Identification of two major loci and linked marker for oil content in peanut (Arachis hypogaea L.)

Peanut is one of major sources for vegetable oil. Improving oil content is an important goal for peanut breeding programs. Major loci with linked markers for oil content could facilitate rapid development of high-oil varieties through marker-assisted breeding. To identify major loci underlying the oil content, we conducted the QTL analysis based on the high-dense genetic map, using RIL population derived from Zhonghua10 and ICG12625. A total of 18 additive QTLs, including two major and stable QTLs (qOCB06 and qOCB10.1), were identified in three environments. Besides, 26 pairs of QTLs with epistatic (additivexadditive) interaction were mapped on 17 linkage groups. qOCB06 with up to 22.59% of the phenotypic variations was located in a 0.6-Mb interval of B06. qOCB10.1 on B10 explained 9.18-12.55% of the phenotypic variations. The additive effect of two QTLs ranged from 0.70 to 1.13% oil content in different environments. Favorable alleles of the two loci were from male and female parent, respectively. Pyramiding the two favorable alleles in the RIL population could increase "2.66 +/- 0.48%" oil content across multiple environments. The marker Ai06B29452 and AGGS2133-1 linked to qOCB06 and qOCB10.1, respectively, were validated to be associated with oil content in peanut germplasms with diverse phenotypes. These markers were valuable in marker-assisted selection and pyramiding breeding for improving oil content in peanut. Major and stable QTLs with linked markers in the present study provided resources to discovery candidate genes in the future and to guide marker-assisted selection for improving oil content in peanut.