Grain size and shape are important for grain yield and quality in rice (Oryza sativa L.). Grain thickness (GT) is one of the constituent characteristics of grain shape and has a strong influence on grain weight in rice. In this study, a japonica cultivar (02428) with a thick grain phenotype was crossed with an indica cultivar (YZX) with a thin grain phenotype to construct a set of 192 recombinant inbred lines (RILs). Quantitative trait locus (QTL) analysis was performed with a high-density genetic map harbouring 2711 bin markers. We identified 6 QTLs for GT in three environments and two stable QTLs with high heritability residing on the known grain width (GW) genes GW5 and GL7/GW7, verifying the effectiveness and reliability of our study. We detected a novel QTL on chromosome 9 with strong association signals for both GW and GT. Using transcript profiles and quantitative RT-PCR, we identified a candidate gene, Os09g0535500, which encodes a zinc finger C3HC4-type domain, that showed the highest expression level and significant differential expression between parents in the development of young panicle and grain. Further haplotype-phenotype association analysis revealed that Os09g0535500 was strongly correlated with GW and GT. Thus, our results indicated that Os09g0535500 was the most promising candidate gene in WTG9 and is likely important for rice grain development, which lays a foundation for further functional validation and breeding utilization.

谷物的大小和形状对于水稻（Oryza sativa L.）的谷物产量和品质至关重要。谷粒厚度（GT）是谷粒形状的组成特征之一，并且对稻米的谷粒重量有很大影响。在这项研究中，一个粳稻品种（02428）用粗颗粒的表型，用一个交叉籼稻品种（YZX）具有薄的颗粒的表型来构造一组192个重组近交系（RIL）。使用包含2711个bin标记的高密度遗传图进行定量性状基因座（QTL）分析。我们在三种环境中确定了6个用于GT的QTL，并在已知的晶粒宽度（GW）基因GW5和GL7 / GW7上存在两个具有高遗传力的稳定QTL。，验证我们研究的有效性和可靠性。我们在9号染色体上检测到一个新的QTL，对GW和GT均具有强的缔合信号。使用转录本谱和定量RT-PCR，我们鉴定了一个候选基因Os09g0535500，该基因编码一个锌指C3HC4型结构域，该基因在幼穗和谷粒的发育中表现出最高的表达水平和父母之间的显着差异表达。进一步的单倍型-表型关联分析表明，Os09g0535500与GW和GT密切相关。因此，我们的研究结果表明，Os09g0535500是最有希望的候选基因WTG9 可能对稻米的发育很重要，这为进一步的功能验证和育种利用奠定了基础。