing 17 linkage groups and 95 information loci has a total distance of 3599.2 cM, averaging 37.9 cM between two loci. Flag leaf angles were investigated at heading stage. Seven QTLs of flag leaf angle were detected. They located on chromosome4,5,7 and 8. qFLA-4 located between RM518- and RM5951 on chromosome 4 explained 56.09% of phenotypic variance. qFLA-5a located between RM3068 and RM459 on chromosome 5 explained 48.21% of phenotypic variance. qFLA-5b located between RM5720 and RM21 on chromosome 5 explained 47.99% of phenotypic variance. qFLA-a located between RM336 and RM5455 on chromosome 7 explained 21.68% of phenotypic variance. qFLA-7b located between RM5720 and RM214 on chromosome 7 explained 7.77% of phenotypic variance. qFLA-8 located between RM152 and RM8423 on chromosome 8 explained 7.77% of phenotypic variance. qFLA-9 located between RM8206 and RM5786 on chromosome 9 explained 7.77% of phenotypic variance. qFLA-4, qFLA-5a, qFLA-5b, and qFLA-9 positive alleles came from A7466. qFLA-7a qFLA-7b and qFLA-8 positive alleles came from 9311. |
