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QTL mapping of resistance to stalk tunneling by the European corn borer in RILs of maize population B73 X De811

Krakowsky, M.D., Lee, M., Woodman-Clikeman, W.L., Long, M.J., Sharopova, N.
Crop science 2004 v.44 no.1 pp. 274-282
Zea mays, corn, inbred lines, Ostrinia nubilalis, corn stover, boring insects, pest resistance, genes, quantitative trait loci, flowering, chromosome mapping, alleles, phenotype, phenotypic variation, genetic variation, field experimentation, Iowa
Considerable effort has been expended toward the genetic characterization of native resistance to stalk tunneling by the European corn borer [ECB; Ostrinia nubilalis (Hbner)], indicative of the importance of this pest and the difficulty in obtaining conclusive results. In this study, 191 recombinant inbred lines (RILs) of B73 maize (Zea mays L.) (susceptible to stalk tunneling by ECB) x De811 (resistant) were evaluated for stalk tunneling, anthesis, and plant height in Iowa at two locations in 1998 and one location in 1999 with the objectives of (i) determining the genetic relationship between these traits and (ii) mapping quantitative trait loci (QTL) associated with resistance to stalk tunneling. The genotypic correlation between plant height and stalk tunneling (rg = 0.1) was negligible, but the correlation between stalk tunneling and anthesis was very high (rg = -0.8) necessitating the adjustment of the means of former with the latter. Ten QTL for stalk tunneling adjusted for anthesis associated with 42% of the phenotypic variation were observed in the mean across trials, only one of which was observed in each of the individual trials. The lack of consistent QTL detection across environments is a common characteristic among studies of ECB tunneling and underscores a major problem of breeding for resistance. QTL observed in F3 lines of the same cross and in RILs of B73 x B52 are linked to three QTL each for the mean across trials herein, providing further evidence of association between these genomic regions and resistance to stalk tunneling.