Mapping Of QTL Associated With Panicle Traits In The Rice Variety, R1126

The rice panicle related traits are the main factors determined to rice yield. To breed rice variety with large panicle has become a main objective in high-yield rice breeding. The panicle traits are mostly controlled by quantitative trait loci. Mapping of QTL associated with rice panicle traits is of great importance for reveal the genetic mechanisms of the large panicle in rice and breed high yielding rice varieties. In this study, a set of recombinant inbred line (RIL) population derived from a cross of the indica rice R1126and the japonica rice Nipponbare (NPB), was developed to identify quantitative trait loci (QTL) for panicle related traits. The main research results are as the following:1. The continuous distributions were observed for all panicle related traits, which includes plant height (PH), panicle length (PL), grain number per panicle (GNP), primary branch number (PBN), secondary branch number (SBN), filled grain per panicle (FGP) and seed setting rate (SSR), in the NPB/R1126RIL population containing217lines. All the traits except SSR show normal distribution. The correlations between each two traits were significantly at the level of1%. The most significantly correlation was observed between the secondary branch number and grain number per panicle.2.362pairs of primers, which show polymorphism between the parent R1126and Nipponbare, were screened from848pairs of SSR primers and66pairs of SFP primers. Among them,122pairs of primers, which evenly distributed on the12chromosomes of the rice genome, were used to construct the genetic linkage map. The linkage map, which with an average distance of9.9cM between adjacent markers, spanned1205.6cM in length for the whole genome.3. Seventeen QTL for six panicle traits except the trait of PBN, were located in the fourteen marker intervals on the chromosome1,2,3,5,6,7and11.2,4,3,1,4and3QTL were detected for PH, PL, GNP, FGP, SSR and SBN, respectively. The LOD score of the seventeen QTL, which explained the phenotypic variation of3.94%-59.09%, ranged from2.53to25.31. Interesting, four QTL controlling PL, FGP, SSR and SBN, respectively, were detected in the marker interval of RM420-RM427on chromosome7. Two QTL associated with GNP and SBN were also detected in the same chromosome interval of RM254-RM7557on chromosome11. The results of this study provided a basis for further fine mapping the gene of panicle traits and breeding large-panicle yielding rice varieties by molecular marker-assisted selection.