Two major QTL, one for shelf life that corresponds to qSL4 and one, qDEV7, for developmental rate, were identified. Associated markers will be useful in breeding for improved fresh-cut lettuce. Fresh-cut lettuce in packaged salad can have short shelf life, and visible deterioration may start within a week after processing. Yield and developmental rate are an important aspect of lettuce production. Genetic diversity and genome-wide association studies (GWAS) were performed on 493 accessions with the genotypic data of 4615 high-quality single nucleotide polymorphism markers. Population structure (Q), principal component (PC), and phylogenetic analyses displayed genetic relationships associated with lettuce types and geographic distribution. Data for shelf life, yield, developmental rate, and their stability indices were used for statistical analysis, and GWAS was performed by general and mixed linear models. The genetic relationship among the individuals was incorporated into the models using kinship matrix, PC, and Q. Broad-sense heritability (H2) across environments was 0.43 for shelf life, 0.36 for yield, and 0.60 for developmental rate. There was a negative correlation between yield and developmental rate. Significant marker-trait association (SMTA) was detected for shelf life on chromosome 4. The most significant quantitative trait locus (QTL, qSL4, P = 2.23E-17) explained 24% of the total phenotypic variation (R2). The major QTL for developmental rate was detected on chromosome 7 (qDEV7, P = 2.43E-16, R2 = 17%), while additional QTLs with smaller effect were found in all chromosomes. No SMTA was detected for yield. The study identified lettuce accessions with extended and stable shelf life, stable yield, and desirable developmental rate. Molecular markers closely linked to traits can be applied for selection of preferable genotypes and for identification of genes associated with these traits.

中文翻译：

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全基因组关联图谱揭示了生菜保质期和发育速率的位点。


确定了两个主要 QTL，一个对应于 qSL4 的保质期，另一个对应于发育速率的 qDEV7。相关标记将有助于改良鲜切生菜的育种。包装沙拉中的鲜切生菜保质期较短，加工后一周内可能会开始明显变质。产量和发育速度是生菜生产的一个重要方面。对493份材料进行了遗传多样性和全基因组关联研究（GWAS），并获得了4615个高质量单核苷酸多态性标记的基因型数据。群体结构（Q）、主成分（PC）和系统发育分析显示了与生菜类型和地理分布相关的遗传关系。利用货架期、产量、发育率及其稳定性指标的数据进行统计分析，并通过一般线性模型和混合线性模型进行GWAS。使用亲属关系矩阵、PC 和 Q 将个体之间的遗传关系纳入模型中。跨环境的广义遗传力 (H2) 的保质期为 0.43，产量为 0.36，发育率为 0.60。产量与发育率呈负相关。在 4 号染色体上检测到保质期的显着标记-性状关联 (SMTA)。最显着的数量性状位点 (QTL、qSL4、P = 2.23E-17) 解释了总表型变异 (R2) 的 24%。发育率的主要 QTL 在 7 号染色体上检测到（qDEV7，P = 2.43E-16，R2 = 17%），而在所有染色体上都发现了影响较小的附加 QTL。没有检测到 SMTA 的产量。该研究确定了生菜品种具有延长且稳定的保质期、稳定的产量和理想的发育速度。 与性状密切相关的分子标记可用于选择优选的基因型并鉴定与这些性状相关的基因。