Mapping of quantitative trait loci for resistance to turcicum leaf blight in maize (Zea mays L.)

Abstract

Turcicum Leaf Blight (TLB) is a common foliar disease of maize. The aim of this study was to find quantitative trait loci (QTL) for TLB resistance in maize. By crossing two inbred lines, CM 212 (susceptible) and CM 145 (resistant), a mapping population was developed, which was evaluated in two environments namely E₁ (Varanasi, U.P., India; 25⁰ N, 83⁰ E) and E₂ (Nagenahalli, Karnataka, India; 12⁰ N, 76⁰ E). Data on four disease severity traits viz., Percent Disease Index (PDI), Area Under Disease Progress Curve based on PDI (AUDPC-PDI), Lesion Area (LA), and Area Under Disease Progress Curve based on LA (AUDPC-LA) were generated for locating QTLs. Fifteen QTL intervals for resistance to TLB were located on chromosomes 1, 2, 4, 5, 6 and 9. Out of these fifteen QTLs, two QTLs were reported for trait PDI on chromosomes 1 and 5 for TLB resistance at E₁; seven QTLs were identified at E₂, where two QTLs were reported for PDI on chromosome 4, four QTLs for trait area under disease progress curve based on PDI and one QTL was reported for trait lesion area. Additionally, identified at pooled environment, six QTLs exhibited the LOD values in the range of 2.64 and 7.77, and corresponding R² in the range of 10.80 and 17.74 in the individual environments and across the environments