| As one of the backbone parents currently used in hybrid rice breeding Shuhui 527 has many merits, such as high general combining ability, strong heterosis of hybrid combination, and many derivative R-lines. In order to clarify the genetic composition and the key genome regions of yield related characters of Shuhui 527, genomic scanning and QTLs analysis of Shuhui 527 were performed in this study. Main results were as the following:1. The genetic composition and the key genome regions of yield related characters of Shuhui 527 were defined by genomic scanning and hereditas analysis of yield related traits.(1). The results showed that seed-setting rate, filled grain number per panicle, grain number per panicle and panicles were possibly derived from the pedigree of IR24-Shuhui527; the weight of a thousand seeds, plant weight and panicles were possibly derived from the pedigree of Gui630-R1318-Shuhui 527.(2).The genetic originated map of Shuhui 527 and its related ancestral parents were constructed by genomic scanning of materials in the pedigree with 1050 SSR primers. The results revealed that①the shared fragments of all varieties (i.e. none polymorphic fragments) accounted for 62.94%;②putative multi-originated fragments (polymorphic marker was unable to identify its origin) accounted for approximately 17.53%;③in the breeding process of Shuhui 527, R1318 had contributed 13.68% fragments, Fu36-2 had contributed 0.53% fragments, and IR24 had contributed 1.32% fragments;④Shuhui 527 had contributed 4% itself fragments.(3). The key genome regions of Shuhui 527 was initially determined by the results of genomic scanning and hereditas analysis of yield related traits. Yield related key genormic regions of Shuhui527 were involved of those regions called Shuhui527 specific fragments, IR24 Originated fragments and R1318 originated fragments.2. Using 288 G46B×Shuhui527 F2 descendants as mapping population, we constructed a rice SSR linkage map. By means of SSR linkage map, quantitative trait loci (QTLs) with 6 yield related traits including 1000-grain weight, Filled grain number per panicle, Grain number per panicle, seed setting rate, Pancile number, and Weight per plant were positioned and analyzed. Main results were as the following:(1).244 SSR markers coming from 1895 SSR markers overlaying the rice genome had expressed polymorphism in both G46B and Shuhui527, polymorphism frequency was 12.88%.(2).We constructed a molecular genetic map included 102 pairs of SSR markers which covered 2256.2 cM of rice genome, and the average distance between two markers spanned 22.12 cM with the population of G46BXShuhui527 F2. Two linkage groups of the chromosome 2 covered the longest (550.3cM) genome region, and the the linkage group of the chromosome 11 is the shortest (57.9 cM). The longest average distance between two markers spanned 34.1 cM and the shortest average distance between two markers spanned 14.48 cM, respectively. The linkage relationship of the markers was almost identical to previous studies.(3). A total of 17 yield related QTLs were detected on chromosome 1,2, 4,5,7,8, respectively. Variation percentage explained by individual QTL ranged from 3.02% to 20.73%, out of which 5 QTLs explained more than 10% phenotypic variation and 3 QTLs explained less than 5% phenotypic variation. The detailed informations of 17 QTLs were as the following:①Three QTLs were detected for 1000-grain weight, named qKGW-2-1, KGW-2-2 and qKGW-8-1. Totally, they explained 20.2% of the phenotypic variation. Among them, the qKGW-2-1 and qKGW-2-2 in the marker interval RM3316～RM3774 and RM3680～RM6853 of chromosome 2,accounting for 6.99% and 5.17% variation, respectively, the qKGW-8-1 were located in the marker interval RM1019-RM6925 of chromosome 8, accounting for 7.88% variation. The additive effects of qKGW-2-1 and qKGW-8-1 came from the male parent Shuhui527, however qKGW-2-2 came from the female parent G46B. The dominant effects of qKGW-2-1 and qKGW-8-1came from thefemale parent G46B, however qKGW-2-2 came from the male parent Shuhui527。②Three QTLs were detected for filled grain number, named qFGP-1-1, qFGP-2-1, and qFGP-4-1. Totally, they explained 30.16% of the phenotypic variation. Among them, the qFGP-1-1 in the marker interval RM1003-RM8084 of chromosome 1, accounting for 9.30% variation, the qFGP-2-1 were located in the marker interval RM3692～RM208 of chromosome 2, accounting for 16.58% variation. the qFGP-4-1 in the marker interval RM8213～RM3658 of chromosome 4, accounting for 4.28% variation. The additive effects of qFGP-2-1 and qFGP-4-1 came from the male parent Shuhui527, however qFGP-1-1 came from the female parent G46B. The dominant effects of qFGP-1-land qFGP-2-1came from the female parent G46B, however qFGP-4-1came from the male parent Shuhui527。③Two QTLs were detected for grain per panicle, named qGPP-2-land qGPP-4-1. Totally, they explained 10.13% of the phenotypic variation. Among them, the qGPP-2-1 in the marker interval RM3316-RM3774 of chromosome 2, accounting for 7.11% variation, the qGPP-4-1 were located in the marker interval RM7051～RM7187 of chromosome 4, accounting for 3.02% variation. The additive effects of qGPP-2-1 came from the male parent Shuhui527, however qGPP-4-1 came from the female parent G46B. The dominant effects of qGPP-2-land qGPP-4-1 came from thefemale parent G46B。④Five QTLs were detected for seed setting rate, named qSS-1-1, qSS-2-1, qSS-7-1, qSS-7-2 and qSS-8-1. Totally, they explained 43.86% of the phenotypic variation. Among them, the qSS-1-1 in the marker interval RM5718- RM5919 of chromosome 1, accounting for 8.69% variation, the qSS-2-1 were located in the marker interval RM3692-RM208 of chromosome 2, accounting for 11.72% variation, the qSS-7-1 in the marker interval RM3831～RM5344 of chromosome 7, accounting for 7.92% variation. the qSS-7-2 were located in the marker interval RM3635～RM7110 of chromosome 7, accounting for 12.49% variation. the qSSS-1 were located in the marker interval RM7057-RM6010 of chromosome 8, accounting for 3.04% variation. The additive effects of qSS-1-1,qSS-2-land qSS-7-1 came from the male parent Shuhui527, however qSS-7-2 and qSSS-1 came from the female parent G46B. The dominant effects of qSS-7-2 came from the female parent G46B, however qSS-1-1 qSS-2-1,qSS-7-1 and qSS-8-1 came from the male parent Shuhui527。⑤Two QTLs were detected for panicle number, named qPN-5-1 and qPN-8-1. Totally, they explained 25.89% of the phenotypic variation. Among them, the qPN-5-1 in the marker interval RM7653～RM3663 of chromosome 5, accounting for 5.16% variation, the qPN-8-1 were located in the marker interval RM4955-RM7057 of chromosome 8, accounting for 20.73% variation. The additive effects of qPN-5-land qPN-8-1 came from the female parent G46B. The dominant effects of qPN-5-land qPN-8-1 came from the female parent G46B.⑥Two QTLs were detected for yield per plant, named qGYD-2-1 and qGYD-8-1. Totally, they explained 15.92% of the phenotypic variation. Among them, the qGYD-2-1 in the marker interval RM3355-RM6318 of chromosome 2, accounting for 5.34% variation, the qGYD-8-1 were located in the marker interval RM4955-RM7057 of chromosome 8, accounting for 10.58% variation. The additive effects of qGYD-2-1 came from the male parent Shuhui527, however qGYD-8-1 came from the female parent G46B. The dominant effects of qGYD-2-land qGYD-8-1 came from the female parent G46B.(4) 288 F2 individuals derived from G46B and Shuhui527 were used to construct a genetic linkage map. Among the 131 markers,15 SSR markers, occupying 11.5% of the difference SSR markers showed genetic segregation distortion(P<0.05). RM5586, RM6554 and RM8121 inclined to the genotype of G46B;RM594,RM1092,RM5665,RM3308,RM20285 and RM336 inclined to the genotype of Shuhui527; RM6717, RM1339 and RM1364 inclined to the genotype of both G46B and Shuhui527,less heterozygous genotype;RM8240 and RM1384 inclined to the heterozygous genotype, less isozygoty genotype;RM3572 inclined to the genotype of both G46B and heterozygous genotype.3 Candidate yield related QTLs in key fragments of Shuhui 527The candidate QTLs of Shuhui 527 was initially determined by comparing the results of the key genomic fragments and the QTL locations and effects. Comparation suggested that qKGW-2-1,qKGW-2-2 and qKGW-8-1 for 1000-grain weight, qGYD-2-1 for weight per plant, qFGP-2-1 and qFGP-4-1 for filled grain number, qGPP-2-1 for grain per panicle, qSS-1-1,qSS-2-1,qSS-7-1 and qSS-8-1 for seed setting rate were candidate QTLs for the yield related traits of Shuhui 527.Besides, some other potential candidate QTLs were also discussed by integrating their genomic locations reported previously to the key genomic fragments of Shuhui 527.
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