Genetic Analysis And Fine Mapping Of Grain Shape In Rice Landrace Pangxiegu(Oryza Sativa L. Ssp Japonica)

Rice is one of the most important food in the world, increase grain production is of great significance. Rice yield characters belong to quantitative traits, which is largely decided by panicles, grain number per panicle, grain weight, etc. Grain shape is specified by grain length, width and thickness, which is the determinant of grain weight. Grain shape is not only affect the yield of rice, but also affect the quality of rice, rice grain shape research has important guiding significance for breeding.To better understand the genetic characteristics of grain shape in rice, we chose a large grain variety Pangxiegu (japonica) and a narrow grain variety N643 (indica) as the parental lines, the 93-11(indica) with the small grain varieties SWWR(indica) from Sri Lanka to hybridization, Selfing, backcross, gradually resolved grain QTL, combined with the use of molecular markers and phenotypic analysis, locate QTL grain shape. The results summarized as follows:First, we used F4 grain length separation genealogy crossed by Pangxiegu and N643, grain length for QTL detection, found three long grain QTL loci. The QTL located in chromosome 3 between RM15280 and RM15164 is anastomosed with the GS3, another QTL located in the chromosome 1 between RM7564 and RM1132 is qGS7. Located in the chromosome 1 between RM258 and RM583, need to further build group to locate.Second, in the BC2 groups, we detected a new grain width of main effect QTL, qGW5.2,located in the chromosome 5 between RMw513 and RM 18068, the LOD value is 17.5, explain 57.3% of the phenotypic variation, the loci increase grain width from Pangxiegu, according to the preliminary mapping of qGW5.2, we construct a large population for the follow fine mapping, developing new InDel markers, and the exchange of plant markers and phenotypic analysis, finally, the region of qGW5.2 was narrow down to a 140kb interval between molecular marker L513 and L529, and there are thirteen ORFs was predicted from the Rice Genome Browser.the area was about kb near GW5/qSW5,six. of them expressed in inforescence, clever shell, young panicle tissue.Third, in addition, by using the BC2F2 population crossed by 93-11 and SWWR, we found a main grain length effect QTL on chromosome 3,which was the same region as the cloned gene GS3.