Biotech Updates

QTL Mapping for Resistance to 1st and 2nd Generation of European Corn Borer

May 6, 2011

The European corn borer (ECB) is one of the predominant pests of maize in North America and Europe, causing extensive losses in yield. Thus, E. Orsini and colleagues at the University of Hohenheim mapped and characterized the complex traits that influence the resistance to the first (ECB1) and second (ECB2) generation of ECB and plant height using single-nucleotide polymorphism (SNP) and 88 microsatellites. A total of 144 testcross (TC) progenies of double haploid (DH) lines developed from a cross of two parental lines from the Stiff Stalk germplasm pool were tested at six different locations in the USA under both natural and artificial infestation with ECB larvae. They assessed the resistance by measuring leaf feeding and stalk breakage for ECB1 and ECB2, respectively.

Results showed that there is significant genotypic variance in all traits among the TC progenies. Heritabilities, the proportion of phenotypic variation due to genetic variation between individuals, were moderately high for stalk breakage and plant height, but only moderate for leaf feeding. Three qualitative trait loci (QTL) were found for stalk breakage, one QTL for leaf feeding, and two QTL for plant height. The QTL for leaf feeding was found in chromosomal regions adjacent to those reported for other maize germplasm, and consequently, might be used for market-assisted selection during line development in maize.