Genome-wide association study of low nitrogen tolerance traits at the seedling stage of rapeseed

The large application of nitrogen fertilizer will cause soil deterioration and pollute the environment. Reduction of nitrogen inputs and maintaining high yields are therefore essential to ensure a more sustainable agriculture. However, little information is available about rapeseed (Brassica napus L.) low nitrogen tolerance. We evaluated low nitrogen tolerance of 304 rapeseed accessions at seedling stage and performed a genome-wide association study to detect low nitrogen tolerance-related quantitative trait loci. A natural population comprising 304 B. napus inbred lines was genotyped with a Brassica 60K Illumina Infinium SNP array. Finally, 11 single-nucleotide polymorphisms were associated with 3 low nitrogen tolerance-related traits, which explained 5.79 - 7.57 % of the phenotypic variation. In addition, three possible candidate genes were located near the genetic region. Our results provide valuable information for understanding the genetic control of rapeseed low nitrogen tolerance at seedling stage and may facilitate a marker-based breeding for rapeseed low nitrogen tolerance.