【目的】在已鉴定的稻谷粒长、粒宽和粒厚QTL的基础上,对控制粒厚的主效QTL进行精细定位和候选基因分析,以解析川106B(C-106B)细长粒形的遗传基础,为进一步通过分子技术改良其产量水平提供科学依据。【方法】以细长粒形的优质籼稻保持系川106B与籽粒较宽厚的籼稻保持系川345B(C-345B)杂交,构建包含182个单株的F_2群体,采用QTL Catographer v2.5软件基于复合区间作图法发掘与稻谷粒形性状相关的QTL;进一步从BC_3F_2群体筛选隐性单株(稻谷厚度较薄)对粒厚主效QTL(qGT8)进行精细定位,并对候选基因进行测序和荧光定量PCR分析。分别构建qGT8位点携带川106B等位基因的近等基因系(NIL-gt8~(C-106B))和携带川345B等位基因的近等基因系(NIL-GT8~(C-345B))并调查其稻米外观品质及产量性状。【结果】川106B和川345B的粒长、粒宽和粒厚表型存在显著差异。利用F_2群体检测到2个粒长QTL、3个粒宽QTL和3个粒厚QTL,其中,位于第7染色体区间RM21892—RM3589的粒长主效QTL(qGL7)可解释粒长变异的68.23%,川106B等位基因在该位点可增加粒长0.47 mm。控制稻谷粒宽和粒厚的主效QTL(qGW8和qGT8)位于第8染色体上相同区间RM6070—RM447,分别解释相应表型变异的26.48%和34.89%,增加粒宽或粒厚的等位基因均来自于川345B。利用1 732个BC_3F_2隐性单株,将粒厚主效位点qGT8精细定位在标记SG930和SG950间的11.2 kb区段,该区段仅包含1个注释基因LOC_os08g41940(OsSPL16)。对该基因测序分析发现,川106B和川345B在起始密码子ATG上游2 kb区段存在7个差异位点,在编码区有5个多态性位点,其中,川106B在第3外显子插入2 bp(c.1006_1007插入CT)引起移码突变,且位于qGT8的OsmiR156结合位点,推测为川106B籽粒厚度变薄、宽度变细的关键位点。实时荧光定量PCR分析发现,qGT8在幼穗中表达量较高,且在川106B和川345B中的表达方式相似,表达量在1—8 cm长幼穗发育时期随幼穗发育逐渐增加,8 cm时达到最高,之后随幼穗发育逐渐降低,但2个亲本在各时期的表达水平存在差异。近等基因系NIL-GT8~(C-345B)的粒厚、粒宽、千粒重、单株产量和垩白粒率显著高于NIL-gt8~(C-106B),而粒长、透明度、株高、单株有效穗数、穗长、每穗实粒数、结实率和播抽期与NIL-gt8~(C-106B)相当。【结论】控制粒长的主效QTL(qGL7)位于第7染色体区间RM21892—RM3589,控制粒宽和粒厚的主效QTL位于第8染色体的相同区间RM6070-RM447。粒厚主效QTL(qGT8)被精细定位在仅包含GW8的片段上,是控制粒形和产量的关键基因,但在近等基因系中高粒重与高垩白紧密连锁,表明该位点存在高产与外观品质改良的矛盾。 【Objective】 Based on the identified QTLs for grain length, grain width and grain thickness, fine mapping and candidate gene analysis were conducted on major QTLs controlling grain thickness in order to analyze the slender grain shape of Sichuan 106B (C-106B) Genetic basis for further through the molecular technology to improve its level of production to provide a scientific basis. 【Method】 The F2 population containing 182 individuals was constructed by crossing slender, grain-shaped high-quality indica rice lines Daixuan 106B and a relatively wide-grained indica rice line Daqing 345B (C-345B). QTL-based Catographer v2.5 software QTLs related to grain-shape traits were explored by composite interval mapping method. Further, the QTLs for QTLs for major grain-thickness traits (QGT8) were further screened from the BC_3F_2 population and the candidate genes were sequenced and analyzed Fluorescent quantitative PCR analysis. (NIL-GT8 ~ (C-106B)) carrying the Chuan 106B allele at qGT8 and NIL-GT8 ~ (C-345B) carrying the Chuan 345B allele at qGT8 locus The rice appearance quality and yield traits were investigated. 【Result】 There were significant differences in the grain length, grain width and grain thickness phenotype between Sichuan 106B and Sichuan 345B. Two QTLs for grain length, three grain width QTLs and three QTLs for grain thickness were detected by F_2 population. Among them, qGL7, a major grain length locus located on chromosome 7 RM21892-RM3589, accounted for 68.23% , Sichuan 106B allele at this site can increase the grain length 0.47 mm. The major QTLs controlling grain width and grain thickness (qGW8 and qGT8) were located in the same region of RM6070-RM447 on chromosome 8, accounting for 26.48% and 34.89% of the corresponding phenotypic variation respectively. Increasing grain width or grain thickness alleles Are from Sichuan 345B. Using 1 732 BC_3F_2 recessive plants, the qGT8 locus was finely mapped to the 11.2 kb region between SG930 and SG950, which contained only one annotation gene, LOC_os08g41940 (OsSPL16). Sequence analysis of this gene revealed that there were 7 different sites in the 2 kb upstream of ATG in Sichuan 106B and Sichuan 345B and 5 polymorphic sites in the coding region, Exon insertion at 2 bp (c.1006_1007 insertion CT) caused a frameshift mutation, and located at the OsmiR156 binding site of qGT8, which was presumed to be the key point for the thickness and width of Chuan 106B to be thinner. Quantitative real-time PCR analysis showed that qGT8 expressed higher in panicle, and expressed in Sichuan 106B and Sichuan 345B in a similar manner. The expression level of qGT8 increased gradually with the development of young panicles at the age of 1-8 cm cm, then decreased with young panicle development, but the expression levels of the two parents were different at different stages. The grain size, grain width, grain weight, grain yield per plant and chalkiness rate of NIL-GT8 ~ (C-345B) were significantly higher than that of NIL-gt8 ~ (C-106B) High, the number of panicle per panicle, panicle length, grain number per panicle, seed setting rate and sowing date were similar to those of NIL-gt8 ~ (C-106B). 【Conclusion】 The major QTL controlling grain length (qGL7) is located on chromosome 7 RM21892-RM3589. The major QTLs controlling grain width and grain thickness are located in the same interval RM6070-RM447 on chromosome 8. The major grain-thickness QTL (qGT8) was finely mapped on the fragment containing only GW8 and was the key gene controlling grain size and yield, whereas the high grain weight was closely linked to high chalkiness in the near-isogenic lines, indicating that the locus Contradiction between high yield and appearance quality improvement.