Genetic Analysis And Mapping Of A Rice QTL QFLL6for Flag Leaf Length

Rice is one of the most important cereal crops that supplies food and nutrition for more than half of the world’s population, The super rice breeding and molecular design breeding with ideal plant type as model will be effective ways for the improvement of rice yield after the semidwarf breeding and hybrid breeding. The flag leaf shape is an important part of the ideal plant type, and the leaf length is also important for the flag leaf. Therefore, identification and characterization of quantitative trait loci(QTL) for the flag leaf length(FLL) have great theoretical and practical value for rice high-yield breeding.In this study, an near-isogenic line(NIL) was developed by advanced backcrossing with9311as the recipient and9516as the donor. The line with longer FLL was selected to build a segregating population for genetic analysis and mapping. In the population, most of the individuals had short flag leave (32.4cm on average) and slender culms while the rest had long flag leave (51.1cm on average) and thick culms, the analysis of the cross-section showed that the different thickness of the culms was caused by the different size of the stem cells. In the population, the individuals were segregated into two groups, most of the individuals in the first group had short leave and the rest in the second group had long leave, the segregation was fit for the ratio of3:1(χ2=3.075<χ20.05=3.841). the FLL was very significantly positively correlated with yield per plant、panicle number、panicle length、primary branch and grain number, but FLL was very significantly negatively correlated with setting percentage. With the260molecular markers evenly distributing on the12rice chromosomes we analysed the background of the pupolation, six imported segments were detected on chromosome1、2、6and8, we found that the imported segment between RM6395and RM20438took responsible for the leaf length segregation. To be analysed with SSR markers, the QTL was narrowed down to a region between RM20489 and S6-253, spanning about700kb.