Inclusive Market-Oriented Development (IMOD) – our approach to bringing prosperity in the drylands. ICRISAT is a member of the CGIAR Consortium. 1 International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, India 2 CGIAR Generation Challenge Programme, c/o CIMMYT, Mexico DF, Mexico 3 The University of Georgia, Tifton, USA; *Address for correspondence: [email protected] Three elite peanut cultivars improved for rust resistance by introgressing a QTL genomic region through marker- assisted backcrossing (MABC) approach QTL introgressed through MABC approach into the genetic background of three elite cultivars (ICGV 91114, JL 24 and TAG 24) using four linked markers (Theor Appl Genet 2013, under review) A total of 81 promising introgression lines identified with high rust resistance i.e., with disease score of <2.0 on 1.0-9.0 scale At present, promising lines are grown in replication for yield assessment and superior lines will be selected for multilocation evaluation in target areas of SAT region Improved varieties with enhanced disease resistance will provide better yield and higher income, and, sustain the livelihood of resource poor farmers of the semi-arid regions of the world Leaf rust, caused by Puccinia arachidis, is one of the major devastating diseases in peanut (Arachis hypogaea L.). After validating a major QTL (82.62% phenotypic variation) for resistance to rust, it was introgressed in three susceptible varieties namely ICGV 91114, JL 24 and TAG 24 using GPBD 4 variety as donor through MABC approach. A total of 81 introgression lines developed from 2 to 3 backcrosses with high level of rust resistance were selected with disease score of <2.0 on 1.0-9.0 scale as par the donor. Screening of 43 promising lines with 13 markers present on the carrier linkage group showed introgression of only target genomic region from resistant donor in 11 lines. Multi-location field evaluation of most promising lines 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. Further, this study highlights the utility of four markers for improving rust resistance in any peanut molecular breeding programme of the world. Abstract Acknowledgements Summary Rajeev K Varshney 1,2 *, Manish K Pandey 1,3 , Pasupuleti Janila 1 , Shyam N Nigam 1 , Hari Sudhini 1 , MVC Gowda 1 , Manda Sriswathi 1 , T Radhakrishnan 1 , P Nagesh 1 This work has been undertaken as part of the CGIAR Research Program on Grain Legumes. Financial support from Bill & Melinda Gates Foundation through CGIAR Generation Challenge Programme (GCP) is gratefully acknowledged. Thanks are also due to Bryan J Moss and V Papaiah for their help. Disease screening during rainy 2012 ICGV 91114 ICGV 91114 + QTL GPBD 4 JL 24 JL 24 + Rust QTL Replicated yield assessment of improved lines, rainy 2013 Disease symptom at harvesting stage Post rainy 2008-09 Disease screening of BC 2 F 3 progenies and BC 3 F 2 plants, selection of 75 homozygous BC 3 F 2 plants based on MAS Screening of homozygous resistant BC 3 F 3 progenies for agronomic performance and seed multiplication from BC 2 F 4 plants Rainy 2011 Post rainy 2011-12 Rainy 2012 Marker assisted introgression of rust QTL Foreground markers: IPAHM103, GM2079, GM1536, GM2301 Post rainy 2010-11 183 plants screened for MAS, 53 plants selected 186 BC 3 F 1 and 498 BC 2 F 2 plants screened for MAS, 55 heterozygous BC 3 F 1 & 158 homozygous BC 2 F 2 plants selected Crosses made between GPBD 4 with ICGV 91114, JL 24 and TAG 24 Rainy 2009 True hybrids selected based on SSR markers Post rainy 2009-10 186 plants screened for MAS, 52 plants selected Selfing Rainy 2010 Selfing Selfing Selfing ICGV 91114, JL 24, TAG 24 GPBD 4 F 1 BC 1 F 1 BC 2 F 1 BC 3 F 1 BC 2 F 2 BC 3 F 2 BC 2 F 3 BC 3 F 3 BC 2 F 4 BC 3 F 4 BC 3 F 5 x A major QTL contributing up to 82.96% PVE for rust resistance identified and linked SSR markers (IPAHM103, GM2079, GM1536 and GM2301) validated (Theor Appl Genet 2010, 121:971-98; Mol Breed 2012, 32:773-788)