High-density genetic mapping is a valuable tool for mapping loci that control specific traits for perennial fruit trees. Peach is an economically important fruit tree and a model Rosaceae species for genomic and genetic research. In peach, even though many molecular markers, genetic maps and QTL mappings have been reported, further research on the improvement of marker numbers, map densities, QTL accuracy and candidate gene identification is still warranted. A high-density single nucleotide polymorphism (SNP)-based peach linkage map was constructed using specific locus amplified fragment sequencing (SLAF-seq). This genetic map consisted of 7998 SLAF markers, spanning 1098.79 cM with an average distance of 0.17 cM between adjacent markers. A total of 40 QTLs and 885 annotated candidate genes were detected for 10 fruit-related traits, including fruit weight (FW), fruit diameter (FD), percentage of red skin colour (PSC), eating quality (EQ), fruit flavour (FV), red in flesh (RF), red around pit (RP), adherence to pit (AP), fruit development period (FDP) and fruit fibre content (FFC). Eighteen QTLs for soluble solid content (SSC) were identified along LGs 1, 4, 5, and 6 in 2015 and 2016, and 540 genes were annotated in QTL intervals. Thirty-two QTLs for fruit acidity content (FA) were detected on LG1, and 2, 4, 5, 6, and 1232 candidate genes were identified. The expression profiles of 2 candidate genes for SSC and 4 for FA were analysed in parents and their offspring. We constructed a high-density genetic map in peach based on SLAF-seq, which may contribute to the identification of important agronomic trait loci. Ninety QTLs for 12 fruit-related traits were identified, most of which overlapped with previous reports, and some new QTLs were obtained. A large number of candidate genes for fruit-related traits were screened and identified. These results may improve our understanding of the genetic control of fruit quality traits and provide useful information in marker-assisted selection for fruit quality in peach breeding programmes.

中文翻译：

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高密度基于SNP的遗传图谱的构建及桃相关果实QTL和候选基因的鉴定[Prunus persica（L.）Batsch]。

高密度遗传作图是对控制多年生果树特定性状的基因座作图的有价值的工具。桃是一种经济上重要的果树，是用于基因组和遗传研究的蔷薇科树种。在桃子中，尽管已经报道了许多分子标记，遗传图谱和QTL图谱，但仍需要对标记数，图谱密度，QTL准确性和候选基因鉴定进行进一步的研究。使用特定的基因座扩增片段测序（SLAF-seq）构建了一个基于高密度单核苷酸多态性（SNP）的桃链图。该遗传图谱由7998个SLAF标记组成，跨度为1098.79 cM，相邻标记之间的平均距离为0.17 cM。共检测到40个QTL和885个带注释的候选基因，涉及10个与水果相关的性状，包括水果重量（FW），水果直径（FD），红色皮肤百分比（PSC），进食品质（EQ），水果风味（FV），果肉红色（RF），坑周围红色（RP），坚持坑（AP），果实发育期（FDP）和果实纤维含量（FFC）。在2015年和2016年，沿着LG 1、4、5和6鉴定出18个可溶性固形物（SSC）QTL，并在QTL间隔中注释了540个基因。在LG1上检测到32个水果酸度（FA）的QTL，并鉴定了2、4、5、6和1232个候选基因。在父母及其后代中分析了SSC的2个候选基因和FA的4个候选基因的表达谱。我们基于SLAF-seq构建了桃子的高密度遗传图谱，这可能有助于重要农艺性状基因座的鉴定。确定了针对12个与水果相关的性状的90个QTL，其中大多数与以前的报告重叠，并且获得了一些新的QTL。筛选和鉴定了与水果相关性状的大量候选基因。这些结果可能会增进我们对果实品质性状遗传控制的理解，并为桃育种计划中果实品质的标记辅助选择提供有用的信息。