Marker-Assisted Introgression of a QTL Region to Improve Rust Resistance in Three Elite and Popular Varieties of Peanut (Arachis hypogaea L.)

Leaf rust, caused by fungal pathogen Puccinia arachidis, is one of the major devastating diseases in groundnut or peanut (Arachis hypogaea L.). One QTL region, identified in TAG 24 × GPBD 4 population with 82.62% phenotypic variation for rust resistance, was validated and introgressed in three susceptible varieties (ICGV 91114, JL 24 and TAG 24) using GPBD 4 as donor parent through marker-assisted backcrossing (MABC) approach. MABC approach employed a total of four markers including one dominant (IPAHM103) and three co-dominant (GM2079, GM1536, GM2301) markers present in the QTL region. After undertaking 2 to 3 backcrosses followed by selfing, a total of 200 introgression lines (ILs) were developed. Field evaluation identified 81 lines with high level of rust resistance (disease score of 2.0 on 1.0-9.0 scale) on par with donor. Screening of 43 promising ILs, based on disease score and other agro-morphological traits, with 13 markers present on carrier linkage group showed introgression of only target genomic region from resistant donor in 11 ILs. Multi-location field evaluation of most promising ILs should provide entries for possible release of the improved varieties with enhanced disease resistance that will eventually provide better yield and higher income to resource poor farmers of the semi-arid regions of the world. This study also highlights the utility of four markers from the QTL region, available in public domain without any restriction, for improving rust resistance in elite varieties through MABC or for accelerated development of superior varieties through MAS in any breeding programme of the world.