QTL identification for nine seed-related traits in Brassica juncea using a multiparent advanced generation intercross (MAGIC) population

Abstract

Agronomic traits are usually determined by multiple quantitative trait loci (QTLs) that can have pleiotropic effects. A multiparent advanced generation intercross (MAGIC) population is well suited for genetically analysing the effects of multiple QTLs on the traits of interest because it contains more QTL alleles than a biparental population and can overcome the problem of confounding the population structure of the natural germplasm population. We previously developed the B. juncea MAGIC population, derived from eight B. juncea lines with great diversity in agronomic and quality traits. In this study, we show that the B. juncea MAGIC population is also effective for the evaluation of multiple QTLs for complex agronomic traits in B. juncea. A total of twenty-two QTLs for nine seed-related traits were identified, including one QTL for each oil content, seed number per silique and thousand-seed weight; two QTLs for each acid detergent lignin and neutral detergent fibre; three QTLs for each acid detergent fibre and protein content; four QTLs for the seed maturity time; and five QTLs for the white index. Some of these QTLs overlapped. These results should be helpful for further fine mapping, gene cloning, plant breeding and marker-assisted selection (MAS) in B. juncea.