Improvement of three popular Indian groundnut varieties for foliar disease resistance and high oleic acid using SSR markers and SNP array in marker-assisted backcrossing

Foliar fungal diseases (rust and late leaf spot) incur large yield losses, in addition to the deterioration of fodder quality in groundnut worldwide. High oleic acid has emerged as a key market trait in groundnut, as it increases the shelf life of the produce/products in addition to providing health benefits to consumers. Marker-assisted backcrossing (MABC) is the most successful approach to introgressing or pyramiding one or more traits using trait-linked markers. We used MABC to improve three popular Indian cultivars (GJG 9, GG 20, and GJGHPS 1) for foliar disease resistance (FDR) and high oleic acid content. A total of 22 BC3F4 and 30 BC2F4 introgression lines (ILs) for FDR and 46 BC3F4 and 41 BC2F4 ILs for high oleic acid were developed. Recurrent parent genome analysis using the 58 K Axiom_Arachis array identified several lines showing upto 94% of genome recovery among second and third backcross progenies. Phenotyping of these ILs revealed FDR scores comparable to the resistant parent, GPBD 4, and ILs with high (~80%) oleic acid in addition to high genome recovery. These ILs provide further opportunities for pyramiding FDR and high oleic acid in all three genetic backgrounds as well as for conducting multi-location yield trials for further evaluation and release for cultivation in target regions of India. Keywords: Foliar disease resistance, High oleic acid, Late leaf spot, Marker-assisted backcrossing, SNP array, Background genome recovery