水稻大剑叶角度有利于免割叶机械化繁殖制种。本申请项目拟在前期对剑叶角度QTLqFla8-2精细定位和候选基因分析的基础上，通过qRT-PCR,结合候选基因DNA序列分析，确定大剑叶角度等位基因qFla8-2-L；构建qFla8-2-L的植物转化载体，进行转基因互补验证；利用近等基因系和转基因后代分析qFla8-2-L在组织器官中的时空表达；根据测序数据，结合生物信息学分析，阐明qFla8-2-L等位基因的作用机理。调查不同地理来源水稻342份种质qFla8-2位点等位基因多态性，分析qFla8-2位点等位基因的演变规律。利用具有显性的紫色叶片性状的品种为父本，与qFla8-2位点近等基因系相间种植，根据F1代中紫叶出现频率，评价qFla8-2-L的繁殖制种利用价值。

Large flag leaf angle is a beneficial trait to hybrid rice seed production by using machine since leaf-cutting labour at heading stage could be relieved. In our early research, a gene locus QTLqFla8-2, underlying flag leaf angle, was finely mapped, and its cadidate genes were predicted by searching against the related rice genome annotation database. On this basis, through detecting the expression characteristics of candidate genes by qRT-PCR, combined with sequencing results of genome DNA of candidate genes, qFla8-2-L allele will be confirmed. Plant transformation vector will be constructed and transgenic function confirmation will be done for qFla8-2-L. Temporal and spatial expression of qFla8-2-L in tissues and organs will be analyzed using near-isogenic lines and transgenic offsprings. The mechanism of qFla8-2-L on enlarged flag leaf angle will be elucidated by applying bioinformatics methods according to the sequencing results. The evolution of alleles at qFla8-2 locus and its relationship with domestication of rice will be studied by investigating and analyzing the allelic polymorphism at qFla8-2 locus in 342 accessions of cultivated rice collected from different geographic origin.The application value of qFla8-2-L in hybrid seed production will be evaluated according to the frequencies of plants with purple leaf in the F1 populations obtained by crossing the near-isogeneic lines with pollen parent with dominant purple leaf trait.