Association Study of Agronomic and Oil Traits in Rapeseed (Brassica napus L.) Mutant Lines Using Genotyping-by-Sequencing

Abstract

Rapeseed (Brassica napus L.) is one of the most oil crop, and its commercial value is contingent upon its agronomic characteristics and oil quality. In this study, 73,226 single nucleotide polymorphisms (SNPs) across 95 rapeseed mutant lines derived from gamma rays and their original cultivar (‘Tamra’) obtained from genotyping-by-sequencing (GBS) was investigated gene ontology (GO) analysis and genome-wide association study (GWAS). GWAS was conducted on agronomic (plant height, ear length, thousand seed weight and seed yield) and oil (fatty acid and crude fat) traits. GO analysis showed that many genes displaying SNPs were involved in cellular processes, intracellular anatomical structures and organic cyclic compound binding. A total of 149 significant SNPs were associated with the agronomic traits (76 SNPs) and oil traits (73 SNPs). Bna.A05p02350D (SFGH) and Bna.C02p22490D (MDN1) were selected as novel candid genes for thousand seed weight. In addition, Bna.C03p14350D (EXO70) and Bna.A09p05630D (PI4Kα1) were selected as novel candidate genes for the erucic acid and crude fat content, respectively. These findings could facilitate the identification of optimal genotypes for breeding new cultivars, and association studies represent an economically efficient tool for mutant screening and the selection of elite rapeseed-breeding lines.