Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 2006
Publication Date: March 1, 2007
Citation: Krakowsky, M.D., Lee, M., Holland, J.B. 2007. Genotypic correlation and multivariate qtl analyses for cell wall components and resistance to stalk tunneling by the european corn borer in maize. Crop Science 47:485-488. Interpretive Summary: This research was conducted to improve our understanding of the relationship in maize between resistance to feeding by the European corn borer (ECB) and fiber content of the plant. Previous studies have shown a relationship between increased fiber levels and resistance to stalk tunneling by ECB in several maize populations. However, increasing fiber levels as a method increasing resistance to ECB can reduce the quality of the plant as animal food, since fiber is largely indigestible. Fiber contents were measured in the leaf sheath and stalk and compared with stalk tunneling, and no correlation was observed for this population. The results of this experiment are important because they diverge from previous reports that showed a correlation between fiber and ECB damage, indicating that selection for increased resistance to ECB damage will not necessarily result in decreased digestibility of the plant matter.
Technical Abstract: Correlations between concentrations of cell wall components (CWCs) in the leaf sheath and stalk and resistance to stalk tunneling by the European corn borer (ECB; Ostrinia nubilalis Hübner) have been reported in some maize (Zea mays L.) populations. Evaluations of resistance to ECB stalk tunneling (ECB-ST) and concentrations of neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) have been performed on F3 and recombinant inbred lines (RILs) developed from the cross of maize inbred lines B73 (susceptible to ECB-ST, low to moderate CWC concentrations) and De811 (resistant to ECB-ST, high CWC concentrations), providing an opportunity to assess the genetic correlations and the associations between quantitative trait loci (QTL) for the traits in this population. The genetic correlations with ECB-ST were low to moderate for leaf sheath NDF and ADF in the F3 lines but not significant for stalk NDF, ADF and ADL in the F3 lines nor for any of the CWCs in the RILs. The differences in the two populations may have been due to the environments used in the evaluations or to linkage disequilibrium. Positive correlations between CWCs were observed in the RILs of B73 x B52, in concordance with the earlier reports and suggesting that CWCs are a plausible mechanism of resistance to ECB-ST in other populations. Only quantitative differences in CWCs were measured in these studies, and qualitative modifications in the cell wall could be associated with resistance to ECB-ST.