Quantitative Trait Loci for First- and Second-Generation European Corn Borer Resistance Derived from the Maize Inbred Mo47

Abstract

European corn borer (ECB), Ostrinia nubilalis (Hübner), family Crambidae, order Lepidoptera, is a serious insect pest of maize (Zea mays L.) in the USA. Understanding the genetic basis for ECB resistance should increase the efficiency of breeding insect-resistant germplasm. The objectives of this study were to determine the number, genomic positions, and genetic effects of quantitative trait loci (QTL) conferring resistance to leaf feeding damage cause by first-generation ECB (1ECB, defined as the trait of leaf feeding damage) and stalk tunneling caused by second-generation ECB (2ECB, defined as the trait of stalk tunnel damage). The study included 244 F2:3 families derived from the cross of B73Ht (susceptible) × Mo47 (resistant). Inbred Mo47 represented a novel source of ECB resistance containing 50% tropical germplasm. The QTL analyses for three individual environments and combined across environments were performed by composite interval mapping using QTL Cartographer. Nine QTLs were identified for 1ECB on chromosomes 1 (three QTLs), 2, 4 (two QTLs), 5, 6, and 8, on the basis of data combined across environments. Seven QTLs for 2ECB were found on chromosomes 2, 5 (two QTLs), 6 (two QTLs), 8, and 9. Several of the QTLs detected are located in genomic regions reported for resistance to other stem borer pests of maize. Inconsistency of QTLs across environments complicates use of Mo47 for marker-assisted selection of ECB resistance.