Ordas et al. BMC Genomics 2010, 11:174 http://www.biomedcentral.com/1471-2164/11/174 R E S E A R C H A R T I C L E Open Access QTL mapping for Mediterranean corn borer resistance in European flint germplasm using recombinant inbred lines Bernardo Ordas*, Rosa A Malvar, Rogelio Santiago, Ana Butron Abstract Background: Ostrinia nubilalis (ECB) and Sesamia nonagrioides (MCB) are two maize stem borers which cause important losses in temperate maize production, but QTL analyses for corn borer resistance were mostly restricted to ECB resistance and maize materials genetically related (mapping populations derived from B73). Therefore, the objective of this work was to identify and characterize QTLs for MCB resistance and agronomic traits in a RILs population derived from European flint inbreds. Results: Three QTLs were detected for stalk tunnel length at bins 1.02, 3.05 and 8.05 which explained 7.5% of the RILs genotypic variance. The QTL at bin 3.05 was co-located to a QTL related to plant height and grain humidity and the QTL at bin 8.05 was located near a QTL related to yield. Conclusions: Our results, when compared with results from other authors, suggest the presence of genes involved in cell wall biosynthesis or fortification with effects on resistance to different corn borer species and digestibility for dairy cattle. Particularly, we proposed five candidate genes related to cell wall characteristics which could explain the QTL for stalk tunnelling in the region 3.05. However, the small proportion of genotypic variance explained by the QTLs suggest that there are also many other genes of small effect regulating MCB resistance and we conclude that MAS seems not promising for this trait. Two QTLs detected for stalk tunnelling overlap with QTLs for agronomic traits, indicating the presence of pleitropism or linkage between genes affecting resistance and agronomic traits. Background Ostrinia nubilalis (ECB) and Sesamia nonagrioides (MCB) are two maize stem borers which cause impor- tant losses in temperate maize production. ECB is pre- sent in United States and Central and South Europe, while Sesamia nonagrioides (MCB) is restricted to Medi- terranean areas, including South Europe, North Africa and Middle East [1,2]. Larvae feed on the stem, produ- cing tunnels that weaken the plant and, as consequence, stalk lodging is increased and yield reduced. Further- more, larvae can also feed directly on the ear which pro- motes infections by Fusarium spp at levels that may affect human and animal health [3,4]. Although the type of damage caused by the two species is similar, MCB larvae are more voracious and produce more damage * Correspondence: bernardo@mbg.cesga.es Misión Biológica de Galicia, Spanish National Research Council (CSIC). Apartado 28, 36080 Pontevedra, Spain than ECB larvae [2]. Phenotypic evaluations for resis- tance to ECB and MCB suggest that maize has common mechanisms of resistance to both pests [5,6]. Several studies have been carried out to map genetic factors for resistance to ECB tunnelling [7-9], but only one QTL analysis for resistance to MCB tunnelling has been reported so far [10]. The two QTLs for MCB resis- tance detected were located close to QTLs for ECB resistance which could indicate the presence of gene clusters or common mechanisms of resistance to differ- ent pests. However, more QTL experiments for resis- tance to MCB are needed to confirm the co-localization of QTLs for resistance to both pests. The search for QTLs rather should be done with no previously pros- pected maize materials than with materials extensively studied such as those derived from B73 [7-10] in order to likely increase the number of known genomic regions © 2010 Ordas et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.