Inheritance and QTL mapping identify multi-effect loci for fatty acid related traits in peanut (Arachis hypogaea L.)

Peanut (Arachis hypogaea L.) is an important oil and edible protein crop. Its fatty acid composition not only influences the quality of peanut oil but also impacts flavor, shelf life, and consumer health. Peanut oil is comprised of approximately 80% oleic acid (C18:1) and linoleic acid (C18:2), 10% palmitic acid (C16:0), and the remaining 10% includes stearic acid (C18:0), arachidic acid (C20:0), gadoleic acid (C20:1), behenic acid (C22:0), and lignoceric acid (C24:0). To unravel the genetic foundation of fatty acid content and delve into QTL localization, high-density SNP microarrays were used to genotype the RIL population of ‘SunOleic 97R’ × ‘NC94022’. A genetic linkage map was constructed with 3,141 SNP markers, covering a total genetic distance of 3,051.81 cM. Sixty quantitative trait loci (QTLs) associated with fatty acids were distributed in 11 linkage groups, with phenotypic variance explained (PVE) ranging from 1.37 to 44.92%. Notably, the QTLs qFAT_A05.1 and qFAT_A08.1 are multiple-effect loci contributing to various fatty acid compositions. Moreover, 15 haplotypes for the QTLs qFAT_A05.1 and qFAT_A08.1 were identified through genotyping 178 peanut germplasms. Haplotype analysis in a natural population confirmed the close relationship of the QTLs with the contents of oil, oleic acid, lignoceric acid, palmitic acid and behenic acid. This study serves as a valuable reference for selecting improved peanut genotypes with superior oil quality and desirable fatty acid composition.