Genetic improvement of seed yield per plant (SY) is one of the major objectives in Brassica napus breeding programme. SY, being a complex quantitative trait is directly and indirectly influenced by yield-component traits such as siliqua length (SL), number of seeds per siliqua (NSS), and thousand seed weight (TSW). Therefore, concurrent improvement in SL, NSS and TSW can lead to higher SY in B. napus. This study was conducted to identify significant SNPs and putative candidate genes governing SY and its component traits (SL, NSS, TSW). All these traits were evaluated in a diverse set of 200 genotypes representing diversity from wide geographical locations. Of these, a set of 125 genotypes were chosen based on pedigree diversity and multi-location trait variation for genotyping by sequencing (GBS). Best linear unbiased predictors (BLUPs) of all the traits were used for genome-wide association study (GWAS) with 85,126 SNPs obtained from GBS. A total of 16, 18, 27 and 18 SNPs were found to be significantly associated for SL, NSS, TSW and SY respectively. Based on linkage disequilibrium decay analysis, 150 kb genomic region flanking the SNP was used for the identification of underlying candidate genes for each test trait. Important candidate genes involved in phytohormone signaling (WAT1, OSR1, ARR8, CKX1, REM7, REM9, BG1) and seed storage proteins (Cruciferin) were found to have significant influence on seed weight and yield. Genes involved in sexual reproduction and fertilization (PERK7, PERK13, PRK3, GATA15, NFD6) were found to determine the number of seeds per siliqua. Several genes found in this study namely ATS3A, CKX1, SPL2, SPL6, SPL9, WAT1 showed pleiotropic effect with yield component traits. Significant SNPs and putative candidate genes identified for SL, NSS, TSW and SY could be used in marker-assisted breeding for improvement of crop yield in B. napus. Genotypes identified with high SL, NSS, TSW and SY could serve as donors in crop improvement programs in B. napus.

单株种子产量（SY）的遗传改良是欧洲 油菜 育种计划的主要目标之一。SY是一种复杂的数量性状，直接和间接地受到产量组成性状的影响，例如角果长度（SL）、每角果的种子数（NSS）和千粒重（TSW）。因此，同时改进 SL、NSS 和 TSW 可导致欧洲 油菜中更高的 SY. 本研究旨在鉴定重要的 SNP 和推定的控制 SY 及其组成性状（SL、NSS、TSW）的候选基因。所有这些性状都在代表来自广泛地理位置的多样性的 200 种基因型中进行了评估。其中，基于谱系多样性和多位置性状变异选择了一组 125 个基因型，用于测序基因分型 (GBS)。所有性状的最佳线性无偏预测因子 (BLUP) 用于全基因组关联研究 (GWAS)，其中 85,126 个 SNP 从 GBS 获得。共发现 16、18、27 和 18 个 SNP 分别与 SL、NSS、TSW 和 SY 显着相关。基于连锁不平衡衰减分析，SNP侧翼的150 kb基因组区域用于鉴定每个测试性状的潜在候选基因。WAT1、OSR1、ARR8、CKX1、REM7、REM9、BG1）和种子贮藏蛋白（十字花科）被发现对种子重量和产量有显着影响。发现参与有性繁殖和受精的基因（PERK7、PERK13、PRK3、GATA15、NFD6）来确定每个角果的种子数量。本研究中发现的几个基因，即 ATS3A、CKX1、SPL2、SPL6、SPL9、WAT1 显示出与产量成分性状的多效性。为 SL、NSS、TSW 和 SY 鉴定的重要 SNP 和推定的候选基因可用于标记辅助育种，以提高 欧洲油菜的作物产量。鉴定出具有高 SL、NSS、TSW 和 SY 的基因型可作为欧洲 油菜作物改良计划的供体。