Author
Willmot, David | |
Hibbard, Bruce | |
Darrah, Larry | |
Pollak, Linda | |
MONTGOMERY, KEVIN - GOLDEN HARVEST RES-IL | |
PRATT, RICHARD - OHIO STATE UNIVERSITY | |
HAWK, JAMES - UNIVERSITY OF DELAWARE | |
WELDEKIDAN, TECLE - UNIVERSITY OF DELAWARE | |
Abel, Craig | |
FOSTER, JOHN - UNIVERSITY OF NEBRASKA |
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/1/2004 Publication Date: 10/1/2004 Citation: Willmot, D.B., Hibbard, B.E., Darrah, L.L., Pollak, L.M., Montgomery, K., Pratt, R., Hawk, J., Weldekidan, T., Abel, C.A., Foster, J. 2004. Effect of environment on resistance to the european corn borer (lepidoptera: pyralidae) in maize. Journal of Economic Entomology. 97(5):1745-1751. Interpretive Summary: The European corn borer is a major pest of corn (maize) in the United States and many temperate parts of the world. Genotype-by-environment interaction effects sometimes make relative performance of genetic strains unpredictable and, as with any trait, hamper selection for consistent resistance to European corn borer. The objective of this study was to determine the effect of environment on genotypic reaction to European corn borer. A set of 12 strains was chosen to represent a range of European corn borer responses. Testing environments (11) ranged from Delaware, Ohio, Illinois, Iowa, Nebraska, Missouri, to Mississippi. Ten environments had adequate insect infestation levels for evaluating second-generation tunneling damage. Length of tunneling means for genotypes (across environments) ranged from 4 to 14 inches with an overall mean of 8 inches. Several reportedly resistant genotypes grouped with the susceptible checks, B73 and Mo17. By developing a prediction equation based on genotype and environment, we observed that GEMS-0001 had a contrasting level of reduced susceptibility in both Mississippi environments as well as Nebraska. B73 and Mo17 showed several similar rank changes. B73 still consistently grouped as highly susceptible, whereas Mo17 fell with the intermediate genotypes in some environments. Elizabeth, MS; Clinton, IL; and Ithica, NE, displayed several specific rank changes each. This indicates that European corn borer screening at these sites would not necessarily apply to other locations and vice versa -whether by small differences in experimental conduct and/or environmental effects. The five most resistant genotypes were fairly consistent across environments. This information will make scientists working on European corn borer host-plant resistance aware of the necessity for evaluating germplasm over the whole range of environments where it may be utilized. Technical Abstract: The European corn borer (Ostrinia nubilalis Hübner) (Lepidoptera: Pyralidae) is a major pest of maize (Zea mays L.) in many temperate parts of the world. Genotype-by-environment interaction effects sometimes make relative performance unpredictable and, as with any trait, hamper selection for resistance to European corn borer. The objective of this study was to determine the effect of environment on genotypic reaction to European corn borer. A set of 12 lines was chosen to represent a range of European corn borer responses. Testing environments (11) ranged from Delaware, Ohio, Illinois, Iowa, Nebraska, Missouri, to Mississippi. All environments were treated essentially the same and developed adequate infestation levels to evaluate first-generation leaf feeding damage and 10 of the 11 environments were adequate to evaluate second-generation tunneling damage. For the main trait of interest, length of tunneling, environmental and genotypic main effects (estimated by restricted maximum likelihood) were more than 20- and 10-fold larger than their interaction effect, respectively. Length of tunneling means for genotypes (across environments) ranged from 10.1 to 35.4 cm with an overall mean of 19.8 cm. Several putatively-resistant genotypes grouped with the susceptible checks, B73 and Mo17. By breaking factors and the interaction into single-degree-of-freedom components, we observed that GEMS-0001 had significant crossover interactions toward less susceptibility in both Mississippi environments as well as Nebraska. B73 and Mo17 showed several crossover interactions. B73 still consistently grouped as highly susceptible, whereas the interactions placed Mo17 with the intermediate genotypes in some environments. Elizabeth, MS, and Clinton, IL, (which had the lowest length of tunneling means) were involved in two significant crossover interactions each, and the Ithica, NE, site had three. This indicates that European corn borer screening at these sites would not necessarily apply to other locations and vice versa whether by small differences in experimental conduct and/or environmental effects. The five most resistant genotypes were fairly consistent across environments. |