Spike density (SD), an important spike morphological trait associated with wheat yield, is the spikelet number per spike (SNS) divided by spike length (SL). In this study, phenotypic data from eight environments were collected and a recombinant inbred line population (RIL) constructed by the wheat line 20828 and the cultivar 'Chuannong16' and a Wheat55K SNP array‐based constructed genetic linkage map were used to identify SD quantitative trait locus (QTL). Correlation between SD and other agronomic traits was calculated. Genes associated with plant growth and development for major loci were predicted. The results showed that 24 QTLs associated with SD were detected in eight environments. Among them, three major QTL, namely QSd.sicau‐5B.2, QSd.sicau‐2D.3 and QSd.sicau‐4B.1, explained up to 35.62%, 14.21% and 11.23% of phenotypic variation, respectively. The positive alleles of them were all derived from 'Chuannong16'. The significant relationships between SD and other agronomic traits were detected and discussed. Taken together, the stably expressed SD QTL under different environments identified in this study provided theoretical guidance for further fine mapping and germplasm improvement.

中文翻译：

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在多种环境中几个稳定表达普通小麦穗密度的QTL

穗密度（SD）是与小麦产量相关的重要穗形态特征，是穗的小穗数（SNS）除以穗长（SL）。在这项研究中，收集了来自八个环境的表型数据，并使用小麦20828品系和'Chuaannong16'品种构建了一个重组自交系种群（RIL），并使用了基于Wheat55K SNP阵列构建的遗传连锁图谱来鉴定SD数量性状位点（QTL）。计算了SD与其他农艺性状之间的相关性。预测了与主要基因座的植物生长和发育相关的基因。结果表明，在8个环境中检测到24个与SD相关的QTL。其中，三个主要的QTL，即QSd.sicau-5B.2，QSd.sicau-2D.3和QSd.sicau-4B.1分别解释了多达35.62％，14.21％和11.23％的表型变异。它们的阳性等位基因均来自“ Chuanong16”。SD和其他农艺性状之间的重要关系进行了检测和讨论。综上所述，本研究确定的在不同环境下稳定表达的SD QTL为进一步的精细作图和种质改良提供了理论指导。