Abstract
BackgroundOstrinia 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.ResultsThree 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.ConclusionsOur 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.
Highlights
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
We detected three genomic regions involved in resistance to stalk tunnelling by MCB that were close to genomic regions related to resistance to stalk tunnelling by ECB detected in genetically different populations
Our results, when compared with results from other authors, suggest that genes involved in cell wall biosynthesis or fortification could be good candidate genes for the QTLs detected for stem tunnelling in our experiment
Summary
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). Ostrinia nubilalis (ECB) and Sesamia nonagrioides (MCB) are two maize stem borers which cause important losses in temperate maize production. Several studies have been carried out to map genetic factors for resistance to ECB tunnelling [7,8,9], but only one QTL analysis for resistance to MCB tunnelling has been reported so far [10]. The search for QTLs rather should be done with no previously prospected maize materials than with materials extensively studied such as those derived from B73 [7,8,9,10] in order to likely increase the number of known genomic regions involved in borer resistance, as, in general, different subsets of QTLs can segregate in different populations [11]
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