QTL mapping of quality traits in peanut using whole-genome resequencing

Oil and protein content and fatty acid composition are quality traits in peanut. Elucidating the genetic mechanisms underlying these traits may help researchers to obtain improved cultivars by molecular breeding. Whole-genome resequencing of a recombinant inbred population of 318 lines was performed to construct a high-density linkage map and identify QTL for peanut quality. The map, containing 4561 bin markers, covered 2032 cM with a mean marker density of 0.45 cM. A total of 110 QTL for oil and protein content, and fatty acid composition were mapped on the 18 peanut chromosomes. The QTL qA05.1 was detected in four environments and showed a major phenotypic effect on the contents of oil, protein, and six fatty acids. The genomic region spanned by qA05.1, corresponding to a physical interval of approximately 1.5 Mb, contains two SNPs polymorphic between the parents that could cause missense mutations. The two SNP sites were employed as KASP markers and validated using lines with extremely high and low oil contents. These sites may be useful in the marker-assisted breeding of peanut cultivars with high oil contents.