Optimal root system architecture (RSA) is essential for vigorous growth and yield in crops. Plants have evolved adaptive mechanisms in response to low phosphorus (LP) stress, and one of those is changes in RSA. Here, more than five million single-nucleotide polymorphisms (SNPs) obtained from whole-genome re-sequencing data (WGR) of an association panel of 370 oilseed rape (Brassica napus L.) were used to conduct a genome-wide association study (GWAS) of RSA traits of the panel at LP in “pouch and wick” system. Fifty-two SNPs were forcefully associated with lateral root length (LRL), total root length (TRL), lateral root density (LRD), lateral root number (LRN), mean lateral root length (MLRL), and root dry weight (RDW) at LP. There were significant correlations between phenotypic variation and the number of favorable alleles of the associated loci on chromosomes A06 (chrA06_20030601), C03 (chrC03_3535483), and C07 (chrC07_42348561), respectively. Three candidate genes (BnaA06g29270D, BnaC03g07130D, and BnaC07g43230D) were detected by combining transcriptome, candidate gene association analysis, and haplotype analysis. Cultivar carrying “CCGC” at BnaA06g29270DHap1, “CAAT” at BnaC03g07130DHap1, and “ATC” at BnaC07g43230DHap1 had greater LRL, LRN, and RDW than lines carrying other haplotypes at LP supply. The RSA of a cultivar harboring the three favorable haplotypes was further confirmed by solution culture experiments. These findings define exquisite insights into genetic architectures underlying B. napus RSA at LP and provide valuable gene resources for root breeding.

最佳根系结构（RSA）对于作物的旺盛生长和产量至关重要。植物已经进化出了适应低磷（LP）胁迫的机制，其中之一就是 RSA 的变化。在这里，从 370 个油菜 ( Brassica napus L. ) 的关联组的全基因组重测序数据 (WGR) 中获得超过 500 万个单核苷酸多态性 (SNP)，用于进行全基因组关联研究。 GWAS）显示 LP 小组在“袋和灯芯”系统中的 RSA 特征。52 个 SNP 与侧根长度 (LRL)、总根长度 (TRL)、侧根密度 (LRD)、侧根数量 (LRN)、平均侧根长度 (MLRL) 和根干重 (RDW) 密切相关）在LP。表型变异与染色体 A06 (chrA06_20030601)、C03 (chrC03_3535483) 和 C07 (chrC07_42348561) 上相关位点的有利等位基因数量之间存在显着相关性。通过结合转录组、候选基因关联分析和单倍型分析，检测到三个候选基因（BnaA06g29270D、BnaC03g07130D和BnaC07g43230D ）。在BnaA06g29270DHap1处携带“CCGC” 、在BnaC03g07130DHap1处携带“CAAT”和在BnaC07g43230DHap1处携带“ATC”的品种比在 LP 供应时携带其他单倍型的品系具有更大的 LRL、LRN 和 RDW。溶液培养实验进一步证实了含有三种有利单倍型的品种的RSA。这些发现为 LP 的甘蓝型油菜RSA 的遗传结构提供了深刻的见解，并为根系育种提供了宝贵的基因资源。