Watermelon is an economic horticultural crop of the Cucurbitaceae family. An in-depth genetic understanding of fruit and seed associated traits is important for the effective breeding of watermelon. In the present study, we conducted genotyping by sequencing (GBS)-based high-resolution genetic mapping and performed QTL mapping of twelve horticultural traits using segregated mapping populations (F₂ and F_2:3) derived from the breeding of two contrasting inbred parent lines. The developed genetic linkage map comprised of 6,164 SNP loci and 1,004 bins, which spanned a total genetic length of 1,261.13 cM with an average interval of 1.26 cM (329.31 kb) between adjacent whole-genome markers. Overall, a total of 34 QTLs were identified, and 16 QTLs exhibited moderate and major-effect QTLs; however, 25 were novel QTLs that were not identified in earlier studies. The mapped genetic loci of RC, RSP, and FFC traits were identified as closely overlapping with previously reported loci and exhibited delimited genetic intervals located on chromosomes 8, 6, and 4, respectively. The identified novel QTL (qfd2.1) of FD and QTL (qfl2.1) of FL were tightly localized with QTL (qfsi2.1) of FSI over chromosome 2, but a minor QTL (qfw3.2) positioned on chromosome 3 was consistent with previously published QTLs (qfd3.1, qfl3.1, and qfsi3.1) of fruit shape. A total of five minor-effect QTLs (qbcc2.1, qbce2.1, qbce2.2, qbcc5.1, and qbce5.1) identified in the novel genetic region which controlled the average Brix content of edible fruit. The seed width QTL (qsw10.1) was found to be localized with 20-seed weight QTL (q20swt10.1) on chromosome 10. The collected phenotypic dataset of two environmental experiments across the two years also revealed highly significant correlations among fruit and seed traits. Hence, we concluded that our GBS-based identified novel QTLs positions would expand powerful molecular breeding prospects for the genetic improvement of quality-related traits of watermelon.

西瓜是葫芦科的经济园艺作物。深入了解果实和种子相关性状的遗传对西瓜的有效育种非常重要。在本研究中，我们通过基于测序 (GBS) 的高分辨率遗传作图进行基因分型，并使用分离的作图群体 (F ₂和 F _{2:3 ) 对 12 个园艺性状进行 QTL 作图。}) 来自两个对比鲜明的近交亲本系的育种。开发的遗传连锁图由 6,164 个 SNP 位点和 1,004 个 bin 组成，总遗传长度为 1,261.13 cM，相邻全基因组标记之间的平均间隔为 1.26 cM (329.31 kb)。总体而言，共鉴定出34个QTL，其中16个QTL表现出中效和重效QTL；然而，有 25 个是早期研究中未发现的新 QTL。RC、RSP 和 FFC 性状的映射遗传基因座被确定为与先前报道的基因座密切重叠，并分别显示位于染色体 8、6 和 4 上的定界遗传区间。FD的新QTL ( qfd2.1 ) 和FL的QTL ( qfl2.1 ) 与QTL ( qfsi2.1 ) 紧密定位。) 的 FSI 超过 2 号染色体，但位于 3 号染色体上的次要 QTL ( qfw3.2 ) 与先前公布的果实形状QTL ( qfd3.1 、 qfl3.1和qfsi3.1 ) 一致。在控制食用水果平均白利糖度的新遗传区域中鉴定出总共5个微效QTL（qbcc2.1、qbce2.1、qbce2.2、qbcc5.1和qbce5.1 ）。发现种子宽度 QTL ( qsw10.1 ) 与 20 种子重量 QTL ( q20swt10.1) 在 10 号染色体上。两年内两次环境实验收集的表型数据集也揭示了果实和种子性状之间的高度显着相关性。因此，我们得出结论，我们基于 GBS 鉴定的新 QTL 位置将为西瓜品质相关性状的遗传改良拓展强大的分子育种前景。