Correlation Between Leaf-feeding Resistance to European Corn Borer (Lepidoptera: Pyralidae) and Resistance to Northern Corn Leaf Blight

Abstract

A total of 7,537 genotypes of maize, Zea mays L., was evaluated for resistance to European corn borer (ECB), Ostrinia nubilalis (Hübner), and for resistance to northern corn leaf blight (NCLB), caused by Helminthosporium turcicum Pass. All genotypes were evaluated under artificial infestations by ECB and under artificial inoculations by NCLB. Previous research (using small numbers of genotypes) showed that DIMBOA [2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one] genes condition resistance in maize to both ECB and NCLB. Our data show that, by using the insect and pathogen as selection agents, genotypes with resistance to both pest species can be developed (1.5% of the 7,537 genotypes rated resistance to both species). Researchers, however, cannot select for resistance to one species and expect to have resistance to the other species (25.1% of the genotypes were resistant to ECB but susceptible to NCLB; 1.2% of the genotypes were susceptible to ECB but resistant to NCLB). There was no correlation between ECB resistance and NCLB resistance.